WIPjarred/workers

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diff --git a/src/javascript/jsc/bindings/webcore/Supplementable.h b/src/javascript/jsc/bindings/webcore/Supplementable.h
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+/*
+ * Copyright (C) 2012 Google, 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 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 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 Supplementable_h
+#define Supplementable_h
+
+#include <wtf/Assertions.h>
+#include <wtf/HashMap.h>
+#include <wtf/MainThread.h>
+
+#if ASSERT_ENABLED
+#include <wtf/Threading.h>
+#endif
+
+namespace WebCore {
+
+// What you should know about Supplementable and Supplement
+// ========================================================
+// Supplementable and Supplement instances are meant to be thread local. They
+// should only be accessed from within the thread that created them. The
+// 2 classes are not designed for safe access from another thread. Violating
+// this design assumption can result in memory corruption and unpredictable
+// behavior.
+//
+// What you should know about the Supplement keys
+// ==============================================
+// The Supplement is expected to use the same const char* string instance
+// as its key. The Supplementable's SupplementMap will use the address of the
+// string as the key and not the characters themselves. Hence, 2 strings with
+// the same characters will be treated as 2 different keys.
+//
+// In practice, it is recommended that Supplements implements a static method
+// for returning its key to use. For example:
+//
+//     class MyClass : public Supplement<MySupplementable> {
+//         ...
+//         static const char* supplementName();
+//     }
+//
+//     const char* MyClass::supplementName()
+//     {
+//         return "MyClass";
+//     }
+//
+// An example of the using the key:
+//
+//     MyClass* MyClass::from(MySupplementable* host)
+//     {
+//         return reinterpret_cast<MyClass*>(Supplement<MySupplementable>::from(host, supplementName()));
+//     }
+
+template<typename T>
+class Supplementable;
+
+template<typename T>
+class Supplement {
+public:
+    virtual ~Supplement() = default;
+#if ASSERT_ENABLED || ENABLE(SECURITY_ASSERTIONS)
+    virtual bool isRefCountedWrapper() const { return false; }
+#endif
+
+    static void provideTo(Supplementable<T>* host, const char* key, std::unique_ptr<Supplement<T>> supplement)
+    {
+        host->provideSupplement(key, WTFMove(supplement));
+    }
+
+    static Supplement<T>* from(Supplementable<T>* host, const char* key)
+    {
+        return host ? host->requireSupplement(key) : 0;
+    }
+};
+
+template<typename T>
+class Supplementable {
+public:
+    void provideSupplement(const char* key, std::unique_ptr<Supplement<T>> supplement)
+    {
+        ASSERT(canCurrentThreadAccessThreadLocalData(m_thread));
+        ASSERT(!m_supplements.get(key));
+        m_supplements.set(key, WTFMove(supplement));
+    }
+
+    void removeSupplement(const char* key)
+    {
+        ASSERT(canCurrentThreadAccessThreadLocalData(m_thread));
+        m_supplements.remove(key);
+    }
+
+    Supplement<T>* requireSupplement(const char* key)
+    {
+        ASSERT(canCurrentThreadAccessThreadLocalData(m_thread));
+        return m_supplements.get(key);
+    }
+
+#if ASSERT_ENABLED
+protected:
+    Supplementable() = default;
+#endif
+
+private:
+    typedef HashMap<const char*, std::unique_ptr<Supplement<T>>, PtrHash<const char*>> SupplementMap;
+    SupplementMap m_supplements;
+#if ASSERT_ENABLED
+    Ref<Thread> m_thread { Thread::current() };
+#endif
+};
+
+} // namespace WebCore
+
+#endif // Supplementable_h
+