1 /*

     2  * Copyright (C) 2009 Google Inc. All rights reserved.

     3  *

     4  * Redistribution and use in source and binary forms, with or without

     5  * modification, are permitted provided that the following conditions are

     6  * met:

     7  *

     8  *     * Redistributions of source code must retain the above copyright

     9  * notice, this list of conditions and the following disclaimer.

    10  *     * Redistributions in binary form must reproduce the above

    11  * copyright notice, this list of conditions and the following disclaimer

    12  * in the documentation and/or other materials provided with the

    13  * distribution.

    14  *     * Neither the name of Google Inc. nor the names of its

    15  * contributors may be used to endorse or promote products derived from

    16  * this software without specific prior written permission.

    17  *

    18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

    19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

    20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

    21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

    22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

    23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

    24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

    25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

    26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

    27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    29  */

    30 

    31 #ifndef ThreadIdentifierDataPthreads_h

    32 #define ThreadIdentifierDataPthreads_h

    33 

    34 #include <wtf/Noncopyable.h>

    35 #include <wtf/Threading.h>

    36 

    37 namespace WTF {

    38 

    39 // Holds ThreadIdentifier in the thread-specific storage and employs pthreads-specific 2-pass destruction to reliably remove

    40 // ThreadIdentifier from threadMap. It assumes regular ThreadSpecific types don't use multiple-pass destruction.

    41 class ThreadIdentifierData : public Noncopyable {

    42 public:

    43     ~ThreadIdentifierData();

    44 

    45     // Creates and puts an instance of ThreadIdentifierData into thread-specific storage.

    46     static void initialize(ThreadIdentifier identifier);

    47 

    48     // Returns 0 if thread-specific storage was not initialized.

    49     static ThreadIdentifier identifier();

    50 

    51 private:

    52     ThreadIdentifierData(ThreadIdentifier identifier)

    53         : m_identifier(identifier)

    54         , m_isDestroyedOnce(false)

    55     {

    56     }

    57 

    58     // This thread-specific destructor is called 2 times when thread terminates:

    59     // - first, when all the other thread-specific destructors are called, it simply remembers it was 'destroyed once'

    60     // and re-sets itself into the thread-specific slot to make Pthreads to call it again later.

    61     // - second, after all thread-specific destructors were invoked, it gets called again - this time, we remove the

    62     // ThreadIdentifier from the threadMap, completing the cleanup.

    63     static void destruct(void* data);

    64 

    65     static void initializeKeyOnceHelper();

    66     static void initializeKeyOnce();

    67 

    68     ThreadIdentifier m_identifier;

    69     bool m_isDestroyedOnce;

    70     static pthread_key_t m_key;

    71 };

    72 

    73 } // namespace WTF

    74 

    75 #endif // ThreadIdentifierDataPthreads_h

    76 

    77