Browser Plugin: PpapiCommandBufferProxy should see a lost context if the embedder has deleted the P…

ppapi/proxy/ppapi_command_buffer_proxy.cc

Index: ppapi/proxy/ppapi_command_buffer_proxy.cc
diff --git a/ppapi/proxy/ppapi_command_buffer_proxy.cc b/ppapi/proxy/ppapi_command_buffer_proxy.cc
index 5e0f45486aab667646784b8aa7fc6a80696da2fd..43b2b1cbb368307b46bfb9781aa0f9aef1d81720 100644
--- a/ppapi/proxy/ppapi_command_buffer_proxy.cc
+++ b/ppapi/proxy/ppapi_command_buffer_proxy.cc
@@ -99,9 +99,10 @@ gpu::CommandBuffer::State PpapiCommandBufferProxy::GetState() {
   // Send will flag state with lost context if IPC fails.
   if (last_state_.error == gpu::error::kNoError) {
     gpu::CommandBuffer::State state;
+    bool success = false;
     if (Send(new PpapiHostMsg_PPBGraphics3D_GetState(
-             ppapi::API_ID_PPB_GRAPHICS_3D, resource_, &state))) {
-      UpdateState(state);
+             ppapi::API_ID_PPB_GRAPHICS_3D, resource_, &state, &success))) {
+      UpdateState(state, success);
     }
   }
 
@@ -132,10 +133,11 @@ gpu::CommandBuffer::State PpapiCommandBufferProxy::FlushSync(int32 put_offset,
     // Send will flag state with lost context if IPC fails.
     if (last_state_.error == gpu::error::kNoError) {
       gpu::CommandBuffer::State state;
+      bool success = false;
       if (Send(new PpapiHostMsg_PPBGraphics3D_Flush(
                ppapi::API_ID_PPB_GRAPHICS_3D, resource_, put_offset,
-              last_known_get, &state))) {
-        UpdateState(state);
+              last_known_get, &state, &success))) {
+        UpdateState(state, success);
       }
     }
   } else {
@@ -259,11 +261,14 @@ bool PpapiCommandBufferProxy::Send(IPC::Message* msg) {
 }
 
 void PpapiCommandBufferProxy::UpdateState(
-    const gpu::CommandBuffer::State& state) {
+    const gpu::CommandBuffer::State& state,
+    bool success) {
   // Handle wraparound. It works as long as we don't have more than 2B state
   // updates in flight across which reordering occurs.
   if (state.generation - last_state_.generation < 0x80000000U)
     last_state_ = state;

[piman, 2012/05/18 20:01:43]

Don't do that if !success, because then you would be overwriting last_state_
with uninitialized data.

[Fady Samuel, 2012/05/18 20:44:42]

Done.

+  if (!success)
+    last_state_.error = gpu::error::kLostContext;

[piman, 2012/05/18 20:01:43]

To be fully correct, you should also increase the generation since you changed
the state.

[Fady Samuel, 2012/05/18 20:44:42]

Done.

 }
 
 }  // namespace proxy