70 lines
1.8 KiB
C++
70 lines
1.8 KiB
C++
// Copyright 2015 Citra Emulator Project
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <algorithm>
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#include <mutex>
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namespace Common {
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/**
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* Wraps an object, only allowing access to it via a locking reference wrapper. Good to ensure no
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* one forgets to lock a mutex before acessing an object. To access the wrapped object construct a
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* SyncronizedRef on this wrapper. Inspired by Rust's Mutex type (http://doc.rust-lang.org/std/sync/struct.Mutex.html).
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*/
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template <typename T>
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class SynchronizedWrapper {
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public:
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template <typename... Args>
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SynchronizedWrapper(Args&&... args) :
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data(std::forward<Args>(args)...) {
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}
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private:
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template <typename U>
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friend class SynchronizedRef;
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std::mutex mutex;
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T data;
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};
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/**
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* Synchronized reference, that keeps a SynchronizedWrapper's mutex locked during its lifetime. This
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* greatly reduces the chance that someone will access the wrapped resource without locking the
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* mutex.
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*/
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template <typename T>
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class SynchronizedRef {
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public:
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SynchronizedRef(SynchronizedWrapper<T>& wrapper) : wrapper(&wrapper) {
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wrapper.mutex.lock();
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}
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SynchronizedRef(SynchronizedRef&) = delete;
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SynchronizedRef(SynchronizedRef&& o) : wrapper(o.wrapper) {
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o.wrapper = nullptr;
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}
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~SynchronizedRef() {
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if (wrapper)
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wrapper->mutex.unlock();
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}
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SynchronizedRef& operator=(SynchronizedRef&) = delete;
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SynchronizedRef& operator=(SynchronizedRef&& o) {
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std::swap(wrapper, o.wrapper);
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}
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T& operator*() { return wrapper->data; }
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const T& operator*() const { return wrapper->data; }
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T* operator->() { return &wrapper->data; }
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const T* operator->() const { return &wrapper->data; }
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private:
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SynchronizedWrapper<T>* wrapper;
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};
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} // namespace Common
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