mirror of
https://github.com/klzgrad/naiveproxy.git
synced 2024-11-24 14:26:09 +03:00
100 lines
3.2 KiB
C++
100 lines
3.2 KiB
C++
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
// WARNING: Thread local storage is a bit tricky to get right. Please make sure
|
|
// that this is really the proper solution for what you're trying to achieve.
|
|
// Don't prematurely optimize, most likely you can just use a Lock.
|
|
//
|
|
// These classes implement a wrapper around ThreadLocalStorage::Slot. On
|
|
// construction, they will allocate a TLS slot, and free the TLS slot on
|
|
// destruction. No memory management (creation or destruction) is handled. This
|
|
// means for uses of ThreadLocalPointer, you must correctly manage the memory
|
|
// yourself, these classes will not destroy the pointer for you. There are no
|
|
// at-thread-exit actions taken by these classes.
|
|
//
|
|
// ThreadLocalPointer<Type> wraps a Type*. It performs no creation or
|
|
// destruction, so memory management must be handled elsewhere. The first call
|
|
// to Get() on a thread will return NULL. You can update the pointer with a call
|
|
// to Set().
|
|
//
|
|
// ThreadLocalBoolean wraps a bool. It will default to false if it has never
|
|
// been set otherwise with Set().
|
|
//
|
|
// Thread Safety: An instance of ThreadLocalStorage is completely thread safe
|
|
// once it has been created. If you want to dynamically create an instance, you
|
|
// must of course properly deal with safety and race conditions. This means a
|
|
// function-level static initializer is generally inappropiate.
|
|
//
|
|
// In Android, the system TLS is limited.
|
|
//
|
|
// Example usage:
|
|
// // My class is logically attached to a single thread. We cache a pointer
|
|
// // on the thread it was created on, so we can implement current().
|
|
// MyClass::MyClass() {
|
|
// DCHECK(Singleton<ThreadLocalPointer<MyClass> >::get()->Get() == NULL);
|
|
// Singleton<ThreadLocalPointer<MyClass> >::get()->Set(this);
|
|
// }
|
|
//
|
|
// MyClass::~MyClass() {
|
|
// DCHECK(Singleton<ThreadLocalPointer<MyClass> >::get()->Get() != NULL);
|
|
// Singleton<ThreadLocalPointer<MyClass> >::get()->Set(NULL);
|
|
// }
|
|
//
|
|
// // Return the current MyClass associated with the calling thread, can be
|
|
// // NULL if there isn't a MyClass associated.
|
|
// MyClass* MyClass::current() {
|
|
// return Singleton<ThreadLocalPointer<MyClass> >::get()->Get();
|
|
// }
|
|
|
|
#ifndef BASE_THREADING_THREAD_LOCAL_H_
|
|
#define BASE_THREADING_THREAD_LOCAL_H_
|
|
|
|
#include "base/macros.h"
|
|
#include "base/threading/thread_local_storage.h"
|
|
|
|
namespace base {
|
|
|
|
template <typename Type>
|
|
class ThreadLocalPointer {
|
|
public:
|
|
ThreadLocalPointer() = default;
|
|
~ThreadLocalPointer() = default;
|
|
|
|
Type* Get() {
|
|
return static_cast<Type*>(slot_.Get());
|
|
}
|
|
|
|
void Set(Type* ptr) {
|
|
slot_.Set(const_cast<void*>(static_cast<const void*>(ptr)));
|
|
}
|
|
|
|
private:
|
|
ThreadLocalStorage::Slot slot_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(ThreadLocalPointer<Type>);
|
|
};
|
|
|
|
class ThreadLocalBoolean {
|
|
public:
|
|
ThreadLocalBoolean() = default;
|
|
~ThreadLocalBoolean() = default;
|
|
|
|
bool Get() {
|
|
return tlp_.Get() != nullptr;
|
|
}
|
|
|
|
void Set(bool val) {
|
|
tlp_.Set(val ? this : nullptr);
|
|
}
|
|
|
|
private:
|
|
ThreadLocalPointer<void> tlp_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(ThreadLocalBoolean);
|
|
};
|
|
|
|
} // namespace base
|
|
|
|
#endif // BASE_THREADING_THREAD_LOCAL_H_
|