1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_GWP_ASAN_CLIENT_LIGHTWEIGHT_DETECTOR_SHARED_STATE_H_
#define COMPONENTS_GWP_ASAN_CLIENT_LIGHTWEIGHT_DETECTOR_SHARED_STATE_H_
#include <stdint.h>
#include <utility>
#include "base/check.h"
#include "base/compiler_specific.h"
namespace gwp_asan::internal::lud {
template <typename T>
class SharedState;
template <typename T>
class SharedStateHolder {
private:
static bool initialized_;
static uint8_t buffer_[];
friend class SharedState<T>;
};
template <typename T>
bool SharedStateHolder<T>::initialized_ = false;
template <typename T>
alignas(T) uint8_t SharedStateHolder<T>::buffer_[sizeof(T)];
// Special purpose shared state type. Uses a static buffer to reduce the number
// of pointer dereferences, requires explicit initialization, and doesn't
// provide thread safety.
template <typename T>
class SharedState {
public:
template <typename... Args>
static void Init(Args&&... args) {
DCHECK(!Holder::initialized_);
Holder::initialized_ = true;
new (Holder::buffer_) T(std::forward<Args>(args)...);
}
ALWAYS_INLINE static T* Get() {
DCHECK(Holder::initialized_);
return reinterpret_cast<T*>(Holder::buffer_);
}
static void ResetForTesting() {
if (Holder::initialized_) {
Get()->~T();
Holder::initialized_ = false;
}
}
private:
using Holder = SharedStateHolder<T>;
};
} // namespace gwp_asan::internal::lud
#endif // COMPONENTS_GWP_ASAN_CLIENT_LIGHTWEIGHT_DETECTOR_SHARED_STATE_H_
|
