The Tor Browser: ipc/chromium/src/base/thread_local.h@6474c204b198 (annotated)

ipc/chromium/src/base/thread_local.h@6474c204b198 (annotated)

ipc/chromium/src/base/thread_local.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2006-2008 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 warpper around the platform's TLS storage
 // mechanism.  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.
 //
 // 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_THREAD_LOCAL_H_
 #define BASE_THREAD_LOCAL_H_
 #include "base/basictypes.h"
 #if defined(OS_POSIX)
 #include <pthread.h>
 #endif
 namespace base {
 // Helper functions that abstract the cross-platform APIs.  Do not use directly.
 struct ThreadLocalPlatform {
 #if defined(OS_WIN)
   typedef int SlotType;
 #elif defined(OS_POSIX)
   typedef pthread_key_t SlotType;
 #endif
   static void AllocateSlot(SlotType& slot);
   static void FreeSlot(SlotType& slot);
   static void* GetValueFromSlot(SlotType& slot);
   static void SetValueInSlot(SlotType& slot, void* value);
 };
 template <typename Type>
 class ThreadLocalPointer {
  public:
   ThreadLocalPointer() : slot_() {
     ThreadLocalPlatform::AllocateSlot(slot_);
   }
   ~ThreadLocalPointer() {
     ThreadLocalPlatform::FreeSlot(slot_);
   }
   Type* Get() {
     return static_cast<Type*>(ThreadLocalPlatform::GetValueFromSlot(slot_));
   }
   void Set(Type* ptr) {
     ThreadLocalPlatform::SetValueInSlot(slot_, ptr);
   }
  private:
   typedef ThreadLocalPlatform::SlotType SlotType;
   SlotType slot_;
   DISALLOW_COPY_AND_ASSIGN(ThreadLocalPointer<Type>);
 };
 class ThreadLocalBoolean {
  public:
   ThreadLocalBoolean() { }
   ~ThreadLocalBoolean() { }
   bool Get() {
     return tlp_.Get() != NULL;
   }
   void Set(bool val) {
     tlp_.Set(reinterpret_cast<void*>(val ? 1 : 0));
   }
  private:
   ThreadLocalPointer<void> tlp_;
   DISALLOW_COPY_AND_ASSIGN(ThreadLocalBoolean);
 };
 }  // namespace base
 #endif  // BASE_THREAD_LOCAL_H_

The Tor Browser / annotate

ipc/chromium/src/base/thread_local.h@6474c204b198 (annotated)

ipc/chromium/src/base/thread_local.h