Read from BufferReleaseChannel in background thread

Bug: 294133380
Flag: com.android.graphics.libgui.flags.buffer_release_channel
Test: BLASTBufferQueueTest
Change-Id: I99c5da3bd99d6893ae24f5d55e7553b02bfc07ab
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 7b12a80..3c8af19 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1951,15 +1951,24 @@
 void Layer::callReleaseBufferCallback(const sp<ITransactionCompletedListener>& listener,
                                       const sp<GraphicBuffer>& buffer, uint64_t framenumber,
                                       const sp<Fence>& releaseFence) {
-    if (!listener) {
+    if (!listener && !mBufferReleaseChannel) {
         return;
     }
+
     SFTRACE_FORMAT_INSTANT("callReleaseBufferCallback %s - %" PRIu64, getDebugName(), framenumber);
+
+    ReleaseCallbackId callbackId{buffer->getId(), framenumber};
+    const sp<Fence>& fence = releaseFence ? releaseFence : Fence::NO_FENCE;
     uint32_t currentMaxAcquiredBufferCount =
             mFlinger->getMaxAcquiredBufferCountForCurrentRefreshRate(mOwnerUid);
-    listener->onReleaseBuffer({buffer->getId(), framenumber},
-                              releaseFence ? releaseFence : Fence::NO_FENCE,
-                              currentMaxAcquiredBufferCount);
+
+    if (listener) {
+        listener->onReleaseBuffer(callbackId, fence, currentMaxAcquiredBufferCount);
+    }
+
+    if (mBufferReleaseChannel) {
+        mBufferReleaseChannel->writeReleaseFence(callbackId, fence, currentMaxAcquiredBufferCount);
+    }
 }
 
 sp<CallbackHandle> Layer::findCallbackHandle() {
@@ -2077,6 +2086,7 @@
 
 void Layer::releasePendingBuffer(nsecs_t dequeueReadyTime) {
     for (const auto& handle : mDrawingState.callbackHandles) {
+        handle->bufferReleaseChannel = mBufferReleaseChannel;
         handle->transformHint = mTransformHint;
         handle->dequeueReadyTime = dequeueReadyTime;
         handle->currentMaxAcquiredBufferCount =
@@ -3508,6 +3518,11 @@
     return haveTrustedPresentationListener;
 }
 
+void Layer::setBufferReleaseChannel(
+        const std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint>& channel) {
+    mBufferReleaseChannel = channel;
+}
+
 void Layer::updateLastLatchTime(nsecs_t latchTime) {
     mLastLatchTime = latchTime;
 }
diff --git a/services/surfaceflinger/Layer.h b/services/surfaceflinger/Layer.h
index 3692fb8..1e4f2dc 100644
--- a/services/surfaceflinger/Layer.h
+++ b/services/surfaceflinger/Layer.h
@@ -537,6 +537,7 @@
     };
 
     BufferInfo mBufferInfo;
+    std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint> mBufferReleaseChannel;
 
     // implements compositionengine::LayerFE
     const compositionengine::LayerFECompositionState* getCompositionState() const;
@@ -724,6 +725,8 @@
 
     bool setTrustedPresentationInfo(TrustedPresentationThresholds const& thresholds,
                                     TrustedPresentationListener const& listener);
+    void setBufferReleaseChannel(
+            const std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint>& channel);
 
     // Creates a new handle each time, so we only expect
     // this to be called once.
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index ce83475..f4bff8f 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -5063,6 +5063,10 @@
         }
     }
 
+    if (what & layer_state_t::eBufferReleaseChannelChanged) {
+        layer->setBufferReleaseChannel(s.bufferReleaseChannel);
+    }
+
     const auto& requestedLayerState = mLayerLifecycleManager.getLayerFromId(layer->getSequence());
     bool willPresentCurrentTransaction = requestedLayerState &&
             (requestedLayerState->hasReadyFrame() ||
diff --git a/services/surfaceflinger/TransactionCallbackInvoker.cpp b/services/surfaceflinger/TransactionCallbackInvoker.cpp
index 881bf35..c6856ae 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.cpp
+++ b/services/surfaceflinger/TransactionCallbackInvoker.cpp
@@ -149,6 +149,13 @@
                                                     handle->transformHint,
                                                     handle->currentMaxAcquiredBufferCount,
                                                     eventStats, handle->previousReleaseCallbackId);
+        if (handle->bufferReleaseChannel &&
+            handle->previousReleaseCallbackId != ReleaseCallbackId::INVALID_ID) {
+            mBufferReleases.emplace_back(handle->bufferReleaseChannel,
+                                         handle->previousReleaseCallbackId,
+                                         handle->previousReleaseFence,
+                                         handle->currentMaxAcquiredBufferCount);
+        }
     }
     return NO_ERROR;
 }
@@ -158,6 +165,12 @@
 }
 
 void TransactionCallbackInvoker::sendCallbacks(bool onCommitOnly) {
+    for (const auto& bufferRelease : mBufferReleases) {
+        bufferRelease.channel->writeReleaseFence(bufferRelease.callbackId, bufferRelease.fence,
+                                                 bufferRelease.currentMaxAcquiredBufferCount);
+    }
+    mBufferReleases.clear();
+
     // For each listener
     auto completedTransactionsItr = mCompletedTransactions.begin();
     ftl::SmallVector<ListenerStats, 10> listenerStatsToSend;
diff --git a/services/surfaceflinger/TransactionCallbackInvoker.h b/services/surfaceflinger/TransactionCallbackInvoker.h
index 7853a9f..14a7487 100644
--- a/services/surfaceflinger/TransactionCallbackInvoker.h
+++ b/services/surfaceflinger/TransactionCallbackInvoker.h
@@ -16,18 +16,14 @@
 
 #pragma once
 
-#include <condition_variable>
 #include <deque>
-#include <mutex>
 #include <optional>
-#include <queue>
-#include <thread>
 #include <unordered_map>
-#include <unordered_set>
 
 #include <android-base/thread_annotations.h>
 #include <binder/IBinder.h>
 #include <ftl/future.h>
+#include <gui/BufferReleaseChannel.h>
 #include <gui/ITransactionCompletedListener.h>
 #include <ui/Fence.h>
 #include <ui/FenceResult.h>
@@ -59,6 +55,7 @@
     uint64_t frameNumber = 0;
     uint64_t previousFrameNumber = 0;
     ReleaseCallbackId previousReleaseCallbackId = ReleaseCallbackId::INVALID_ID;
+    std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint> bufferReleaseChannel;
 };
 
 class TransactionCallbackInvoker {
@@ -86,6 +83,14 @@
     std::unordered_map<sp<IBinder>, std::deque<TransactionStats>, IListenerHash>
         mCompletedTransactions;
 
+    struct BufferRelease {
+        std::shared_ptr<gui::BufferReleaseChannel::ProducerEndpoint> channel;
+        ReleaseCallbackId callbackId;
+        sp<Fence> fence;
+        uint32_t currentMaxAcquiredBufferCount;
+    };
+    std::vector<BufferRelease> mBufferReleases;
+
     sp<Fence> mPresentFence;
 };