Implement renderer AudioDevice API for low-latency audio output...

webkit/glue/webaudiodevice_impl.cc

+// 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 "webkit/glue/webaudiodevice_impl.h"
+
+using WebKit::WebAudioDevice;
+using WebKit::WebVector;
+
+namespace webkit_glue {
+
+WebAudioDeviceImpl::WebAudioDeviceImpl(size_t buffer_size,
+                                       unsigned channels,
+                                       double sample_rate,
+                                       WebAudioDevice::RenderCallback* callback)
+  : audio_device_(buffer_size,

[scherkus (not reviewing), 2011/01/10 23:42:32]

nit: should be indented extra 2 spaces

nit: the audio_device_ line can fit on a single line

[Chris Rogers, 2011/01/11 23:01:02]

Done.

+                  channels,
+                  sample_rate,
+                  this),
+    client_callback_(callback) {
+}
+
+WebAudioDeviceImpl::~WebAudioDeviceImpl() {
+  stop();
+}
+
+void WebAudioDeviceImpl::start() {
+  audio_device_.Start();
+}
+
+void WebAudioDeviceImpl::stop() {
+  audio_device_.Stop();
+}
+
+void WebAudioDeviceImpl::render(const std::vector<float*>& audio_data,
+                                size_t number_of_frames) {
+  // Make the client callback to get rendered audio.
+  if (client_callback_) {

[scherkus (not reviewing), 2011/01/10 23:42:32]

is client_callback_ allowed to be NULL?

looks like it's set once (in ctor)

[Chris Rogers, 2011/01/11 23:01:02]

It's not allowed to be NULL.  This is just a safety check.  I just added a
DCHECK as well...

On 2011/01/10 23:42:32, scherkus wrote:

+    // Wrap the pointers using WebVector.
+    WebVector<float*> web_audio_data(audio_data.size());
+    for (unsigned i = 0; i < audio_data.size(); ++i)

[scherkus (not reviewing), 2011/01/10 23:42:32]

unsigned -> size_t

[Chris Rogers, 2011/01/11 23:01:02]

Done.

+      web_audio_data[i] = audio_data[i];
+
+    client_callback_->render(web_audio_data, number_of_frames);
+  }
+}
+
+}  // namespace webkit_glue