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15a0c880cf
The previous manual way of triggering the deferred callbacks was very error-prone, and this was also forgotten at a few places. We can do better. Using the RAII programming idiom, the callbacks are now ensured to be called before returning from public methods. Also added additional debug checks to ensure that there is a ScopedDeferrer active whenever callbacks are deferred. Bug: webrtc:13217 Change-Id: I16a8343b52c00fb30acb018d3846acd0a64318e0 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/233242 Commit-Queue: Victor Boivie <boivie@webrtc.org> Reviewed-by: Florent Castelli <orphis@webrtc.org> Cr-Commit-Position: refs/heads/main@{#35117}
93 lines
3.5 KiB
C++
93 lines
3.5 KiB
C++
/*
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* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
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#define NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
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#include <cstdint>
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#include <functional>
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#include <memory>
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#include <string>
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#include <utility>
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#include <vector>
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#include "absl/strings/string_view.h"
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#include "api/array_view.h"
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#include "api/ref_counted_base.h"
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#include "api/scoped_refptr.h"
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#include "net/dcsctp/public/dcsctp_message.h"
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#include "net/dcsctp/public/dcsctp_socket.h"
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#include "rtc_base/ref_counted_object.h"
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namespace dcsctp {
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// Defers callbacks until they can be safely triggered.
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//
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// There are a lot of callbacks from the dcSCTP library to the client,
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// such as when messages are received or streams are closed. When the client
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// receives these callbacks, the client is expected to be able to call into the
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// library - from within the callback. For example, sending a reply message when
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// a certain SCTP message has been received, or to reconnect when the connection
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// was closed for any reason. This means that the dcSCTP library must always be
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// in a consistent and stable state when these callbacks are delivered, and to
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// ensure that's the case, callbacks are not immediately delivered from where
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// they originate, but instead queued (deferred) by this class. At the end of
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// any public API method that may result in callbacks, they are triggered and
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// then delivered.
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//
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// There are a number of exceptions, which is clearly annotated in the API.
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class CallbackDeferrer : public DcSctpSocketCallbacks {
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public:
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class ScopedDeferrer {
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public:
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explicit ScopedDeferrer(CallbackDeferrer& callback_deferrer)
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: callback_deferrer_(callback_deferrer) {
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callback_deferrer_.Prepare();
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}
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~ScopedDeferrer() { callback_deferrer_.TriggerDeferred(); }
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private:
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CallbackDeferrer& callback_deferrer_;
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};
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explicit CallbackDeferrer(DcSctpSocketCallbacks& underlying)
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: underlying_(underlying) {}
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// Implementation of DcSctpSocketCallbacks
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SendPacketStatus SendPacketWithStatus(
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rtc::ArrayView<const uint8_t> data) override;
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std::unique_ptr<Timeout> CreateTimeout() override;
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TimeMs TimeMillis() override;
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uint32_t GetRandomInt(uint32_t low, uint32_t high) override;
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void OnMessageReceived(DcSctpMessage message) override;
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void OnError(ErrorKind error, absl::string_view message) override;
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void OnAborted(ErrorKind error, absl::string_view message) override;
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void OnConnected() override;
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void OnClosed() override;
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void OnConnectionRestarted() override;
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void OnStreamsResetFailed(rtc::ArrayView<const StreamID> outgoing_streams,
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absl::string_view reason) override;
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void OnStreamsResetPerformed(
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rtc::ArrayView<const StreamID> outgoing_streams) override;
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void OnIncomingStreamsReset(
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rtc::ArrayView<const StreamID> incoming_streams) override;
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void OnBufferedAmountLow(StreamID stream_id) override;
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void OnTotalBufferedAmountLow() override;
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private:
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void Prepare();
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void TriggerDeferred();
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DcSctpSocketCallbacks& underlying_;
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bool prepared_ = false;
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std::vector<std::function<void(DcSctpSocketCallbacks& cb)>> deferred_;
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};
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} // namespace dcsctp
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#endif // NET_DCSCTP_SOCKET_CALLBACK_DEFERRER_H_
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