Media Remoting: Add remoting control logic for encrypted contents.

media/remoting/remoting_source_impl.cc

+// Copyright 2016 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 "media/remoting/remoting_source_impl.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+
+namespace media {
+
+RemotingSourceImpl::RemotingSourceImpl(
+    mojom::RemotingSourceRequest source_request,
+    mojom::RemoterPtr remoter)
+    : binding_(this, std::move(source_request)), remoter_(std::move(remoter)) {}
+
+RemotingSourceImpl::~RemotingSourceImpl() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (!clients_.empty()) {
+    Shutdown();
+    clients_.clear();
+  }
+}
+
+void RemotingSourceImpl::OnSinkAvailable() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (state_ == RemotingSessionState::SESSION_UNAVAILABLE)
+    UpdateAndNotifyState(RemotingSessionState::SESSION_CAN_START);
+}
+
+void RemotingSourceImpl::OnSinkGone() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (state_ == RemotingSessionState::SESSION_PERMANENTLY_STOPPED)
+    return;
+  if (state_ == RemotingSessionState::SESSION_CAN_START) {
+    UpdateAndNotifyState(RemotingSessionState::SESSION_UNAVAILABLE);
+    return;
+  }
+  if (state_ == RemotingSessionState::SESSION_STARTED ||
+      state_ == RemotingSessionState::SESSION_STARTING) {
+    VLOG(1) << "Sink is gone in a remoting session.";
+    // Remoting is being stopped by Remoter.
+    UpdateAndNotifyState(RemotingSessionState::SESSION_STOPPING);
+  }
+}
+
+void RemotingSourceImpl::OnStarted() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  VLOG(1) << "Remoting started successively.";
+  if (clients_.empty() ||
+      state_ == RemotingSessionState::SESSION_PERMANENTLY_STOPPED ||
+      state_ == RemotingSessionState::SESSION_STOPPING) {
+    for (Client* client : clients_)
+      client->OnStarted(false);
+    return;
+  }
+  for (Client* client : clients_)
+    client->OnStarted(true);

[xhwang, 2016/11/01 08:21:29]

Actually you notify all clients, so the comment is a bit misleading.

[xjz, 2016/11/01 21:55:53]

In general, no. Only when there are requests from multiple clients to
StartRemoting() at almost same time while the session is not started yet, then
all these clients will get notified when the session is started. If the session
is already started, only the client that call StartRemoting() will get notified.
Note: The same session is shared by multiple (might be 2 in our case) clients.

+  state_ = RemotingSessionState::SESSION_STARTED;
+}
+
+void RemotingSourceImpl::OnStartFailed(mojom::RemotingStartFailReason reason) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  VLOG(1) << "Failed to start remoting:" << reason;
+  for (Client* client : clients_)
+    client->OnStarted(false);
+  if (state_ == RemotingSessionState::SESSION_PERMANENTLY_STOPPED)
+    return;
+  state_ = RemotingSessionState::SESSION_UNAVAILABLE;
+}
+
+void RemotingSourceImpl::OnStopped(mojom::RemotingStopReason reason) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  VLOG(1) << "Remoting stopped: " << reason;
+  if (state_ == RemotingSessionState::SESSION_PERMANENTLY_STOPPED)
+    return;
+  RemotingSessionState state = RemotingSessionState::SESSION_UNAVAILABLE;
+  UpdateAndNotifyState(state);
+}
+
+void RemotingSourceImpl::OnMessageFromSink(
+    const std::vector<uint8_t>& message) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  // TODO(xjz): Merge with Eric's CL to handle the RPC messages here.
+  NOTIMPLEMENTED();
+}
+
+void RemotingSourceImpl::UpdateAndNotifyState(RemotingSessionState state) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (state_ == state)
+    return;
+  state_ = state;
+  for (Client* client : clients_)
+    client->OnSessionStateChanged();
+}
+
+void RemotingSourceImpl::StartRemoting(Client* client) {
+  DCHECK(std::find(clients_.begin(), clients_.end(), client) != clients_.end());
+
+  switch (state_) {
+    case SESSION_CAN_START:
+      remoter_->Start();
+      UpdateAndNotifyState(RemotingSessionState::SESSION_STARTING);
+      break;
+    case SESSION_STARTING:
+      break;
+    case SESSION_STARTED:
+      client->OnStarted(true);
+      break;
+    case SESSION_STOPPING:
+    case SESSION_UNAVAILABLE:
+    case SESSION_PERMANENTLY_STOPPED:
+      client->OnStarted(false);

[xhwang, 2016/11/01 08:21:29]

hmm, now I see why you have |client|...

Does it make sense to make sure clients call StartRemoting() only in the right
state (CAN_START)?

[xjz, 2016/11/01 21:55:53]

That may make the switching logic more complicate. Both CdmController and
RendererController share same session, and the session might be already started
(SESSION_STARTED) when create remoting cdm, the current logic allow
RendererController call StartRemoting() to switch to remoting renderer, just
same as that for non-EME case.

+      break;
+  }
+}
+
+void RemotingSourceImpl::StopRemoting(Client* client) {
+  DCHECK(std::find(clients_.begin(), clients_.end(), client) != clients_.end());
+
+  VLOG(1) << "RemotingSourceImpl::StopRemoting: " << state_;
+
+  if (state_ != RemotingSessionState::SESSION_STARTING &&
+      state_ != RemotingSessionState::SESSION_STARTED)
+    return;
+
+  remoter_->Stop(mojom::RemotingStopReason::LOCAL_PLAYBACK);
+  UpdateAndNotifyState(RemotingSessionState::SESSION_STOPPING);
+}
+
+void RemotingSourceImpl::AddClient(Client* client) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (std::find(clients_.begin(), clients_.end(), client) != clients_.end())
+    return;

[xhwang, 2016/11/01 08:21:29]

If this happens, it'll be a programming error... DCHECK?

[xjz, 2016/11/01 21:55:53]

Done.

+  clients_.push_back(client);
+  client->OnSessionStateChanged();
+}
+
+void RemotingSourceImpl::RemoveClient(Client* client) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  auto it = std::find(clients_.begin(), clients_.end(), client);
+  if (it == clients_.end())
+    return;

[xhwang, 2016/11/01 08:21:29]

ditto, DCHECK?

[xjz, 2016/11/01 21:55:53]

Done.

+
+  clients_.erase(it);
+  if (clients_.empty() && (state_ == RemotingSessionState::SESSION_STARTED ||
+                           state_ == RemotingSessionState::SESSION_STARTING)) {
+    remoter_->Stop(mojom::RemotingStopReason::SOURCE_GONE);
+    state_ = RemotingSessionState::SESSION_STOPPING;
+  }
+}
+
+void RemotingSourceImpl::Shutdown() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (state_ == RemotingSessionState::SESSION_STARTED ||
+      state_ == RemotingSessionState::SESSION_STARTING)
+    remoter_->Stop(mojom::RemotingStopReason::UNEXPECTED_FAILURE);
+  UpdateAndNotifyState(RemotingSessionState::SESSION_PERMANENTLY_STOPPED);
+}
+
+}  // namespace media