More complete implementation for condition and log matchers in statsd.

+ also synced proto from google3 to fix the LogEntryMatcher proto

+ MetricsManager represents StatsdConfig, it's responsible for initializing and managing all
LogEntryMatcher, Condition, and Metrics. Start review from here.

+ Added more complete StatsdConfig initialization, including building the map for:
    LogEntryMatcher -> Metrics
    LogEntryMatcher -> Condition
    Condition       -> Metrics.

    All the maps use index(int). The extra amount of memory for storing mappings help us
    quickly process log events.

  The StatsdConfig initialization process detects malformed config
  - Circle dependency
  - Missing definition
  etc.

 And once we detect ANY error, statsd will reject the config. And the resources related to this
 config will be released.

Test: Added unit tests
Change-Id: I2c4aefdbf3e2aa1701eacbb2fb5e653819ec1fbb
diff --git a/cmds/statsd/Android.mk b/cmds/statsd/Android.mk
index ca36d27..24a598a 100644
--- a/cmds/statsd/Android.mk
+++ b/cmds/statsd/Android.mk
@@ -42,24 +42,7 @@
 LOCAL_SRC_FILES := \
     ../../core/java/android/os/IStatsCompanionService.aidl \
     ../../core/java/android/os/IStatsManager.aidl \
-    src/StatsService.cpp \
-    src/AnomalyMonitor.cpp \
-    src/LogEntryPrinter.cpp \
-    src/LogReader.cpp \
-    src/main.cpp \
-    src/DropboxWriter.cpp \
-    src/parse_util.cpp \
-    src/StatsLogProcessor.cpp \
-    src/stats_log.proto \
-    src/statsd_config.proto \
-    src/StatsPullerManager.cpp \
-    src/KernelWakelockPuller.cpp \
-    src/DropboxReader.cpp \
-    src/matchers/LogEntryMatcherManager.cpp \
-    src/metrics/CountMetricProducer.cpp \
-    src/metrics/ConditionTracker.cpp \
-    src/metrics/MetricsManager.cpp \
-    src/metrics/CountAnomalyTracker.cpp \
+    $(call all-cpp-files-under,src) \
 
 LOCAL_CFLAGS += \
     -Wall \
@@ -129,13 +112,19 @@
     ../../core/java/android/os/IStatsCompanionService.aidl \
     ../../core/java/android/os/IStatsManager.aidl \
     src/StatsService.cpp \
-    tests/indexed_priority_queue_test.cpp \
-    src/parse_util.cpp \
+    src/stats_util.cpp \
     src/LogEntryPrinter.cpp \
     src/LogReader.cpp \
-    src/matchers/LogEntryMatcherManager.cpp \
-    tests/LogReader_test.cpp \
-    tests/LogEntryMatcher_test.cpp \
+    src/matchers/matcher_util.cpp \
+    src/condition/SimpleConditionTracker.cpp \
+    src/condition/CombinationConditionTracker.cpp \
+    src/matchers/SimpleLogMatchingTracker.cpp \
+    src/matchers/CombinationLogMatchingTracker.cpp \
+    src/metrics/metrics_manager_util.cpp \
+    src/metrics/CountMetricProducer.cpp \
+    src/metrics/CountAnomalyTracker.cpp \
+    src/condition/condition_util.cpp \
+    $(call all-cpp-files-under, tests) \
 
 LOCAL_STATIC_LIBRARIES := \
     libgmock \
diff --git a/cmds/statsd/src/StatsLogProcessor.cpp b/cmds/statsd/src/StatsLogProcessor.cpp
index 117fb5e..1d2f586 100644
--- a/cmds/statsd/src/StatsLogProcessor.cpp
+++ b/cmds/statsd/src/StatsLogProcessor.cpp
@@ -20,7 +20,6 @@
 #include <frameworks/base/cmds/statsd/src/stats_log.pb.h>
 #include <log/log_event_list.h>
 #include <metrics/CountMetricProducer.h>
-#include <parse_util.h>
 #include <utils/Errors.h>
 
 using namespace android;
@@ -41,28 +40,6 @@
 StatsLogProcessor::~StatsLogProcessor() {
 }
 
-StatsdConfig StatsLogProcessor::buildFakeConfig() {
-    // HACK: Hard code a test metric for counting screen on events...
-    StatsdConfig config;
-    config.set_config_id(12345L);
-
-    CountMetric* metric = config.add_count_metric();
-    metric->set_metric_id(20150717L);
-    metric->set_what("SCREEN_IS_ON");
-    metric->mutable_bucket()->set_bucket_size_millis(30 * 1000L);
-
-    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
-    eventMatcher->set_name("SCREEN_IS_ON");
-
-    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
-    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
-    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()
-            ->set_key(1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
-    simpleLogEntryMatcher->mutable_key_value_matcher(0)
-            ->set_eq_int(2/*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
-    return config;
-}
-
 // TODO: what if statsd service restarts? How do we know what logs are already processed before?
 void StatsLogProcessor::OnLogEvent(const log_msg& msg) {
     // TODO: Use EventMetric to filter the events we want to log.
@@ -83,7 +60,14 @@
 
     ALOGD("Updated configuration for source %i", config_source);
 
-    mMetricsManagers.insert({config_source, std::make_unique<MetricsManager>(config)});
+    unique_ptr<MetricsManager> newMetricsManager = std::make_unique<MetricsManager>(config);
+    if (newMetricsManager->isConfigValid()) {
+        mMetricsManagers.insert({config_source, std::move(newMetricsManager)});
+        ALOGD("StatsdConfig valid");
+    } else {
+        // If there is any error in the config, don't use it.
+        ALOGD("StatsdConfig NOT valid");
+    }
 }
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/StatsLogProcessor.h b/cmds/statsd/src/StatsLogProcessor.h
index 88c63fa..ab1b44e 100644
--- a/cmds/statsd/src/StatsLogProcessor.h
+++ b/cmds/statsd/src/StatsLogProcessor.h
@@ -16,11 +16,11 @@
 #ifndef STATS_LOG_PROCESSOR_H
 #define STATS_LOG_PROCESSOR_H
 
-#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 #include "DropboxWriter.h"
 #include "LogReader.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 #include "metrics/MetricsManager.h"
-#include "parse_util.h"
+#include "stats_util.h"
 
 #include <log/logprint.h>
 #include <stdio.h>
@@ -44,8 +44,6 @@
     DropboxWriter m_dropbox_writer;
 
     std::unordered_map<int, std::unique_ptr<MetricsManager>> mMetricsManagers;
-
-    static StatsdConfig buildFakeConfig();
 };
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/condition/CombinationConditionTracker.cpp b/cmds/statsd/src/condition/CombinationConditionTracker.cpp
new file mode 100644
index 0000000..6188383
--- /dev/null
+++ b/cmds/statsd/src/condition/CombinationConditionTracker.cpp
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#define LOG_TAG "CombinationConditionTracker"
+#define DEBUG true  // STOPSHIP if true
+#define VLOG(...) \
+    if (DEBUG) ALOGD(__VA_ARGS__);
+
+#include "CombinationConditionTracker.h"
+#include <cutils/log.h>
+#include <log/logprint.h>
+using std::string;
+using std::unique_ptr;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+CombinationConditionTracker::CombinationConditionTracker(const string& name, const int index)
+    : ConditionTracker(name, index) {
+    VLOG("creating CombinationConditionTracker %s", mName.c_str());
+}
+
+CombinationConditionTracker::~CombinationConditionTracker() {
+    VLOG("~CombinationConditionTracker() %s", mName.c_str());
+}
+
+bool CombinationConditionTracker::init(const vector<Condition>& allConditionConfig,
+                                       const vector<sp<ConditionTracker>>& allConditionTrackers,
+                                       const unordered_map<string, int>& conditionNameIndexMap,
+                                       vector<bool>& stack) {
+    VLOG("Combiniation condition init() %s", mName.c_str());
+    if (mInitialized) {
+        return true;
+    }
+
+    // mark this node as visited in the recursion stack.
+    stack[mIndex] = true;
+
+    Condition_Combination combinationCondition = allConditionConfig[mIndex].combination();
+
+    if (!combinationCondition.has_operation()) {
+        return false;
+    }
+    mLogicalOperation = combinationCondition.operation();
+
+    if (mLogicalOperation == LogicalOperation::NOT && combinationCondition.condition_size() != 1) {
+        return false;
+    }
+
+    for (string child : combinationCondition.condition()) {
+        auto it = conditionNameIndexMap.find(child);
+
+        if (it == conditionNameIndexMap.end()) {
+            ALOGW("Condition %s not found in the config", child.c_str());
+            return false;
+        }
+
+        int childIndex = it->second;
+        const auto& childTracker = allConditionTrackers[childIndex];
+        // if the child is a visited node in the recursion -> circle detected.
+        if (stack[childIndex]) {
+            ALOGW("Circle detected!!!");
+            return false;
+        }
+
+        bool initChildSucceeded = childTracker->init(allConditionConfig, allConditionTrackers,
+                                                     conditionNameIndexMap, stack);
+
+        if (!initChildSucceeded) {
+            ALOGW("Child initialization failed %s ", child.c_str());
+            return false;
+        } else {
+            ALOGW("Child initialization success %s ", child.c_str());
+        }
+
+        mChildren.push_back(childIndex);
+
+        mTrackerIndex.insert(childTracker->getLogTrackerIndex().begin(),
+                             childTracker->getLogTrackerIndex().end());
+    }
+
+    // unmark this node in the recursion stack.
+    stack[mIndex] = false;
+
+    mInitialized = true;
+
+    return true;
+}
+
+bool CombinationConditionTracker::evaluateCondition(
+        const LogEventWrapper& event, const std::vector<MatchingState>& eventMatcherValues,
+        const std::vector<sp<ConditionTracker>>& mAllConditions,
+        std::vector<ConditionState>& conditionCache, std::vector<bool>& changedCache) {
+    // value is up to date.
+    if (conditionCache[mIndex] != ConditionState::kNotEvaluated) {
+        return false;
+    }
+
+    for (const int childIndex : mChildren) {
+        if (conditionCache[childIndex] == ConditionState::kNotEvaluated) {
+            const sp<ConditionTracker>& child = mAllConditions[childIndex];
+            child->evaluateCondition(event, eventMatcherValues, mAllConditions, conditionCache,
+                                     changedCache);
+        }
+    }
+
+    ConditionState newCondition =
+            evaluateCombinationCondition(mChildren, mLogicalOperation, conditionCache);
+
+    bool changed = (mConditionState != newCondition);
+    mConditionState = newCondition;
+
+    conditionCache[mIndex] = mConditionState;
+
+    changedCache[mIndex] = changed;
+    return changed;
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/condition/CombinationConditionTracker.h b/cmds/statsd/src/condition/CombinationConditionTracker.h
new file mode 100644
index 0000000..38780e7
--- /dev/null
+++ b/cmds/statsd/src/condition/CombinationConditionTracker.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef COMBINATION_CONDITION_TRACKER_H
+#define COMBINATION_CONDITION_TRACKER_H
+
+#include "ConditionTracker.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+class CombinationConditionTracker : public virtual ConditionTracker {
+public:
+    CombinationConditionTracker(const std::string& name, const int index);
+
+    ~CombinationConditionTracker();
+
+    bool init(const std::vector<Condition>& allConditionConfig,
+              const std::vector<sp<ConditionTracker>>& allConditionTrackers,
+              const std::unordered_map<std::string, int>& conditionNameIndexMap,
+              std::vector<bool>& stack) override;
+
+    bool evaluateCondition(const LogEventWrapper& event,
+                           const std::vector<MatchingState>& eventMatcherValues,
+                           const std::vector<sp<ConditionTracker>>& mAllConditions,
+                           std::vector<ConditionState>& conditionCache,
+                           std::vector<bool>& changedCache) override;
+
+private:
+    LogicalOperation mLogicalOperation;
+    // Store index of the children Conditions.
+    // We don't store string name of the Children, because we want to get rid of the hash map to
+    // map the name to object. We don't want to store smart pointers to children, because it
+    // increases the risk of circular dependency and memory leak.
+    std::vector<int> mChildren;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+
+#endif  // COMBINATION_CONDITION_TRACKER_H
diff --git a/cmds/statsd/src/condition/ConditionTracker.h b/cmds/statsd/src/condition/ConditionTracker.h
new file mode 100644
index 0000000..2da8fa0
--- /dev/null
+++ b/cmds/statsd/src/condition/ConditionTracker.h
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef CONDITION_TRACKER_H
+#define CONDITION_TRACKER_H
+
+#include <cutils/log.h>
+#include <log/logprint.h>
+#include <utils/RefBase.h>
+#include <unordered_map>
+#include "../matchers/LogMatchingTracker.h"
+#include "../matchers/matcher_util.h"
+#include "condition_util.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+class ConditionTracker : public virtual RefBase {
+public:
+    ConditionTracker(const std::string& name, const int index)
+        : mName(name),
+          mIndex(index),
+          mInitialized(false),
+          mConditionState(ConditionState::kUnknown),
+          mTrackerIndex(){};
+
+    virtual ~ConditionTracker(){};
+
+    // Initialize this ConditionTracker. This initialization is done recursively (DFS). It can also
+    // be done in the constructor, but we do it separately because (1) easy to return a bool to
+    // indicate whether the initialization is successful. (2) makes unit test easier.
+    // allConditionConfig: the list of all Condition config from statsd_config.
+    // allConditionTrackers: the list of all ConditionTrackers (this is needed because we may also
+    //                       need to call init() on children conditions)
+    // conditionNameIndexMap: the mapping from condition name to its index.
+    // stack: a bit map to keep track which nodes have been visited on the stack in the recursion.
+    virtual bool init(const std::vector<Condition>& allConditionConfig,
+                      const std::vector<sp<ConditionTracker>>& allConditionTrackers,
+                      const std::unordered_map<std::string, int>& conditionNameIndexMap,
+                      std::vector<bool>& stack) = 0;
+
+    // evaluate current condition given the new event.
+    // return true if the condition state changed, false if the condition state is not changed.
+    // event: the new log event
+    // eventMatcherValues: the results of the LogMatcherTrackers. LogMatcherTrackers always process
+    //                     event before ConditionTrackers, because ConditionTracker depends on
+    //                     LogMatchingTrackers.
+    // mAllConditions: the list of all ConditionTracker
+    // conditionCache: the cached results of the ConditionTrackers for this new event.
+    // changedCache: the bit map to record whether the condition has changed.
+    virtual bool evaluateCondition(const LogEventWrapper& event,
+                                   const std::vector<MatchingState>& eventMatcherValues,
+                                   const std::vector<sp<ConditionTracker>>& mAllConditions,
+                                   std::vector<ConditionState>& conditionCache,
+                                   std::vector<bool>& changedCache) = 0;
+
+    // Return the current condition state.
+    virtual ConditionState isConditionMet() {
+        ALOGW("Condition %s value %d", mName.c_str(), mConditionState);
+        return mConditionState;
+    };
+
+    // return the list of LogMatchingTracker index that this ConditionTracker uses.
+    virtual const std::set<int>& getLogTrackerIndex() const {
+        return mTrackerIndex;
+    }
+
+protected:
+    // We don't really need the string name, but having a name here makes log messages
+    // easy to debug.
+    const std::string mName;
+
+    // the index of this condition in the manager's condition list.
+    const int mIndex;
+
+    // if it's properly initialized.
+    bool mInitialized;
+
+    // current condition state.
+    ConditionState mConditionState;
+
+    // the list of LogMatchingTracker index that this ConditionTracker uses.
+    std::set<int> mTrackerIndex;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+
+#endif  // CONDITION_TRACKER_H
diff --git a/cmds/statsd/src/condition/SimpleConditionTracker.cpp b/cmds/statsd/src/condition/SimpleConditionTracker.cpp
new file mode 100644
index 0000000..14ec72e
--- /dev/null
+++ b/cmds/statsd/src/condition/SimpleConditionTracker.cpp
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Stats_SimpleConditionTracker"
+#define DEBUG true  // STOPSHIP if true
+#define VLOG(...) \
+    if (DEBUG) ALOGD(__VA_ARGS__);
+
+#include "SimpleConditionTracker.h"
+#include <cutils/log.h>
+#include <log/logprint.h>
+
+using std::string;
+using std::unique_ptr;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+SimpleConditionTracker::SimpleConditionTracker(
+        const string& name, const int index, const SimpleCondition& simpleCondition,
+        const unordered_map<string, int>& trackerNameIndexMap)
+    : ConditionTracker(name, index) {
+    VLOG("creating SimpleConditionTracker %s", mName.c_str());
+    mCountNesting = simpleCondition.count_nesting();
+
+    if (simpleCondition.has_start()) {
+        auto pair = trackerNameIndexMap.find(simpleCondition.start());
+        if (pair == trackerNameIndexMap.end()) {
+            ALOGW("Start matcher %s not found in the config", simpleCondition.start().c_str());
+            return;
+        }
+        mStartLogMatcherIndex = pair->second;
+        mTrackerIndex.insert(mStartLogMatcherIndex);
+    } else {
+        mStartLogMatcherIndex = -1;
+    }
+
+    if (simpleCondition.has_stop()) {
+        auto pair = trackerNameIndexMap.find(simpleCondition.stop());
+        if (pair == trackerNameIndexMap.end()) {
+            ALOGW("Stop matcher %s not found in the config", simpleCondition.stop().c_str());
+            return;
+        }
+        mStopLogMatcherIndex = pair->second;
+        mTrackerIndex.insert(mStartLogMatcherIndex);
+    } else {
+        mStopLogMatcherIndex = -1;
+    }
+
+    if (simpleCondition.has_stop_all()) {
+        auto pair = trackerNameIndexMap.find(simpleCondition.stop_all());
+        if (pair == trackerNameIndexMap.end()) {
+            ALOGW("Stop matcher %s not found in the config", simpleCondition.stop().c_str());
+            return;
+        }
+        mStopAllLogMatcherIndex = pair->second;
+        mTrackerIndex.insert(mStopAllLogMatcherIndex);
+    } else {
+        mStopAllLogMatcherIndex = -1;
+    }
+
+    mInitialized = true;
+}
+
+SimpleConditionTracker::~SimpleConditionTracker() {
+    VLOG("~SimpleConditionTracker()");
+}
+
+bool SimpleConditionTracker::init(const vector<Condition>& allConditionConfig,
+                                  const vector<sp<ConditionTracker>>& allConditionTrackers,
+                                  const unordered_map<string, int>& conditionNameIndexMap,
+                                  vector<bool>& stack) {
+    // SimpleConditionTracker does not have dependency on other conditions, thus we just return
+    // if the initialization was successful.
+    return mInitialized;
+}
+
+bool SimpleConditionTracker::evaluateCondition(const LogEventWrapper& event,
+                                               const vector<MatchingState>& eventMatcherValues,
+                                               const vector<sp<ConditionTracker>>& mAllConditions,
+                                               vector<ConditionState>& conditionCache,
+                                               vector<bool>& changedCache) {
+    if (conditionCache[mIndex] != ConditionState::kNotEvaluated) {
+        // it has been evaluated.
+        VLOG("Yes, already evaluated, %s %d", mName.c_str(), mConditionState);
+        return false;
+    }
+
+    // Ignore nesting, because we know we cannot trust ourselves on tracking nesting conditions.
+    ConditionState newCondition = mConditionState;
+    // Note: The order to evaluate the following start, stop, stop_all matters.
+    // The priority of overwrite is stop_all > stop > start.
+    if (mStartLogMatcherIndex >= 0 &&
+        eventMatcherValues[mStartLogMatcherIndex] == MatchingState::kMatched) {
+        newCondition = ConditionState::kTrue;
+    }
+
+    if (mStopLogMatcherIndex >= 0 &&
+        eventMatcherValues[mStopLogMatcherIndex] == MatchingState::kMatched) {
+        newCondition = ConditionState::kFalse;
+    }
+
+    if (mStopAllLogMatcherIndex >= 0 &&
+        eventMatcherValues[mStopAllLogMatcherIndex] == MatchingState::kMatched) {
+        newCondition = ConditionState::kFalse;
+    }
+
+    bool changed = (mConditionState != newCondition);
+    mConditionState = newCondition;
+    conditionCache[mIndex] = mConditionState;
+    changedCache[mIndex] = changed;
+    return changed;
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/condition/SimpleConditionTracker.h b/cmds/statsd/src/condition/SimpleConditionTracker.h
new file mode 100644
index 0000000..41e1707
--- /dev/null
+++ b/cmds/statsd/src/condition/SimpleConditionTracker.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SIMPLE_CONDITION_TRACKER_H
+#define SIMPLE_CONDITION_TRACKER_H
+
+#include "ConditionTracker.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+class SimpleConditionTracker : public virtual ConditionTracker {
+public:
+    SimpleConditionTracker(const std::string& name, const int index,
+                           const SimpleCondition& simpleCondition,
+                           const std::unordered_map<std::string, int>& trackerNameIndexMap);
+
+    ~SimpleConditionTracker();
+
+    bool init(const std::vector<Condition>& allConditionConfig,
+              const std::vector<sp<ConditionTracker>>& allConditionTrackers,
+              const std::unordered_map<std::string, int>& conditionNameIndexMap,
+              std::vector<bool>& stack) override;
+
+    bool evaluateCondition(const LogEventWrapper& event,
+                           const std::vector<MatchingState>& eventMatcherValues,
+                           const std::vector<sp<ConditionTracker>>& mAllConditions,
+                           std::vector<ConditionState>& conditionCache,
+                           std::vector<bool>& changedCache) override;
+
+private:
+    // The index of the LogEventMatcher which defines the start.
+    int mStartLogMatcherIndex;
+
+    // The index of the LogEventMatcher which defines the end.
+    int mStopLogMatcherIndex;
+
+    // if the start end needs to be nested.
+    bool mCountNesting;
+
+    // The index of the LogEventMatcher which defines the stop all.
+    int mStopAllLogMatcherIndex;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+
+#endif  // SIMPLE_CONDITION_TRACKER_H
diff --git a/cmds/statsd/src/condition/condition_util.cpp b/cmds/statsd/src/condition/condition_util.cpp
new file mode 100644
index 0000000..cb07d15
--- /dev/null
+++ b/cmds/statsd/src/condition/condition_util.cpp
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "condition_util.h"
+
+#include <cutils/log.h>
+#include <log/event_tag_map.h>
+#include <log/log_event_list.h>
+#include <log/logprint.h>
+#include <utils/Errors.h>
+#include <unordered_map>
+#include "ConditionTracker.h"
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+#include "stats_util.h"
+
+using std::set;
+using std::string;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+ConditionState evaluateCombinationCondition(const std::vector<int>& children,
+                                            const LogicalOperation& operation,
+                                            const std::vector<ConditionState>& conditionCache) {
+    ConditionState newCondition;
+
+    bool hasUnknown = false;
+    bool hasFalse = false;
+    bool hasTrue = false;
+
+    for (auto childIndex : children) {
+        ConditionState childState = conditionCache[childIndex];
+        if (childState == ConditionState::kUnknown) {
+            hasUnknown = true;
+            break;
+        }
+        if (childState == ConditionState::kFalse) {
+            hasFalse = true;
+        }
+        if (childState == ConditionState::kTrue) {
+            hasTrue = true;
+        }
+    }
+
+    // If any child condition is in unknown state, the condition is unknown too.
+    if (hasUnknown) {
+        return ConditionState::kUnknown;
+    }
+
+    switch (operation) {
+        case LogicalOperation::AND: {
+            newCondition = hasFalse ? ConditionState::kFalse : ConditionState::kTrue;
+            break;
+        }
+        case LogicalOperation::OR: {
+            newCondition = hasTrue ? ConditionState::kTrue : ConditionState::kFalse;
+            break;
+        }
+        case LogicalOperation::NOT:
+            newCondition = (conditionCache[children[0]] == ConditionState::kFalse)
+                                   ? ConditionState::kTrue
+                                   : ConditionState::kFalse;
+            break;
+        case LogicalOperation::NAND:
+            newCondition = hasFalse ? ConditionState::kTrue : ConditionState::kFalse;
+            break;
+        case LogicalOperation::NOR:
+            newCondition = hasTrue ? ConditionState::kFalse : ConditionState::kTrue;
+            break;
+    }
+    return newCondition;
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/metrics/ConditionTracker.h b/cmds/statsd/src/condition/condition_util.h
similarity index 60%
rename from cmds/statsd/src/metrics/ConditionTracker.h
rename to cmds/statsd/src/condition/condition_util.h
index b94d5ab..a4fcea3 100644
--- a/cmds/statsd/src/metrics/ConditionTracker.h
+++ b/cmds/statsd/src/condition/condition_util.h
@@ -14,38 +14,28 @@
  * limitations under the License.
  */
 
-#ifndef CONDITION_TRACKER_H
-#define CONDITION_TRACKER_H
+#ifndef CONDITION_UTIL_H
+#define CONDITION_UTIL_H
 
-#include <utils/RefBase.h>
-#include "../matchers/LogEntryMatcherManager.h"
+#include <vector>
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 
 namespace android {
 namespace os {
 namespace statsd {
 
-class ConditionTracker : public RefBase {
-public:
-    ConditionTracker();
-
-    ConditionTracker(const Condition& condition);
-
-    ~ConditionTracker();
-
-    void evaluateCondition(const LogEventWrapper& event);
-
-    bool isConditionMet() const;
-
-private:
-    // this is the definition of the Condition.
-    Condition mCondition;
-
-    bool mIsConditionMet;
+enum ConditionState {
+    kNotEvaluated = -2,
+    kUnknown = -1,
+    kFalse = 0,
+    kTrue = 1,
 };
 
+ConditionState evaluateCombinationCondition(const std::vector<int>& children,
+                                            const LogicalOperation& operation,
+                                            const std::vector<ConditionState>& conditionCache);
 }  // namespace statsd
 }  // namespace os
 }  // namespace android
-
-#endif  // CONDITION_TRACKER_H
+#endif  // CONDITION_UTIL_H
diff --git a/cmds/statsd/src/matchers/CombinationLogMatchingTracker.cpp b/cmds/statsd/src/matchers/CombinationLogMatchingTracker.cpp
new file mode 100644
index 0000000..9f9b648
--- /dev/null
+++ b/cmds/statsd/src/matchers/CombinationLogMatchingTracker.cpp
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "CombinationLogMatchingTracker.h"
+
+#include <cutils/log.h>
+#include "matcher_util.h"
+using std::set;
+using std::string;
+using std::unique_ptr;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+CombinationLogMatchingTracker::CombinationLogMatchingTracker(const string& name, const int index)
+    : LogMatchingTracker(name, index) {
+}
+
+CombinationLogMatchingTracker::~CombinationLogMatchingTracker() {
+}
+
+bool CombinationLogMatchingTracker::init(const vector<LogEntryMatcher>& allLogMatchers,
+                                         const vector<sp<LogMatchingTracker>>& allTrackers,
+                                         const unordered_map<string, int>& matcherMap,
+                                         vector<bool>& stack) {
+    if (mInitialized) {
+        return true;
+    }
+
+    // mark this node as visited in the recursion stack.
+    stack[mIndex] = true;
+
+    LogEntryMatcher_Combination matcher = allLogMatchers[mIndex].combination();
+
+    // LogicalOperation is missing in the config
+    if (!matcher.has_operation()) {
+        return false;
+    }
+
+    mLogicalOperation = matcher.operation();
+
+    if (mLogicalOperation == LogicalOperation::NOT && matcher.matcher_size() != 1) {
+        return false;
+    }
+
+    for (const string& child : matcher.matcher()) {
+        auto pair = matcherMap.find(child);
+        if (pair == matcherMap.end()) {
+            ALOGW("Matcher %s not found in the config", child.c_str());
+            return false;
+        }
+
+        int childIndex = pair->second;
+
+        // if the child is a visited node in the recursion -> circle detected.
+        if (stack[childIndex]) {
+            ALOGE("Circle detected in matcher config");
+            return false;
+        }
+
+        if (!allTrackers[childIndex]->init(allLogMatchers, allTrackers, matcherMap, stack)) {
+            ALOGW("child matcher init failed %s", child.c_str());
+            return false;
+        }
+
+        mChildren.push_back(childIndex);
+
+        const set<int>& childTagIds = allTrackers[childIndex]->getTagIds();
+        mTagIds.insert(childTagIds.begin(), childTagIds.end());
+    }
+
+    mInitialized = true;
+    // unmark this node in the recursion stack.
+    stack[mIndex] = false;
+    return true;
+}
+
+void CombinationLogMatchingTracker::onLogEvent(const LogEventWrapper& event,
+                                               const vector<sp<LogMatchingTracker>>& allTrackers,
+                                               vector<MatchingState>& matcherResults) {
+    // this event has been processed.
+    if (matcherResults[mIndex] != MatchingState::kNotComputed) {
+        return;
+    }
+
+    if (mTagIds.find(event.tagId) == mTagIds.end()) {
+        matcherResults[mIndex] = MatchingState::kNotMatched;
+        return;
+    }
+
+    // evaluate children matchers if they haven't been evaluated.
+    for (const int childIndex : mChildren) {
+        if (matcherResults[childIndex] == MatchingState::kNotComputed) {
+            const sp<LogMatchingTracker>& child = allTrackers[childIndex];
+            child->onLogEvent(event, allTrackers, matcherResults);
+        }
+    }
+
+    bool matched = combinationMatch(mChildren, mLogicalOperation, matcherResults);
+    matcherResults[mIndex] = matched ? MatchingState::kMatched : MatchingState::kNotMatched;
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/matchers/CombinationLogMatchingTracker.h b/cmds/statsd/src/matchers/CombinationLogMatchingTracker.h
new file mode 100644
index 0000000..51ee232
--- /dev/null
+++ b/cmds/statsd/src/matchers/CombinationLogMatchingTracker.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef COMBINATION_LOG_MATCHING_TRACKER_H
+#define COMBINATION_LOG_MATCHING_TRACKER_H
+
+#include <log/log_read.h>
+#include <log/logprint.h>
+#include <set>
+#include <unordered_map>
+#include <vector>
+#include "LogMatchingTracker.h"
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+// Represents a LogEntryMatcher_Combination in the StatsdConfig.
+class CombinationLogMatchingTracker : public virtual LogMatchingTracker {
+public:
+    CombinationLogMatchingTracker(const std::string& name, const int index);
+
+    bool init(const std::vector<LogEntryMatcher>& allLogMatchers,
+              const std::vector<sp<LogMatchingTracker>>& allTrackers,
+              const std::unordered_map<std::string, int>& matcherMap,
+              std::vector<bool>& stack);
+
+    ~CombinationLogMatchingTracker();
+
+    void onLogEvent(const LogEventWrapper& event,
+                    const std::vector<sp<LogMatchingTracker>>& allTrackers,
+                    std::vector<MatchingState>& matcherResults) override;
+
+private:
+    LogicalOperation mLogicalOperation;
+
+    std::vector<int> mChildren;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+#endif  // COMBINATION_LOG_MATCHING_TRACKER_H
diff --git a/cmds/statsd/src/matchers/LogMatchingTracker.h b/cmds/statsd/src/matchers/LogMatchingTracker.h
new file mode 100644
index 0000000..4244bd5
--- /dev/null
+++ b/cmds/statsd/src/matchers/LogMatchingTracker.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LOG_MATCHING_TRACKER_H
+#define LOG_MATCHING_TRACKER_H
+
+#include <log/log_read.h>
+#include <log/logprint.h>
+#include <utils/RefBase.h>
+#include <set>
+#include <unordered_map>
+
+#include <vector>
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+#include "matcher_util.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+class LogMatchingTracker : public virtual RefBase {
+public:
+    LogMatchingTracker(const std::string& name, const int index)
+        : mName(name), mIndex(index), mInitialized(false){};
+
+    virtual ~LogMatchingTracker(){};
+
+    // Initialize this LogMatchingTracker.
+    // allLogMatchers: the list of the LogEntryMatcher proto config. This is needed because we don't
+    //                 store the proto object in memory. We only need it during initilization.
+    // allTrackers: the list of the LogMatchingTracker objects. It's a one-to-one mapping with
+    //              allLogMatchers. This is needed because the initialization is done recursively
+    //              for CombinationLogMatchingTrackers using DFS.
+    // stack: a bit map to record which matcher has been visited on the stack. This is for detecting
+    //        circle dependency.
+    virtual bool init(const std::vector<LogEntryMatcher>& allLogMatchers,
+                      const std::vector<sp<LogMatchingTracker>>& allTrackers,
+                      const std::unordered_map<std::string, int>& matcherMap,
+                      std::vector<bool>& stack) = 0;
+
+    // Called when a log event comes.
+    // event: the log event.
+    // allTrackers: the list of all LogMatchingTrackers. This is needed because the log processing
+    //              is done recursively.
+    // matcherResults: The cached results for all matchers for this event. Parent matchers can
+    //                 directly access the children's matching results if they have been evaluated.
+    //                 Otherwise, call children matchers' onLogEvent.
+    virtual void onLogEvent(const LogEventWrapper& event,
+                            const std::vector<sp<LogMatchingTracker>>& allTrackers,
+                            std::vector<MatchingState>& matcherResults) = 0;
+
+    // Get the tagIds that this matcher cares about. The combined collection is stored
+    // in MetricMananger, so that we can pass any LogEvents that are not interest of us. It uses
+    // some memory but hopefully it can save us much CPU time when there is flood of events.
+    virtual const std::set<int>& getTagIds() const {
+        return mTagIds;
+    }
+
+protected:
+    // Name of this matching. We don't really need the name, but it makes log message easy to debug.
+    const std::string mName;
+
+    // Index of this LogMatchingTracker in MetricsManager's container.
+    const int mIndex;
+
+    // Whether this LogMatchingTracker has been properly initialized.
+    bool mInitialized;
+
+    // The collection of the event tag ids that this LogMatchingTracker cares. So we can quickly
+    // return kNotMatched when we receive an event with an id not in the list. This is especially
+    // useful when we have a complex CombinationLogMatcherTracker.
+    // TODO: Consider use an array instead of stl set. In reality, the number of the tag ids a
+    // LogMatchingTracker cares is only a few.
+    std::set<int> mTagIds;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+
+#endif  // LOG_MATCHING_TRACKER_H
diff --git a/cmds/statsd/src/matchers/SimpleLogMatchingTracker.cpp b/cmds/statsd/src/matchers/SimpleLogMatchingTracker.cpp
new file mode 100644
index 0000000..1c83039
--- /dev/null
+++ b/cmds/statsd/src/matchers/SimpleLogMatchingTracker.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "SimpleLogMatchingTracker"
+#define DEBUG true  // STOPSHIP if true
+#define VLOG(...) \
+    if (DEBUG) ALOGD(__VA_ARGS__);
+
+#include "SimpleLogMatchingTracker.h"
+#include <cutils/log.h>
+#include <log/logprint.h>
+
+using std::string;
+using std::unique_ptr;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+SimpleLogMatchingTracker::SimpleLogMatchingTracker(const string& name, const int index,
+                                                   const SimpleLogEntryMatcher& matcher)
+    : LogMatchingTracker(name, index), mMatcher(matcher) {
+    for (int i = 0; i < matcher.tag_size(); i++) {
+        mTagIds.insert(matcher.tag(i));
+    }
+    mInitialized = true;
+}
+
+SimpleLogMatchingTracker::~SimpleLogMatchingTracker() {
+}
+
+bool SimpleLogMatchingTracker::init(const vector<LogEntryMatcher>& allLogMatchers,
+                                    const vector<sp<LogMatchingTracker>>& allTrackers,
+                                    const unordered_map<string, int>& matcherMap,
+                                    vector<bool>& stack) {
+    // no need to do anything.
+    return true;
+}
+
+void SimpleLogMatchingTracker::onLogEvent(const LogEventWrapper& event,
+                                          const vector<sp<LogMatchingTracker>>& allTrackers,
+                                          vector<MatchingState>& matcherResults) {
+    if (matcherResults[mIndex] != MatchingState::kNotComputed) {
+        VLOG("Matcher %s already evaluated ", mName.c_str());
+        return;
+    }
+
+    if (mTagIds.find(event.tagId) == mTagIds.end()) {
+        matcherResults[mIndex] = MatchingState::kNotMatched;
+        return;
+    }
+
+    bool matched = matchesSimple(mMatcher, event);
+    matcherResults[mIndex] = matched ? MatchingState::kMatched : MatchingState::kNotMatched;
+    VLOG("Stats SimpleLogMatcher %s matched? %d", mName.c_str(), matched);
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/matchers/SimpleLogMatchingTracker.h b/cmds/statsd/src/matchers/SimpleLogMatchingTracker.h
new file mode 100644
index 0000000..65dbe64
--- /dev/null
+++ b/cmds/statsd/src/matchers/SimpleLogMatchingTracker.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SIMPLE_LOG_MATCHING_TRACKER_H
+#define SIMPLE_LOG_MATCHING_TRACKER_H
+
+#include <log/log_read.h>
+#include <log/logprint.h>
+#include <set>
+#include <unordered_map>
+#include <vector>
+#include "LogMatchingTracker.h"
+#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+class SimpleLogMatchingTracker : public virtual LogMatchingTracker {
+public:
+    SimpleLogMatchingTracker(const std::string& name, const int index,
+                             const SimpleLogEntryMatcher& matcher);
+
+    ~SimpleLogMatchingTracker();
+
+    bool init(const std::vector<LogEntryMatcher>& allLogMatchers,
+              const std::vector<sp<LogMatchingTracker>>& allTrackers,
+              const std::unordered_map<std::string, int>& matcherMap,
+              std::vector<bool>& stack) override;
+
+    void onLogEvent(const LogEventWrapper& event,
+                    const std::vector<sp<LogMatchingTracker>>& allTrackers,
+                    std::vector<MatchingState>& matcherResults) override;
+
+private:
+    const SimpleLogEntryMatcher mMatcher;
+};
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+#endif  // SIMPLE_LOG_MATCHING_TRACKER_H
diff --git a/cmds/statsd/src/matchers/LogEntryMatcherManager.cpp b/cmds/statsd/src/matchers/matcher_util.cpp
similarity index 69%
rename from cmds/statsd/src/matchers/LogEntryMatcherManager.cpp
rename to cmds/statsd/src/matchers/matcher_util.cpp
index ab7b2b1d..557c032 100644
--- a/cmds/statsd/src/matchers/LogEntryMatcherManager.cpp
+++ b/cmds/statsd/src/matchers/matcher_util.cpp
@@ -14,26 +14,28 @@
  * limitations under the License.
  */
 
-#include "LogEntryMatcherManager.h"
+#include "matcher_util.h"
 #include <cutils/log.h>
 #include <log/event_tag_map.h>
 #include <log/log_event_list.h>
 #include <log/logprint.h>
 #include <utils/Errors.h>
 #include <unordered_map>
+#include "LogMatchingTracker.h"
 #include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
-#include "parse_util.h"
+#include "stats_util.h"
 
 using std::set;
 using std::string;
 using std::unordered_map;
+using std::vector;
 
 namespace android {
 namespace os {
 namespace statsd {
 
-LogEventWrapper LogEntryMatcherManager::parseLogEvent(log_msg msg) {
+LogEventWrapper parseLogEvent(log_msg msg) {
     LogEventWrapper wrapper;
     wrapper.timestamp_ns = msg.entry_v1.sec * NS_PER_SEC + msg.entry_v1.nsec;
     wrapper.tagId = getTagId(msg);
@@ -67,7 +69,9 @@
                     break;
                 case EVENT_TYPE_STRING:
                     if (index % 2 == 1) {
-                        wrapper.strMap[key] = elem.data.string;
+                        // without explicit calling string() constructor, there will be an
+                        // additional 0 in the end of the string.
+                        wrapper.strMap[key] = string(elem.data.string);
                     }
                     index++;
                     break;
@@ -99,57 +103,56 @@
     return wrapper;
 }
 
-bool LogEntryMatcherManager::matches(const LogEntryMatcher& matcher, const LogEventWrapper& event) {
-    const int tagId = event.tagId;
-    const unordered_map<int, long>& intMap = event.intMap;
-    const unordered_map<int, string>& strMap = event.strMap;
-    const unordered_map<int, float>& floatMap = event.floatMap;
-    const unordered_map<int, bool>& boolMap = event.boolMap;
-
-    if (matcher.has_combination()) {  // Need to evaluate composite matching
-        switch (matcher.combination().operation()) {
-            case LogicalOperation::AND:
-                for (auto nestedMatcher : matcher.combination().matcher()) {
-                    if (!matches(nestedMatcher, event)) {
-                        return false;  // return false if any nested matcher is false;
-                    }
+bool combinationMatch(const vector<int>& children, const LogicalOperation& operation,
+                      const vector<MatchingState>& matcherResults) {
+    bool matched;
+    switch (operation) {
+        case LogicalOperation::AND: {
+            matched = true;
+            for (const int childIndex : children) {
+                if (matcherResults[childIndex] != MatchingState::kMatched) {
+                    matched = false;
+                    break;
                 }
-                return true;  // Otherwise, return true.
-            case LogicalOperation::OR:
-                for (auto nestedMatcher : matcher.combination().matcher()) {
-                    if (matches(nestedMatcher, event)) {
-                        return true;  // return true if any nested matcher is true;
-                    }
-                }
-                return false;
-            case LogicalOperation::NOT:
-                return !matches(matcher.combination().matcher(0), event);
-
-            // Case NAND is just inverting the return statement of AND
-            case LogicalOperation::NAND:
-                for (auto nestedMatcher : matcher.combination().matcher()) {
-                    auto simple = nestedMatcher.simple_log_entry_matcher();
-                    if (!matches(nestedMatcher, event)) {
-                        return true;  // return false if any nested matcher is false;
-                    }
-                }
-                return false;  // Otherwise, return true.
-            case LogicalOperation::NOR:
-                for (auto nestedMatcher : matcher.combination().matcher()) {
-                    if (matches(nestedMatcher, event)) {
-                        return false;  // return true if any nested matcher is true;
-                    }
-                }
-                return true;
+            }
+            break;
         }
-        return false;
-    } else {
-        return matchesSimple(matcher.simple_log_entry_matcher(), event);
+        case LogicalOperation::OR: {
+            matched = false;
+            for (const int childIndex : children) {
+                if (matcherResults[childIndex] == MatchingState::kMatched) {
+                    matched = true;
+                    break;
+                }
+            }
+            break;
+        }
+        case LogicalOperation::NOT:
+            matched = matcherResults[children[0]] == MatchingState::kNotMatched;
+            break;
+        case LogicalOperation::NAND:
+            matched = false;
+            for (const int childIndex : children) {
+                if (matcherResults[childIndex] != MatchingState::kMatched) {
+                    matched = true;
+                    break;
+                }
+            }
+            break;
+        case LogicalOperation::NOR:
+            matched = true;
+            for (const int childIndex : children) {
+                if (matcherResults[childIndex] == MatchingState::kMatched) {
+                    matched = false;
+                    break;
+                }
+            }
+            break;
     }
+    return matched;
 }
 
-bool LogEntryMatcherManager::matchesSimple(const SimpleLogEntryMatcher& simpleMatcher,
-                                           const LogEventWrapper& event) {
+bool matchesSimple(const SimpleLogEntryMatcher& simpleMatcher, const LogEventWrapper& event) {
     const int tagId = event.tagId;
     const unordered_map<int, long>& intMap = event.intMap;
     const unordered_map<int, string>& strMap = event.strMap;
@@ -249,26 +252,6 @@
     return false;
 }
 
-set<int> LogEntryMatcherManager::getTagIdsFromMatcher(const LogEntryMatcher& matcher) {
-    set<int> result;
-    switch (matcher.contents_case()) {
-        case LogEntryMatcher::kCombination:
-            for (auto sub_matcher : matcher.combination().matcher()) {
-                set<int> tagSet = getTagIdsFromMatcher(sub_matcher);
-                result.insert(tagSet.begin(), tagSet.end());
-            }
-            break;
-        case LogEntryMatcher::kSimpleLogEntryMatcher:
-            for (int i = 0; i < matcher.simple_log_entry_matcher().tag_size(); i++) {
-                result.insert(matcher.simple_log_entry_matcher().tag(i));
-            }
-            break;
-        case LogEntryMatcher::CONTENTS_NOT_SET:
-            break;
-    }
-    return result;
-}
-
 }  // namespace statsd
 }  // namespace os
 }  // namespace android
diff --git a/cmds/statsd/src/matchers/LogEntryMatcherManager.h b/cmds/statsd/src/matchers/matcher_util.h
similarity index 63%
rename from cmds/statsd/src/matchers/LogEntryMatcherManager.h
rename to cmds/statsd/src/matchers/matcher_util.h
index fc8e6a1..6d8e762 100644
--- a/cmds/statsd/src/matchers/LogEntryMatcherManager.h
+++ b/cmds/statsd/src/matchers/matcher_util.h
@@ -14,8 +14,8 @@
  * limitations under the License.
  */
 
-#ifndef LOG_ENTRY_MATCHER_MANAGER_H
-#define LOG_ENTRY_MATCHER_MANAGER_H
+#ifndef MATCHER_UTIL_H
+#define MATCHER_UTIL_H
 
 #include <log/log_read.h>
 #include <log/logprint.h>
@@ -25,9 +25,6 @@
 #include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 
-using std::string;
-using std::unordered_map;
-
 namespace android {
 namespace os {
 namespace statsd {
@@ -41,26 +38,20 @@
     std::unordered_map<int, float> floatMap;
 } LogEventWrapper;
 
-/**
- * Keeps track per log entry which simple log entry matchers match.
- */
-class LogEntryMatcherManager {
-public:
-    LogEntryMatcherManager();
-
-    ~LogEntryMatcherManager(){};
-
-    static LogEventWrapper parseLogEvent(log_msg msg);
-
-    static std::set<int> getTagIdsFromMatcher(const LogEntryMatcher& matcher);
-
-    static bool matches(const LogEntryMatcher& matcher, const LogEventWrapper& wrapper);
-
-    static bool matchesSimple(const SimpleLogEntryMatcher& simpleMatcher,
-                              const LogEventWrapper& wrapper);
+enum MatchingState {
+    kNotComputed = -1,
+    kNotMatched = 0,
+    kMatched = 1,
 };
 
+LogEventWrapper parseLogEvent(log_msg msg);
+
+bool combinationMatch(const std::vector<int>& children, const LogicalOperation& operation,
+                      const std::vector<MatchingState>& matcherResults);
+
+bool matchesSimple(const SimpleLogEntryMatcher& simpleMatcher, const LogEventWrapper& wrapper);
+
 }  // namespace statsd
 }  // namespace os
 }  // namespace android
-#endif  // LOG_ENTRY_MATCHER_MANAGER_H
+#endif  // MATCHER_UTIL_H
diff --git a/cmds/statsd/src/metrics/ConditionTracker.cpp b/cmds/statsd/src/metrics/ConditionTracker.cpp
deleted file mode 100644
index 684ffdb..0000000
--- a/cmds/statsd/src/metrics/ConditionTracker.cpp
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define LOG_TAG "ConditionTracker"
-#define DEBUG true  // STOPSHIP if true
-#define VLOG(...) \
-    if (DEBUG) ALOGD(__VA_ARGS__);
-
-#include "ConditionTracker.h"
-#include <cutils/log.h>
-
-namespace android {
-namespace os {
-namespace statsd {
-
-ConditionTracker::ConditionTracker() : mIsConditionMet(true) {
-    VLOG("ConditionTracker()");
-}
-
-ConditionTracker::ConditionTracker(const Condition& condition)
-    : mCondition(condition), mIsConditionMet(true) {
-    VLOG("ConditionTracker()");
-}
-
-ConditionTracker::~ConditionTracker() {
-    VLOG("~ConditionTracker()");
-}
-
-void ConditionTracker::evaluateCondition(const LogEventWrapper& event) {
-    // modify condition.
-    VLOG("evaluateCondition");
-}
-
-bool ConditionTracker::isConditionMet() const {
-    VLOG("isConditionMet() %d", mIsConditionMet);
-    return mIsConditionMet;
-}
-
-}  // namespace statsd
-}  // namespace os
-}  // namespace android
\ No newline at end of file
diff --git a/cmds/statsd/src/metrics/CountMetricProducer.cpp b/cmds/statsd/src/metrics/CountMetricProducer.cpp
index 635777f..e98999e 100644
--- a/cmds/statsd/src/metrics/CountMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/CountMetricProducer.cpp
@@ -21,7 +21,6 @@
 
 #include "CountMetricProducer.h"
 #include "CountAnomalyTracker.h"
-#include "parse_util.h"
 
 #include <cutils/log.h>
 #include <limits.h>
@@ -33,15 +32,14 @@
 namespace os {
 namespace statsd {
 
-CountMetricProducer::CountMetricProducer(const CountMetric& metric,
-                                         const sp<ConditionTracker> condition)
+CountMetricProducer::CountMetricProducer(const CountMetric& metric, const bool hasCondition)
     : mMetric(metric),
-      mConditionTracker(condition),
-      mStartTime(std::time(nullptr)),
+      mStartTime(time(nullptr)),
       mCounter(0),
       mCurrentBucketStartTime(mStartTime),
       // TODO: read mAnomalyTracker parameters from config file.
-      mAnomalyTracker(6, 10) {
+      mAnomalyTracker(6, 10),
+      mCondition(hasCondition ? ConditionState::kUnknown : ConditionState::kTrue) {
     // TODO: evaluate initial conditions. and set mConditionMet.
     if (metric.has_bucket() && metric.bucket().has_bucket_size_millis()) {
         mBucketSize_sec = metric.bucket().bucket_size_millis() / 1000;
@@ -52,10 +50,6 @@
     VLOG("created. bucket size %lu start_time: %lu", mBucketSize_sec, mStartTime);
 }
 
-CountMetricProducer::CountMetricProducer(const CountMetric& metric)
-    : CountMetricProducer(metric, new ConditionTracker()) {
-}
-
 CountMetricProducer::~CountMetricProducer() {
     VLOG("~CountMetricProducer() called");
 }
@@ -63,13 +57,17 @@
 void CountMetricProducer::finish() {
     // TODO: write the StatsLogReport to dropbox using
     // DropboxWriter.
-    onDumpReport();
 }
 
 void CountMetricProducer::onDumpReport() {
     VLOG("dump report now...");
 }
 
+void CountMetricProducer::onConditionChanged(const bool conditionMet) {
+    VLOG("onConditionChanged");
+    mCondition = conditionMet;
+}
+
 void CountMetricProducer::onMatchedLogEvent(const LogEventWrapper& event) {
     time_t eventTime = event.timestamp_ns / 1000000000;
 
@@ -78,22 +76,24 @@
         return;
     }
 
-    if (mConditionTracker->isConditionMet()) {
+    if (mCondition == ConditionState::kTrue) {
         flushCounterIfNeeded(eventTime);
         mCounter++;
         mAnomalyTracker.checkAnomaly(mCounter);
+        VLOG("metric %lld count %d", mMetric.metric_id(), mCounter);
     }
 }
 
-// When a new matched event comes in, we check if it falls into the current bucket. And flush the
-// counter to the StatsLogReport and adjust the bucket if needed.
+// When a new matched event comes in, we check if it falls into the current
+// bucket. And flush the counter to the StatsLogReport and adjust the bucket if
+// needed.
 void CountMetricProducer::flushCounterIfNeeded(const time_t& eventTime) {
     if (mCurrentBucketStartTime + mBucketSize_sec > eventTime) {
         return;
     }
 
     // TODO: add a KeyValuePair to StatsLogReport.
-    ALOGD("CountMetric: dump counter %d", mCounter);
+    ALOGD("%lld:  dump counter %d", mMetric.metric_id(), mCounter);
 
     // adjust the bucket start time
     time_t numBucketsForward = (eventTime - mCurrentBucketStartTime)
@@ -106,7 +106,7 @@
     mAnomalyTracker.addPastBucket(mCounter, numBucketsForward);
     mCounter = 0;
 
-    VLOG("new bucket start time: %lu", mCurrentBucketStartTime);
+    VLOG("%lld: new bucket start time: %lu", mMetric.metric_id(), mCurrentBucketStartTime);
 }
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/metrics/CountMetricProducer.h b/cmds/statsd/src/metrics/CountMetricProducer.h
index 7502320..0729e2c 100644
--- a/cmds/statsd/src/metrics/CountMetricProducer.h
+++ b/cmds/statsd/src/metrics/CountMetricProducer.h
@@ -17,13 +17,11 @@
 #ifndef COUNT_METRIC_PRODUCER_H
 #define COUNT_METRIC_PRODUCER_H
 
-#include <mutex>
-#include <thread>
 #include <unordered_map>
-#include "../matchers/LogEntryMatcherManager.h"
+
 #include "CountAnomalyTracker.h"
-#include "ConditionTracker.h"
-#include "DropboxWriter.h"
+#include "../condition/ConditionTracker.h"
+#include "../matchers/matcher_util.h"
 #include "MetricProducer.h"
 #include "frameworks/base/cmds/statsd/src/stats_log.pb.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
@@ -34,14 +32,14 @@
 
 class CountMetricProducer : public MetricProducer {
 public:
-    CountMetricProducer(const CountMetric& countMetric, const sp<ConditionTracker> condition);
-
-    CountMetricProducer(const CountMetric& countMetric);
+    CountMetricProducer(const CountMetric& countMetric, const bool hasCondition);
 
     virtual ~CountMetricProducer();
 
     void onMatchedLogEvent(const LogEventWrapper& event) override;
 
+    void onConditionChanged(const bool conditionMet) override;
+
     void finish() override;
 
     void onDumpReport() override;
@@ -49,8 +47,6 @@
 private:
     const CountMetric mMetric;
 
-    const sp<ConditionTracker> mConditionTracker;
-
     const time_t mStartTime;
     // TODO: Add dimensions.
     // Counter value for the current bucket.
@@ -62,6 +58,8 @@
 
     CountAnomalyTracker mAnomalyTracker;
 
+    bool mCondition;
+
     void flushCounterIfNeeded(const time_t& newEventTime);
 };
 
diff --git a/cmds/statsd/src/metrics/MetricProducer.h b/cmds/statsd/src/metrics/MetricProducer.h
index 44a778b..7d3d661 100644
--- a/cmds/statsd/src/metrics/MetricProducer.h
+++ b/cmds/statsd/src/metrics/MetricProducer.h
@@ -18,7 +18,8 @@
 #define METRIC_PRODUCER_H
 
 #include <log/logprint.h>
-#include "../matchers/LogEntryMatcherManager.h"
+#include <utils/RefBase.h>
+#include "../matchers/matcher_util.h"
 
 namespace android {
 namespace os {
@@ -26,13 +27,15 @@
 
 // A MetricProducer is responsible for compute one single metrics, creating stats log report, and
 // writing the report to dropbox.
-class MetricProducer {
+class MetricProducer : public virtual RefBase {
 public:
     virtual ~MetricProducer(){};
 
-    // Consume the stats log if it's interesting to this metric.
+    // Consume the parsed stats log entry that already matched the "what" of the metric.
     virtual void onMatchedLogEvent(const LogEventWrapper& event) = 0;
 
+    virtual void onConditionChanged(const bool condition) = 0;
+
     // This is called when the metric collecting is done, e.g., when there is a new configuration
     // coming. MetricProducer should do the clean up, and dump existing data to dropbox.
     virtual void finish() = 0;
diff --git a/cmds/statsd/src/metrics/MetricsManager.cpp b/cmds/statsd/src/metrics/MetricsManager.cpp
index cb74206..1e65f58 100644
--- a/cmds/statsd/src/metrics/MetricsManager.cpp
+++ b/cmds/statsd/src/metrics/MetricsManager.cpp
@@ -21,13 +21,17 @@
 #include "MetricsManager.h"
 #include <cutils/log.h>
 #include <log/logprint.h>
+#include "../condition/CombinationConditionTracker.h"
+#include "../condition/SimpleConditionTracker.h"
+#include "../matchers/CombinationLogMatchingTracker.h"
+#include "../matchers/SimpleLogMatchingTracker.h"
 #include "CountMetricProducer.h"
-#include "parse_util.h"
+#include "metrics_manager_util.h"
+#include "stats_util.h"
 
 using std::make_unique;
 using std::set;
 using std::string;
-using std::unique_ptr;
 using std::unordered_map;
 using std::vector;
 
@@ -35,93 +39,90 @@
 namespace os {
 namespace statsd {
 
-MetricsManager::MetricsManager(const StatsdConfig& config) : mConfig(config), mLogMatchers() {
-    std::unordered_map<string, LogEntryMatcher> matcherMap;
-    std::unordered_map<string, sp<ConditionTracker>> conditionMap;
-
-    for (int i = 0; i < config.log_entry_matcher_size(); i++) {
-        const LogEntryMatcher& logMatcher = config.log_entry_matcher(i);
-        mMatchers.push_back(logMatcher);
-
-        matcherMap[config.log_entry_matcher(i).name()] = logMatcher;
-
-        mLogMatchers[logMatcher.name()] = vector<unique_ptr<MetricProducer>>();
-        // Collect all the tag ids that are interesting
-        set<int> tagIds = LogEntryMatcherManager::getTagIdsFromMatcher(logMatcher);
-
-        mTagIds.insert(tagIds.begin(), tagIds.end());
-    }
-
-    for (int i = 0; i < config.condition_size(); i++) {
-        const Condition& condition = config.condition(i);
-        conditionMap[condition.name()] = new ConditionTracker(condition);
-    }
-
-    // Build MetricProducers for each metric defined in config.
-    // (1) build CountMetricProducer
-    for (int i = 0; i < config.count_metric_size(); i++) {
-        const CountMetric& metric = config.count_metric(i);
-        auto it = mLogMatchers.find(metric.what());
-        if (it == mLogMatchers.end()) {
-            ALOGW("cannot find the LogEntryMatcher %s in config", metric.what().c_str());
-            continue;
-        }
-
-        if (metric.has_condition()) {
-            auto condition_it = conditionMap.find(metric.condition());
-            if (condition_it == conditionMap.end()) {
-                ALOGW("cannot find the Condition %s in the config", metric.condition().c_str());
-                continue;
-            }
-            it->second.push_back(make_unique<CountMetricProducer>(metric, condition_it->second));
-        } else {
-            it->second.push_back(make_unique<CountMetricProducer>(metric));
-        }
-    }
-
-    // TODO: build other types of metrics too.
+MetricsManager::MetricsManager(const StatsdConfig& config) {
+    mConfigValid = initStatsdConfig(config, mTagIds, mAllLogEntryMatchers, mAllConditionTrackers,
+                                    mAllMetricProducers, mConditionToMetricMap, mTrackerToMetricMap,
+                                    mTrackerToConditionMap);
 }
 
 MetricsManager::~MetricsManager() {
     VLOG("~MetricManager()");
 }
 
+bool MetricsManager::isConfigValid() const {
+    return mConfigValid;
+}
+
 void MetricsManager::finish() {
-    for (auto const& entryPair : mLogMatchers) {
-        for (auto const& metric : entryPair.second) {
-            metric->finish();
-        }
+    for (auto& metricProducer : mAllMetricProducers) {
+        metricProducer->finish();
     }
 }
 
 // Consume the stats log if it's interesting to this metric.
 void MetricsManager::onLogEvent(const log_msg& logMsg) {
+    if (!mConfigValid) {
+        return;
+    }
+
     int tagId = getTagId(logMsg);
     if (mTagIds.find(tagId) == mTagIds.end()) {
         // not interesting...
         return;
     }
-    // Since at least one of the metrics is interested in this event, we parse it now.
-    LogEventWrapper event = LogEntryMatcherManager::parseLogEvent(logMsg);
 
-    // Evaluate the conditions. Order matters, this should happen
-    // before sending the event to metrics
-    for (auto& condition : mConditionTracker) {
-        condition->evaluateCondition(event);
+    // Since at least one of the metrics is interested in this event, we parse it now.
+    LogEventWrapper event = parseLogEvent(logMsg);
+    vector<MatchingState> matcherCache(mAllLogEntryMatchers.size(), MatchingState::kNotComputed);
+
+    for (auto& matcher : mAllLogEntryMatchers) {
+        matcher->onLogEvent(event, mAllLogEntryMatchers, matcherCache);
     }
 
-    // Now find out which LogMatcher matches this event, and let relevant metrics know.
-    for (auto matcher : mMatchers) {
-        if (LogEntryMatcherManager::matches(matcher, event)) {
-            auto it = mLogMatchers.find(matcher.name());
-            if (it != mLogMatchers.end()) {
-                for (auto const& it2 : it->second) {
-                    // Only metrics that matches this event get notified.
-                    it2->onMatchedLogEvent(event);
+    // A bitmap to see which ConditionTracker needs to be re-evaluated.
+    vector<bool> conditionToBeEvaluated(mAllConditionTrackers.size(), false);
+
+    for (const auto& pair : mTrackerToConditionMap) {
+        if (matcherCache[pair.first] == MatchingState::kMatched) {
+            const auto& conditionList = pair.second;
+            for (const int conditionIndex : conditionList) {
+                conditionToBeEvaluated[conditionIndex] = true;
+            }
+        }
+    }
+
+    vector<ConditionState> conditionCache(mAllConditionTrackers.size(),
+                                          ConditionState::kNotEvaluated);
+    // A bitmap to track if a condition has changed value.
+    vector<bool> changedCache(mAllConditionTrackers.size(), false);
+    for (size_t i = 0; i < mAllConditionTrackers.size(); i++) {
+        if (conditionToBeEvaluated[i] == false) {
+            continue;
+        }
+
+        sp<ConditionTracker>& condition = mAllConditionTrackers[i];
+        condition->evaluateCondition(event, matcherCache, mAllConditionTrackers, conditionCache,
+                                     changedCache);
+        if (changedCache[i]) {
+            auto pair = mConditionToMetricMap.find(i);
+            if (pair != mConditionToMetricMap.end()) {
+                auto& metricList = pair->second;
+                for (auto metricIndex : metricList) {
+                    mAllMetricProducers[metricIndex]->onConditionChanged(conditionCache[i]);
                 }
-            } else {
-                // TODO: we should remove any redundant matchers that the config provides.
-                ALOGW("Matcher not used by any metrics.");
+            }
+        }
+    }
+
+    // For matched LogEntryMatchers, tell relevant metrics that a matched event has come.
+    for (size_t i = 0; i < mAllLogEntryMatchers.size(); i++) {
+        if (matcherCache[i] == MatchingState::kMatched) {
+            auto pair = mTrackerToMetricMap.find(i);
+            if (pair != mTrackerToMetricMap.end()) {
+                auto& metricList = pair->second;
+                for (const int metricIndex : metricList) {
+                    mAllMetricProducers[metricIndex]->onMatchedLogEvent(event);
+                }
             }
         }
     }
diff --git a/cmds/statsd/src/metrics/MetricsManager.h b/cmds/statsd/src/metrics/MetricsManager.h
index 77d7535..70c34db 100644
--- a/cmds/statsd/src/metrics/MetricsManager.h
+++ b/cmds/statsd/src/metrics/MetricsManager.h
@@ -20,8 +20,8 @@
 #include <cutils/log.h>
 #include <log/logprint.h>
 #include <unordered_map>
-#include "../matchers/LogEntryMatcherManager.h"
-#include "ConditionTracker.h"
+#include "../condition/ConditionTracker.h"
+#include "../matchers/LogMatchingTracker.h"
 #include "MetricProducer.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 
@@ -36,25 +36,58 @@
 
     ~MetricsManager();
 
-    // Consume the stats log if it's interesting to this metric.
+    // Return whether the configuration is valid.
+    bool isConfigValid() const;
+
     void onLogEvent(const log_msg& logMsg);
 
+    // Called when everything should wrap up. We are about to finish (e.g., new config comes).
     void finish();
 
 private:
-    const StatsdConfig mConfig;
-
     // All event tags that are interesting to my metrics.
     std::set<int> mTagIds;
 
-    // The matchers that my metrics share.
-    std::vector<LogEntryMatcher> mMatchers;
+    // We only store the sp of LogMatchingTracker, MetricProducer, and ConditionTracker in
+    // MetricManager. There are relationship between them, and the relationship are denoted by index
+    // instead of poiters. The reasons for this are: (1) the relationship between them are
+    // complicated, store index instead of pointers reduce the risk of A holds B's sp, and B holds
+    // A's sp. (2) When we evaluate matcher results, or condition results, we can quickly get the
+    // related results from a cache using the index.
+    // TODO: using unique_ptr may be more appriopreate?
 
-    // The conditions that my metrics share.
-    std::vector<sp<ConditionTracker>> mConditionTracker;
+    // Hold all the log entry matchers from the config.
+    std::vector<sp<LogMatchingTracker>> mAllLogEntryMatchers;
 
-    // the map from LogEntryMatcher names to the metrics that use this matcher.
-    std::unordered_map<std::string, std::vector<std::unique_ptr<MetricProducer>>> mLogMatchers;
+    // Hold all the conditions from the config.
+    std::vector<sp<ConditionTracker>> mAllConditionTrackers;
+
+    // Hold all metrics from the config.
+    std::vector<sp<MetricProducer>> mAllMetricProducers;
+
+    // To make the log processing more efficient, we want to do as much filtering as possible
+    // before we go into individual trackers and conditions to match.
+
+    // 1st filter: check if the event tag id is in mTagIds.
+    // 2nd filter: if it is, we parse the event because there is at least one member is interested.
+    //             then pass to all LogMatchingTrackers (itself also filter events by ids).
+    // 3nd filter: for LogMatchingTrackers that matched this event, we pass this event to the
+    //             ConditionTrackers and MetricProducers that use this matcher.
+    // 4th filter: for ConditionTrackers that changed value due to this event, we pass
+    //             new conditions to  metrics that use this condition.
+
+    // The following map is initialized from the statsd_config.
+
+    // maps from the index of the LogMatchingTracker to index of MetricProducer.
+    std::unordered_map<int, std::vector<int>> mTrackerToMetricMap;
+
+    // maps from LogMatchingTracker to ConditionTracker
+    std::unordered_map<int, std::vector<int>> mTrackerToConditionMap;
+
+    // maps from ConditionTracker to MetricProducer
+    std::unordered_map<int, std::vector<int>> mConditionToMetricMap;
+
+    bool mConfigValid;
 };
 
 }  // namespace statsd
diff --git a/cmds/statsd/src/metrics/metrics_manager_util.cpp b/cmds/statsd/src/metrics/metrics_manager_util.cpp
new file mode 100644
index 0000000..6fdd228
--- /dev/null
+++ b/cmds/statsd/src/metrics/metrics_manager_util.cpp
@@ -0,0 +1,200 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "../condition/CombinationConditionTracker.h"
+#include "../condition/SimpleConditionTracker.h"
+#include "../matchers/CombinationLogMatchingTracker.h"
+#include "../matchers/SimpleLogMatchingTracker.h"
+#include "CountMetricProducer.h"
+#include "stats_util.h"
+
+using std::set;
+using std::string;
+using std::unordered_map;
+using std::vector;
+
+namespace android {
+namespace os {
+namespace statsd {
+
+bool initLogTrackers(const StatsdConfig& config, unordered_map<string, int>& logTrackerMap,
+                     vector<sp<LogMatchingTracker>>& allLogEntryMatchers, set<int>& allTagIds) {
+    vector<LogEntryMatcher> matcherConfigs;
+
+    for (int i = 0; i < config.log_entry_matcher_size(); i++) {
+        const LogEntryMatcher& logMatcher = config.log_entry_matcher(i);
+
+        int index = allLogEntryMatchers.size();
+        switch (logMatcher.contents_case()) {
+            case LogEntryMatcher::ContentsCase::kSimpleLogEntryMatcher:
+                allLogEntryMatchers.push_back(new SimpleLogMatchingTracker(
+                        logMatcher.name(), index, logMatcher.simple_log_entry_matcher()));
+                break;
+            case LogEntryMatcher::ContentsCase::kCombination:
+                allLogEntryMatchers.push_back(
+                        new CombinationLogMatchingTracker(logMatcher.name(), index));
+                break;
+            default:
+                ALOGE("Matcher %s malformed", logMatcher.name().c_str());
+                return false;
+                // continue;
+        }
+        if (logTrackerMap.find(logMatcher.name()) != logTrackerMap.end()) {
+            ALOGE("Duplicate LogEntryMatcher found!");
+            return false;
+        }
+        logTrackerMap[logMatcher.name()] = index;
+        matcherConfigs.push_back(logMatcher);
+    }
+
+    vector<bool> stackTracker2(allLogEntryMatchers.size(), false);
+    for (auto& matcher : allLogEntryMatchers) {
+        if (!matcher->init(matcherConfigs, allLogEntryMatchers, logTrackerMap, stackTracker2)) {
+            return false;
+        }
+        // Collect all the tag ids that are interesting. TagIds exist in leaf nodes only.
+        const set<int>& tagIds = matcher->getTagIds();
+        allTagIds.insert(tagIds.begin(), tagIds.end());
+    }
+    return true;
+}
+
+bool initConditions(const StatsdConfig& config, const unordered_map<string, int>& logTrackerMap,
+                    unordered_map<string, int>& conditionTrackerMap,
+                    vector<sp<ConditionTracker>>& allConditionTrackers,
+                    unordered_map<int, std::vector<int>>& trackerToConditionMap) {
+    vector<Condition> conditionConfigs;
+
+    for (int i = 0; i < config.condition_size(); i++) {
+        const Condition& condition = config.condition(i);
+        int index = allConditionTrackers.size();
+        switch (condition.contents_case()) {
+            case Condition::ContentsCase::kSimpleCondition: {
+                allConditionTrackers.push_back(new SimpleConditionTracker(
+                        condition.name(), index, condition.simple_condition(), logTrackerMap));
+                break;
+            }
+            case Condition::ContentsCase::kCombination: {
+                allConditionTrackers.push_back(
+                        new CombinationConditionTracker(condition.name(), index));
+                break;
+            }
+            default:
+                ALOGE("Condition %s malformed", condition.name().c_str());
+                return false;
+        }
+        if (conditionTrackerMap.find(condition.name()) != conditionTrackerMap.end()) {
+            ALOGE("Duplicate Condition found!");
+            return false;
+        }
+        conditionTrackerMap[condition.name()] = index;
+        conditionConfigs.push_back(condition);
+    }
+
+    vector<bool> stackTracker(allConditionTrackers.size(), false);
+    for (size_t i = 0; i < allConditionTrackers.size(); i++) {
+        auto& conditionTracker = allConditionTrackers[i];
+        if (!conditionTracker->init(conditionConfigs, allConditionTrackers, conditionTrackerMap,
+                                    stackTracker)) {
+            return false;
+        }
+        for (const int trackerIndex : conditionTracker->getLogTrackerIndex()) {
+            auto& conditionList = trackerToConditionMap[trackerIndex];
+            conditionList.push_back(i);
+        }
+    }
+    return true;
+}
+
+bool initMetrics(const StatsdConfig& config, const unordered_map<string, int>& logTrackerMap,
+                 const unordered_map<string, int>& conditionTrackerMap,
+                 vector<sp<MetricProducer>>& allMetricProducers,
+                 unordered_map<int, std::vector<int>>& conditionToMetricMap,
+                 unordered_map<int, std::vector<int>>& trackerToMetricMap) {
+    // Build MetricProducers for each metric defined in config.
+    // (1) build CountMetricProducer
+    for (int i = 0; i < config.count_metric_size(); i++) {
+        const CountMetric& metric = config.count_metric(i);
+        if (!metric.has_what()) {
+            ALOGW("cannot find what in CountMetric %lld", metric.metric_id());
+            return false;
+        }
+
+        auto logTrackerIt = logTrackerMap.find(metric.what());
+        if (logTrackerIt == logTrackerMap.end()) {
+            ALOGW("cannot find the LogEntryMatcher %s in config", metric.what().c_str());
+            return false;
+        }
+
+        sp<MetricProducer> countProducer;
+        int metricIndex = allMetricProducers.size();
+        if (metric.has_condition()) {
+            auto condition_it = conditionTrackerMap.find(metric.condition());
+            if (condition_it == conditionTrackerMap.end()) {
+                ALOGW("cannot find the Condition %s in the config", metric.condition().c_str());
+                return false;
+            }
+            countProducer = new CountMetricProducer(metric, true /*has condition*/);
+            // will create new vector if not exist before.
+            auto& metricList = conditionToMetricMap[condition_it->second];
+            metricList.push_back(metricIndex);
+        } else {
+            countProducer = new CountMetricProducer(metric, false /*no condition*/);
+        }
+
+        int logTrackerIndex = logTrackerIt->second;
+        auto& metric_list = trackerToMetricMap[logTrackerIndex];
+        metric_list.push_back(metricIndex);
+        allMetricProducers.push_back(countProducer);
+    }
+
+    // TODO: build other types of metrics too.
+
+    return true;
+}
+
+bool initStatsdConfig(const StatsdConfig& config, set<int>& allTagIds,
+                      vector<sp<LogMatchingTracker>>& allLogEntryMatchers,
+                      vector<sp<ConditionTracker>>& allConditionTrackers,
+                      vector<sp<MetricProducer>>& allMetricProducers,
+                      unordered_map<int, std::vector<int>>& conditionToMetricMap,
+                      unordered_map<int, std::vector<int>>& trackerToMetricMap,
+                      unordered_map<int, std::vector<int>>& trackerToConditionMap) {
+    unordered_map<string, int> logTrackerMap;
+    unordered_map<string, int> conditionTrackerMap;
+
+    if (!initLogTrackers(config, logTrackerMap, allLogEntryMatchers, allTagIds)) {
+        ALOGE("initLogMatchingTrackers failed");
+        return false;
+    }
+
+    if (!initConditions(config, logTrackerMap, conditionTrackerMap, allConditionTrackers,
+                        trackerToConditionMap)) {
+        ALOGE("initConditionTrackers failed");
+        return false;
+    }
+
+    if (!initMetrics(config, logTrackerMap, conditionTrackerMap, allMetricProducers,
+                     conditionToMetricMap, trackerToMetricMap)) {
+        ALOGE("initMetricProducers failed");
+        return false;
+    }
+    return true;
+}
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/metrics/metrics_manager_util.h b/cmds/statsd/src/metrics/metrics_manager_util.h
new file mode 100644
index 0000000..5f1f295
--- /dev/null
+++ b/cmds/statsd/src/metrics/metrics_manager_util.h
@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef METRIC_UTIL_H
+#define METRIC_UTIL_H
+#include <memory>
+#include <set>
+#include <unordered_map>
+#include <vector>
+
+#include "../condition/ConditionTracker.h"
+#include "../matchers/LogMatchingTracker.h"
+#include "CountMetricProducer.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+// Helper functions for MetricsManager to initialize from StatsdConfig.
+// *Note*: only initStatsdConfig() should be called from outside.
+// All other functions are intermediate
+// steps, created to make unit tests easier. And most of the parameters in these
+// functions are temporary objects in the initialization phase.
+
+// Initialize the LogMatchingTrackers.
+// input:
+// [config]: the input StatsdConfig
+// output:
+// [logTrackerMap]: this map should contain matcher name to index mapping
+// [allLogEntryMatchers]: should store the sp to all the LogMatchingTracker
+// [allTagIds]: contains the set of all interesting tag ids to this config.
+bool initLogTrackers(const StatsdConfig& config,
+                     std::unordered_map<std::string, int>& logTrackerMap,
+                     std::vector<sp<LogMatchingTracker>>& allLogEntryMatchers,
+                     std::set<int>& allTagIds);
+
+// Initialize ConditionTrackers
+// input:
+// [config]: the input config
+// [logTrackerMap]: LogMatchingTracker name to index mapping from previous step.
+// output:
+// [conditionTrackerMap]: this map should contain condition name to index mapping
+// [allConditionTrackers]: stores the sp to all the ConditionTrackers
+// [trackerToConditionMap]: contain the mapping from index of
+//                        log tracker to condition trackers that use the log tracker
+bool initConditions(const StatsdConfig& config,
+                    const std::unordered_map<std::string, int>& logTrackerMap,
+                    std::unordered_map<std::string, int>& conditionTrackerMap,
+                    std::vector<sp<ConditionTracker>>& allConditionTrackers,
+                    std::unordered_map<int, std::vector<int>>& trackerToConditionMap);
+
+// Initialize MetricProducers.
+// input:
+// [config]: the input config
+// [logTrackerMap]: LogMatchingTracker name to index mapping from previous step.
+// [conditionTrackerMap]: condition name to index mapping
+// output:
+// [allMetricProducers]: contains the list of sp to the MetricProducers created.
+// [conditionToMetricMap]: contains the mapping from condition tracker index to
+//                          the list of MetricProducer index
+// [trackerToMetricMap]: contains the mapping from log tracker to MetricProducer index.
+bool initMetrics(const StatsdConfig& config,
+                 const std::unordered_map<std::string, int>& logTrackerMap,
+                 const std::unordered_map<std::string, int>& conditionTrackerMap,
+                 std::vector<sp<MetricProducer>>& allMetricProducers,
+                 std::unordered_map<int, std::vector<int>>& conditionToMetricMap,
+                 std::unordered_map<int, std::vector<int>>& trackerToMetricMap);
+
+// Initialize MetricManager from StatsdConfig.
+// Parameters are the members of MetricsManager. See MetricsManager for declaration.
+bool initStatsdConfig(const StatsdConfig& config, std::set<int>& allTagIds,
+                      std::vector<sp<LogMatchingTracker>>& allLogEntryMatchers,
+                      std::vector<sp<ConditionTracker>>& allConditionTrackers,
+                      std::vector<sp<MetricProducer>>& allMetricProducers,
+                      std::unordered_map<int, std::vector<int>>& conditionToMetricMap,
+                      std::unordered_map<int, std::vector<int>>& trackerToMetricMap,
+                      std::unordered_map<int, std::vector<int>>& trackerToConditionMap);
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
+#endif  // METRIC_UTIL_H
diff --git a/cmds/statsd/src/parse_util.cpp b/cmds/statsd/src/parse_util.cpp
deleted file mode 100644
index 61421880..0000000
--- a/cmds/statsd/src/parse_util.cpp
+++ /dev/null
@@ -1,132 +0,0 @@
-/*
- * Copyright (C) 2017 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <log/log_event_list.h>
-#include <parse_util.h>
-
-namespace android {
-namespace os {
-namespace statsd {
-
-static inline uint32_t get4LE(const char* src) {
-    return src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
-}
-
-int getTagId(log_msg msg) {
-    return get4LE(msg.msg());
-}
-
-EventMetricData parse(log_msg msg) {
-    // dump all statsd logs to dropbox for now.
-    // TODO: Add filtering, aggregation, etc.
-    EventMetricData eventMetricData;
-
-    // set tag.
-    int tag = getTagId(msg);
-    // TODO: Replace the following line when we can serialize on the fly.
-    //eventMetricData.set_tag(tag);
-
-    // set timestamp of the event.
-    eventMetricData.set_timestamp_nanos(msg.entry_v1.sec * NS_PER_SEC + msg.entry_v1.nsec);
-
-    // start iterating k,v pairs.
-    android_log_context context =
-            create_android_log_parser(const_cast<log_msg*>(&msg)->msg() + sizeof(uint32_t),
-                                      const_cast<log_msg*>(&msg)->len() - sizeof(uint32_t));
-    android_log_list_element elem;
-
-    if (context) {
-        memset(&elem, 0, sizeof(elem));
-        size_t index = 0;
-        int32_t key = -1;
-
-        do {
-            elem = android_log_read_next(context);
-            switch ((int)elem.type) {
-                case EVENT_TYPE_INT:
-                    if (index % 2 == 0) {
-                        key = elem.data.int32;
-                    } else {
-                        // TODO: Fix the following lines when we can serialize on the fly.
-                        /*
-                        int32_t val = elem.data.int32;
-                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
-                        keyValuePair->set_key(key);
-                        keyValuePair->set_value_int(val);
-                        */
-                    }
-                    index++;
-                    break;
-                case EVENT_TYPE_FLOAT:
-                    if (index % 2 == 1) {
-                        // TODO: Fix the following lines when we can serialize on the fly.
-                        /*
-                        float val = elem.data.float32;
-                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
-                        keyValuePair->set_key(key);
-                        keyValuePair->set_value_float(val);
-                        */
-                    }
-                    index++;
-                    break;
-                case EVENT_TYPE_STRING:
-                    if (index % 2 == 1) {
-                        // TODO: Fix the following lines when we can serialize on the fly.
-                        /*
-                        char* val = elem.data.string;
-                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
-                        keyValuePair->set_key(key);
-                        keyValuePair->set_value_str(val);
-                        */
-                    }
-                    index++;
-                    break;
-                case EVENT_TYPE_LONG:
-                    if (index % 2 == 1) {
-                        // TODO: Fix the following lines when we can serialize on the fly.
-                        /*
-                        int64_t val = elem.data.int64;
-                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
-                        keyValuePair->set_key(key);
-                        keyValuePair->set_value_int(val);
-                        */
-                    }
-                    index++;
-                    break;
-                case EVENT_TYPE_LIST:
-                    break;
-                case EVENT_TYPE_LIST_STOP:
-                    break;
-                case EVENT_TYPE_UNKNOWN:
-                    break;
-                default:
-                    elem.complete = true;
-                    break;
-            }
-
-            if (elem.complete) {
-                break;
-            }
-        } while ((elem.type != EVENT_TYPE_UNKNOWN) && !elem.complete);
-
-        android_log_destroy(&context);
-    }
-
-    return eventMetricData;
-}
-}  // namespace statsd
-}  // namespace os
-}  // namespace android
diff --git a/cmds/statsd/src/stats_log.proto b/cmds/statsd/src/stats_log.proto
index 2dc0cc7..6421b70 100644
--- a/cmds/statsd/src/stats_log.proto
+++ b/cmds/statsd/src/stats_log.proto
@@ -55,6 +55,43 @@
   repeated CountBucketInfo bucket_info = 2;
 }
 
+message DurationBucketInfo {
+  optional int64 start_bucket_nanos = 1;
+
+  optional int64 end_bucket_nanos = 2;
+
+  optional int64 duration_nanos = 3;
+}
+
+message DurationMetricData {
+  repeated KeyValuePair dimension = 1;
+
+  repeated DurationBucketInfo bucket_info = 2;
+}
+
+message UidMapping {
+  message AppInfo {
+    optional string app = 1;
+
+    optional int32 version = 2;
+
+    optional int32 uid = 3;
+  }
+
+  repeated AppInfo initial = 1;
+
+  message Change {
+    optional bool deletion = 1;
+
+    optional int64 timestamp = 2;
+    optional string app = 3;
+    optional int32 uid = 4;
+
+    optional int32 version = 5;
+  }
+  repeated Change changes = 2;
+}
+
 message StatsLogReport {
   optional int32 metric_id = 1;
 
@@ -68,8 +105,12 @@
   message CountMetricDataWrapper {
     repeated CountMetricData data = 1;
   }
+  message DurationMetricDataWrapper {
+    repeated CountMetricData data = 1;
+  }
   oneof data {
     EventMetricDataWrapper event_metrics = 4;
     CountMetricDataWrapper count_metrics = 5;
+    DurationMetricDataWrapper duration_metrics = 6;
   }
 }
diff --git a/cmds/statsd/src/stats_util.cpp b/cmds/statsd/src/stats_util.cpp
new file mode 100644
index 0000000..978b228
--- /dev/null
+++ b/cmds/statsd/src/stats_util.cpp
@@ -0,0 +1,289 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <log/log_event_list.h>
+#include "stats_util.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+static inline uint32_t get4LE(const char* src) {
+    return src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
+}
+
+int getTagId(log_msg msg) {
+    return get4LE(msg.msg());
+}
+
+EventMetricData parse(log_msg msg) {
+    // dump all statsd logs to dropbox for now.
+    // TODO: Add filtering, aggregation, etc.
+    EventMetricData eventMetricData;
+
+    // set tag.
+    int tag = getTagId(msg);
+    // TODO: Replace the following line when we can serialize on the fly.
+    // eventMetricData.set_tag(tag);
+
+    // set timestamp of the event.
+    eventMetricData.set_timestamp_nanos(msg.entry_v1.sec * NS_PER_SEC + msg.entry_v1.nsec);
+
+    // start iterating k,v pairs.
+    android_log_context context =
+            create_android_log_parser(const_cast<log_msg*>(&msg)->msg() + sizeof(uint32_t),
+                                      const_cast<log_msg*>(&msg)->len() - sizeof(uint32_t));
+    android_log_list_element elem;
+
+    if (context) {
+        memset(&elem, 0, sizeof(elem));
+        size_t index = 0;
+        int32_t key = -1;
+
+        do {
+            elem = android_log_read_next(context);
+            switch ((int)elem.type) {
+                case EVENT_TYPE_INT:
+                    if (index % 2 == 0) {
+                        key = elem.data.int32;
+                    } else {
+                        // TODO: Fix the following lines when we can serialize on the fly.
+                        /*
+                        int32_t val = elem.data.int32;
+                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
+                        keyValuePair->set_key(key);
+                        keyValuePair->set_value_int(val);
+                        */
+                    }
+                    index++;
+                    break;
+                case EVENT_TYPE_FLOAT:
+                    if (index % 2 == 1) {
+                        // TODO: Fix the following lines when we can serialize on the fly.
+                        /*
+                        float val = elem.data.float32;
+                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
+                        keyValuePair->set_key(key);
+                        keyValuePair->set_value_float(val);
+                        */
+                    }
+                    index++;
+                    break;
+                case EVENT_TYPE_STRING:
+                    if (index % 2 == 1) {
+                        // TODO: Fix the following lines when we can serialize on the fly.
+                        /*
+                        char* val = elem.data.string;
+                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
+                        keyValuePair->set_key(key);
+                        keyValuePair->set_value_str(val);
+                        */
+                    }
+                    index++;
+                    break;
+                case EVENT_TYPE_LONG:
+                    if (index % 2 == 1) {
+                        // TODO: Fix the following lines when we can serialize on the fly.
+                        /*
+                        int64_t val = elem.data.int64;
+                        KeyValuePair* keyValuePair = eventMetricData.add_key_value_pair();
+                        keyValuePair->set_key(key);
+                        keyValuePair->set_value_int(val);
+                        */
+                    }
+                    index++;
+                    break;
+                case EVENT_TYPE_LIST:
+                    break;
+                case EVENT_TYPE_LIST_STOP:
+                    break;
+                case EVENT_TYPE_UNKNOWN:
+                    break;
+                default:
+                    elem.complete = true;
+                    break;
+            }
+
+            if (elem.complete) {
+                break;
+            }
+        } while ((elem.type != EVENT_TYPE_UNKNOWN) && !elem.complete);
+
+        android_log_destroy(&context);
+    }
+
+    return eventMetricData;
+}
+
+StatsdConfig buildFakeConfig() {
+    // HACK: Hard code a test metric for counting screen on events...
+    StatsdConfig config;
+    config.set_config_id(12345L);
+
+    // One count metric to count screen on
+    CountMetric* metric = config.add_count_metric();
+    metric->set_metric_id(20150717L);
+    metric->set_what("SCREEN_IS_ON");
+    metric->mutable_bucket()->set_bucket_size_millis(30 * 1000L);
+
+    // One count metric to count PHOTO_CHANGE_OR_CHROME_CRASH
+    metric = config.add_count_metric();
+    metric->set_metric_id(20150718L);
+    metric->set_what("PHOTO_PROCESS_STATE_CHANGE");
+    metric->mutable_bucket()->set_bucket_size_millis(60 * 1000L);
+    metric->set_condition("SCREEN_IS_ON");
+
+
+    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_ON");
+
+    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            2 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_OFF");
+
+    simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_OFF*/);
+
+
+
+    LogEntryMatcher* procEventMatcher = config.add_log_entry_matcher();
+    procEventMatcher->set_name("PHOTO_CRASH");
+
+    SimpleLogEntryMatcher* simpleLogMatcher2 = procEventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogMatcher2->add_tag(1112 /*PROCESS_STATE_CHANGE*/);
+    KeyValueMatcher* keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                1002 /*pkg*/);
+    keyValueMatcher->set_eq_string(
+            "com.google.android.apps.photos" /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                                   1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    keyValueMatcher->set_eq_int(2);
+
+
+    procEventMatcher = config.add_log_entry_matcher();
+    procEventMatcher->set_name("PHOTO_START");
+
+    simpleLogMatcher2 = procEventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogMatcher2->add_tag(1112 /*PROCESS_STATE_CHANGE*/);
+    keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                1002 /*pkg*/);
+    keyValueMatcher->set_eq_string(
+            "com.google.android.apps.photos" /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                                   1 /*STATE*/);
+    keyValueMatcher->set_eq_int(1);
+
+
+    procEventMatcher = config.add_log_entry_matcher();
+    procEventMatcher->set_name("PHOTO_PROCESS_STATE_CHANGE");
+    LogEntryMatcher_Combination* combinationMatcher = procEventMatcher->mutable_combination();
+    combinationMatcher->set_operation(LogicalOperation::OR);
+    combinationMatcher->add_matcher("PHOTO_START");
+    combinationMatcher->add_matcher("PHOTO_CRASH");
+
+
+    procEventMatcher = config.add_log_entry_matcher();
+    procEventMatcher->set_name("CHROME_CRASH");
+
+    simpleLogMatcher2 = procEventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogMatcher2->add_tag(1112 /*PROCESS_STATE_CHANGE*/);
+    keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                1002 /*pkg*/);
+    keyValueMatcher->set_eq_string(
+            "com.android.chrome" /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    keyValueMatcher = simpleLogMatcher2->add_key_value_matcher();
+    keyValueMatcher->mutable_key_matcher()->set_key(
+                                   1 /*STATE*/);
+    keyValueMatcher->set_eq_int(2);
+
+
+
+    procEventMatcher = config.add_log_entry_matcher();
+    procEventMatcher->set_name("PHOTO_CHANGE_OR_CHROME_CRASH");
+    combinationMatcher = procEventMatcher->mutable_combination();
+    combinationMatcher->set_operation(LogicalOperation::OR);
+    combinationMatcher->add_matcher("PHOTO_PROCESS_STATE_CHANGE");
+    combinationMatcher->add_matcher("CHROME_CRASH");
+
+
+
+    Condition* condition = config.add_condition();
+    condition->set_name("SCREEN_IS_ON");
+    SimpleCondition* simpleCondition = condition->mutable_simple_condition();
+    simpleCondition->set_start("SCREEN_IS_ON");
+    simpleCondition->set_stop("SCREEN_IS_OFF");
+
+
+    condition = config.add_condition();
+        condition->set_name("PHOTO_STARTED");
+
+        simpleCondition = condition->mutable_simple_condition();
+        simpleCondition->set_start("PHOTO_START");
+        simpleCondition->set_stop("PHOTO_CRASH");
+
+
+    condition = config.add_condition();
+    condition->set_name("SCREEN_IS_OFF");
+
+    simpleCondition = condition->mutable_simple_condition();
+    simpleCondition->set_start("SCREEN_IS_OFF");
+    simpleCondition->set_stop("SCREEN_IS_ON");
+
+
+    condition = config.add_condition();
+    condition->set_name("SCREEN_IS_EITHER_ON_OFF");
+
+    Condition_Combination* combination = condition->mutable_combination();
+    combination->set_operation(LogicalOperation::OR);
+    combination->add_condition("SCREEN_IS_ON");
+    combination->add_condition("SCREEN_IS_OFF");
+
+
+    condition = config.add_condition();
+    condition->set_name("SCREEN_IS_NEITHER_ON_OFF");
+
+    combination = condition->mutable_combination();
+    combination->set_operation(LogicalOperation::NOR);
+    combination->add_condition("SCREEN_IS_ON");
+    combination->add_condition("SCREEN_IS_OFF");
+
+    return config;
+}
+
+
+}  // namespace statsd
+}  // namespace os
+}  // namespace android
diff --git a/cmds/statsd/src/parse_util.h b/cmds/statsd/src/stats_util.h
similarity index 90%
rename from cmds/statsd/src/parse_util.h
rename to cmds/statsd/src/stats_util.h
index 8b82e7b..25b9bba 100644
--- a/cmds/statsd/src/parse_util.h
+++ b/cmds/statsd/src/stats_util.h
@@ -20,6 +20,7 @@
 #include "LogReader.h"
 
 #include <log/logprint.h>
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 
 namespace android {
 namespace os {
@@ -29,6 +30,8 @@
 
 int getTagId(log_msg msg);
 
+StatsdConfig buildFakeConfig();
+
 }  // namespace statsd
 }  // namespace os
 }  // namespace android
diff --git a/cmds/statsd/src/statsd_config.proto b/cmds/statsd/src/statsd_config.proto
index 3e4ebaf..d7702cd 100644
--- a/cmds/statsd/src/statsd_config.proto
+++ b/cmds/statsd/src/statsd_config.proto
@@ -65,7 +65,8 @@
 
   message Combination {
     optional LogicalOperation operation = 1;
-    repeated LogEntryMatcher matcher = 2;
+
+    repeated string matcher = 2;
   }
   oneof contents {
     SimpleLogEntryMatcher simple_log_entry_matcher = 2;
@@ -122,6 +123,24 @@
   optional Bucket bucket = 5;
 }
 
+message DurationMetric {
+  optional int64 metric_id = 1;
+
+  enum AggregationType {
+    DURATION_SUM = 1;
+
+    DURATION_MAX_SPARSE = 2;
+    DURATION_MIN_SPARSE = 3;
+  }
+  optional AggregationType type = 2;
+
+  optional string predicate = 3;
+
+  repeated KeyMatcher dimension = 4;
+
+  optional Bucket bucket = 5;
+}
+
 message StatsdConfig {
   optional int64 config_id = 1;
 
diff --git a/cmds/statsd/tests/ConditionTracker_test.cpp b/cmds/statsd/tests/ConditionTracker_test.cpp
new file mode 100644
index 0000000..f8b0fd0
--- /dev/null
+++ b/cmds/statsd/tests/ConditionTracker_test.cpp
@@ -0,0 +1,162 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#define LOG_TAG "statsd_test"
+
+#include <gtest/gtest.h>
+#include "../src/condition/condition_util.h"
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+#include <stdio.h>
+#include <vector>
+
+using namespace android::os::statsd;
+using std::vector;
+
+
+#ifdef __ANDROID__
+TEST(ConditionTrackerTest, TestUnknownCondition) {
+    LogicalOperation operation = LogicalOperation::AND;
+
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+    children.push_back(2);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kUnknown);
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kTrue);
+
+    EXPECT_EQ(evaluateCombinationCondition(children, operation, conditionResults),
+            ConditionState::kUnknown);
+}
+TEST(ConditionTrackerTest, TestAndCondition) {
+    // Set up the matcher
+    LogicalOperation operation = LogicalOperation::AND;
+
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+    children.push_back(2);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kTrue);
+
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kTrue);
+
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+}
+
+TEST(ConditionTrackerTest, TestOrCondition) {
+    // Set up the matcher
+    LogicalOperation operation = LogicalOperation::OR;
+
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+    children.push_back(2);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kTrue);
+
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kFalse);
+
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+}
+
+TEST(ConditionTrackerTest, TestNotCondition) {
+    // Set up the matcher
+    LogicalOperation operation = LogicalOperation::NOT;
+
+    vector<int> children;
+    children.push_back(0);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kTrue);
+
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kFalse);
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+}
+
+TEST(ConditionTrackerTest, TestNandCondition) {
+    // Set up the matcher
+    LogicalOperation operation = LogicalOperation::NAND;
+
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kFalse);
+
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kFalse);
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kTrue);
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+}
+
+TEST(ConditionTrackerTest, TestNorCondition) {
+    // Set up the matcher
+    LogicalOperation operation = LogicalOperation::NOR;
+
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+
+    vector<ConditionState> conditionResults;
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kFalse);
+
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kFalse);
+    conditionResults.push_back(ConditionState::kFalse);
+    EXPECT_TRUE(evaluateCombinationCondition(children, operation, conditionResults));
+
+    conditionResults.clear();
+    conditionResults.push_back(ConditionState::kTrue);
+    conditionResults.push_back(ConditionState::kTrue);
+    EXPECT_FALSE(evaluateCombinationCondition(children, operation, conditionResults));
+}
+
+#else
+GTEST_LOG_(INFO) << "This test does nothing.\n";
+#endif
diff --git a/cmds/statsd/tests/LogEntryMatcher_test.cpp b/cmds/statsd/tests/LogEntryMatcher_test.cpp
index 473704a..6069801 100644
--- a/cmds/statsd/tests/LogEntryMatcher_test.cpp
+++ b/cmds/statsd/tests/LogEntryMatcher_test.cpp
@@ -18,14 +18,15 @@
 #include <log/log_event_list.h>
 #include <log/log_read.h>
 #include <log/logprint.h>
-#include "../src/matchers/LogEntryMatcherManager.h"
-#include "../src/parse_util.h"
+#include "../src/matchers/matcher_util.h"
+#include "../src/stats_util.h"
 #include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
 
 #include <stdio.h>
 
 using namespace android::os::statsd;
 using std::unordered_map;
+using std::vector;
 
 const int kTagIdWakelock = 123;
 const int kKeyIdState = 45;
@@ -41,7 +42,7 @@
     LogEventWrapper wrapper;
     wrapper.tagId = kTagIdWakelock;
 
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 TEST(LogEntryMatcherTest, TestBoolMatcher) {
@@ -57,13 +58,13 @@
 
     keyValue->set_eq_bool(true);
     wrapper.boolMap[kKeyIdState] = true;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 
     keyValue->set_eq_bool(false);
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
 
-    wrapper.boolMap[kTagIdWakelock] = false;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    wrapper.boolMap[kKeyIdState] = false;
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 TEST(LogEntryMatcherTest, TestStringMatcher) {
@@ -80,7 +81,7 @@
 
     wrapper.strMap[kKeyIdState] = "wakelock_name";
 
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 TEST(LogEntryMatcherTest, TestIntComparisonMatcher) {
@@ -96,19 +97,19 @@
 
     keyValue->set_lt_int(10);
     wrapper.intMap[kKeyIdState] = 11;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 10;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 9;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 
     keyValue->set_gt_int(10);
     wrapper.intMap[kKeyIdState] = 11;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 10;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 9;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 TEST(LogEntryMatcherTest, TestIntWithEqualityComparisonMatcher) {
@@ -124,19 +125,19 @@
 
     keyValue->set_lte_int(10);
     wrapper.intMap[kKeyIdState] = 11;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 10;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 9;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 
     keyValue->set_gte_int(10);
     wrapper.intMap[kKeyIdState] = 11;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 10;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.intMap[kKeyIdState] = 9;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 TEST(LogEntryMatcherTest, TestFloatComparisonMatcher) {
@@ -152,15 +153,15 @@
 
     keyValue->set_lt_float(10.0);
     wrapper.floatMap[kKeyIdState] = 10.1;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.floatMap[kKeyIdState] = 9.9;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
 
     keyValue->set_gt_float(10.0);
     wrapper.floatMap[kKeyIdState] = 10.1;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(matchesSimple(*simpleMatcher, wrapper));
     wrapper.floatMap[kKeyIdState] = 9.9;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(matchesSimple(*simpleMatcher, wrapper));
 }
 
 // Helper for the composite matchers.
@@ -173,141 +174,117 @@
 
 TEST(LogEntryMatcherTest, TestAndMatcher) {
     // Set up the matcher
-    LogEntryMatcher matcher;
-    auto combination = matcher.mutable_combination();
-    combination->set_operation(LogicalOperation::AND);
+    LogicalOperation operation = LogicalOperation::AND;
 
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-                     kTagIdWakelock, kKeyIdState, 3);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-                     kTagIdWakelock, kKeyIdPackageVersion, 4);
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+    children.push_back(2);
 
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
+    vector<MatchingState> matcherResults;
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kMatched);
 
-    wrapper.intMap[1003] = 4;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap.clear();
-    wrapper.intMap[1] = 3;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap.clear();
-    wrapper.intMap[1] = 3;
-    wrapper.intMap[1003] = 4;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
+
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kMatched);
+
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
 }
 
 TEST(LogEntryMatcherTest, TestOrMatcher) {
     // Set up the matcher
-    LogEntryMatcher matcher;
-    auto combination = matcher.mutable_combination();
-    combination->set_operation(LogicalOperation::OR);
+    LogicalOperation operation = LogicalOperation::OR;
 
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdState, 3);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdPackageVersion, 4);
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
+    children.push_back(2);
 
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
+    vector<MatchingState> matcherResults;
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kMatched);
 
-    // Don't set any key-value pairs.
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[1003] = 4;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap.clear();
-    wrapper.intMap[1] = 3;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap.clear();
-    wrapper.intMap[1] = 3;
-    wrapper.intMap[1003] = 4;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
+
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
 }
 
 TEST(LogEntryMatcherTest, TestNotMatcher) {
     // Set up the matcher
-    LogEntryMatcher matcher;
-    auto combination = matcher.mutable_combination();
-    combination->set_operation(LogicalOperation::NOT);
+    LogicalOperation operation = LogicalOperation::NOT;
 
-    // Define first simpleMatcher
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdState, 3);
+    vector<int> children;
+    children.push_back(0);
 
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
+    vector<MatchingState> matcherResults;
+    matcherResults.push_back(MatchingState::kMatched);
 
-    // Don't set any key-value pairs.
-    wrapper.intMap[kKeyIdState] = 3;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
+
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kNotMatched);
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
 }
 
-TEST(LogEntryMatcherTest, TestNANDMatcher) {
+TEST(LogEntryMatcherTest, TestNandMatcher) {
     // Set up the matcher
-    LogEntryMatcher matcher;
-    auto combination = matcher.mutable_combination();
-    combination->set_operation(LogicalOperation::NAND);
+    LogicalOperation operation = LogicalOperation::NAND;
 
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdState, 3);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdPackageVersion, 4);
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
 
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
+    vector<MatchingState> matcherResults;
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
 
-    // Don't set any key-value pairs.
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdState] = 3;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdPackageVersion] = 4;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
+
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
+
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kMatched);
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
 }
 
-TEST(LogEntryMatcherTest, TestNORMatcher) {
+TEST(LogEntryMatcherTest, TestNorMatcher) {
     // Set up the matcher
-    LogEntryMatcher matcher;
-    auto combination = matcher.mutable_combination();
-    combination->set_operation(LogicalOperation::NOR);
+    LogicalOperation operation = LogicalOperation::NOR;
 
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdState, 3);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdPackageVersion, 4);
+    vector<int> children;
+    children.push_back(0);
+    children.push_back(1);
 
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
+    vector<MatchingState> matcherResults;
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
 
-    // Don't set any key-value pairs.
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdState] = 3;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdPackageVersion] = 4;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
-}
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
 
-// Tests that a NOT on top of AND is the same as NAND
-TEST(LogEntryMatcherTest, TestMultipleLayerMatcher) {
-    LogEntryMatcher matcher;
-    auto not_combination = matcher.mutable_combination();
-    not_combination->set_operation(LogicalOperation::NOT);
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kNotMatched);
+    matcherResults.push_back(MatchingState::kNotMatched);
+    EXPECT_TRUE(combinationMatch(children, operation, matcherResults));
 
-    // Now add the AND
-    auto combination = not_combination->add_matcher()->mutable_combination();
-    combination->set_operation(LogicalOperation::AND);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdState, 3);
-    addSimpleMatcher(combination->add_matcher()->mutable_simple_log_entry_matcher(),
-        kTagIdWakelock, kKeyIdPackageVersion, 4);
-
-    LogEventWrapper wrapper;
-    wrapper.tagId = kTagIdWakelock;
-
-    // Don't set any key-value pairs.
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdState] = 3;
-    EXPECT_TRUE(LogEntryMatcherManager::matches(matcher, wrapper));
-    wrapper.intMap[kKeyIdPackageVersion] = 4;
-    EXPECT_FALSE(LogEntryMatcherManager::matches(matcher, wrapper));
+    matcherResults.clear();
+    matcherResults.push_back(MatchingState::kMatched);
+    matcherResults.push_back(MatchingState::kMatched);
+    EXPECT_FALSE(combinationMatch(children, operation, matcherResults));
 }
 
 #else
diff --git a/cmds/statsd/tests/MetricsManager_test.cpp b/cmds/statsd/tests/MetricsManager_test.cpp
new file mode 100644
index 0000000..673c156
--- /dev/null
+++ b/cmds/statsd/tests/MetricsManager_test.cpp
@@ -0,0 +1,231 @@
+// Copyright (C) 2017 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#define LOG_TAG "statsd_test"
+
+#include <gtest/gtest.h>
+#include "../src/condition/ConditionTracker.h"
+#include "../src/matchers/LogMatchingTracker.h"
+#include "../src/metrics/CountMetricProducer.h"
+#include "../src/metrics/MetricProducer.h"
+#include "../src/metrics/metrics_manager_util.h"
+
+#include "frameworks/base/cmds/statsd/src/statsd_config.pb.h"
+
+#include <stdio.h>
+#include <set>
+#include <unordered_map>
+#include <vector>
+
+using namespace android::os::statsd;
+using android::sp;
+using std::set;
+using std::unordered_map;
+using std::vector;
+
+#ifdef __ANDROID__
+
+// TODO: ADD MORE TEST CASES.
+
+StatsdConfig buildGoodConfig() {
+    StatsdConfig config;
+    config.set_config_id(12345L);
+
+    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_ON");
+
+    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            2 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_OFF");
+
+    simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_OFF*/);
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_ON_OR_OFF");
+
+    LogEntryMatcher_Combination* combination = eventMatcher->mutable_combination();
+    combination->set_operation(LogicalOperation::OR);
+    combination->add_matcher("SCREEN_IS_ON");
+    combination->add_matcher("SCREEN_IS_OFF");
+
+    return config;
+}
+
+StatsdConfig buildCircleMatchers() {
+    StatsdConfig config;
+    config.set_config_id(12345L);
+
+    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_ON");
+
+    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            2 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_ON_OR_OFF");
+
+    LogEntryMatcher_Combination* combination = eventMatcher->mutable_combination();
+    combination->set_operation(LogicalOperation::OR);
+    combination->add_matcher("SCREEN_IS_ON");
+    // Circle dependency
+    combination->add_matcher("SCREEN_ON_OR_OFF");
+
+    return config;
+}
+
+StatsdConfig buildMissingMatchers() {
+    StatsdConfig config;
+    config.set_config_id(12345L);
+
+    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_ON");
+
+    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            2 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_ON_OR_OFF");
+
+    LogEntryMatcher_Combination* combination = eventMatcher->mutable_combination();
+    combination->set_operation(LogicalOperation::OR);
+    combination->add_matcher("SCREEN_IS_ON");
+    // undefined matcher
+    combination->add_matcher("ABC");
+
+    return config;
+}
+
+StatsdConfig buildCircleConditions() {
+    StatsdConfig config;
+    config.set_config_id(12345L);
+
+    LogEntryMatcher* eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_ON");
+
+    SimpleLogEntryMatcher* simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            2 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_ON*/);
+
+    eventMatcher = config.add_log_entry_matcher();
+    eventMatcher->set_name("SCREEN_IS_OFF");
+
+    simpleLogEntryMatcher = eventMatcher->mutable_simple_log_entry_matcher();
+    simpleLogEntryMatcher->add_tag(2 /*SCREEN_STATE_CHANGE*/);
+    simpleLogEntryMatcher->add_key_value_matcher()->mutable_key_matcher()->set_key(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE*/);
+    simpleLogEntryMatcher->mutable_key_value_matcher(0)->set_eq_int(
+            1 /*SCREEN_STATE_CHANGE__DISPLAY_STATE__STATE_OFF*/);
+
+    Condition* condition = config.add_condition();
+    condition->set_name("SCREEN_IS_ON");
+    SimpleCondition* simpleCondition = condition->mutable_simple_condition();
+    simpleCondition->set_start("SCREEN_IS_ON");
+    simpleCondition->set_stop("SCREEN_IS_OFF");
+
+    condition = config.add_condition();
+    condition->set_name("SCREEN_IS_EITHER_ON_OFF");
+
+    Condition_Combination* combination = condition->mutable_combination();
+    combination->set_operation(LogicalOperation::OR);
+    combination->add_condition("SCREEN_IS_ON");
+    combination->add_condition("SCREEN_IS_EITHER_ON_OFF");
+
+    return config;
+}
+
+TEST(MetricsManagerTest, TestGoodConfig) {
+    StatsdConfig config = buildGoodConfig();
+    set<int> allTagIds;
+    vector<sp<LogMatchingTracker>> allLogEntryMatchers;
+    vector<sp<ConditionTracker>> allConditionTrackers;
+    vector<sp<MetricProducer>> allMetricProducers;
+    unordered_map<int, std::vector<int>> conditionToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToConditionMap;
+
+    EXPECT_TRUE(initStatsdConfig(config, allTagIds, allLogEntryMatchers, allConditionTrackers,
+                                 allMetricProducers, conditionToMetricMap, trackerToMetricMap,
+                                 trackerToConditionMap));
+}
+
+TEST(MetricsManagerTest, TestCircleLogMatcherDependency) {
+    StatsdConfig config = buildCircleMatchers();
+    set<int> allTagIds;
+    vector<sp<LogMatchingTracker>> allLogEntryMatchers;
+    vector<sp<ConditionTracker>> allConditionTrackers;
+    vector<sp<MetricProducer>> allMetricProducers;
+    unordered_map<int, std::vector<int>> conditionToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToConditionMap;
+
+    EXPECT_FALSE(initStatsdConfig(config, allTagIds, allLogEntryMatchers, allConditionTrackers,
+                                  allMetricProducers, conditionToMetricMap, trackerToMetricMap,
+                                  trackerToConditionMap));
+}
+
+TEST(MetricsManagerTest, TestMissingMatchers) {
+    StatsdConfig config = buildMissingMatchers();
+    set<int> allTagIds;
+    vector<sp<LogMatchingTracker>> allLogEntryMatchers;
+    vector<sp<ConditionTracker>> allConditionTrackers;
+    vector<sp<MetricProducer>> allMetricProducers;
+    unordered_map<int, std::vector<int>> conditionToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToConditionMap;
+
+    EXPECT_FALSE(initStatsdConfig(config, allTagIds, allLogEntryMatchers, allConditionTrackers,
+                                  allMetricProducers, conditionToMetricMap, trackerToMetricMap,
+                                  trackerToConditionMap));
+}
+
+TEST(MetricsManagerTest, TestCircleConditionDependency) {
+    StatsdConfig config = buildCircleConditions();
+    set<int> allTagIds;
+    vector<sp<LogMatchingTracker>> allLogEntryMatchers;
+    vector<sp<ConditionTracker>> allConditionTrackers;
+    vector<sp<MetricProducer>> allMetricProducers;
+    unordered_map<int, std::vector<int>> conditionToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToMetricMap;
+    unordered_map<int, std::vector<int>> trackerToConditionMap;
+
+    EXPECT_FALSE(initStatsdConfig(config, allTagIds, allLogEntryMatchers, allConditionTrackers,
+                                  allMetricProducers, conditionToMetricMap, trackerToMetricMap,
+                                  trackerToConditionMap));
+}
+
+#else
+GTEST_LOG_(INFO) << "This test does nothing.\n";
+#endif