1 files changed, 110 insertions, 0 deletions
diff --git a/Source/WebCore/bindings/js/JSDynamicDowncast.h b/Source/WebCore/bindings/js/JSDynamicDowncast.h
new file mode 100644
index 000000000..0160126e1
--- /dev/null
+++ b/Source/WebCore/bindings/js/JSDynamicDowncast.h
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2016 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 AND ITS 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 APPLE OR ITS 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.
+ */
+
+#pragma once
+
+#include <runtime/JSCJSValueInlines.h>
+#include <runtime/JSCellInlines.h>
+#include <type_traits>
+
+namespace WebCore {
+
+template<typename To, typename From>
+using JSDynamicCastResult = typename std::conditional<std::is_const<From>::value, const To, To>::type*;
+
+class JSNode;
+template<typename From>
+JSDynamicCastResult<JSNode, From> jsNodeCast(From* value);
+class JSElement;
+template<typename From>
+JSDynamicCastResult<JSElement, From> jsElementCast(From* value);
+class JSDocument;
+template<typename From>
+JSDynamicCastResult<JSDocument, From> jsDocumentCast(From* value);
+class JSEvent;
+template<typename From>
+JSDynamicCastResult<JSEvent, From> jsEventCast(From* value);
+
+template<typename Select>
+struct JSDynamicCastTrait {
+    template<typename To, typename From>
+    ALWAYS_INLINE static To cast(JSC::VM& vm, From* from)
+    {
+        return JSC::jsDynamicCast<To>(vm, from);
+    }
+};
+
+template<>
+struct JSDynamicCastTrait<JSNode> {
+    template<typename To, typename From>
+    ALWAYS_INLINE static To cast(JSC::VM&, From* from)
+    {
+        return jsNodeCast(from);
+    }
+};
+
+template<>
+struct JSDynamicCastTrait<JSElement> {
+    template<typename To, typename From>
+    ALWAYS_INLINE static To cast(JSC::VM&, From* from)
+    {
+        return jsElementCast(from);
+    }
+};
+
+template<>
+struct JSDynamicCastTrait<JSDocument> {
+    template<typename To, typename From>
+    ALWAYS_INLINE static To cast(JSC::VM&, From* from)
+    {
+        return jsDocumentCast(from);
+    }
+};
+
+template<>
+struct JSDynamicCastTrait<JSEvent> {
+    template<typename To, typename From>
+    ALWAYS_INLINE static To cast(JSC::VM&, From* from)
+    {
+        return jsEventCast(from);
+    }
+};
+
+template<typename To, typename From>
+ALWAYS_INLINE To jsDynamicDowncast(JSC::VM& vm, From* from)
+{
+    typedef JSDynamicCastTrait<typename std::remove_cv<typename std::remove_pointer<To>::type>::type> Dispatcher;
+    return Dispatcher::template cast<To>(vm, from);
+}
+
+template<typename To>
+ALWAYS_INLINE To jsDynamicDowncast(JSC::VM& vm, JSC::JSValue from)
+{
+    if (UNLIKELY(!from.isCell()))
+        return nullptr;
+    return jsDynamicDowncast<To>(vm, from.asCell());
+}
+
+}