Move LayerHistoryV2 to LayerHistory

The old class LayerHistory (content detection v1) no longer exists
so LayerHisotryV2 can take its place.

Bug: 174120566
Test: presubmit
Change-Id: I84f33255b04ab082bbc5ae6e3ae4d7a793bfcd14
diff --git a/services/surfaceflinger/Scheduler/LayerInfo.h b/services/surfaceflinger/Scheduler/LayerInfo.h
new file mode 100644
index 0000000..e434670
--- /dev/null
+++ b/services/surfaceflinger/Scheduler/LayerInfo.h
@@ -0,0 +1,223 @@
+/*
+ * Copyright 2020 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.
+ */
+
+#pragma once
+
+#include <utils/Timers.h>
+
+#include <chrono>
+#include <deque>
+
+#include "LayerHistory.h"
+#include "RefreshRateConfigs.h"
+#include "Scheduler/Seamlessness.h"
+#include "SchedulerUtils.h"
+
+namespace android {
+
+class Layer;
+
+namespace scheduler {
+
+using namespace std::chrono_literals;
+
+// Maximum period between presents for a layer to be considered active.
+constexpr std::chrono::nanoseconds MAX_ACTIVE_LAYER_PERIOD_NS = 1200ms;
+
+// Earliest present time for a layer to be considered active.
+constexpr nsecs_t getActiveLayerThreshold(nsecs_t now) {
+    return now - MAX_ACTIVE_LAYER_PERIOD_NS.count();
+}
+
+// Stores history of present times and refresh rates for a layer.
+class LayerInfo {
+    using LayerUpdateType = LayerHistory::LayerUpdateType;
+
+    // Layer is considered frequent if the earliest value in the window of most recent present times
+    // is within a threshold. If a layer is infrequent, its average refresh rate is disregarded in
+    // favor of a low refresh rate.
+    static constexpr size_t FREQUENT_LAYER_WINDOW_SIZE = 3;
+    static constexpr float MIN_FPS_FOR_FREQUENT_LAYER = 10.0f;
+    static constexpr auto MAX_FREQUENT_LAYER_PERIOD_NS =
+            std::chrono::nanoseconds(static_cast<nsecs_t>(1e9f / MIN_FPS_FOR_FREQUENT_LAYER)) + 1ms;
+
+    friend class LayerHistoryTest;
+
+public:
+    // Holds information about the layer vote
+    struct LayerVote {
+        LayerHistory::LayerVoteType type = LayerHistory::LayerVoteType::Heuristic;
+        float fps = 0.0f;
+        Seamlessness seamlessness = Seamlessness::Default;
+    };
+
+    static void setTraceEnabled(bool enabled) { sTraceEnabled = enabled; }
+
+    static void setRefreshRateConfigs(const RefreshRateConfigs& refreshRateConfigs) {
+        sRefreshRateConfigs = &refreshRateConfigs;
+    }
+
+    LayerInfo(const std::string& name, nsecs_t highRefreshRatePeriod,
+              LayerHistory::LayerVoteType defaultVote);
+
+    LayerInfo(const LayerInfo&) = delete;
+    LayerInfo& operator=(const LayerInfo&) = delete;
+
+    // Records the last requested present time. It also stores information about when
+    // the layer was last updated. If the present time is farther in the future than the
+    // updated time, the updated time is the present time.
+    void setLastPresentTime(nsecs_t lastPresentTime, nsecs_t now, LayerUpdateType updateType,
+                            bool pendingConfigChange);
+
+    // Sets an explicit layer vote. This usually comes directly from the application via
+    // ANativeWindow_setFrameRate API
+    void setLayerVote(LayerVote vote) { mLayerVote = vote; }
+
+    // Sets the default layer vote. This will be the layer vote after calling to resetLayerVote().
+    // This is used for layers that called to setLayerVote() and then removed the vote, so that the
+    // layer can go back to whatever vote it had before the app voted for it.
+    void setDefaultLayerVote(LayerHistory::LayerVoteType type) { mDefaultVote = type; }
+
+    // Resets the layer vote to its default.
+    void resetLayerVote() { mLayerVote = {mDefaultVote, 0.0f, Seamlessness::Default}; }
+
+    LayerVote getRefreshRateVote(nsecs_t now);
+
+    // Return the last updated time. If the present time is farther in the future than the
+    // updated time, the updated time is the present time.
+    nsecs_t getLastUpdatedTime() const { return mLastUpdatedTime; }
+
+    // Returns a C string for tracing a vote
+    const char* getTraceTag(LayerHistory::LayerVoteType type) const;
+
+    void onLayerInactive(nsecs_t now) {
+        // Mark mFrameTimeValidSince to now to ignore all previous frame times.
+        // We are not deleting the old frame to keep track of whether we should treat the first
+        // buffer as Max as we don't know anything about this layer or Min as this layer is
+        // posting infrequent updates.
+        const auto timePoint = std::chrono::nanoseconds(now);
+        mFrameTimeValidSince = std::chrono::time_point<std::chrono::steady_clock>(timePoint);
+        mLastRefreshRate = {};
+        mRefreshRateHistory.clear();
+    }
+
+    void clearHistory(nsecs_t now) {
+        onLayerInactive(now);
+        mFrameTimes.clear();
+    }
+
+private:
+    // Used to store the layer timestamps
+    struct FrameTimeData {
+        nsecs_t presetTime; // desiredPresentTime, if provided
+        nsecs_t queueTime;  // buffer queue time
+        bool pendingConfigChange;
+    };
+
+    // Holds information about the calculated and reported refresh rate
+    struct RefreshRateHeuristicData {
+        // Rate calculated on the layer
+        float calculated = 0.0f;
+        // Last reported rate for LayerInfo::getRefreshRate()
+        float reported = 0.0f;
+        // Whether the last reported rate for LayerInfo::getRefreshRate()
+        // was due to animation or infrequent updates
+        bool animatingOrInfrequent = false;
+    };
+
+    // Class to store past calculated refresh rate and determine whether
+    // the refresh rate calculated is consistent with past values
+    class RefreshRateHistory {
+    public:
+        static constexpr auto HISTORY_SIZE = 90;
+        static constexpr std::chrono::nanoseconds HISTORY_DURATION = 2s;
+
+        RefreshRateHistory(const std::string& name) : mName(name) {}
+
+        // Clears History
+        void clear();
+
+        // Adds a new refresh rate and returns true if it is consistent
+        bool add(float refreshRate, nsecs_t now);
+
+    private:
+        friend class LayerHistoryTest;
+
+        // Holds the refresh rate when it was calculated
+        struct RefreshRateData {
+            float refreshRate = 0.0f;
+            nsecs_t timestamp = 0;
+
+            bool operator<(const RefreshRateData& other) const {
+                return refreshRate < other.refreshRate;
+            }
+        };
+
+        // Holds tracing strings
+        struct HeuristicTraceTagData {
+            std::string min;
+            std::string max;
+            std::string consistent;
+            std::string average;
+        };
+
+        bool isConsistent() const;
+        HeuristicTraceTagData makeHeuristicTraceTagData() const;
+
+        const std::string mName;
+        mutable std::optional<HeuristicTraceTagData> mHeuristicTraceTagData;
+        std::deque<RefreshRateData> mRefreshRates;
+        static constexpr float MARGIN_FPS = 1.0;
+    };
+
+    bool isFrequent(nsecs_t now) const;
+    bool isAnimating(nsecs_t now) const;
+    bool hasEnoughDataForHeuristic() const;
+    std::optional<float> calculateRefreshRateIfPossible(nsecs_t now);
+    std::optional<nsecs_t> calculateAverageFrameTime() const;
+    bool isFrameTimeValid(const FrameTimeData&) const;
+
+    const std::string mName;
+
+    // Used for sanitizing the heuristic data
+    const nsecs_t mHighRefreshRatePeriod;
+    LayerHistory::LayerVoteType mDefaultVote;
+
+    LayerVote mLayerVote;
+
+    nsecs_t mLastUpdatedTime = 0;
+
+    nsecs_t mLastAnimationTime = 0;
+
+    RefreshRateHeuristicData mLastRefreshRate;
+
+    std::deque<FrameTimeData> mFrameTimes;
+    std::chrono::time_point<std::chrono::steady_clock> mFrameTimeValidSince =
+            std::chrono::steady_clock::now();
+    static constexpr size_t HISTORY_SIZE = RefreshRateHistory::HISTORY_SIZE;
+    static constexpr std::chrono::nanoseconds HISTORY_DURATION = 1s;
+
+    RefreshRateHistory mRefreshRateHistory;
+
+    mutable std::unordered_map<LayerHistory::LayerVoteType, std::string> mTraceTags;
+
+    // Shared for all LayerInfo instances
+    static const RefreshRateConfigs* sRefreshRateConfigs;
+    static bool sTraceEnabled;
+};
+
+} // namespace scheduler
+} // namespace android