Add a fake audio input stream for testing purposes.

This will be used by unit tests in subsequent patches.
BUG=none
TEST=no new features added and nothing new to test

Review URL: http://codereview.chromium.org/2909015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@52464 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 80 insertions, 0 deletions

diff --git a/media/audio/fake_audio_input_stream.cc b/media/audio/fake_audio_input_stream.cc
new file mode 100644
index 0000000..9748d8e
--- /dev/null
+++ b/media/audio/fake_audio_input_stream.cc
@@ -0,0 +1,80 @@
+// Copyright (c) 2010 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/audio/fake_audio_input_stream.h"
+
+#include "base/at_exit.h"
+
+using base::Time;
+using base::TimeDelta;
+
+AudioInputStream* FakeAudioInputStream::MakeFakeStream(int channels,
+                                                       int bits_per_sample,
+                                                       int sampling_rate,
+                                                       int samples_per_packet) {
+  return new FakeAudioInputStream(channels, bits_per_sample, sampling_rate,
+                                  samples_per_packet);
+}
+
+FakeAudioInputStream::FakeAudioInputStream(int channels, int bits_per_sample,
+                                           int sampling_rate,
+                                           int samples_per_packet)
+    : callback_(NULL),
+      buffer_size_((channels * bits_per_sample * samples_per_packet) / 8),
+      thread_("FakeAudioRecordingThread"),
+      callback_interval_ms_((samples_per_packet * 1000) / sampling_rate) {
+  // This object is ref counted (so that it can be used with Thread, PostTask)
+  // but the caller expects a plain pointer. So we take a reference here and
+  // will Release() ourselves in Close().
+  AddRef();
+}
+
+bool FakeAudioInputStream::Open() {
+  buffer_.reset(new uint8[buffer_size_]);
+  memset(buffer_.get(), 0, buffer_size_);
+  return true;
+}
+
+void FakeAudioInputStream::Start(AudioInputCallback* callback)  {
+  DCHECK(!thread_.IsRunning());
+  callback_ = callback;
+  last_callback_time_ = Time::Now();
+  thread_.Start();
+  thread_.message_loop()->PostDelayedTask(
+      FROM_HERE,
+      NewRunnableMethod(this, &FakeAudioInputStream::DoCallback),
+      callback_interval_ms_);
+}
+
+void FakeAudioInputStream::DoCallback() {
+  DCHECK(callback_);
+  callback_->OnData(this, buffer_.get(), buffer_size_);
+
+  Time now = Time::Now();
+  int64 next_callback_ms = (last_callback_time_ +
+      TimeDelta::FromMilliseconds(callback_interval_ms_ * 2) -
+      now).InMilliseconds();
+  // If we are falling behind, try to catch up as much as we can in the next
+  // callback.
+  if (next_callback_ms < 0)
+    next_callback_ms = 0;
+
+  last_callback_time_ = now;
+  thread_.message_loop()->PostDelayedTask(
+      FROM_HERE,
+      NewRunnableMethod(this, &FakeAudioInputStream::DoCallback),
+      next_callback_ms);
+}
+
+void FakeAudioInputStream::Stop() {
+  thread_.Stop();
+}
+
+void FakeAudioInputStream::Close() {
+  if (callback_) {
+    callback_->OnClose(this);
+    callback_ = NULL;
+  }
+  Release();  // Destoys this object.
+}