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

webkit/port/bindings/v8/JSNSResolver.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 "JSNSResolver.h"
+
+#include "v8_proxy.h"
+#include "v8_binding.h"
+#include "ExceptionContext.h"
+#include "PlatformString.h"
+
+namespace WebCore {
+
+JSNSResolver::JSNSResolver(v8::Handle<v8::Object> resolver)
+    : m_resolver(resolver)
+{
+}
+
+JSNSResolver::~JSNSResolver()
+{
+}
+
+String JSNSResolver::lookupNamespaceURI(ExceptionContext* exceptionContext,
+                                        const String& prefix)
+{
+    v8::Handle<v8::Function> lookupNamespaceURIFunc;
+    v8::Handle<v8::String> lookupNamespaceURIName = 
+        v8::String::New("lookupNamespaceURI");
+
+    // Check if the resolver has a function property named lookupNamespaceURI.
+    if (m_resolver->Has(lookupNamespaceURIName)) {
+        v8::Handle<v8::Value> lookupNamespaceURI = m_resolver->Get(
+            lookupNamespaceURIName);
+        if (lookupNamespaceURI->IsFunction()) {
+            lookupNamespaceURIFunc = v8::Handle<v8::Function>::Cast(
+                lookupNamespaceURI);
+        }
+    }
+
+    if (lookupNamespaceURIFunc.IsEmpty() && !m_resolver->IsFunction()) {
+        Frame* frame = ScriptController::retrieveActiveFrame();
+        log_info(frame, "NSResolver does not have a lookupNamespaceURI method.",
+                 String());
+        return String();
+    }
+
+    // Catch exceptions from calling the namespace resolver.
+    ExceptionCatcher exceptionCatcher(exceptionContext);
+
+    const int argc = 1;
+    v8::Handle<v8::Value> argv[argc] = { v8String(prefix) };
+    v8::Handle<v8::Function> function = lookupNamespaceURIFunc.IsEmpty()
+        ? v8::Handle<v8::Function>::Cast(m_resolver)
+        : lookupNamespaceURIFunc;
+
+    V8Proxy* proxy = V8Proxy::retrieve();
+    v8::Handle<v8::Value> retval = proxy->CallFunction(function, m_resolver,
+                                                       argc, argv);
+
+    // Eat exceptions from namespace resolver and return an empty string. This
+    // will most likely cause NAMESPACE_ERR.
+    if (exceptionContext->hadException())
+        return String();
+
+    return ToWebCoreString(retval);
+}
+
+}