Build WebRTC with data channel only.

webrtc/pc/createpeerconnectionfactory.cc

Index: webrtc/pc/createpeerconnectionfactory.cc
diff --git a/webrtc/pc/createpeerconnectionfactory.cc b/webrtc/pc/createpeerconnectionfactory.cc
new file mode 100644
index 0000000000000000000000000000000000000000..a17a545e4e239b4201eea5ed6a2a90366974640f
--- /dev/null
+++ b/webrtc/pc/createpeerconnectionfactory.cc
@@ -0,0 +1,120 @@
+/*
+ *  Copyright 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/api/audio_codecs/builtin_audio_decoder_factory.h"
+#include "webrtc/api/audio_codecs/builtin_audio_encoder_factory.h"
+#include "webrtc/api/peerconnectioninterface.h"
+#include "webrtc/base/bind.h"
+#include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/base/thread.h"
+#include "webrtc/call/callfactoryinterface.h"
+#include "webrtc/logging/rtc_event_log/rtc_event_log_factory_interface.h"
+#include "webrtc/media/engine/webrtcmediaengine.h"
+
+namespace webrtc {
+
+class MediaEngineCreator {
+ public:
+  std::unique_ptr<cricket::MediaEngineInterface> CreateMediaEngine_w(
+      AudioDeviceModule* default_adm,
+      rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory,
+      rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory,
+      cricket::WebRtcVideoEncoderFactory* video_encoder_factory,
+      cricket::WebRtcVideoDecoderFactory* video_decoder_factory,
+      rtc::scoped_refptr<AudioMixer> audio_mixer) {
+    return std::unique_ptr<cricket::MediaEngineInterface>(
+        cricket::WebRtcMediaEngineFactory::Create(
+            default_adm, audio_encoder_factory, audio_decoder_factory,
+            video_encoder_factory, video_decoder_factory, audio_mixer));
+  }
+};
+
+rtc::scoped_refptr<PeerConnectionFactoryInterface> CreatePeerConnectionFactory(
+    rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory,
+    rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory) {
+  // Create and start the worker thread to jcreate the MediaEngine.
+  rtc::Thread* worker_thread = rtc::Thread::Create().release();
+  worker_thread->Start();
+
+  MediaEngineCreator media_engine_creator;
+  std::unique_ptr<cricket::MediaEngineInterface> media_engine =
+      worker_thread->Invoke<std::unique_ptr<cricket::MediaEngineInterface>>(
+          RTC_FROM_HERE,
+          rtc::Bind(
+              &MediaEngineCreator::CreateMediaEngine_w, &media_engine_creator,
+              nullptr /*default_adm*/, audio_encoder_factory,
+              audio_decoder_factory, nullptr /*video_encoder_factory*/,
+              nullptr /*video_decoder_factory*/, nullptr /*audio_mixer*/));
+
+  std::unique_ptr<CallFactoryInterface> call_factory = CreateCallFactory();
+
+  std::unique_ptr<RtcEventLogFactoryInterface> event_log_factory =
+      CreateRtcEventLogFactory();
+
+  return CreateModularPeerConnectionFactory(
+      worker_thread, audio_encoder_factory, audio_decoder_factory,
+      std::move(media_engine), std::move(call_factory),
+      std::move(event_log_factory));
+}
+
+rtc::scoped_refptr<PeerConnectionFactoryInterface>
+CreatePeerConnectionFactory() {
+  return CreatePeerConnectionFactory(CreateBuiltinAudioEncoderFactory(),
+                                     CreateBuiltinAudioDecoderFactory());
+}
+
+rtc::scoped_refptr<PeerConnectionFactoryInterface>
+CreatePeerConnectionFactoryWithAudioMixer(
+    rtc::Thread* network_thread,
+    rtc::Thread* worker_thread,
+    rtc::Thread* signaling_thread,
+    AudioDeviceModule* default_adm,
+    rtc::scoped_refptr<AudioEncoderFactory> audio_encoder_factory,
+    rtc::scoped_refptr<AudioDecoderFactory> audio_decoder_factory,
+    cricket::WebRtcVideoEncoderFactory* video_encoder_factory,
+    cricket::WebRtcVideoDecoderFactory* video_decoder_factory,
+    rtc::scoped_refptr<AudioMixer> audio_mixer) {
+  MediaEngineCreator media_engine_creator;
+  std::unique_ptr<cricket::MediaEngineInterface> media_engine =
+      worker_thread->Invoke<std::unique_ptr<cricket::MediaEngineInterface>>(
+          RTC_FROM_HERE,
+          rtc::Bind(&MediaEngineCreator::CreateMediaEngine_w,
+                    &media_engine_creator, default_adm, audio_encoder_factory,
+                    audio_decoder_factory, video_encoder_factory,
+                    video_decoder_factory, audio_mixer));
+
+  std::unique_ptr<CallFactoryInterface> call_factory = CreateCallFactory();

[the sun, 2017/06/12 20:58:41]

Is there any way we could avoid the extra interface for the call factory and
just send in a lambda, function pointer, etc? Agree that requiring the caller of
CreateModularPCF() to have created the Call on the right thread isn't a good
idea.

[the sun, 2017/06/12 21:33:26]

You could use
https://chromium.googlesource.com/external/webrtc/+/master/webrtc/base/functi...

[Zhi Huang, 2017/06/12 22:18:58]

Sorry, I didn't get it. Are you suggestion passing in something like a function
ptr instead of the call_factory so that we don't need to call
call_factory.CreateCall() and we should replace all the "call_factory" with a
function ptr then?

Is it OK to use a factory here? It feels natural to me to pass in a factory when
creating a peerconnectionfactory.

+
+  std::unique_ptr<RtcEventLogFactoryInterface> event_log_factory =
+      CreateRtcEventLogFactory();
+
+  return CreateModularPeerConnectionFactory(
+      network_thread, worker_thread, signaling_thread, default_adm,
+      audio_encoder_factory, audio_decoder_factory, video_encoder_factory,
+      video_decoder_factory, audio_mixer, std::move(media_engine),
+      std::move(call_factory), std::move(event_log_factory));
+}
+
+rtc::scoped_refptr<PeerConnectionFactoryInterface>
+CreatePeerConnectionFactoryWithAudioMixer(
+    rtc::Thread* network_thread,
+    rtc::Thread* worker_thread,
+    rtc::Thread* signaling_thread,
+    AudioDeviceModule* default_adm,
+    cricket::WebRtcVideoEncoderFactory* encoder_factory,
+    cricket::WebRtcVideoDecoderFactory* decoder_factory,
+    rtc::scoped_refptr<AudioMixer> audio_mixer) {
+  return CreatePeerConnectionFactoryWithAudioMixer(
+      network_thread, worker_thread, signaling_thread, default_adm,
+      CreateBuiltinAudioEncoderFactory(), CreateBuiltinAudioDecoderFactory(),
+      encoder_factory, decoder_factory, audio_mixer);
+}
+
+}  // namespace webrtc