Blink JavaScript shared memory prototype.

Source/core/dom/LockManager.h

 /*
- * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ * Copyright (C) 2014 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 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 MessageChannel_h
-#define MessageChannel_h
+#ifndef LockManager_h
+#define LockManager_h
 
 #include "bindings/v8/ScriptWrappable.h"
+#include "wtf/HashMap.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
+#include "wtf/ThreadSafeRefCounted.h"
+#include "wtf/ThreadingPrimitives.h"
 
 namespace WebCore {
 
-class MessagePort;
 class ExecutionContext;
 
-class MessageChannel : public RefCounted<MessageChannel>, public ScriptWrappable {
+class LockInfo;
+
+typedef WTF::HashMap<uint32_t, LockInfo*> LockHashMap;
+
+class LockShard {
 public:
-    static PassRefPtr<MessageChannel> create(ExecutionContext* context) { return adoptRef(new MessageChannel(context)); }
-    ~MessageChannel();
+    ~LockShard();
 
-    MessagePort* port1() const { return m_port1.get(); }
-    MessagePort* port2() const { return m_port2.get(); }
+    LockInfo* get(uint32_t uid);
+
+    Mutex mutex;
+private:
+    LockHashMap locks;
+};
+
+#define SHARD_BITS 5
+#define NUM_SHARDS (1 << SHARD_BITS)
+#define SHARD_MASK (NUM_SHARDS-1)
+
+class LockManagerImpl FINAL : public ThreadSafeRefCounted<LockManagerImpl> {
+public:
+    void lock(uint32_t uid);
+    void unlock(uint32_t uid);
 
 private:
-    explicit MessageChannel(ExecutionContext*);
+    LockShard shards[NUM_SHARDS];
+};
 
-    RefPtr<MessagePort> m_port1;
-    RefPtr<MessagePort> m_port2;
+class LockManager FINAL : public RefCounted<LockManager>
+    , public ScriptWrappable {
+public:
+    static PassRefPtr<LockManager> create(ExecutionContext* context)
+    {
+        return adoptRef(new LockManager(context));
+    }
+
+    void lock(unsigned long uid);
+    void unlock(unsigned long uid);
+
+    // HACK for performance testing.
+    void nop();
+
+private:
+    explicit LockManager(ExecutionContext*);
+
+    RefPtr<LockManagerImpl> impl;
 };
 
 } // namespace WebCore
 
-#endif // MessageChannel_h
+#endif // LockManager_h