Add Pepper VideoReader and VideoWriter plumbing

content/renderer/pepper/pepper_video_reader_host.cc

+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/renderer/pepper/pepper_video_reader_host.h"
+
+#include "base/bind.h"
+#include "content/public/renderer/renderer_ppapi_host.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/host/dispatch_host_message.h"
+#include "ppapi/host/host_message_context.h"
+#include "ppapi/host/ppapi_host.h"
+#include "ppapi/proxy/ppapi_messages.h"
+
+using ppapi::host::HostMessageContext;
+using ppapi::host::ReplyMessageContext;
+
+namespace content {
+
+PepperVideoReaderHost::PepperVideoReaderHost(
+    RendererPpapiHost* host,
+    PP_Instance instance,
+    PP_Resource resource)
+    : ResourceHost(host->GetPpapiHost(), instance, resource),
+      renderer_ppapi_host_(host),
+      weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
+}
+
+PepperVideoReaderHost::~PepperVideoReaderHost() {
+}
+
+int32_t PepperVideoReaderHost::OnResourceMessageReceived(
+    const IPC::Message& msg,
+    HostMessageContext* context) {
+  if (!host()->permissions().HasPermission(ppapi::PERMISSION_PRIVATE))
+    return PP_ERROR_FAILED;
+
+  IPC_BEGIN_MESSAGE_MAP(PepperVideoReaderHost, msg)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL(PpapiHostMsg_VideoReader_Open,
+                                      OnHostMsgOpen)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_VideoReader_GetFrame,
+                                        OnHostMsgGetFrame)
+    PPAPI_DISPATCH_HOST_RESOURCE_CALL_0(PpapiHostMsg_VideoReader_Close,
+                                        OnHostMsgClose)
+  IPC_END_MESSAGE_MAP()
+  return PP_ERROR_FAILED;
+}
+
+int32_t PepperVideoReaderHost::OnHostMsgOpen(HostMessageContext* context,
+                                             const std::string& stream_id) {
+  ReplyMessageContext reply_context = context->MakeReplyMessageContext();
+  // Create the video stream here and return error / result code.
+  reply_context.params.set_result(PP_ERROR_FAILED);
+  host()->SendReply(reply_context,
+                    PpapiPluginMsg_VideoReader_OpenReply());
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperVideoReaderHost::OnHostMsgGetFrame(HostMessageContext* context) {
+  ReplyMessageContext reply_context = context->MakeReplyMessageContext();
+  // Create an image data resource and copy the stream's next frame into it.

[Ronghua Wu (Left Chromium), 2013/04/08 22:34:39]

Will the plugin need to call this GetFrame for every frame? Or can plugin just
register a callback and we will push the frame to plugin when it's ready.

[bbudge, 2013/04/08 22:38:01]

My understanding of this API is that the plugin 'pulls' frames from the stream.
I guess that means you should retrieve the most recent frame from the stream
here. Perhaps that implies keeping the timestamp of the last frame returned to
the plugin so you don't return the same frame more than once. The place to put
all of this state is in this class.

On 2013/04/08 22:34:39, Ronghua Wu wrote:

+  // Return a timestamp.
+  ppapi::HostResource image_data;
+  double timestamp = 0;
+  reply_context.params.set_result(PP_ERROR_FAILED);
+  host()->SendReply(
+      reply_context,
+      PpapiPluginMsg_VideoReader_GetFrameReply(image_data, timestamp));
+  return PP_OK_COMPLETIONPENDING;
+}
+
+int32_t PepperVideoReaderHost::OnHostMsgClose(HostMessageContext* context) {
+  // Close the video stream.
+  return PP_OK;
+}
+
+}  // namespace content