WebCore/bindings/v8/OwnHandle.h
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/bindings/v8/OwnHandle.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2009 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:
+ *
+ *     * 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
+ * (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 OwnHandle_h
+#define OwnHandle_h
+
+#include <v8.h>
+
+namespace WebCore {
+
+    template<typename T>
+    class OwnHandle {
+    public:
+        OwnHandle() { }
+        explicit OwnHandle(v8::Handle<T> handle) : m_handle(v8::Persistent<T>::New(handle)) { }
+        ~OwnHandle() { clear(); }
+
+        v8::Handle<T> get() const { return m_handle; }
+        void set(v8::Handle<T> handle) { clear(); m_handle = v8::Persistent<T>::New(handle); }
+
+        // Note: This is clear in the OwnPtr sense, not the v8::Handle sense.
+        void clear()
+        {
+            if (m_handle.IsEmpty())
+                return;
+            if (m_handle.IsWeak())
+                m_handle.ClearWeak();
+            m_handle.Dispose();
+            m_handle.Clear();
+        }
+
+        // Make the underlying handle weak.  The client doesn't get a callback,
+        // we just make the handle empty.
+        void makeWeak()
+        {
+            if (m_handle.IsEmpty())
+                return;
+            m_handle.MakeWeak(this, &OwnHandle<T>::weakCallback);
+        }
+
+    private:
+        static void weakCallback(v8::Persistent<v8::Value> object, void* ownHandle)
+        {
+            OwnHandle<T>* handle = static_cast<OwnHandle<T>*>(ownHandle);
+            handle->clear();
+        }
+
+        v8::Persistent<T> m_handle;
+    };
+
+} // namespace WebCore
+
+#endif // OwnHandle_h