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6962758c8c
This allows the use of C++ lambdas and functors, in addition to plain old functions. rdar://90776105
48 lines
1.6 KiB
C++
48 lines
1.6 KiB
C++
//===--- Once.h - Runtime support for lazy initialization -------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Swift runtime functions in support of lazy initialization.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_THREADING_ONCE_H
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#define SWIFT_THREADING_ONCE_H
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#include "Impl.h"
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namespace swift {
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using once_t = threading_impl::once_t;
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/// Runs the given function with the given context argument exactly once.
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/// The predicate argument must refer to a global or static variable of static
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/// extent of type swift::once_t.
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inline void once(once_t &predicate, void (*fn)(void *),
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void *context = nullptr) {
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threading_impl::once_impl(predicate, fn, context);
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}
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/// Executes the given callable exactly once.
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/// The predicate argument must refer to a global or static variable of static
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/// extent of type swift::once_t.
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template <typename Callable>
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inline void once(once_t &predicate, const Callable &callable) {
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once(predicate, [](void *ctx) {
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const Callable &callable = *(const Callable*)(ctx);
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callable();
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}, (void *)(&callable));
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}
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} // namespace swift
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#endif // SWIFT_THREADING_ONCE_H
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