Implement better JS exception handling by abstracting KJS::ExecState into an ...

webkit/port/bridge/ExceptionContextV8.cpp

+// Copyright (c) 2008, 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.
+
+#include "config.h"
+#include "ExceptionContext.h"
+
+#include "Node.h"
+
+namespace WebCore {
+
+ExceptionContext::ExceptionContext()
+    : m_exceptionCatcher(0)
+    , m_exception()
+{
+}
+
+ExceptionContext::~ExceptionContext()
+{
+}
+
+void ExceptionContext::setExceptionCatcher(ExceptionCatcher* exceptionCatcher)
+{
+    if (m_exceptionCatcher && exceptionCatcher)
+        m_exceptionCatcher->detachContext();
+
+    m_exceptionCatcher = exceptionCatcher;
+}
+
+bool ExceptionContext::hadException()
+{
+    if (m_exceptionCatcher)
+        m_exceptionCatcher->updateContext();
+
+    return !m_exception.IsEmpty();
+}
+
+ExceptionContext* ExceptionContext::createFromNode(Node*)
+{
+    // Unlike JSC, which stores exceptions in ExecState that is accessible from
+    // ScriptController that is retrievable from Node*, V8 uses static chain of
+    // handlers (encapsulated as v8::TryCatch and here as ExceptionCatcher)
+    // to track exceptions, so it has no need for Node*.
+    return new ExceptionContext();
+}
+
+JSException ExceptionContext::NoException()
+{
+    return v8::Local<v8::Value>();
+}
+
+ExceptionCatcher::ExceptionCatcher(ExceptionContext* exceptionContext)
+    : m_catcher()
+    , m_context(exceptionContext)
+{
+    exceptionContext->setExceptionCatcher(this);
+}
+
+void ExceptionCatcher::detachContext()
+{
+    m_context = 0;
+}
+
+void ExceptionCatcher::updateContext()
+{
+    ASSERT(m_context);
+
+    if (m_catcher.HasCaught())
+        m_context->setException(m_catcher.Exception());
+    else
+        m_context->setException(ExceptionContext::NoException());
+}
+
+ExceptionCatcher::~ExceptionCatcher()
+{
+    if (!m_context)
+        return;
+
+    updateContext();
+    m_context->setExceptionCatcher(0);
+}
+
+}  // namespace WebCore