Add the copresence DirectiveHandler.

components/copresence/handlers/audio/audio_directive_handler.cc

+// Copyright 2014 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 "components/copresence/handlers/audio/audio_directive_handler.h"
+
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/message_loop/message_loop.h"

[xiyuan, 2014/07/25 21:02:08]

nit: not used?

[rkc, 2014/07/28 21:02:01]

Done.

+#include "base/time/time.h"
+#include "components/copresence/mediums/audio/audio_player.h"
+#include "components/copresence/mediums/audio/audio_recorder.h"
+#include "components/copresence/proto/data.pb.h"
+#include "media/base/audio_bus.h"
+
+namespace copresence {
+
+// Public methods.
+
+AudioDirectiveHandler::AudioDirectiveHandler(
+    const AudioRecorder::DecodeSamplesCallback& decode_cb,
+    const AudioDirectiveList::EncodeTokenCallback& encode_cb)
+    : directive_list_(encode_cb,
+                      base::Bind(&AudioDirectiveHandler::ExecuteNextTransmit,

[xiyuan, 2014/07/25 21:02:09]

nit: #include "base/bind.h"

[rkc, 2014/07/28 21:02:00]

Done.

+                                 base::Unretained(this))),
+      player_(new AudioPlayer()),
+      recorder_(new AudioRecorder(decode_cb)) {
+}
+
+AudioDirectiveHandler::AudioDirectiveHandler(
+    const AudioDirectiveList::EncodeTokenCallback& encode_cb)
+    : directive_list_(encode_cb,
+                      base::Bind(&AudioDirectiveHandler::ExecuteNextTransmit,
+                                 base::Unretained(this))),
+      player_(NULL),
+      recorder_(NULL) {
+}
+
+AudioDirectiveHandler::~AudioDirectiveHandler() {
+  if (player_)
+    player_->Finalize();
+  if (recorder_)
+    recorder_->Finalize();
+}
+
+void AudioDirectiveHandler::AddInstruction(
+    const copresence::TokenInstruction& instruction,

[Daniel Erat, 2014/07/25 23:09:01]

isn't all this code already in the copresence namespace?

[rkc, 2014/07/28 21:02:00]

Yep, whoops. This is a vestige of the open sourcing process, they weren't in the
same namespace then :)
Fixed.

+    base::TimeDelta ttl) {
+  switch (instruction.token_instruction_type()) {
+    case copresence::TRANSMIT:

[Daniel Erat, 2014/07/25 23:09:01]

please rename these enums to be more descriptive, e.g. TRANSMIT_INSTRUCTION,
RECEIVE_INSTRUCTION, etc.

[rkc, 2014/07/28 21:02:01]

The enums are created by the protoc compiler. We pull the protos automatically
from the Copresence code, so any changes I'd make to them locally will get wiped
anytime we pull again.

+      DVLOG(2) << "Audio Transmit Directive received. Token: "
+               << instruction.token_id()
+               << " with TTL=" << ttl.InMilliseconds();
+      // TODO(rkc): Fill in the op_id once we get it from the directive.
+      directive_list_.AddTransmitDirective(
+          instruction.token_id(), std::string(), ttl);
+      break;
+    case copresence::RECEIVE:
+      DVLOG(2) << "Audio Receive Directive received. TTL="
+               << ttl.InMilliseconds();
+      // TODO(rkc): Fill in the op_id once we get it from the directive.
+      directive_list_.AddReceiveDirective(std::string(), ttl);
+      break;
+    case copresence::UNKNOWN_TOKEN_INSTRUCTION_TYPE:
+    default:

[xiyuan, 2014/07/25 21:02:09]

nit: If we don't use "default" here, the compiler would catch missing cases.

[Daniel Erat, 2014/07/25 23:09:01]

yeah, but then the code won't be able to detect invalid values that don't
correspond to valid enum values :-(

[rkc, 2014/07/28 21:02:00]

Done.

[rkc, 2014/07/28 21:02:01]

So.. I'll keep this as is then :)

+      LOG(WARNING) << "Unknown Audio Transmit Directive received.";
+      break;
+  }
+  // ExecuteNextTransmit will be called by the directive_list_ when Add is done.

[Daniel Erat, 2014/07/25 23:09:01]

s/the directive_list_/|directive_list_|/

[rkc, 2014/07/28 21:02:00]

Done.

+  ExecuteNextReceive();
+}
+
+// Private methods.
+
+void AudioDirectiveHandler::ExecuteNextTransmit() {
+  scoped_ptr<AudioDirective> transmit(directive_list_.GetNextTransmit());
+  if (transmit.get())

[xiyuan, 2014/07/25 21:02:09]

nit: get rid of ".get()"

[rkc, 2014/07/28 21:02:01]

Done.

+    PlayAudio(transmit->samples, transmit->end_time - base::Time::Now());
+}
+
+void AudioDirectiveHandler::ExecuteNextReceive() {
+  scoped_ptr<AudioDirective> receive(directive_list_.GetNextReceive());
+  if (receive.get())

[xiyuan, 2014/07/25 21:02:08]

nit: get rid of ".get()"

[rkc, 2014/07/28 21:02:00]

Done.

+    RecordAudio(receive->end_time - base::Time::Now());
+}
+
+void AudioDirectiveHandler::PlayAudio(

[Daniel Erat, 2014/07/25 23:09:01]

please reorder the methods in the .cc file to match the order in the .h file

[rkc, 2014/07/28 21:02:00]

Done.

+    const scoped_refptr<media::AudioBusRefCounted>& samples,
+    base::TimeDelta duration) {
+  player_->Play(samples);
+  stop_playback_timer_.Start(
+      FROM_HERE, duration, this, &AudioDirectiveHandler::StopPlayback);
+}
+
+void AudioDirectiveHandler::RecordAudio(base::TimeDelta duration) {
+  recorder_->Record();
+  stop_recording_timer_.Start(
+      FROM_HERE, duration, this, &AudioDirectiveHandler::StopRecording);
+}
+
+void AudioDirectiveHandler::StopPlayback() {
+  player_->Stop();
+  DVLOG(2) << "Done playing audio.";
+  ExecuteNextTransmit();
+}
+
+void AudioDirectiveHandler::StopRecording() {
+  recorder_->Stop();
+  DVLOG(2) << "Done recording audio.";
+  ExecuteNextReceive();
+}
+
+}  // namespace copresence