65 lines
2.1 KiB
C++
65 lines
2.1 KiB
C++
/*
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* Copyright 2017 Discord, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is furnished to do
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* so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*
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*/
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#ifndef DISCORD_MSG_QUEUE_H
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#define DISCORD_MSG_QUEUE_H
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#include <atomic>
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// A simple queue. No locks, but only works with a single thread as producer and a single thread as
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// a consumer. Mutex up as needed.
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namespace discord_rpc {
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template<typename ElementType, std::size_t QueueSize>
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class MsgQueue {
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ElementType queue_[QueueSize];
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std::atomic_uint nextAdd_ { 0 };
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std::atomic_uint nextSend_ { 0 };
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std::atomic_uint pendingSends_ { 0 };
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public:
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MsgQueue() {}
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ElementType *GetNextAddMessage() {
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// if we are falling behind, bail
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if (pendingSends_.load() >= QueueSize) {
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return nullptr;
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}
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auto index = (nextAdd_++) % QueueSize;
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return &queue_[index];
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}
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void CommitAdd() { ++pendingSends_; }
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bool HavePendingSends() const { return pendingSends_.load() != 0; }
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ElementType *GetNextSendMessage() {
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auto index = (nextSend_++) % QueueSize;
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return &queue_[index];
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}
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void CommitSend() { --pendingSends_; }
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};
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} // namespace discord_rpc
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#endif // DISCORD_MSG_QUEUE_H
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