ThreadHolderPthreads.cpp   [plain text]

/*
 * Copyright (C) 2009, 2011 Google Inc. All rights reserved.
 * Copyright (C) 2017 Yusuke Suzuki <utatane.tea@gmail.com>.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "ThreadHolder.h"

#include <wtf/Threading.h>

namespace WTF {

void ThreadHolder::initializeOnce()
{
    threadSpecificKeyCreate(&m_key, destruct);
}

ThreadHolder* ThreadHolder::current()
{
    ASSERT(m_key != InvalidThreadSpecificKey);
    return static_cast<ThreadHolder*>(threadSpecificGet(m_key));
}

void ThreadHolder::initialize(Thread& thread)
{
    if (!current()) {
        // Ideally we'd have this as a release assert everywhere, but that would hurt performance.
        // Having this release assert here means that we will catch "didn't call
        // WTF::initializeThreading() soon enough" bugs in release mode.
        ASSERT(m_key != InvalidThreadSpecificKey);
        threadSpecificSet(m_key, new ThreadHolder(thread));
    }
}

void ThreadHolder::destruct(void* data)
{
    ThreadHolder* threadIdentifierData = static_cast<ThreadHolder*>(data);
    ASSERT(threadIdentifierData);

    if (threadIdentifierData->m_isDestroyedOnce) {
        delete threadIdentifierData;
        return;
    }

    threadIdentifierData->m_isDestroyedOnce = true;
    // Re-setting the value for key causes another destruct() call after all other thread-specific destructors were called.
    threadSpecificSet(m_key, threadIdentifierData);
}

} // namespace WTF