Update ValueMetric to use NO_DATA

Bug: 157155330
Test: atest statsd_test
Change-Id: I9b5655a2a7e81cca150ffe91662ef51e64f66cdf
diff --git a/cmds/statsd/src/metrics/ValueMetricProducer.cpp b/cmds/statsd/src/metrics/ValueMetricProducer.cpp
index f03ce45..c33d1ac 100644
--- a/cmds/statsd/src/metrics/ValueMetricProducer.cpp
+++ b/cmds/statsd/src/metrics/ValueMetricProducer.cpp
@@ -108,7 +108,7 @@
       mSkipZeroDiffOutput(metric.skip_zero_diff_output()),
       mUseZeroDefaultBase(metric.use_zero_default_base()),
       mHasGlobalBase(false),
-      mCurrentBucketIsInvalid(false),
+      mCurrentBucketIsSkipped(false),
       mMaxPullDelayNs(metric.max_pull_delay_sec() > 0 ? metric.max_pull_delay_sec() * NS_PER_SEC
                                                       : StatsdStats::kPullMaxDelayNs),
       mSplitBucketForAppUpgrade(metric.split_bucket_for_app_upgrade()),
@@ -383,15 +383,12 @@
 
 void ValueMetricProducer::invalidateCurrentBucketWithoutResetBase(const int64_t dropTimeNs,
                                                                   const BucketDropReason reason) {
-    if (!mCurrentBucketIsInvalid) {
+    if (!mCurrentBucketIsSkipped) {
         // Only report to StatsdStats once per invalid bucket.
         StatsdStats::getInstance().noteInvalidatedBucket(mMetricId);
     }
 
-    if (!maxDropEventsReached()) {
-        mCurrentSkippedBucket.dropEvents.emplace_back(buildDropEvent(dropTimeNs, reason));
-    }
-    mCurrentBucketIsInvalid = true;
+    skipCurrentBucket(dropTimeNs, reason);
 }
 
 void ValueMetricProducer::invalidateCurrentBucket(const int64_t dropTimeNs,
@@ -400,6 +397,14 @@
     resetBase();
 }
 
+void ValueMetricProducer::skipCurrentBucket(const int64_t dropTimeNs,
+                                            const BucketDropReason reason) {
+    if (!maxDropEventsReached()) {
+        mCurrentSkippedBucket.dropEvents.emplace_back(buildDropEvent(dropTimeNs, reason));
+    }
+    mCurrentBucketIsSkipped = true;
+}
+
 void ValueMetricProducer::resetBase() {
     for (auto& slice : mCurrentBaseInfo) {
         for (auto& baseInfo : slice.second) {
@@ -961,12 +966,10 @@
     int64_t conditionTrueDuration = mConditionTimer.newBucketStart(bucketEndTime);
     bool isBucketLargeEnough = bucketEndTime - mCurrentBucketStartTimeNs >= mMinBucketSizeNs;
     if (!isBucketLargeEnough) {
-        if (!maxDropEventsReached()) {
-            mCurrentSkippedBucket.dropEvents.emplace_back(
-                    buildDropEvent(eventTimeNs, BucketDropReason::BUCKET_TOO_SMALL));
-        }
+        skipCurrentBucket(eventTimeNs, BucketDropReason::BUCKET_TOO_SMALL);
     }
-    if (isBucketLargeEnough && !mCurrentBucketIsInvalid) {
+    bool bucketHasData = false;
+    if (!mCurrentBucketIsSkipped) {
         // The current bucket is large enough to keep.
         for (const auto& slice : mCurrentSlicedBucket) {
             ValueBucket bucket = buildPartialBucket(bucketEndTime, slice.second);
@@ -975,9 +978,16 @@
             if (bucket.valueIndex.size() > 0) {
                 auto& bucketList = mPastBuckets[slice.first];
                 bucketList.push_back(bucket);
+                bucketHasData = true;
             }
         }
-    } else {
+    }
+
+    if (!bucketHasData && !mCurrentBucketIsSkipped) {
+        skipCurrentBucket(eventTimeNs, BucketDropReason::NO_DATA);
+    }
+
+    if (mCurrentBucketIsSkipped) {
         mCurrentSkippedBucket.bucketStartTimeNs = mCurrentBucketStartTimeNs;
         mCurrentSkippedBucket.bucketEndTimeNs = bucketEndTime;
         mSkippedBuckets.emplace_back(mCurrentSkippedBucket);
@@ -1036,13 +1046,13 @@
         // TODO: remove mCurrentBaseInfo entries when obsolete
     }
 
-    mCurrentBucketIsInvalid = false;
+    mCurrentBucketIsSkipped = false;
     mCurrentSkippedBucket.reset();
 
     // If we do not have a global base when the condition is true,
     // we will have incomplete bucket for the next bucket.
     if (mUseDiff && !mHasGlobalBase && mCondition) {
-        mCurrentBucketIsInvalid = false;
+        mCurrentBucketIsSkipped = false;
     }
     mCurrentBucketStartTimeNs = nextBucketStartTimeNs;
     VLOG("metric %lld: new bucket start time: %lld", (long long)mMetricId,
@@ -1051,7 +1061,7 @@
 
 void ValueMetricProducer::appendToFullBucket(int64_t eventTimeNs, int64_t fullBucketEndTimeNs) {
     bool isFullBucketReached = eventTimeNs > fullBucketEndTimeNs;
-    if (mCurrentBucketIsInvalid) {
+    if (mCurrentBucketIsSkipped) {
         if (isFullBucketReached) {
             // If the bucket is invalid, we ignore the full bucket since it contains invalid data.
             mCurrentFullBucket.clear();
diff --git a/cmds/statsd/src/metrics/ValueMetricProducer.h b/cmds/statsd/src/metrics/ValueMetricProducer.h
index 751fef2..bb4a661 100644
--- a/cmds/statsd/src/metrics/ValueMetricProducer.h
+++ b/cmds/statsd/src/metrics/ValueMetricProducer.h
@@ -144,6 +144,10 @@
     void invalidateCurrentBucket(const int64_t dropTimeNs, const BucketDropReason reason);
     void invalidateCurrentBucketWithoutResetBase(const int64_t dropTimeNs,
                                                  const BucketDropReason reason);
+    // Skips the current bucket without notifying StatsdStats of the skipped bucket.
+    // This should only be called from #flushCurrentBucketLocked. Otherwise, a future event that
+    // causes the bucket to be invalidated will not notify StatsdStats.
+    void skipCurrentBucket(const int64_t dropTimeNs, const BucketDropReason reason);
 
     const int mWhatMatcherIndex;
 
@@ -250,11 +254,9 @@
     // diff against.
     bool mHasGlobalBase;
 
-    // Invalid bucket. There was a problem in collecting data in the current bucket so we cannot
-    // trust any of the data in this bucket.
-    //
-    // For instance, one pull failed.
-    bool mCurrentBucketIsInvalid;
+    // This is to track whether or not the bucket is skipped for any of the reasons listed in
+    // BucketDropReason, many of which make the bucket potentially invalid.
+    bool mCurrentBucketIsSkipped;
 
     const int64_t mMaxPullDelayNs;
 
diff --git a/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp b/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
index 474aa22..7a9eaa9 100644
--- a/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
+++ b/cmds/statsd/tests/metrics/ValueMetricProducer_test.cpp
@@ -1115,13 +1115,21 @@
     EXPECT_EQ(false, curInterval.hasValue);
     assertPastBucketValuesSingleKey(valueProducer->mPastBuckets, {12}, {bucketSizeNs},
                                     {bucket2StartTimeNs}, {bucket3StartTimeNs});
+    // The 1st bucket is dropped because of no data
     // The 3rd bucket is dropped due to multiple buckets being skipped.
-    ASSERT_EQ(1, valueProducer->mSkippedBuckets.size());
-    EXPECT_EQ(bucket3StartTimeNs, valueProducer->mSkippedBuckets[0].bucketStartTimeNs);
-    EXPECT_EQ(bucket4StartTimeNs, valueProducer->mSkippedBuckets[0].bucketEndTimeNs);
+    ASSERT_EQ(2, valueProducer->mSkippedBuckets.size());
+
+    EXPECT_EQ(bucketStartTimeNs, valueProducer->mSkippedBuckets[0].bucketStartTimeNs);
+    EXPECT_EQ(bucket2StartTimeNs, valueProducer->mSkippedBuckets[0].bucketEndTimeNs);
     ASSERT_EQ(1, valueProducer->mSkippedBuckets[0].dropEvents.size());
-    EXPECT_EQ(MULTIPLE_BUCKETS_SKIPPED, valueProducer->mSkippedBuckets[0].dropEvents[0].reason);
-    EXPECT_EQ(bucket6StartTimeNs, valueProducer->mSkippedBuckets[0].dropEvents[0].dropTimeNs);
+    EXPECT_EQ(NO_DATA, valueProducer->mSkippedBuckets[0].dropEvents[0].reason);
+    EXPECT_EQ(bucket2StartTimeNs, valueProducer->mSkippedBuckets[0].dropEvents[0].dropTimeNs);
+
+    EXPECT_EQ(bucket3StartTimeNs, valueProducer->mSkippedBuckets[1].bucketStartTimeNs);
+    EXPECT_EQ(bucket4StartTimeNs, valueProducer->mSkippedBuckets[1].bucketEndTimeNs);
+    ASSERT_EQ(1, valueProducer->mSkippedBuckets[1].dropEvents.size());
+    EXPECT_EQ(MULTIPLE_BUCKETS_SKIPPED, valueProducer->mSkippedBuckets[1].dropEvents[0].reason);
+    EXPECT_EQ(bucket6StartTimeNs, valueProducer->mSkippedBuckets[1].dropEvents[0].dropTimeNs);
 }
 
 /*
@@ -2214,7 +2222,7 @@
     valueProducer->mCondition = ConditionState::kFalse;
 
     valueProducer->onConditionChanged(true, bucketStartTimeNs + 2);
-    EXPECT_EQ(true, valueProducer->mCurrentBucketIsInvalid);
+    EXPECT_EQ(true, valueProducer->mCurrentBucketIsSkipped);
     ASSERT_EQ(0UL, valueProducer->mCurrentSlicedBucket.size());
     ASSERT_EQ(0UL, valueProducer->mSkippedBuckets.size());
 
@@ -3464,16 +3472,18 @@
     // Condition change event that skips forward by three buckets.
     valueProducer->onConditionChanged(false, bucket4StartTimeNs + 10);
 
+    int64_t dumpTimeNs = bucket4StartTimeNs + 1000;
+
     // Check dump report.
     ProtoOutputStream output;
     std::set<string> strSet;
-    valueProducer->onDumpReport(bucket4StartTimeNs + 1000, true /* include recent buckets */, true,
+    valueProducer->onDumpReport(dumpTimeNs, true /* include current buckets */, true,
                                 NO_TIME_CONSTRAINTS /* dumpLatency */, &strSet, &output);
 
     StatsLogReport report = outputStreamToProto(&output);
     EXPECT_TRUE(report.has_value_metrics());
     ASSERT_EQ(0, report.value_metrics().data_size());
-    ASSERT_EQ(1, report.value_metrics().skipped_size());
+    ASSERT_EQ(2, report.value_metrics().skipped_size());
 
     EXPECT_EQ(NanoToMillis(bucketStartTimeNs),
               report.value_metrics().skipped(0).start_bucket_elapsed_millis());
@@ -3484,6 +3494,19 @@
     auto dropEvent = report.value_metrics().skipped(0).drop_event(0);
     EXPECT_EQ(BucketDropReason::MULTIPLE_BUCKETS_SKIPPED, dropEvent.drop_reason());
     EXPECT_EQ(NanoToMillis(bucket4StartTimeNs + 10), dropEvent.drop_time_millis());
+
+    // This bucket is skipped because a dumpReport with include current buckets is called.
+    // This creates a new bucket from bucket4StartTimeNs to dumpTimeNs in which we have no data
+    // since the condition is false for the entire bucket interval.
+    EXPECT_EQ(NanoToMillis(bucket4StartTimeNs),
+              report.value_metrics().skipped(1).start_bucket_elapsed_millis());
+    EXPECT_EQ(NanoToMillis(dumpTimeNs),
+              report.value_metrics().skipped(1).end_bucket_elapsed_millis());
+    ASSERT_EQ(1, report.value_metrics().skipped(1).drop_event_size());
+
+    dropEvent = report.value_metrics().skipped(1).drop_event(0);
+    EXPECT_EQ(BucketDropReason::NO_DATA, dropEvent.drop_reason());
+    EXPECT_EQ(NanoToMillis(dumpTimeNs), dropEvent.drop_time_millis());
 }
 
 /*
@@ -3544,6 +3567,41 @@
 }
 
 /*
+ * Test that NO_DATA dump reason is logged when a flushed bucket contains no data.
+ */
+TEST(ValueMetricProducerTest_BucketDrop, TestBucketDropWhenDataUnavailable) {
+    ValueMetric metric = ValueMetricProducerTestHelper::createMetricWithCondition();
+
+    sp<MockStatsPullerManager> pullerManager = new StrictMock<MockStatsPullerManager>();
+
+    sp<ValueMetricProducer> valueProducer =
+            ValueMetricProducerTestHelper::createValueProducerWithCondition(pullerManager, metric);
+
+    // Check dump report.
+    ProtoOutputStream output;
+    std::set<string> strSet;
+    int64_t dumpReportTimeNs = bucketStartTimeNs + 10000000000; // 10 seconds
+    valueProducer->onDumpReport(dumpReportTimeNs, true /* include current bucket */, true,
+                                NO_TIME_CONSTRAINTS /* dumpLatency */, &strSet, &output);
+
+    StatsLogReport report = outputStreamToProto(&output);
+    EXPECT_TRUE(report.has_value_metrics());
+    ASSERT_EQ(0, report.value_metrics().data_size());
+    ASSERT_EQ(1, report.value_metrics().skipped_size());
+
+    EXPECT_EQ(NanoToMillis(bucketStartTimeNs),
+              report.value_metrics().skipped(0).start_bucket_elapsed_millis());
+    EXPECT_EQ(NanoToMillis(dumpReportTimeNs),
+              report.value_metrics().skipped(0).end_bucket_elapsed_millis());
+    ASSERT_EQ(1, report.value_metrics().skipped(0).drop_event_size());
+
+    auto dropEvent = report.value_metrics().skipped(0).drop_event(0);
+    EXPECT_EQ(BucketDropReason::NO_DATA, dropEvent.drop_reason());
+    EXPECT_EQ(NanoToMillis(dumpReportTimeNs), dropEvent.drop_time_millis());
+}
+
+
+/*
  * Test multiple bucket drop events in the same bucket.
  */
 TEST(ValueMetricProducerTest_BucketDrop, TestMultipleBucketDropEvents) {