JavaScriptCore/wtf/WTFThreadData.h
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/JavaScriptCore/wtf/WTFThreadData.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,165 @@
+/*
+ * 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
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ *
+ */
+
+#ifndef WTFThreadData_h
+#define WTFThreadData_h
+
+#include <wtf/HashMap.h>
+#include <wtf/HashSet.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/text/StringHash.h>
+
+// This was ENABLE(WORKERS) in WebCore, but this is not defined when compiling JSC.
+// However this check was not correct anyway, re this comment:
+//    // 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.
+// Always enabling this is safe, and should be a better option until we can come up
+// with a better define.
+#define WTFTHREADDATA_MULTITHREADED 1
+
+#if WTFTHREADDATA_MULTITHREADED
+#include <wtf/ThreadSpecific.h>
+#include <wtf/Threading.h>
+#endif
+
+// FIXME: This is a temporary layering violation while we move more string code to WTF.
+namespace WebCore {
+class AtomicStringTable;
+class StringImpl;
+}
+using WebCore::StringImpl;
+
+typedef void (*AtomicStringTableDestructor)(WebCore::AtomicStringTable*);
+
+#if USE(JSC)
+// FIXME: This is a temporary layering violation while we move more string code to WTF.
+namespace JSC {
+
+typedef HashMap<const char*, RefPtr<StringImpl>, PtrHash<const char*> > LiteralIdentifierTable;
+
+class IdentifierTable : public FastAllocBase {
+public:
+    ~IdentifierTable();
+
+    std::pair<HashSet<StringImpl*>::iterator, bool> add(StringImpl* value);
+    template<typename U, typename V>
+    std::pair<HashSet<StringImpl*>::iterator, bool> add(U value);
+
+    void remove(StringImpl* r) { m_table.remove(r); }
+
+    LiteralIdentifierTable& literalTable() { return m_literalTable; }
+
+private:
+    HashSet<StringImpl*> m_table;
+    LiteralIdentifierTable m_literalTable;
+};
+
+}
+#endif
+
+namespace WTF {
+
+class WTFThreadData : public Noncopyable {
+public:
+    WTFThreadData();
+    ~WTFThreadData();
+
+    WebCore::AtomicStringTable* atomicStringTable()
+    {
+        return m_atomicStringTable;
+    }
+
+#if USE(JSC)
+    void initializeIdentifierTable(JSC::IdentifierTable* identifierTable)
+    {
+        m_defaultIdentifierTable = identifierTable;
+        m_currentIdentifierTable = identifierTable;
+    }
+
+    JSC::IdentifierTable* currentIdentifierTable()
+    {
+        return m_currentIdentifierTable;
+    }
+
+    JSC::IdentifierTable* setCurrentIdentifierTable(JSC::IdentifierTable* identifierTable)
+    {
+        JSC::IdentifierTable* oldIdentifierTable = m_currentIdentifierTable;
+        m_currentIdentifierTable = identifierTable;
+        return oldIdentifierTable;
+    }
+
+    void resetCurrentIdentifierTable()
+    {
+        m_currentIdentifierTable = m_defaultIdentifierTable;
+    }
+#endif
+
+private:
+    WebCore::AtomicStringTable* m_atomicStringTable;
+    AtomicStringTableDestructor m_atomicStringTableDestructor;
+
+#if USE(JSC)
+    JSC::IdentifierTable* m_defaultIdentifierTable;
+    JSC::IdentifierTable* m_currentIdentifierTable;
+#endif
+
+#if WTFTHREADDATA_MULTITHREADED
+    static JS_EXPORTDATA ThreadSpecific<WTFThreadData>* staticData;
+#else
+    static JS_EXPORTDATA WTFThreadData* staticData;
+#endif
+    friend WTFThreadData& wtfThreadData();
+    friend class WebCore::AtomicStringTable;
+};
+
+inline WTFThreadData& wtfThreadData()
+{
+#if WTFTHREADDATA_MULTITHREADED
+    // WRT WebCore:
+    //    WTFThreadData is used on main thread before it could possibly be used
+    //    on secondary ones, so there is no need for synchronization here.
+    // WRT JavaScriptCore:
+    //    wtfThreadData() is initially called from initializeThreading(), ensuring
+    //    this is initially called in a pthread_once locked context.
+    if (!WTFThreadData::staticData)
+        WTFThreadData::staticData = new ThreadSpecific<WTFThreadData>;
+    return **WTFThreadData::staticData;
+#else
+    if (!WTFThreadData::staticData) {
+        WTFThreadData::staticData = static_cast<WTFThreadData*>(fastMalloc(sizeof(WTFThreadData)));
+        // WTFThreadData constructor indirectly uses staticData, so we need to set up the memory before invoking it.
+        new (WTFThreadData::staticData) WTFThreadData;
+    }
+    return *WTFThreadData::staticData;
+#endif
+}
+
+} // namespace WTF
+
+using WTF::WTFThreadData;
+using WTF::wtfThreadData;
+
+#endif // WTFThreadData_h