commit b5b7f260da2c1a2a82e0311e2015d49a82f43667
author Mathias Agopian <mathias@google.com> Fri May 07 15:58:44 2010 -0700
committer Mathias Agopian <mathias@google.com> Wed May 12 17:28:20 2010 -0700
tree 69976a2b04a39bfce83035777ea8d35e4a5fc401
parent d606de6bb6877dc4ab93ec0be0c6bda4a8ee1ce8

SharedBufferStack now can grow up to 16 buffers.

there is a new resize() api, which currently only allows growing.

Change-Id: Ia37b81b73be466d2491ffed7f3a23cd8e113c6fe

libs/surfaceflinger/Layer.cpp

diff --git a/libs/surfaceflinger/Layer.cpp b/libs/surfaceflinger/Layer.cpp
index 71573ac..1fe997d 100644
--- a/libs/surfaceflinger/Layer.cpp
+++ b/libs/surfaceflinger/Layer.cpp
@@ -208,6 +208,30 @@
     drawWithOpenGL(clip, tex);
 }
 
+
+status_t Layer::setBufferCount(int bufferCount)
+{
+    // this ensures our client doesn't go away while we're accessing
+    // the shared area.
+    sp<Client> ourClient(client.promote());
+    if (ourClient == 0) {
+        // oops, the client is already gone
+        return DEAD_OBJECT;
+    }
+
+    status_t err;
+
+    // FIXME: resize() below is NOT thread-safe, we need to synchronize
+    // the users of lcblk in our process (ie: retire), and we assume the
+    // client is not mucking with the SharedStack, which is only enforced
+    // by construction, therefore we need to protect ourselves against
+    // buggy and malicious client (as always)
+
+    err = lcblk->resize(bufferCount);
+
+    return err;
+}
+
 sp<GraphicBuffer> Layer::requestBuffer(int index, int usage)
 {
     sp<GraphicBuffer> buffer;
@@ -642,6 +666,16 @@
     return buffer;
 }
 
+status_t Layer::SurfaceLayer::setBufferCount(int bufferCount)
+{
+    status_t err = DEAD_OBJECT;
+    sp<Layer> owner(getOwner());
+    if (owner != 0) {
+        err = owner->setBufferCount(bufferCount);
+    }
+    return err;
+}
+
 // ---------------------------------------------------------------------------
 
 

libs/surfaceflinger/Layer.h

diff --git a/libs/surfaceflinger/Layer.h b/libs/surfaceflinger/Layer.h
index 26fb6c6..80fbd6a 100644
--- a/libs/surfaceflinger/Layer.h
+++ b/libs/surfaceflinger/Layer.h
@@ -89,6 +89,7 @@
     uint32_t getEffectiveUsage(uint32_t usage) const;
 
     sp<GraphicBuffer> requestBuffer(int index, int usage);
+    status_t setBufferCount(int bufferCount);
     void destroy();
 
     class SurfaceLayer : public LayerBaseClient::Surface {
@@ -98,6 +99,7 @@
         ~SurfaceLayer();
     private:
         virtual sp<GraphicBuffer> requestBuffer(int index, int usage);
+        virtual status_t setBufferCount(int bufferCount);
         sp<Layer> getOwner() const {
             return static_cast<Layer*>(Surface::getOwner().get());
         }

libs/surfaceflinger/LayerBase.cpp

diff --git a/libs/surfaceflinger/LayerBase.cpp b/libs/surfaceflinger/LayerBase.cpp
index 7d8d43f..63b9520 100644
--- a/libs/surfaceflinger/LayerBase.cpp
+++ b/libs/surfaceflinger/LayerBase.cpp
@@ -621,6 +621,11 @@
     return NULL; 
 }
 
+status_t LayerBaseClient::Surface::setBufferCount(int bufferCount)
+{
+    return INVALID_OPERATION;
+}
+
 status_t LayerBaseClient::Surface::registerBuffers(
         const ISurface::BufferHeap& buffers) 
 { 

libs/surfaceflinger/LayerBase.h

diff --git a/libs/surfaceflinger/LayerBase.h b/libs/surfaceflinger/LayerBase.h
index c500dcf..53b848f 100644
--- a/libs/surfaceflinger/LayerBase.h
+++ b/libs/surfaceflinger/LayerBase.h
@@ -302,6 +302,8 @@
 
     private:
         virtual sp<GraphicBuffer> requestBuffer(int index, int usage);
+        virtual status_t setBufferCount(int bufferCount);
+
         virtual status_t registerBuffers(const ISurface::BufferHeap& buffers); 
         virtual void postBuffer(ssize_t offset);
         virtual void unregisterBuffers();