commit cbb288bfe89f585bf48371bd31b2d4aafa32f32e
author Mathias Agopian <mathias@google.com> Mon Sep 07 16:32:45 2009 -0700
committer Mathias Agopian <mathias@google.com> Mon Sep 07 16:32:45 2009 -0700
tree 73d20f36910dcab8c17c686cdd7014cee285bc39
parent f0780974fc31ae88135d1dcb67cb5fd86bb6deb6

fix [2068105] implement queueBuffer/lockBuffer/dequeueBuffer properly

Rewrote SurfaceFlinger's buffer management from the ground-up.
The design now support an arbitrary number of buffers per surface, however the current implementation is limited to four. Currently only 2 buffers are used in practice.

The main new feature is to be able to dequeue all buffers at once (very important when there are only two). 

A client can dequeue all buffers until there are none available, it can lock all buffers except the last one that is used for composition. The client will block then, until a new buffer is enqueued.

The current implementation requires that buffers are locked in the same order they are dequeued and enqueued in the same order they are locked. Only one buffer can be locked at a time.

eg. Allowed sequence:   DQ, DQ, LOCK, Q, LOCK, Q
eg. Forbidden sequence: DQ, DQ, LOCK, LOCK, Q, Q

libs/surfaceflinger/LayerBuffer.cpp

diff --git a/libs/surfaceflinger/LayerBuffer.cpp b/libs/surfaceflinger/LayerBuffer.cpp
index 8a55a3f..433b48e 100644
--- a/libs/surfaceflinger/LayerBuffer.cpp
+++ b/libs/surfaceflinger/LayerBuffer.cpp
@@ -28,6 +28,7 @@
 
 #include <hardware/copybit.h>
 
+#include "Buffer.h"
 #include "BufferAllocator.h"
 #include "LayerBuffer.h"
 #include "SurfaceFlinger.h"
@@ -58,7 +59,7 @@
 void LayerBuffer::onFirstRef()
 {
     LayerBaseClient::onFirstRef();
-    mSurface = new SurfaceBuffer(mFlinger, clientIndex(),
+    mSurface = new SurfaceLayerBuffer(mFlinger, clientIndex(),
             const_cast<LayerBuffer *>(this));
 }
 
@@ -181,21 +182,21 @@
 }
 
 // ============================================================================
-// LayerBuffer::SurfaceBuffer
+// LayerBuffer::SurfaceLayerBuffer
 // ============================================================================
 
-LayerBuffer::SurfaceBuffer::SurfaceBuffer(const sp<SurfaceFlinger>& flinger,
+LayerBuffer::SurfaceLayerBuffer::SurfaceLayerBuffer(const sp<SurfaceFlinger>& flinger,
         SurfaceID id, const sp<LayerBuffer>& owner)
     : LayerBaseClient::Surface(flinger, id, owner->getIdentity(), owner)
 {
 }
 
-LayerBuffer::SurfaceBuffer::~SurfaceBuffer()
+LayerBuffer::SurfaceLayerBuffer::~SurfaceLayerBuffer()
 {
     unregisterBuffers();
 }
 
-status_t LayerBuffer::SurfaceBuffer::registerBuffers(
+status_t LayerBuffer::SurfaceLayerBuffer::registerBuffers(
         const ISurface::BufferHeap& buffers)
 {
     sp<LayerBuffer> owner(getOwner());
@@ -204,21 +205,21 @@
     return NO_INIT;
 }
 
-void LayerBuffer::SurfaceBuffer::postBuffer(ssize_t offset)
+void LayerBuffer::SurfaceLayerBuffer::postBuffer(ssize_t offset)
 {
     sp<LayerBuffer> owner(getOwner());
     if (owner != 0)
         owner->postBuffer(offset);
 }
 
-void LayerBuffer::SurfaceBuffer::unregisterBuffers()
+void LayerBuffer::SurfaceLayerBuffer::unregisterBuffers()
 {
     sp<LayerBuffer> owner(getOwner());
     if (owner != 0)
         owner->unregisterBuffers();
 }
 
-sp<OverlayRef> LayerBuffer::SurfaceBuffer::createOverlay(
+sp<OverlayRef> LayerBuffer::SurfaceLayerBuffer::createOverlay(
         uint32_t w, uint32_t h, int32_t format) {
     sp<OverlayRef> result;
     sp<LayerBuffer> owner(getOwner());
@@ -462,8 +463,8 @@
                 const int tmp_h = floorf(src_height * yscale);
                 
                 if (mTempBitmap==0 || 
-                        mTempBitmap->getWidth() < tmp_w || 
-                        mTempBitmap->getHeight() < tmp_h) {
+                        mTempBitmap->getWidth() < size_t(tmp_w) || 
+                        mTempBitmap->getHeight() < size_t(tmp_h)) {
                     mTempBitmap.clear();
                     mTempBitmap = new android::Buffer(
                             tmp_w, tmp_h, src.img.format,