Add gatherPendingTransactions in BBQ

Instead of applying the pending transactions when a frame wasn't
rendered, we gather the transactions and merge them with the transaction
that will be used to sync. This is to ensure these frames are sent to
the caller that requested the sync so they can ensure it's applied at
the correct time.

Test: Builds and run
Bug: 200284684
Change-Id: I087c67138f31cc93e79df42c29464ab4f7989d52

1 files changed, 15 insertions, 0 deletions

diff --git a/graphics/java/android/graphics/BLASTBufferQueue.java b/graphics/java/android/graphics/BLASTBufferQueue.java
index a9e730d58e65..2678c79d1454 100644
--- a/graphics/java/android/graphics/BLASTBufferQueue.java
+++ b/graphics/java/android/graphics/BLASTBufferQueue.java
@@ -39,6 +39,8 @@ public final class BLASTBufferQueue {
     private static native long nativeGetLastAcquiredFrameNum(long ptr);
     private static native void nativeApplyPendingTransactions(long ptr, long frameNumber);
     private static native boolean nativeIsSameSurfaceControl(long ptr, long surfaceControlPtr);
+    private static native SurfaceControl.Transaction nativeGatherPendingTransactions(long ptr,
+            long frameNumber);
 
     /** Create a new connection with the surface flinger. */
     public BLASTBufferQueue(String name, SurfaceControl sc, int width, int height,
@@ -159,4 +161,17 @@ public final class BLASTBufferQueue {
     public boolean isSameSurfaceControl(SurfaceControl sc) {
         return nativeIsSameSurfaceControl(mNativeObject, sc.mNativeObject);
     }
+
+    /**
+     * Get any transactions that were passed to {@link #mergeWithNextTransaction} with the
+     * specified frameNumber. This is intended to ensure transactions don't get stuck as pending
+     * if the specified frameNumber is never drawn.
+     *
+     * @param frameNumber The frameNumber used to determine which transactions to apply.
+     * @return a Transaction that contains the merge of all the transactions that were sent to
+     *         mergeWithNextTransaction
+     */
+    public SurfaceControl.Transaction gatherPendingTransactions(long frameNumber) {
+        return nativeGatherPendingTransactions(mNativeObject, frameNumber);
+    }
 }