WebCore/platform/ThreadGlobalData.cpp

/*
 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``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 APPLE COMPUTER, INC. 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
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#include "config.h"
#include "ThreadGlobalData.h"

#include "EventNames.h"
#include "StringImpl.h"
#include "ThreadTimers.h"
#include <wtf/UnusedParam.h>

#if USE(ICU_UNICODE) || USE(GLIB_ICU_UNICODE_HYBRID)
#include "TextCodecICU.h"
#endif

#if PLATFORM(MAC)
#include "TextCodecMac.h"
#endif

#if ENABLE(WORKERS)
#include <wtf/Threading.h>
#include <wtf/ThreadSpecific.h>
using namespace WTF;
#endif

namespace WebCore {

ThreadGlobalData& threadGlobalData()
{
    // FIXME: Workers are not necessarily the only feature that make per-thread global data necessary.
    // We need to check for e.g. database objects manipulating strings on secondary threads.
#if ENABLE(WORKERS)
    // ThreadGlobalData is used on main thread before it could possibly be used on secondary ones, so there is no need for synchronization here.
    static ThreadSpecific<ThreadGlobalData>* threadGlobalData = new ThreadSpecific<ThreadGlobalData>;
    return **threadGlobalData;
#else
    static ThreadGlobalData* staticData;
    if (!staticData) {
        staticData = static_cast<ThreadGlobalData*>(fastMalloc(sizeof(ThreadGlobalData)));
        // ThreadGlobalData constructor indirectly uses staticData, so we need to set up the memory before invoking it.
        new (staticData) ThreadGlobalData;
    }
    return *staticData;
#endif
}

ThreadGlobalData::ThreadGlobalData()
    : m_emptyString(new StringImpl)
    , m_atomicStringTable(new HashSet<StringImpl*>)
    , m_eventNames(new EventNames)
    , m_threadTimers(new ThreadTimers)
#ifndef NDEBUG
    , m_isMainThread(isMainThread())
#endif
#if USE(ICU_UNICODE) || USE(GLIB_ICU_UNICODE_HYBRID)
    , m_cachedConverterICU(new ICUConverterWrapper)
#endif
#if PLATFORM(MAC)
    , m_cachedConverterTEC(new TECConverterWrapper)
#endif
{
}

ThreadGlobalData::~ThreadGlobalData()
{
#if PLATFORM(MAC)
    delete m_cachedConverterTEC;
#endif
#if USE(ICU_UNICODE) || USE(GLIB_ICU_UNICODE_HYBRID)
    delete m_cachedConverterICU;
#endif

    delete m_eventNames;
    delete m_atomicStringTable;
    delete m_threadTimers;

    // Using member variable m_isMainThread instead of calling WTF::isMainThread() directly
    // to avoid issues described in https://bugs.webkit.org/show_bug.cgi?id=25973.
    // In short, some pthread-based platforms and ports can not use WTF::CurrentThread() and WTF::isMainThread()
    // in destructors of thread-specific data.
    ASSERT(m_isMainThread || m_emptyString->hasOneRef()); // We intentionally don't clean up static data on application quit, so there will be many strings remaining on the main thread.

    delete m_emptyString;
}

} // namespace WebCore