chromium/third_party/dawn/src/dawn/common/MutexProtected.h

// Copyright 2023 The Dawn & Tint Authors
//
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#ifndef SRC_DAWN_COMMON_MUTEXPROTECTED_H_
#define SRC_DAWN_COMMON_MUTEXPROTECTED_H_

#include <mutex>
#include <utility>

#include "dawn/common/Mutex.h"
#include "dawn/common/NonMovable.h"
#include "dawn/common/Ref.h"
#include "dawn/common/StackAllocated.h"
#include "partition_alloc/pointers/raw_ptr_exclusion.h"

namespace dawn {

template <typename T, template <typename, typename> class Guard>
class MutexProtected;

namespace detail {

template <typename T>
struct MutexProtectedTraits { … };

MutexProtectedTraits<Ref<T>>;

// Guard class is a wrapping class that gives access to a protected resource after acquiring the
// lock related to it. For the lifetime of this class, the lock is held.
template <typename T, typename Traits>
class Guard : public NonMovable, StackAllocated { … };

}  // namespace detail

// Wrapping class used for object members to ensure usage of the resource is protected with a mutex.
// Example usage:
//     class Allocator {
//       public:
//         Allocation Allocate();
//         void Deallocate(Allocation&);
//     };
//     class AllocatorUser {
//       public:
//         void OnlyAllocate() {
//             auto allocation = mAllocator->Allocate();
//         }
//         void AtomicAllocateDeallocate() {
//             // Operations:
//             //   - acquire lock
//             //   - Allocate, Deallocate
//             //   - release lock
//             mAllocator.Use([](auto allocator) {
//                 auto allocation = allocator->Allocate();
//                 allocator->Deallocate(allocation);
//             });
//         }
//         void NonAtomicAllocateDeallocate() {
//             // Operations:
//             //   - acquire lock, Allocate, release lock
//             //   - acquire lock, Deallocate, release lock
//             auto allocation = mAllocator->Allocate();
//             mAllocator->Deallocate(allocation);
//         }
//       private:
//         MutexProtected<Allocator> mAllocator;
//     };
template <typename T, template <typename, typename> class Guard = detail::Guard>
class MutexProtected { … };

}  // namespace dawn

#endif  // SRC_DAWN_COMMON_MUTEXPROTECTED_H_