Changed setSyncTransaction to syncNextTransaction with callback logic.

Replaced setSyncTransation with syncNextTransaciton in BBQ. BBQ will
no longer take in transaction pointers but create transactions inside
of itself and invoke the callback when the transaction is ready.
Also added stopContinuousSyncTransction method to inform BBQ to cease
acquiring buffers into the transaction.

Test: go/wm-smoke.
Test: BLASTBufferQueueTest
Bug: 210714235.
Change-Id: I7103a95046d0251e5bdaec21b2741ff194f8e81e

1 files changed, 87 insertions, 52 deletions

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index b7a7aa0ccb..8e23eb8766 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -137,6 +137,7 @@ BLASTBufferQueue::BLASTBufferQueue(const std::string& name, bool updateDestinati
         mSize(1, 1),
         mRequestedSize(mSize),
         mFormat(PIXEL_FORMAT_RGBA_8888),
+        mTransactionReadyCallback(nullptr),
         mSyncTransaction(nullptr),
         mUpdateDestinationFrame(updateDestinationFrame) {
     createBufferQueue(&mProducer, &mConsumer);
@@ -608,60 +609,69 @@ void BLASTBufferQueue::flushAndWaitForFreeBuffer(std::unique_lock<std::mutex>& l
 }
 
 void BLASTBufferQueue::onFrameAvailable(const BufferItem& item) {
-    BBQ_TRACE();
-    std::unique_lock _lock{mMutex};
+    std::function<void(SurfaceComposerClient::Transaction*)> prevCallback = nullptr;
+    SurfaceComposerClient::Transaction* prevTransaction = nullptr;
+    {
+        BBQ_TRACE();
+        std::unique_lock _lock{mMutex};
+        const bool syncTransactionSet = mTransactionReadyCallback != nullptr;
+        BQA_LOGV("onFrameAvailable-start syncTransactionSet=%s", boolToString(syncTransactionSet));
+
+        if (syncTransactionSet) {
+            bool mayNeedToWaitForBuffer = true;
+            // If we are going to re-use the same mSyncTransaction, release the buffer that may
+            // already be set in the Transaction. This is to allow us a free slot early to continue
+            // processing a new buffer.
+            if (!mAcquireSingleBuffer) {
+                auto bufferData = mSyncTransaction->getAndClearBuffer(mSurfaceControl);
+                if (bufferData) {
+                    BQA_LOGD("Releasing previous buffer when syncing: framenumber=%" PRIu64,
+                             bufferData->frameNumber);
+                    releaseBuffer(bufferData->generateReleaseCallbackId(),
+                                  bufferData->acquireFence);
+                    // Because we just released a buffer, we know there's no need to wait for a free
+                    // buffer.
+                    mayNeedToWaitForBuffer = false;
+                }
+            }
 
-    const bool syncTransactionSet = mSyncTransaction != nullptr;
-    BQA_LOGV("onFrameAvailable-start syncTransactionSet=%s", boolToString(syncTransactionSet));
-
-    if (syncTransactionSet) {
-        bool mayNeedToWaitForBuffer = true;
-        // If we are going to re-use the same mSyncTransaction, release the buffer that may already
-        // be set in the Transaction. This is to allow us a free slot early to continue processing
-        // a new buffer.
-        if (!mAcquireSingleBuffer) {
-            auto bufferData = mSyncTransaction->getAndClearBuffer(mSurfaceControl);
-            if (bufferData) {
-                BQA_LOGD("Releasing previous buffer when syncing: framenumber=%" PRIu64,
-                         bufferData->frameNumber);
-                releaseBuffer(bufferData->generateReleaseCallbackId(), bufferData->acquireFence);
-                // Because we just released a buffer, we know there's no need to wait for a free
-                // buffer.
-                mayNeedToWaitForBuffer = false;
+            if (mayNeedToWaitForBuffer) {
+                flushAndWaitForFreeBuffer(_lock);
             }
         }
 
-        if (mayNeedToWaitForBuffer) {
-            flushAndWaitForFreeBuffer(_lock);
+        // add to shadow queue
+        mNumFrameAvailable++;
+        if (mWaitForTransactionCallback && mNumFrameAvailable >= 2) {
+            acquireAndReleaseBuffer();
         }
-    }
-
-    // add to shadow queue
-    mNumFrameAvailable++;
-    if (mWaitForTransactionCallback && mNumFrameAvailable >= 2) {
-        acquireAndReleaseBuffer();
-    }
-    ATRACE_INT(mQueuedBufferTrace.c_str(),
-               mNumFrameAvailable + mNumAcquired - mPendingRelease.size());
-
-    BQA_LOGV("onFrameAvailable framenumber=%" PRIu64 " syncTransactionSet=%s", item.mFrameNumber,
-             boolToString(syncTransactionSet));
-
-    if (syncTransactionSet) {
-        acquireNextBufferLocked(mSyncTransaction);
-
-        // Only need a commit callback when syncing to ensure the buffer that's synced has been sent
-        // to SF
-        incStrong((void*)transactionCommittedCallbackThunk);
-        mSyncTransaction->addTransactionCommittedCallback(transactionCommittedCallbackThunk,
-                                                          static_cast<void*>(this));
-
-        if (mAcquireSingleBuffer) {
-            mSyncTransaction = nullptr;
+        ATRACE_INT(mQueuedBufferTrace.c_str(),
+                   mNumFrameAvailable + mNumAcquired - mPendingRelease.size());
+
+        BQA_LOGV("onFrameAvailable framenumber=%" PRIu64 " syncTransactionSet=%s",
+                 item.mFrameNumber, boolToString(syncTransactionSet));
+
+        if (syncTransactionSet) {
+            acquireNextBufferLocked(mSyncTransaction);
+
+            // Only need a commit callback when syncing to ensure the buffer that's synced has been
+            // sent to SF
+            incStrong((void*)transactionCommittedCallbackThunk);
+            mSyncTransaction->addTransactionCommittedCallback(transactionCommittedCallbackThunk,
+                                                              static_cast<void*>(this));
+            mWaitForTransactionCallback = true;
+            if (mAcquireSingleBuffer) {
+                prevCallback = mTransactionReadyCallback;
+                prevTransaction = mSyncTransaction;
+                mTransactionReadyCallback = nullptr;
+                mSyncTransaction = nullptr;
+            }
+        } else if (!mWaitForTransactionCallback) {
+            acquireNextBufferLocked(std::nullopt);
         }
-        mWaitForTransactionCallback = true;
-    } else if (!mWaitForTransactionCallback) {
-        acquireNextBufferLocked(std::nullopt);
+    }
+    if (prevCallback) {
+        prevCallback(prevTransaction);
     }
 }
 
@@ -680,12 +690,37 @@ void BLASTBufferQueue::onFrameCancelled(const uint64_t bufferId) {
     mDequeueTimestamps.erase(bufferId);
 };
 
-void BLASTBufferQueue::setSyncTransaction(SurfaceComposerClient::Transaction* t,
-                                          bool acquireSingleBuffer) {
+void BLASTBufferQueue::syncNextTransaction(
+        std::function<void(SurfaceComposerClient::Transaction*)> callback,
+        bool acquireSingleBuffer) {
     BBQ_TRACE();
     std::lock_guard _lock{mMutex};
-    mSyncTransaction = t;
-    mAcquireSingleBuffer = mSyncTransaction ? acquireSingleBuffer : true;
+    mTransactionReadyCallback = callback;
+    if (callback) {
+        mSyncTransaction = new SurfaceComposerClient::Transaction();
+    } else {
+        mSyncTransaction = nullptr;
+    }
+    mAcquireSingleBuffer = mTransactionReadyCallback ? acquireSingleBuffer : true;
+}
+
+void BLASTBufferQueue::stopContinuousSyncTransaction() {
+    std::function<void(SurfaceComposerClient::Transaction*)> prevCallback = nullptr;
+    SurfaceComposerClient::Transaction* prevTransaction = nullptr;
+    {
+        std::lock_guard _lock{mMutex};
+        bool invokeCallback = mTransactionReadyCallback && !mAcquireSingleBuffer;
+        if (invokeCallback) {
+            prevCallback = mTransactionReadyCallback;
+            prevTransaction = mSyncTransaction;
+        }
+        mTransactionReadyCallback = nullptr;
+        mSyncTransaction = nullptr;
+        mAcquireSingleBuffer = true;
+    }
+    if (prevCallback) {
+        prevCallback(prevTransaction);
+    }
 }
 
 bool BLASTBufferQueue::rejectBuffer(const BufferItem& item) {