Added first layer of the echo canceller 3 functionality

webrtc/modules/audio_processing/aec3/block_processor.cc

+/*
+ *  Copyright (c) 2016 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/modules/audio_processing/aec3/block_processor.h"
+
+#include "webrtc/base/atomicops.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/modules/audio_processing/aec3/aec3_constants.h"
+
+namespace webrtc {
+namespace {
+
+class BlockProcessorImpl final : public BlockProcessor {
+ public:
+  explicit BlockProcessorImpl(int sample_rate_hz);
+  ~BlockProcessorImpl() override;
+
+  void ProcessCapture(bool known_echo_path_change,
+                      bool saturated_microphone_signal,
+                      std::vector<std::vector<float>>* capture_block) override;
+
+  bool BufferRender(std::vector<std::vector<float>>* block) override;
+
+  void ReportEchoLeakage(bool leakage_detected) override;
+
+ private:
+  const size_t sample_rate_hz_;
+  static int instance_count_;
+  std::unique_ptr<ApmDataDumper> data_dumper_;
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(BlockProcessorImpl);
+};
+
+int BlockProcessorImpl::instance_count_ = 0;
+
+BlockProcessorImpl::BlockProcessorImpl(int sample_rate_hz)
+    : sample_rate_hz_(sample_rate_hz),
+      data_dumper_(new ApmDataDumper(instance_count_)) {
+  instance_count_ = rtc::AtomicOps::Increment(&instance_count_);

[ivoc, 2016/12/23 10:32:33]

If I understand correctly this is actually wrong. The Increment function will
already increment the variable, so there's no need for the assignment. In fact,
rtc::AtomicOps::Increment returns the old value (before the increment), so the
assignment undoes the increment.
I think the best place to put the Increment operation is on the line above this
one:
data_dumper_(new ApmDataDumper(rtc::AtomicOps::Increment(&instance_count_))
Doing it that way means it can never happen that different ApmDataDumpers are
constructed with the same instance_count_, which can still happen with the
current code depending on the ordering of operation between threads.

[hlundin-webrtc, 2016/12/23 13:38:12]

Oh! Good find! I didn't look into the declaration of Increment, but your
reasoning makes sense to me.

[peah-webrtc, 2017/01/02 08:45:10]

Great find and suggestion! Thanks!!!

Done.

[peah-webrtc, 2017/01/02 08:45:10]

Acknowledged.

+}
+
+BlockProcessorImpl::~BlockProcessorImpl() = default;
+
+void BlockProcessorImpl::ProcessCapture(
+    bool known_echo_path_change,
+    bool saturated_microphone_signal,
+    std::vector<std::vector<float>>* capture_block) {
+  RTC_DCHECK_EQ(NumBandsForRate(sample_rate_hz_), capture_block->size());
+  RTC_DCHECK_EQ(kBlockSize, (*capture_block)[0].size());
+}
+
+bool BlockProcessorImpl::BufferRender(
+    std::vector<std::vector<float>>* render_block) {
+  RTC_DCHECK_EQ(NumBandsForRate(sample_rate_hz_), render_block->size());
+  RTC_DCHECK_EQ(kBlockSize, (*render_block)[0].size());
+  return false;
+}
+
+void BlockProcessorImpl::ReportEchoLeakage(bool leakage_detected) {}
+
+}  // namespace
+
+BlockProcessor* BlockProcessor::Create(int sample_rate_hz) {
+  return new BlockProcessorImpl(sample_rate_hz);
+}
+
+}  // namespace webrtc