[Presentation API] (alternative) 1-UA: send message between controller and receiver page

chrome/browser/media/router/offscreen_presentation_manager.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 "chrome/browser/media/router/offscreen_presentation_manager.h"
+
+#include <utility>
+
+#include "base/memory/ptr_util.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 "url/gurl.h"
+
+namespace media_router {
+
+// OffscreenPresentationManager implementation.
+OffscreenPresentationManager::OffscreenPresentationManager() {}
+
+OffscreenPresentationManager::~OffscreenPresentationManager() {}
+
+OffscreenPresentationManager::OffscreenPresentationMap::iterator

[imcheng, 2016/11/01 17:20:28]

it looks like you can just return OffscreenPresentation* here.

[zhaobin, 2016/11/02 03:55:47]

Done.

+OffscreenPresentationManager::GetOrCreateOffscreenPresentation(
+    const std::string& presentation_id,
+    const GURL& presentation_url) {
+  auto it = offscreen_presentations_.find(presentation_id);
+  if (it == offscreen_presentations_.end()) {
+    it = offscreen_presentations_
+             .insert(std::make_pair(presentation_id,
+                                    base::WrapUnique(new OffscreenPresentation(
+                                        presentation_id, presentation_url))))
+             .first;

[imcheng, 2016/11/01 17:20:29]

add ->second

[zhaobin, 2016/11/02 03:55:47]

Done.

+  }
+  return it;
+}
+
+void OffscreenPresentationManager::RegisterOffscreenPresentationController(
+    const std::string& presentation_id,
+    const GURL& presentation_url,
+    const RenderFrameHostId& render_frame_host_id,
+    content::PresentationConnectionPtr controller) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id
+           << ", [render_frame_host_id]: " << render_frame_host_id.second;
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto presentation =
+      GetOrCreateOffscreenPresentation(presentation_id, presentation_url);
+  presentation->second->RegisterController(render_frame_host_id,
+                                           std::move(controller));
+}
+
+void OffscreenPresentationManager::UnregisterOffscreenPresentationController(
+    const std::string& presentation_id,
+    const RenderFrameHostId& render_frame_host_id) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id
+           << ", [render_frame_host_id]: " << render_frame_host_id.second;
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto it = offscreen_presentations_.find(presentation_id);
+  if (it == offscreen_presentations_.end())
+    return;
+
+  // Remove presentation if no controller and receiver.
+  it->second->UnregisterController(render_frame_host_id);
+  if (it->second->pending_controllers_.size() == 0 &&

[imcheng, 2016/11/01 17:20:28]

nit: define a IsValid method in OffscreenPresentation that encapsulates this
logic.

[zhaobin, 2016/11/02 03:55:47]

Done.

+      it->second->receiver_callback_.is_null())
+    offscreen_presentations_.erase(presentation_id);
+}
+
+void OffscreenPresentationManager::OnOffscreenPresentationReceiverCreated(
+    const std::string& presentation_id,
+    const GURL& presentation_url,
+    const content::ReceiverConnectionAvailableCallback& receiver_callback) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id;
+  DCHECK(thread_checker_.CalledOnValidThread());
+  auto presentation =
+      GetOrCreateOffscreenPresentation(presentation_id, presentation_url);
+  presentation->second->RegisterReceiver(receiver_callback);
+}
+
+void OffscreenPresentationManager::OnOffscreenPresentationReceiverTerminated(

[imcheng, 2016/11/01 17:20:28]

how will the controllers be informed that the PresentationConnection has
terminated?

[zhaobin, 2016/11/02 03:55:46]

Not implemented yet. Controller connection should already connect with receiver
connection by the time we call connection.close() or connection.terminate().
Thinking of doing it by communicating state changes between connections directly
instead of via OPM.

+    const std::string& presentation_id) {
+  DVLOG(2) << __FUNCTION__ << " [presentation_id]: " << presentation_id;
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  offscreen_presentations_.erase(presentation_id);
+}
+
+// OffscreenPresentation implementation.
+OffscreenPresentationManager::OffscreenPresentation::OffscreenPresentation(
+    const std::string& presentation_id,
+    const GURL& presentation_url)
+    : presentation_id_(presentation_id),
+      presentation_url_(presentation_url),
+      receiver_callback_(nullptr) {}

[imcheng, 2016/11/01 17:20:28]

is it necessary to initialize receiver_callback_?

[zhaobin, 2016/11/02 03:55:47]

Done.

+
+OffscreenPresentationManager::OffscreenPresentation::~OffscreenPresentation() {}
+
+void OffscreenPresentationManager::OffscreenPresentation::RegisterController(
+    const RenderFrameHostId& render_frame_host_id,
+    content::PresentationConnectionPtr controller) {
+  if (receiver_callback_) {
+    // Create a receiver PresentationConnectionPtr, and connect it with

[imcheng, 2016/11/01 17:20:28]

It sounds like this comment belongs in the definition of the callback being
passed in.

[zhaobin, 2016/11/02 03:55:47]

Done.

+    // controller PresentationConnectionPtr.
+    receiver_callback_.Run(
+        content::PresentationSessionInfo(presentation_url_, presentation_id_),
+        std::move(controller));
+  } else {
+    pending_controllers_.insert(
+        std::make_pair(render_frame_host_id, std::move(controller)));
+  }
+}
+
+void OffscreenPresentationManager::OffscreenPresentation::UnregisterController(
+    const RenderFrameHostId& render_frame_host_id) {
+  pending_controllers_.erase(render_frame_host_id);
+}
+
+void OffscreenPresentationManager::OffscreenPresentation::RegisterReceiver(
+    const content::ReceiverConnectionAvailableCallback& receiver_callback) {
+  DCHECK(!receiver_callback_);
+
+  for (auto& controller : pending_controllers_) {
+    receiver_callback.Run(
+        content::PresentationSessionInfo(presentation_url_, presentation_id_),
+        std::move(controller.second));
+  }
+  receiver_callback_ = receiver_callback;
+  pending_controllers_.clear();
+}
+
+}  // namespace media_router