forked from OSchip/llvm-project
45 lines
1.3 KiB
C++
45 lines
1.3 KiB
C++
//===--- Cancellation.cpp -----------------------------------------*-C++-*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "Cancellation.h"
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#include <atomic>
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namespace clang {
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namespace clangd {
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char CancelledError::ID = 0;
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// We don't want a cancelable scope to "shadow" an enclosing one.
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struct CancelState {
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std::shared_ptr<std::atomic<int>> Cancelled;
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const CancelState *Parent;
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};
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static Key<CancelState> StateKey;
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std::pair<Context, Canceler> cancelableTask(int Reason) {
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assert(Reason != 0 && "Can't detect cancellation if Reason is zero");
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CancelState State;
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State.Cancelled = std::make_shared<std::atomic<int>>();
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State.Parent = Context::current().get(StateKey);
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return {
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Context::current().derive(StateKey, State),
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[Reason, Flag(State.Cancelled)] { *Flag = Reason; },
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};
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}
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int isCancelled(const Context &Ctx) {
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for (const CancelState *State = Ctx.get(StateKey); State != nullptr;
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State = State->Parent)
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if (int Reason = State->Cancelled->load())
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return Reason;
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return 0;
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}
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} // namespace clangd
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} // namespace clang
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