mirror of
https://github.com/mollyim/webrtc.git
synced 2025-05-17 23:57:59 +01:00
b951dc6f4c
Context: The timer precision of PostDelayedTask() is about to be lowered to include up to 17 ms leeway. In order not to break use cases that require high precision timers, PostDelayedHighPrecisionTask() will continue to have the same precision that PostDelayedTask() has today. webrtc::TaskQueueBase has an enum (kLow, kHigh) to decide which precision to use when calling PostDelayedTaskWithPrecision(). See go/postdelayedtask-precision-in-webrtc for motivation and a table of delayed task use cases in WebRTC that are "high" or "low" precision. Most timers in DCSCTP are believed to only be needing low precision (see table), but the delayed_ack_timer_ of DataTracker[1] is an example of a use case that is likely to break if the timer precision is lowered (if ACK is sent too late, retransmissions may occur). So this is considered a high precision use case. This CL makes it possible to specify the precision of dcsctp::Timer. In a follow-up CL we will update delayed_ack_timer_ to kHigh precision. [1] https://source.chromium.org/chromium/chromium/src/+/main:third_party/webrtc/net/dcsctp/rx/data_tracker.cc;l=340 Bug: webrtc:13604 Change-Id: I8eec5ce37044096978b5dd1985fbb00bc0d8fb7e Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/249081 Reviewed-by: Victor Boivie <boivie@webrtc.org> Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org> Commit-Queue: Henrik Boström <hbos@webrtc.org> Cr-Commit-Position: refs/heads/main@{#35809}
95 lines
3.6 KiB
C++
95 lines
3.6 KiB
C++
/*
|
|
* Copyright (c) 2021 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.
|
|
*/
|
|
#ifndef NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
|
|
#define NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
|
|
|
|
#include <cstdint>
|
|
#include <functional>
|
|
#include <memory>
|
|
#include <string>
|
|
#include <utility>
|
|
#include <vector>
|
|
|
|
#include "absl/strings/string_view.h"
|
|
#include "api/array_view.h"
|
|
#include "api/ref_counted_base.h"
|
|
#include "api/scoped_refptr.h"
|
|
#include "api/task_queue/task_queue_base.h"
|
|
#include "net/dcsctp/public/dcsctp_message.h"
|
|
#include "net/dcsctp/public/dcsctp_socket.h"
|
|
#include "rtc_base/ref_counted_object.h"
|
|
|
|
namespace dcsctp {
|
|
// Defers callbacks until they can be safely triggered.
|
|
//
|
|
// There are a lot of callbacks from the dcSCTP library to the client,
|
|
// such as when messages are received or streams are closed. When the client
|
|
// receives these callbacks, the client is expected to be able to call into the
|
|
// library - from within the callback. For example, sending a reply message when
|
|
// a certain SCTP message has been received, or to reconnect when the connection
|
|
// was closed for any reason. This means that the dcSCTP library must always be
|
|
// in a consistent and stable state when these callbacks are delivered, and to
|
|
// ensure that's the case, callbacks are not immediately delivered from where
|
|
// they originate, but instead queued (deferred) by this class. At the end of
|
|
// any public API method that may result in callbacks, they are triggered and
|
|
// then delivered.
|
|
//
|
|
// There are a number of exceptions, which is clearly annotated in the API.
|
|
class CallbackDeferrer : public DcSctpSocketCallbacks {
|
|
public:
|
|
class ScopedDeferrer {
|
|
public:
|
|
explicit ScopedDeferrer(CallbackDeferrer& callback_deferrer)
|
|
: callback_deferrer_(callback_deferrer) {
|
|
callback_deferrer_.Prepare();
|
|
}
|
|
|
|
~ScopedDeferrer() { callback_deferrer_.TriggerDeferred(); }
|
|
|
|
private:
|
|
CallbackDeferrer& callback_deferrer_;
|
|
};
|
|
|
|
explicit CallbackDeferrer(DcSctpSocketCallbacks& underlying)
|
|
: underlying_(underlying) {}
|
|
|
|
// Implementation of DcSctpSocketCallbacks
|
|
SendPacketStatus SendPacketWithStatus(
|
|
rtc::ArrayView<const uint8_t> data) override;
|
|
std::unique_ptr<Timeout> CreateTimeout(
|
|
webrtc::TaskQueueBase::DelayPrecision precision) override;
|
|
TimeMs TimeMillis() override;
|
|
uint32_t GetRandomInt(uint32_t low, uint32_t high) override;
|
|
void OnMessageReceived(DcSctpMessage message) override;
|
|
void OnError(ErrorKind error, absl::string_view message) override;
|
|
void OnAborted(ErrorKind error, absl::string_view message) override;
|
|
void OnConnected() override;
|
|
void OnClosed() override;
|
|
void OnConnectionRestarted() override;
|
|
void OnStreamsResetFailed(rtc::ArrayView<const StreamID> outgoing_streams,
|
|
absl::string_view reason) override;
|
|
void OnStreamsResetPerformed(
|
|
rtc::ArrayView<const StreamID> outgoing_streams) override;
|
|
void OnIncomingStreamsReset(
|
|
rtc::ArrayView<const StreamID> incoming_streams) override;
|
|
void OnBufferedAmountLow(StreamID stream_id) override;
|
|
void OnTotalBufferedAmountLow() override;
|
|
|
|
private:
|
|
void Prepare();
|
|
void TriggerDeferred();
|
|
|
|
DcSctpSocketCallbacks& underlying_;
|
|
bool prepared_ = false;
|
|
std::vector<std::function<void(DcSctpSocketCallbacks& cb)>> deferred_;
|
|
};
|
|
} // namespace dcsctp
|
|
|
|
#endif // NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
|