1 | /* |
2 | * Copyright (C) 2008 Apple Inc. All rights reserved. |
3 | * Copyright (C) 2009 Jian Li <jianli@chromium.org> |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
8 | * |
9 | * 1. Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * 2. Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
14 | * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
15 | * its contributors may be used to endorse or promote products derived |
16 | * from this software without specific prior written permission. |
17 | * |
18 | * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
19 | * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
20 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
21 | * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
22 | * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
23 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
24 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
25 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
26 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
27 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
28 | */ |
29 | |
30 | /* Thread local storage is implemented by using either pthread API or Windows |
31 | * native API. There is subtle semantic discrepancy for the cleanup function |
32 | * implementation as noted below: |
33 | * @ In pthread implementation, the destructor function will be called |
34 | * repeatedly if there is still non-NULL value associated with the function. |
35 | * @ In Windows native implementation, the destructor function will be called |
36 | * only once. |
37 | * This semantic discrepancy does not impose any problem because nowhere in |
38 | * WebKit the repeated call bahavior is utilized. |
39 | */ |
40 | |
41 | #ifndef WTF_ThreadSpecific_h |
42 | #define WTF_ThreadSpecific_h |
43 | |
44 | #include <wtf/Noncopyable.h> |
45 | |
46 | #if USE(PTHREADS) |
47 | #include <pthread.h> |
48 | #elif PLATFORM(QT) |
49 | #include <QtCore/qthreadstorage.h> |
50 | #elif OS(WINDOWS) |
51 | #include <windows.h> |
52 | #endif |
53 | |
54 | namespace WTF { |
55 | |
56 | #if !USE(PTHREADS) && !PLATFORM(QT) && OS(WINDOWS) |
57 | // ThreadSpecificThreadExit should be called each time when a thread is detached. |
58 | // This is done automatically for threads created with WTF::createThread. |
59 | void ThreadSpecificThreadExit(); |
60 | #endif |
61 | |
62 | template<typename T> class ThreadSpecific : public Noncopyable { |
63 | public: |
64 | ThreadSpecific(); |
65 | T* operator->(); |
66 | operator T*(); |
67 | T& operator*(); |
68 | ~ThreadSpecific(); |
69 | |
70 | private: |
71 | #if !USE(PTHREADS) && !PLATFORM(QT) && OS(WINDOWS) |
72 | friend void ThreadSpecificThreadExit(); |
73 | #endif |
74 | |
75 | T* get(); |
76 | void set(T*); |
77 | void static destroy(void* ptr); |
78 | |
79 | #if USE(PTHREADS) || PLATFORM(QT) || OS(WINDOWS) |
80 | struct Data : Noncopyable { |
81 | Data(T* value, ThreadSpecific<T>* owner) : value(value), owner(owner) {} |
82 | #if PLATFORM(QT) |
83 | ~Data() { owner->destroy(this); } |
84 | #endif |
85 | |
86 | T* value; |
87 | ThreadSpecific<T>* owner; |
88 | #if !USE(PTHREADS) && !PLATFORM(QT) |
89 | void (*destructor)(void*); |
90 | #endif |
91 | }; |
92 | #endif |
93 | |
94 | #if ENABLE(SINGLE_THREADED) |
95 | T* m_value; |
96 | #else |
97 | #if USE(PTHREADS) |
98 | pthread_key_t m_key; |
99 | #elif PLATFORM(QT) |
100 | QThreadStorage<Data*> m_key; |
101 | #elif OS(WINDOWS) |
102 | int m_index; |
103 | #endif |
104 | #endif |
105 | }; |
106 | |
107 | #if ENABLE(SINGLE_THREADED) |
108 | template<typename T> |
109 | inline ThreadSpecific<T>::ThreadSpecific() |
110 | : m_value(0) |
111 | { |
112 | } |
113 | |
114 | template<typename T> |
115 | inline ThreadSpecific<T>::~ThreadSpecific() |
116 | { |
117 | } |
118 | |
119 | template<typename T> |
120 | inline T* ThreadSpecific<T>::get() |
121 | { |
122 | return m_value; |
123 | } |
124 | |
125 | template<typename T> |
126 | inline void ThreadSpecific<T>::set(T* ptr) |
127 | { |
128 | ASSERT(!get()); |
129 | m_value = ptr; |
130 | } |
131 | #else |
132 | #if USE(PTHREADS) |
133 | template<typename T> |
134 | inline ThreadSpecific<T>::ThreadSpecific() |
135 | { |
136 | int error = pthread_key_create(&m_key, destroy); |
137 | if (error) |
138 | CRASH(); |
139 | } |
140 | |
141 | template<typename T> |
142 | inline ThreadSpecific<T>::~ThreadSpecific() |
143 | { |
144 | pthread_key_delete(m_key); // Does not invoke destructor functions. |
145 | } |
146 | |
147 | template<typename T> |
148 | inline T* ThreadSpecific<T>::get() |
149 | { |
150 | Data* data = static_cast<Data*>(pthread_getspecific(m_key)); |
151 | return data ? data->value : 0; |
152 | } |
153 | |
154 | template<typename T> |
155 | inline void ThreadSpecific<T>::set(T* ptr) |
156 | { |
157 | ASSERT(!get()); |
158 | pthread_setspecific(m_key, new Data(ptr, this)); |
159 | } |
160 | |
161 | #elif PLATFORM(QT) |
162 | |
163 | template<typename T> |
164 | inline ThreadSpecific<T>::ThreadSpecific() |
165 | { |
166 | } |
167 | |
168 | template<typename T> |
169 | inline ThreadSpecific<T>::~ThreadSpecific() |
170 | { |
171 | // Does not invoke destructor functions. QThreadStorage will do it |
172 | } |
173 | |
174 | template<typename T> |
175 | inline T* ThreadSpecific<T>::get() |
176 | { |
177 | Data* data = static_cast<Data*>(m_key.localData()); |
178 | return data ? data->value : 0; |
179 | } |
180 | |
181 | template<typename T> |
182 | inline void ThreadSpecific<T>::set(T* ptr) |
183 | { |
184 | ASSERT(!get()); |
185 | Data* data = new Data(ptr, this); |
186 | m_key.setLocalData(data); |
187 | } |
188 | |
189 | #elif OS(WINDOWS) |
190 | |
191 | // TLS_OUT_OF_INDEXES is not defined on WinCE. |
192 | #ifndef TLS_OUT_OF_INDEXES |
193 | #define TLS_OUT_OF_INDEXES 0xffffffff |
194 | #endif |
195 | |
196 | // The maximum number of TLS keys that can be created. For simplification, we assume that: |
197 | // 1) Once the instance of ThreadSpecific<> is created, it will not be destructed until the program dies. |
198 | // 2) We do not need to hold many instances of ThreadSpecific<> data. This fixed number should be far enough. |
199 | const int kMaxTlsKeySize = 256; |
200 | |
201 | long& tlsKeyCount(); |
202 | DWORD* tlsKeys(); |
203 | |
204 | template<typename T> |
205 | inline ThreadSpecific<T>::ThreadSpecific() |
206 | : m_index(-1) |
207 | { |
208 | DWORD tlsKey = TlsAlloc(); |
209 | if (tlsKey == TLS_OUT_OF_INDEXES) |
210 | CRASH(); |
211 | |
212 | m_index = InterlockedIncrement(&tlsKeyCount()) - 1; |
213 | if (m_index >= kMaxTlsKeySize) |
214 | CRASH(); |
215 | tlsKeys()[m_index] = tlsKey; |
216 | } |
217 | |
218 | template<typename T> |
219 | inline ThreadSpecific<T>::~ThreadSpecific() |
220 | { |
221 | // Does not invoke destructor functions. They will be called from ThreadSpecificThreadExit when the thread is detached. |
222 | TlsFree(tlsKeys()[m_index]); |
223 | } |
224 | |
225 | template<typename T> |
226 | inline T* ThreadSpecific<T>::get() |
227 | { |
228 | Data* data = static_cast<Data*>(TlsGetValue(tlsKeys()[m_index])); |
229 | return data ? data->value : 0; |
230 | } |
231 | |
232 | template<typename T> |
233 | inline void ThreadSpecific<T>::set(T* ptr) |
234 | { |
235 | ASSERT(!get()); |
236 | Data* data = new Data(ptr, this); |
237 | data->destructor = &ThreadSpecific<T>::destroy; |
238 | TlsSetValue(tlsKeys()[m_index], data); |
239 | } |
240 | |
241 | #else |
242 | #error ThreadSpecific is not implemented for this platform. |
243 | #endif |
244 | #endif |
245 | |
246 | template<typename T> |
247 | inline void ThreadSpecific<T>::destroy(void* ptr) |
248 | { |
249 | #if !ENABLE(SINGLE_THREADED) |
250 | Data* data = static_cast<Data*>(ptr); |
251 | |
252 | #if USE(PTHREADS) |
253 | // We want get() to keep working while data destructor works, because it can be called indirectly by the destructor. |
254 | // Some pthreads implementations zero out the pointer before calling destroy(), so we temporarily reset it. |
255 | pthread_setspecific(data->owner->m_key, ptr); |
256 | #endif |
257 | #if PLATFORM(QT) |
258 | // See comment as above |
259 | if (!data->owner->m_key.hasLocalData()) |
260 | data->owner->m_key.setLocalData(data); |
261 | #endif |
262 | |
263 | data->value->~T(); |
264 | fastFree(data->value); |
265 | |
266 | #if USE(PTHREADS) |
267 | pthread_setspecific(data->owner->m_key, 0); |
268 | #elif PLATFORM(QT) |
269 | // Do nothing here |
270 | #elif OS(WINDOWS) |
271 | TlsSetValue(tlsKeys()[data->owner->m_index], 0); |
272 | #else |
273 | #error ThreadSpecific is not implemented for this platform. |
274 | #endif |
275 | |
276 | #if !PLATFORM(QT) |
277 | delete data; |
278 | #endif |
279 | #endif |
280 | } |
281 | |
282 | template<typename T> |
283 | inline ThreadSpecific<T>::operator T*() |
284 | { |
285 | T* ptr = static_cast<T*>(get()); |
286 | if (!ptr) { |
287 | // Set up thread-specific value's memory pointer before invoking constructor, in case any function it calls |
288 | // needs to access the value, to avoid recursion. |
289 | ptr = static_cast<T*>(fastMalloc(sizeof(T))); |
290 | set(ptr); |
291 | new (ptr) T; |
292 | } |
293 | return ptr; |
294 | } |
295 | |
296 | template<typename T> |
297 | inline T* ThreadSpecific<T>::operator->() |
298 | { |
299 | return operator T*(); |
300 | } |
301 | |
302 | template<typename T> |
303 | inline T& ThreadSpecific<T>::operator*() |
304 | { |
305 | return *operator T*(); |
306 | } |
307 | |
308 | } |
309 | |
310 | #endif |
311 | |