[Presentation API] 1-UA presentation support + presenter APIs.

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 "content/public/browser/presentation_session_state_listener.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/web_contents.h"
+
+namespace media_router {
+
+OffscreenPresentationManager::OffscreenPresentationSession::
+    OffscreenPresentationSession(
+        OffscreenPresentationManager::OffscreenPresentationConnection*
+            connection)
+    : state_change_listener_(nullptr), connection_(connection) {
+  DCHECK(connection_);
+}
+
+OffscreenPresentationManager::OffscreenPresentationSession::
+    ~OffscreenPresentationSession() {
+  if (connection_)
+    connection_->RemoveSession(this);
+}
+
+void OffscreenPresentationManager::OffscreenPresentationSession::SendMessage(
+    scoped_ptr<content::PresentationSessionMessage> message,
+    const content::SendMessageCallback& callback) {
+  if (!connection_) {
+    callback.Run(false);
+    return;
+  }
+
+  connection_->SendMessageFrom(this, message.Pass(), callback);
+}
+
+void OffscreenPresentationManager::OffscreenPresentationSession::
+    ListenForMessages(
+        const content::PresentationSessionMessageCallback& callback) {
+  DCHECK(messages_callback_.is_null());
+  messages_callback_ = callback;
+}
+
+void OffscreenPresentationManager::OffscreenPresentationSession::
+    ListenForStateChanges(content::PresentationSessionStateListener* listener) {
+  DCHECK(!state_change_listener_);
+  state_change_listener_ = listener;

[whywhat, 2015/10/13 15:21:30]

nit: DCHECK(listener);

[imcheng, 2015/10/17 01:00:23]

Done.

+}
+
+void OffscreenPresentationManager::OffscreenPresentationSession::
+    OnSessionStateChanged(content::PresentationSessionState state) {
+  if (state_change_listener_)

[whywhat, 2015/10/13 15:21:30]

Shouldn't be a DCHECK rather so we always have a listener for state changes
before they happen? Or should we queue them?

[imcheng, 2015/10/17 01:00:23]

I wouldn't expect a listener to always exist when a state change occurs. I don't
think it's important to queue the state changes. The page can get the current
state of the session already.

+    state_change_listener_->OnSessionStateChanged(state);
+
+  if (state == content::PRESENTATION_SESSION_STATE_DISCONNECTED)
+    connection_ = nullptr;
+}
+
+void OffscreenPresentationManager::OffscreenPresentationSession::
+    OnMessageReceived(scoped_ptr<content::PresentationSessionMessage> message) {
+  if (!messages_callback_.is_null()) {

[whywhat, 2015/10/13 15:21:30]

nit: Seems like the inverse condition would be more readable:

if (messages_callback_.is_null())
  return;

Should we queue messages until the callback is given or assert it's there by the
time when the messages come?

[imcheng, 2015/10/17 01:00:23]

Done. For queueing, it can be done along with batching. We can have a bounded
fifo queue for it.

+    ScopedVector<content::PresentationSessionMessage> messages;

[mark a. foltz, 2015/10/12 21:56:10]

Please add a TODO to handle multiple messages at once.

[imcheng, 2015/10/17 01:00:23]

Moved comment from OffscreenPresentationConnection

+    messages.push_back(message.release());
+    messages_callback_.Run(messages.Pass(), true);
+  }
+}
+
+OffscreenPresentationManager::~OffscreenPresentationManager() {}
+
+void OffscreenPresentationManager::RegisterOffscreenPresentationReceiver(
+    const std::string& presentation_id,
+    const ReceiverSessionAvailableCallback& receiver_available_callback) {
+  DCHECK(!ContainsKey(offscreen_presentations_, presentation_id));

[mark a. foltz, 2015/10/12 21:56:10]

How do you intend to handle this case in release builds?

[imcheng, 2015/10/17 01:00:23]

This is a "can't happen" situation since the presentation id comes from MR. But
adding it for sanity check.

+
+  offscreen_presentations_.insert(
+      presentation_id,
+      make_scoped_ptr(new OffscreenPresentation(
+          presentation_id, receiver_available_callback, this)));
+}
+
+void OffscreenPresentationManager::UnregisterOffscreenPresentationReceiver(
+    const std::string& presentation_id) {
+  DCHECK(ContainsKey(offscreen_presentations_, presentation_id));

[mark a. foltz, 2015/10/12 21:56:10]

Similar comments

[imcheng, 2015/10/17 01:00:23]

Ditto.

+  offscreen_presentations_.erase(presentation_id);
+}
+
+scoped_ptr<OffscreenPresentationManager::OffscreenPresentationSession>
+OffscreenPresentationManager::ConnectToOffscreenPresentation(
+    const std::string& presentation_id,
+    const RenderFrameHostId& controller_frame_id) {
+  auto it = offscreen_presentations_.find(presentation_id);
+  if (it == offscreen_presentations_.end())
+    return scoped_ptr<OffscreenPresentationSession>();
+
+  return it->second->AddConnection(controller_frame_id);
+}
+
+OffscreenPresentationManager::OffscreenPresentationManager() {}
+
+OffscreenPresentationManager::OffscreenPresentationConnection::
+    OffscreenPresentationConnection(
+        const RenderFrameHostId& controller_frame_id,
+        OffscreenPresentation* presentation)
+    : controller_frame_id_(controller_frame_id),
+      presentation_(presentation),
+      controller_(nullptr),
+      receiver_(nullptr) {
+  DCHECK(presentation_);
+}
+
+void OffscreenPresentationManager::OffscreenPresentationConnection::Init(
+    OffscreenPresentationManager::OffscreenPresentationSession* controller,
+    OffscreenPresentationManager::OffscreenPresentationSession* receiver) {
+  DCHECK(!controller_);
+  DCHECK(!receiver_);
+  DCHECK(controller);
+  DCHECK(receiver);
+  controller_ = controller;
+  receiver_ = receiver;
+}
+
+OffscreenPresentationManager::OffscreenPresentationConnection::
+    ~OffscreenPresentationConnection() {
+  DCHECK(!controller_ || !receiver_);
+}
+
+void OffscreenPresentationManager::OffscreenPresentationConnection::
+    RemoveSession(OffscreenPresentationSession* session) {
+  DCHECK(session);
+  OffscreenPresentationManager::OffscreenPresentationSession* other_session =
+      nullptr;
+  if (session == controller_) {
+    controller_ = nullptr;
+    other_session = receiver_;
+  } else {
+    DCHECK(session == receiver_);
+    receiver_ = nullptr;
+    other_session = controller_;
+  }
+
+  DCHECK(other_session);
+  other_session->OnSessionStateChanged(
+      content::PRESENTATION_SESSION_STATE_DISCONNECTED);
+  presentation_->RemoveConnection(controller_frame_id_);
+  // |this| is deleted beyond this point.
+}
+
+void OffscreenPresentationManager::OffscreenPresentationConnection::
+    SendMessageFrom(OffscreenPresentationSession* session,
+                    scoped_ptr<content::PresentationSessionMessage> message,
+                    const content::SendMessageCallback& callback) {
+  OffscreenPresentationManager::OffscreenPresentationSession* other_session =
+      session == controller_ ? receiver_ : controller_;
+  DCHECK(other_session);
+
+  // TODO(imcheng): Implement message batching.
+  session->OnMessageReceived(message.Pass());

[whywhat, 2015/10/13 15:21:30]

Did you mean other_session?

[imcheng, 2015/10/17 01:00:23]

Done. Good catch, thanks!

+  callback.Run(true);
+}
+
+OffscreenPresentationManager::OffscreenPresentation::OffscreenPresentation(
+    const std::string& presentation_id,
+    const ReceiverSessionAvailableCallback& receiver_available_callback,
+    OffscreenPresentationManager* manager)
+    : presentation_id_(presentation_id),
+      receiver_available_callback_(receiver_available_callback),
+      manager_(manager) {
+  DCHECK(!receiver_available_callback_.is_null());
+  DCHECK(manager_);
+}
+
+OffscreenPresentationManager::OffscreenPresentation::~OffscreenPresentation() {
+  // The receiver must have destroyed all connections before unregistration.

[mark a. foltz, 2015/10/12 21:56:10]

Can unregistration do this as a side effect?

It would seem cleaner for the OPM to watch the WebContents and the OPM to
coordinate the teardown of all the presentation sessions in response to
window.close(), session.terminate(), failed streaming or navigation, instead of
having each of these code paths manage the lifetimes of the sessions.

[imcheng, 2015/10/17 01:00:23]

All of the scenarios should already be covered by the offscreen WebContents
being destroyed. RPSDImpl's lifetime is already tied to it, so it's pretty
straightforward to destroy all sessions and unregister in RPSDImpl's dtor.

+  DCHECK(connections_.empty());
+}
+
+scoped_ptr<OffscreenPresentationManager::OffscreenPresentationSession>
+OffscreenPresentationManager::OffscreenPresentation::AddConnection(
+    const RenderFrameHostId& controller_frame_id) {
+  DCHECK(!ContainsKey(connections_, controller_frame_id));

[mark a. foltz, 2015/10/12 21:56:10]

Behavior in release builds?

[imcheng, 2015/10/17 01:00:23]

Changed this to LOG(ERROR) and return nullptr. In general we should prevent
having multiple presentations with same id in a controlling context.

+
+  scoped_ptr<OffscreenPresentationConnection> connection(
+      new OffscreenPresentationConnection(controller_frame_id, this));
+  scoped_ptr<OffscreenPresentationSession> controller_session(
+      new OffscreenPresentationSession(connection.get()));
+  scoped_ptr<OffscreenPresentationSession> receiver_session(
+      new OffscreenPresentationSession(connection.get()));
+
+  connection->Init(controller_session.get(), receiver_session.get());
+  connections_.insert(controller_frame_id, connection.Pass());
+  receiver_available_callback_.Run(receiver_session.Pass());
+  return controller_session.Pass();
+}
+
+void OffscreenPresentationManager::OffscreenPresentation::RemoveConnection(
+    const RenderFrameHostId& controller_frame_id) {
+  DCHECK(ContainsKey(connections_, controller_frame_id));

[mark a. foltz, 2015/10/12 21:56:10]

Ditto

[imcheng, 2015/10/17 01:00:23]

erase() is no-op is key is not found so we should be fine here.

+  connections_.erase(controller_frame_id);
+}
+
+}  // namespace media_router