security/sandbox/chromium/base/threading/thread_local_storage.h@925c144e1f1f (annotated)
security/sandbox/chromium/base/threading/thread_local_storage.h
Fri, 16 Jan 2015 18:13:44 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Fri, 16 Jan 2015 18:13:44 +0100
- branch
- TOR_BUG_9701
- changeset 14
- 925c144e1f1f
- permissions
- -rw-r--r--
Integrate suggestion from review to improve consistency with existing code.
| michael@0 | 1 | // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| michael@0 | 2 | // Use of this source code is governed by a BSD-style license that can be |
| michael@0 | 3 | // found in the LICENSE file. |
| michael@0 | 4 | |
| michael@0 | 5 | #ifndef BASE_THREADING_THREAD_LOCAL_STORAGE_H_ |
| michael@0 | 6 | #define BASE_THREADING_THREAD_LOCAL_STORAGE_H_ |
| michael@0 | 7 | |
| michael@0 | 8 | #include "base/base_export.h" |
| michael@0 | 9 | #include "base/basictypes.h" |
| michael@0 | 10 | |
| michael@0 | 11 | #if defined(OS_POSIX) |
| michael@0 | 12 | #include <pthread.h> |
| michael@0 | 13 | #endif |
| michael@0 | 14 | |
| michael@0 | 15 | namespace base { |
| michael@0 | 16 | |
| michael@0 | 17 | // Wrapper for thread local storage. This class doesn't do much except provide |
| michael@0 | 18 | // an API for portability. |
| michael@0 | 19 | class BASE_EXPORT ThreadLocalStorage { |
| michael@0 | 20 | public: |
| michael@0 | 21 | |
| michael@0 | 22 | // Prototype for the TLS destructor function, which can be optionally used to |
| michael@0 | 23 | // cleanup thread local storage on thread exit. 'value' is the data that is |
| michael@0 | 24 | // stored in thread local storage. |
| michael@0 | 25 | typedef void (*TLSDestructorFunc)(void* value); |
| michael@0 | 26 | |
| michael@0 | 27 | // StaticSlot uses its own struct initializer-list style static |
| michael@0 | 28 | // initialization, as base's LINKER_INITIALIZED requires a constructor and on |
| michael@0 | 29 | // some compilers (notably gcc 4.4) this still ends up needing runtime |
| michael@0 | 30 | // initialization. |
| michael@0 | 31 | #define TLS_INITIALIZER {0} |
| michael@0 | 32 | |
| michael@0 | 33 | // A key representing one value stored in TLS. |
| michael@0 | 34 | // Initialize like |
| michael@0 | 35 | // ThreadLocalStorage::StaticSlot my_slot = TLS_INITIALIZER; |
| michael@0 | 36 | // If you're not using a static variable, use the convenience class |
| michael@0 | 37 | // ThreadLocalStorage::Slot (below) instead. |
| michael@0 | 38 | struct BASE_EXPORT StaticSlot { |
| michael@0 | 39 | // Set up the TLS slot. Called by the constructor. |
| michael@0 | 40 | // 'destructor' is a pointer to a function to perform per-thread cleanup of |
| michael@0 | 41 | // this object. If set to NULL, no cleanup is done for this TLS slot. |
| michael@0 | 42 | // Returns false on error. |
| michael@0 | 43 | bool Initialize(TLSDestructorFunc destructor); |
| michael@0 | 44 | |
| michael@0 | 45 | // Free a previously allocated TLS 'slot'. |
| michael@0 | 46 | // If a destructor was set for this slot, removes |
| michael@0 | 47 | // the destructor so that remaining threads exiting |
| michael@0 | 48 | // will not free data. |
| michael@0 | 49 | void Free(); |
| michael@0 | 50 | |
| michael@0 | 51 | // Get the thread-local value stored in slot 'slot'. |
| michael@0 | 52 | // Values are guaranteed to initially be zero. |
| michael@0 | 53 | void* Get() const; |
| michael@0 | 54 | |
| michael@0 | 55 | // Set the thread-local value stored in slot 'slot' to |
| michael@0 | 56 | // value 'value'. |
| michael@0 | 57 | void Set(void* value); |
| michael@0 | 58 | |
| michael@0 | 59 | bool initialized() const { return initialized_; } |
| michael@0 | 60 | |
| michael@0 | 61 | // The internals of this struct should be considered private. |
| michael@0 | 62 | bool initialized_; |
| michael@0 | 63 | #if defined(OS_WIN) |
| michael@0 | 64 | int slot_; |
| michael@0 | 65 | #elif defined(OS_POSIX) |
| michael@0 | 66 | pthread_key_t key_; |
| michael@0 | 67 | #endif |
| michael@0 | 68 | |
| michael@0 | 69 | }; |
| michael@0 | 70 | |
| michael@0 | 71 | // A convenience wrapper around StaticSlot with a constructor. Can be used |
| michael@0 | 72 | // as a member variable. |
| michael@0 | 73 | class BASE_EXPORT Slot : public StaticSlot { |
| michael@0 | 74 | public: |
| michael@0 | 75 | // Calls StaticSlot::Initialize(). |
| michael@0 | 76 | explicit Slot(TLSDestructorFunc destructor = NULL); |
| michael@0 | 77 | |
| michael@0 | 78 | private: |
| michael@0 | 79 | using StaticSlot::initialized_; |
| michael@0 | 80 | #if defined(OS_WIN) |
| michael@0 | 81 | using StaticSlot::slot_; |
| michael@0 | 82 | #elif defined(OS_POSIX) |
| michael@0 | 83 | using StaticSlot::key_; |
| michael@0 | 84 | #endif |
| michael@0 | 85 | DISALLOW_COPY_AND_ASSIGN(Slot); |
| michael@0 | 86 | }; |
| michael@0 | 87 | |
| michael@0 | 88 | DISALLOW_COPY_AND_ASSIGN(ThreadLocalStorage); |
| michael@0 | 89 | }; |
| michael@0 | 90 | |
| michael@0 | 91 | } // namespace base |
| michael@0 | 92 | |
| michael@0 | 93 | #endif // BASE_THREADING_THREAD_LOCAL_STORAGE_H_ |
