MJPEG acceleration for video capture using VAAPI, the GPU and IPC part

content/common/gpu/gpu_channel.cc

Index: content/common/gpu/gpu_channel.cc
diff --git a/content/common/gpu/gpu_channel.cc b/content/common/gpu/gpu_channel.cc
index 2768eea2f41d3968ab8aec97ce446c4204ddcfca..944d8a4e0fbc40508a914c01278d2dc41ce31c77 100644
--- a/content/common/gpu/gpu_channel.cc
+++ b/content/common/gpu/gpu_channel.cc
@@ -666,6 +666,7 @@ bool GpuChannel::OnControlMessageReceived(const IPC::Message& msg) {
                         OnCreateOffscreenCommandBuffer)
     IPC_MESSAGE_HANDLER(GpuChannelMsg_DestroyCommandBuffer,
                         OnDestroyCommandBuffer)
+    IPC_MESSAGE_HANDLER(GpuMsg_CreateJpegDecoder, OnCreateJpegDecoder)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   DCHECK(handled) << msg.type();
@@ -787,6 +788,22 @@ void GpuChannel::OnDestroyCommandBuffer(int32 route_id) {
   }
 }
 
+void GpuChannel::OnCreateJpegDecoder(int32 route_id, bool* succeeded) {
+  scoped_ptr<content::GpuJpegDecodeAccelerator> decoder(
+      new GpuJpegDecodeAccelerator(this, route_id, io_task_runner_));
+
+  *succeeded = decoder->Initialize();
+  DCHECK(jpeg_decoder_map_.get(route_id) == nullptr);
+  jpeg_decoder_map_.set(route_id, decoder.Pass());

[piman, 2015/05/18 22:46:18]

You don't want to do this when Initialize fails.

[kcwu, 2015/05/25 18:57:16]

Done.

[kcwu, 2015/05/25 18:57:16]

Done.

+}
+
+void GpuChannel::ReleaseJpegDecoder(int32 route_id) {
+  scoped_ptr<content::GpuJpegDecodeAccelerator> decoder =
+      jpeg_decoder_map_.take_and_erase(route_id);
+  DCHECK(decoder);
+  ignore_result(decoder.release());

[piman, 2015/05/18 22:46:18]

Yeah, this is another reason the Destroy pattern is super confusing.

If you kept it you should use a regular hash_map, not a ScopedPtrHashMap, since
you never actually use the automatic destruction property. But I think it should
be revisited.

Instead you can keep the ScopedPtrHashMap and have
GpuJpegDecodeAccelerator::OnDestroy call GpuChannel::ReleaseJpegDecoder
directly, and move the rest of the Destroy code either here (e.g. RemoveRoute)
or into the GpuJpegDecodeAccelerator destructor. No need for custom deleters.

[kcwu, 2015/05/25 18:57:16]

Done.

+}
+
 void GpuChannel::MessageProcessed() {
   messages_processed_++;
   if (preempting_flag_.get()) {