BufferQueue no longer hardcodes buffer counts

BufferQueue is now more flexible as it can be used
by SurfaceMediaSource in addition to SurfaceTexture.

Change-Id: I4222be8918d63372c44fcd412d9ad241c6a3eeb9

3 files changed, 30 insertions, 16 deletions

diff --git a/include/gui/BufferQueue.h b/include/gui/BufferQueue.h
index 57b9f8a..14f20d7 100644
--- a/include/gui/BufferQueue.h
+++ b/include/gui/BufferQueue.h
@@ -35,10 +35,6 @@ namespace android {
 class BufferQueue : public BnSurfaceTexture {
 public:
     enum { MIN_UNDEQUEUED_BUFFERS = 2 };
-    enum {
-        MIN_ASYNC_BUFFER_SLOTS = MIN_UNDEQUEUED_BUFFERS + 1,
-        MIN_SYNC_BUFFER_SLOTS  = MIN_UNDEQUEUED_BUFFERS
-    };
     enum { NUM_BUFFER_SLOTS = 32 };
     enum { NO_CONNECTED_API = 0 };
     enum { INVALID_BUFFER_SLOT = -1 };
@@ -99,7 +95,8 @@ public:
     // by producers and consumers.
     // allowSynchronousMode specifies whether or not synchronous mode can be
     // enabled.
-    BufferQueue(bool allowSynchronousMode = true);
+    // bufferCount sets the minimum number of undequeued buffers for this queue
+    BufferQueue(  bool allowSynchronousMode = true, int bufferCount = MIN_UNDEQUEUED_BUFFERS);
     virtual ~BufferQueue();
 
     virtual int query(int what, int* value);
@@ -402,6 +399,18 @@ private:
     // in requestBuffers() if a format of zero is specified.
     uint32_t mPixelFormat;
 
+    // mMinUndequeuedBuffers is a constraint on the number of buffers
+    // not dequeued at any time
+    int mMinUndequeuedBuffers;
+
+    // mMinAsyncBufferSlots is a constraint on the minimum mBufferCount
+    // when this BufferQueue is in asynchronous mode
+    int mMinAsyncBufferSlots;
+
+    // mMinSyncBufferSlots is a constraint on the minimum mBufferCount
+    // when this BufferQueue is in synchronous mode
+    int mMinSyncBufferSlots;
+
     // mBufferCount is the number of buffer slots that the client and server
     // must maintain. It defaults to MIN_ASYNC_BUFFER_SLOTS and can be changed
     // by calling setBufferCount or setBufferCountServer
diff --git a/include/gui/SurfaceTextureClient.h b/include/gui/SurfaceTextureClient.h
index b68fa81..8c1e505 100644
--- a/include/gui/SurfaceTextureClient.h
+++ b/include/gui/SurfaceTextureClient.h
@@ -104,7 +104,6 @@ protected:
     virtual int lock(ANativeWindow_Buffer* outBuffer, ARect* inOutDirtyBounds);
     virtual int unlockAndPost();
 
-    enum { MIN_UNDEQUEUED_BUFFERS = BufferQueue::MIN_UNDEQUEUED_BUFFERS };
     enum { NUM_BUFFER_SLOTS = BufferQueue::NUM_BUFFER_SLOTS };
     enum { DEFAULT_FORMAT = PIXEL_FORMAT_RGBA_8888 };
 
diff --git a/libs/gui/BufferQueue.cpp b/libs/gui/BufferQueue.cpp
index 2d042c8..84ccb3f 100644
--- a/libs/gui/BufferQueue.cpp
+++ b/libs/gui/BufferQueue.cpp
@@ -69,13 +69,16 @@ static int32_t createProcessUniqueId() {
     return android_atomic_inc(&globalCounter);
 }
 
-BufferQueue::BufferQueue( bool allowSynchronousMode ) :
+BufferQueue::BufferQueue(  bool allowSynchronousMode, int bufferCount ) :
     mDefaultWidth(1),
     mDefaultHeight(1),
     mPixelFormat(PIXEL_FORMAT_RGBA_8888),
-    mBufferCount(MIN_ASYNC_BUFFER_SLOTS),
+    mMinUndequeuedBuffers(bufferCount),
+    mMinAsyncBufferSlots(bufferCount + 1),
+    mMinSyncBufferSlots(bufferCount),
+    mBufferCount(mMinAsyncBufferSlots),
     mClientBufferCount(0),
-    mServerBufferCount(MIN_ASYNC_BUFFER_SLOTS),
+    mServerBufferCount(mMinAsyncBufferSlots),
     mSynchronousMode(false),
     mAllowSynchronousMode(allowSynchronousMode),
     mConnectedApi(NO_CONNECTED_API),
@@ -92,6 +95,9 @@ BufferQueue::BufferQueue( bool allowSynchronousMode ) :
     ST_LOGV("BufferQueue");
     sp<ISurfaceComposer> composer(ComposerService::getComposerService());
     mGraphicBufferAlloc = composer->createGraphicBufferAlloc();
+    if (mGraphicBufferAlloc == 0) {
+        ST_LOGE("createGraphicBufferAlloc() failed in BufferQueue()");
+    }
 }
 
 BufferQueue::~BufferQueue() {
@@ -186,7 +192,7 @@ status_t BufferQueue::setBufferCount(int bufferCount) {
         }
 
         const int minBufferSlots = mSynchronousMode ?
-                MIN_SYNC_BUFFER_SLOTS : MIN_ASYNC_BUFFER_SLOTS;
+            mMinSyncBufferSlots : mMinAsyncBufferSlots;
         if (bufferCount == 0) {
             mClientBufferCount = 0;
             bufferCount = (mServerBufferCount >= minBufferSlots) ?
@@ -241,7 +247,7 @@ int BufferQueue::query(int what, int* outValue)
         break;
     case NATIVE_WINDOW_MIN_UNDEQUEUED_BUFFERS:
         value = mSynchronousMode ?
-                (MIN_UNDEQUEUED_BUFFERS-1) : MIN_UNDEQUEUED_BUFFERS;
+                (mMinUndequeuedBuffers-1) : mMinUndequeuedBuffers;
         break;
     default:
         return BAD_VALUE;
@@ -317,7 +323,7 @@ status_t BufferQueue::dequeueBuffer(int *outBuf, uint32_t w, uint32_t h,
             // wait on mDequeueCondition.
 
             const int minBufferCountNeeded = mSynchronousMode ?
-                    MIN_SYNC_BUFFER_SLOTS : MIN_ASYNC_BUFFER_SLOTS;
+                    mMinSyncBufferSlots : mMinAsyncBufferSlots;
 
             const bool numberOfBuffersNeedsToChange = !mClientBufferCount &&
                     ((mServerBufferCount != mBufferCount) ||
@@ -384,15 +390,15 @@ status_t BufferQueue::dequeueBuffer(int *outBuf, uint32_t w, uint32_t h,
 
             // See whether a buffer has been queued since the last
             // setBufferCount so we know whether to perform the
-            // MIN_UNDEQUEUED_BUFFERS check below.
+            // mMinUndequeuedBuffers check below.
             if (mBufferHasBeenQueued) {
                 // make sure the client is not trying to dequeue more buffers
                 // than allowed.
                 const int avail = mBufferCount - (dequeuedCount+1);
-                if (avail < (MIN_UNDEQUEUED_BUFFERS-int(mSynchronousMode))) {
-                    ST_LOGE("dequeueBuffer: MIN_UNDEQUEUED_BUFFERS=%d exceeded "
+                if (avail < (mMinUndequeuedBuffers-int(mSynchronousMode))) {
+                    ST_LOGE("dequeueBuffer: mMinUndequeuedBuffers=%d exceeded "
                             "(dequeued=%d)",
-                            MIN_UNDEQUEUED_BUFFERS-int(mSynchronousMode),
+                            mMinUndequeuedBuffers-int(mSynchronousMode),
                             dequeuedCount);
                     return -EBUSY;
                 }