Add Thread-safe wrapper for RtcpTransceiver

Bug: webrtc:8239
Change-Id: I4cc2f7f2b27c764e1aae734f933902102b345614
Reviewed-on: https://webrtc-review.googlesource.com/21680
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20714}

modules/rtp_rtcp/source/rtcp_transceiver.cc

@@ -0,0 +1,93 @@
+/*
+ *  Copyright (c) 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 "modules/rtp_rtcp/source/rtcp_transceiver.h"
+
+#include <utility>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/event.h"
+#include "rtc_base/ptr_util.h"
+#include "rtc_base/timeutils.h"
+
+namespace webrtc {
+
+RtcpTransceiver::RtcpTransceiver(const RtcpTransceiverConfig& config)
+    : task_queue_(config.task_queue),
+      rtcp_transceiver_(rtc::MakeUnique<RtcpTransceiverImpl>(config)),
+      ptr_factory_(rtcp_transceiver_.get()),
+      // Creating first weak ptr can be done on any thread, but is not
+      // thread-safe, thus do it at construction. Creating second (e.g. making a
+      // copy) is thread-safe.
+      ptr_(ptr_factory_.GetWeakPtr()) {
+  RTC_DCHECK(task_queue_);
+}
+
+RtcpTransceiver::~RtcpTransceiver() {
+  if (task_queue_->IsCurrent())
+    return;
+
+  rtc::Event done(false, false);
+  // TODO(danilchap): Merge cleanup into main closure when task queue does not
+  // silently drop tasks.
+  task_queue_->PostTask(rtc::NewClosure(
+      [this] {
+        // Destructor steps that has to run on the task_queue_.
+        ptr_factory_.InvalidateWeakPtrs();
+        rtcp_transceiver_.reset();
+      },
+      /*cleanup=*/[&done] { done.Set(); }));
+  // Wait until destruction is complete to be sure weak pointers invalidated and
+  // rtcp_transceiver destroyed on the queue while |this| still valid.
+  done.Wait(rtc::Event::kForever);
+  RTC_CHECK(!rtcp_transceiver_) << "Task queue is too busy to handle rtcp";
+}
+
+void RtcpTransceiver::ReceivePacket(rtc::CopyOnWriteBuffer packet) {
+  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
+  int64_t now_us = rtc::TimeMicros();
+  task_queue_->PostTask([ptr, packet, now_us] {
+    if (ptr)
+      ptr->ReceivePacket(packet, now_us);
+  });
+}
+
+void RtcpTransceiver::SendCompoundPacket() {
+  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
+  task_queue_->PostTask([ptr] {
+    if (ptr)
+      ptr->SendCompoundPacket();
+  });
+}
+
+void RtcpTransceiver::SetRemb(int bitrate_bps, std::vector<uint32_t> ssrcs) {
+  // TODO(danilchap): Replace with lambda with move capture when available.
+  struct SetRembClosure {
+    void operator()() {
+      if (ptr)
+        ptr->SetRemb(bitrate_bps, std::move(ssrcs));
+    }
+
+    rtc::WeakPtr<RtcpTransceiverImpl> ptr;
+    int bitrate_bps;
+    std::vector<uint32_t> ssrcs;
+  };
+  task_queue_->PostTask(SetRembClosure{ptr_, bitrate_bps, std::move(ssrcs)});
+}
+
+void RtcpTransceiver::UnsetRemb() {
+  rtc::WeakPtr<RtcpTransceiverImpl> ptr = ptr_;
+  task_queue_->PostTask([ptr] {
+    if (ptr)
+      ptr->UnsetRemb();
+  });
+}
+
+}  // namespace webrtc