Implements ListenForSessionMessages in PresentationServiceImpl; uses Swap to avoid copying large da…

content/browser/presentation/presentation_service_impl.cc

 // Copyright 2015 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/browser/presentation/presentation_service_impl.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "content/browser/presentation/presentation_type_converters.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/navigation_details.h"
+#include "content/public/browser/presentation_session_message.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/frame_navigate_params.h"
 
 namespace content {
 
 PresentationServiceImpl::PresentationServiceImpl(
     RenderFrameHost* render_frame_host,
@@ skipping 305 matching lines @@
     content::RenderFrameHost* render_frame_host) const {
   if (!render_frame_host)
     return false;
 
   return render_frame_host->GetProcess()->GetID() == render_process_id_ &&
          render_frame_host->GetRoutingID() == render_frame_id_;
 }
 
 void PresentationServiceImpl::ListenForSessionMessages(
     const SessionMessagesCallback& callback) {
-  NOTIMPLEMENTED();
+  DVLOG(2) << "ListenForSessionMessages";
+  if (!delegate_) {
+    callback.Run(mojo::Array<presentation::SessionMessagePtr>());
+    return;
+  }
+
+  delegate_->ListenForSessionMessages(
+      render_process_id_, render_frame_id_,
+      base::Bind(&PresentationServiceImpl::OnSessionMessages,
+                 weak_factory_.GetWeakPtr(), callback));

[imcheng (use chromium acct), 2015/04/30 21:52:01]

I am not sure about binding the mojo callback to OnSessionMessages. There is no
guarantee when OnSessionMessages will be invoked and by that time the onmessage
handler could already be gone. (or page navigated, etc.)

One possible approach is to store callback as a scoped_ptr<> in
PresentationServiceImpl and then invoke it when OnSessionMessages comes back.
That way we can also invoke the callback and then reset the ptr on Reset()
(which is called on navigation and frame deletion)

[haibinlu, 2015/05/01 01:37:11]

Done.

+}
+
+void PresentationServiceImpl::OnSessionMessages(
+    const SessionMessagesCallback& callback,
+    scoped_ptr<ScopedVector<PresentationSessionMessage>> messages) {

[imcheng (use chromium acct), 2015/04/30 21:52:01]

should probably add a DCHECK on messages

[haibinlu, 2015/05/01 19:03:19]

Done.

+  mojo::Array<presentation::SessionMessagePtr> mojoMessages(messages->size());
+  for (size_t i = 0; i < messages->size(); ++i)
+    mojoMessages[i] = PresentationServiceImpl::ToMojoSessionMessage(
+        messages.get()->get().at(i));
+
+  callback.Run(mojoMessages.Pass());
+}
+
+// static
+presentation::SessionMessagePtr PresentationServiceImpl::ToMojoSessionMessage(
+    PresentationSessionMessage* input) {
+  presentation::SessionMessagePtr output(presentation::SessionMessage::New());
+  output->presentation_url = input->presentation_url;
+  output->presentation_id = input->presentation_id;
+  if (input->message->size() == 0) {
+    // binary data
+    output->type = presentation::PresentationMessageType::
+        PRESENTATION_MESSAGE_TYPE_ARRAY_BUFFER;
+    output->data.Swap(input->data.get());
+  } else {
+    // string message
+    output->type =
+        presentation::PresentationMessageType::PRESENTATION_MESSAGE_TYPE_TEXT;
+    output->message.Swap(input->message.get());
+  }
+  return output.Pass();
 }
 
 void PresentationServiceImpl::DidNavigateAnyFrame(
     content::RenderFrameHost* render_frame_host,
     const content::LoadCommittedDetails& details,
     const content::FrameNavigateParams& params) {
   DVLOG(2) << "PresentationServiceImpl::DidNavigateAnyFrame";
   if (!FrameMatches(render_frame_host))
     return;
 
@@ skipping 181 matching lines @@
 void PresentationServiceImpl::DefaultSessionStartContext::Reset() {
   ScopedVector<DefaultSessionMojoCallback> callbacks;
   callbacks.swap(callbacks_);
   for (const auto& callback : callbacks)
     callback->Run(presentation::PresentationSessionInfoPtr());
   session_.reset();
 }
 
 }  // namespace content