Have the Surface class track the buffer age.

Have the Surface class track the buffer age, so that Surface::query()
can return the buffer age without having to use a binder call to
BufferQueueProducer::query().  The idea is for
BufferQueueProducer::dequeueBuffer() to return the value, which the
Surface class will cache for later use by Surface::query().

Bug: b/27903668
Test: Use systrace to no ensure query binder call after dequeueBuffer.

Change-Id: I7a4d79d02ea68781b464a463f0ecdf64978b7fb8

1 files changed, 25 insertions, 18 deletions

diff --git a/libs/gui/Surface.cpp b/libs/gui/Surface.cpp
index 409a3cb076..78eb69d132 100644
--- a/libs/gui/Surface.cpp
+++ b/libs/gui/Surface.cpp
@@ -44,21 +44,19 @@
 
 namespace android {
 
-Surface::Surface(
-        const sp<IGraphicBufferProducer>& bufferProducer,
-        bool controlledByApp)
-    : mGraphicBufferProducer(bufferProducer),
-      mCrop(Rect::EMPTY_RECT),
-      mGenerationNumber(0),
-      mSharedBufferMode(false),
-      mAutoRefresh(false),
-      mSharedBufferSlot(BufferItem::INVALID_BUFFER_SLOT),
-      mSharedBufferHasBeenQueued(false),
-      mQueriedSupportedTimestamps(false),
-      mFrameTimestampsSupportsPresent(false),
-      mEnableFrameTimestamps(false),
-      mFrameEventHistory(std::make_unique<ProducerFrameEventHistory>())
-{
+Surface::Surface(const sp<IGraphicBufferProducer>& bufferProducer, bool controlledByApp)
+      : mGraphicBufferProducer(bufferProducer),
+        mCrop(Rect::EMPTY_RECT),
+        mBufferAge(0),
+        mGenerationNumber(0),
+        mSharedBufferMode(false),
+        mAutoRefresh(false),
+        mSharedBufferSlot(BufferItem::INVALID_BUFFER_SLOT),
+        mSharedBufferHasBeenQueued(false),
+        mQueriedSupportedTimestamps(false),
+        mFrameTimestampsSupportsPresent(false),
+        mEnableFrameTimestamps(false),
+        mFrameEventHistory(std::make_unique<ProducerFrameEventHistory>()) {
     // Initialize the ANativeWindow function pointers.
     ANativeWindow::setSwapInterval  = hook_setSwapInterval;
     ANativeWindow::dequeueBuffer    = hook_dequeueBuffer;
@@ -506,9 +504,10 @@ int Surface::dequeueBuffer(android_native_buffer_t** buffer, int* fenceFd) {
     nsecs_t startTime = systemTime();
 
     FrameEventHistoryDelta frameTimestamps;
-    status_t result = mGraphicBufferProducer->dequeueBuffer(&buf, &fence,
-            reqWidth, reqHeight, reqFormat, reqUsage,
-            enableFrameTimestamps ? &frameTimestamps : nullptr);
+    status_t result = mGraphicBufferProducer->dequeueBuffer(&buf, &fence, reqWidth, reqHeight,
+                                                            reqFormat, reqUsage, &mBufferAge,
+                                                            enableFrameTimestamps ? &frameTimestamps
+                                                                                  : nullptr);
     mLastDequeueDuration = systemTime() - startTime;
 
     if (result < 0) {
@@ -845,6 +844,14 @@ int Surface::query(int what, int* value) const {
                 }
                 return err;
             }
+            case NATIVE_WINDOW_BUFFER_AGE: {
+                if (mBufferAge > INT32_MAX) {
+                    *value = 0;
+                } else {
+                    *value = static_cast<int32_t>(mBufferAge);
+                }
+                return NO_ERROR;
+            }
             case NATIVE_WINDOW_LAST_DEQUEUE_DURATION: {
                 int64_t durationUs = mLastDequeueDuration / 1000;
                 *value = durationUs > std::numeric_limits<int>::max() ?