Apply script preprocessor to Web page scripts only.

Source/bindings/v8/ScriptController.cpp

 /*
  * Copyright (C) 2008, 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 656 matching lines @@
 {
     String sourceURL = sourceCode.url();
     const String* savedSourceURL = m_sourceURL;
     m_sourceURL = &sourceURL;
 
     v8::HandleScope handleScope;
     v8::Handle<v8::Context> v8Context = ScriptController::mainWorldContext(m_frame);
     if (v8Context.IsEmpty())
         return ScriptValue();
 
+    String processedString = m_frame->script()->preprocess(sourceCode.source(), sourceURL);
+    ScriptSourceCode processedSourceCode(processedString, sourceCode.url(), sourceCode.startPosition());
+
     v8::Context::Scope scope(v8Context);
     RefPtr<Frame> protect(m_frame);
-    v8::Local<v8::Value> object = compileAndRunScript(sourceCode);
+    v8::Local<v8::Value> object = compileAndRunScript(processedSourceCode);
 
     m_sourceURL = savedSourceURL;
 
     if (object.IsEmpty())
         return ScriptValue();
 
     return ScriptValue(object);
 }
 
 void ScriptController::executeScriptInIsolatedWorld(int worldID, const Vector<ScriptSourceCode>& sources, int extensionGroup, Vector<ScriptValue>* results)
@@ skipping 23 matching lines @@
 
         v8Results = evaluateHandleScope.Close(resultArray);
     }
 
     if (results && !v8Results.IsEmpty()) {
         for (size_t i = 0; i < v8Results->Length(); ++i)
             results->append(ScriptValue(v8Results->Get(i)));
     }
 }
 
+static const String preprocessorName = "$preprocessor.js";

[abarth-chromium, 2013/06/04 06:50:23]

This will create a static initializer, which isn't allowed.

[johnjbarton, 2013/06/04 18:41:22]

Done.

+
+class ScriptController::ScriptPreprocessor {
+    WTF_MAKE_NONCOPYABLE(ScriptPreprocessor);
+public:
+    ScriptPreprocessor(const String& preprocessorScript, ScriptController* controller)
+        : m_controller(controller), m_isolate(controller->m_isolate)
+    {
+        v8::HandleScope scope(m_isolate);
+
+        v8::Local<v8::Context> context = v8::Context::New(m_isolate);

[abarth-chromium, 2013/06/04 06:50:23]

Hum...  I usually push back on calls to v8::Context::New.  We make a number of
assumptions about how contexts are set up, and ah-hoc contexts aren't going to
be set up the way we want.

[johnjbarton, 2013/06/04 18:41:22]

I don't know what to do here: what context shall I use?

+        if (context.IsEmpty())
+            return;
+
+        v8::Local<v8::Value> preprocessorFunction;
+        v8::TryCatch tryCatch;
+
+        v8::Context::Scope contextScope(context);
+        v8::Handle<v8::String> preprocessor = v8::String::New(preprocessorScript.utf8().data(), preprocessorScript.utf8().length());

[abarth-chromium, 2013/06/04 06:50:23]

This isn't the right way to create v8 string from a WTFString.  That's why we
have the v8String function.

[johnjbarton, 2013/06/04 18:41:22]

Done.

+        preprocessorFunction = V8ScriptRunner::compileAndRunInternalScript(preprocessor, m_isolate);
+
+        if (tryCatch.HasCaught()) {
+            reportException(tryCatch, preprocessorName);
+            return;
+        }
+
+        if (preprocessorFunction.IsEmpty())
+            m_creationError = "Internal error: The preprocessor outer script gave no value without throwing.";
+        else if (!preprocessorFunction->IsFunction())
+            m_creationError = "The preprocessor must compile to a function.";
+
+        if (!m_creationError.isEmpty()) {
+            reportErrorMessage(preprocessorName);
+            return;
+        }
+
+        m_utilityContext.set(m_isolate, context);
+        m_preprocessorFunction.set(m_isolate, v8::Handle<v8::Function>::Cast(preprocessorFunction));
+    }
+
+    void reportException(const v8::TryCatch& tryCatch, const String& sourceName)
+    {
+        v8::Local<v8::Message> message = tryCatch.Message();
+        if (!tryCatch.Message().IsEmpty())
+            m_creationError = toWebCoreStringWithUndefinedOrNullCheck(message->Get());
+        else
+            m_creationError = "Unknown exception.";
+
+        RefPtr<ScriptCallStack> callStack = createScriptCallStack(
+            message->GetStackTrace(), ScriptCallStack::maxCallStackSizeToCapture);
+
+        reportErrorMessage(sourceName, message->GetLineNumber(), callStack);
+    }
+
+    void reportErrorMessage(const String& sourceName, int lineNumber = 1, PassRefPtr<ScriptCallStack> callStack = RefPtr<ScriptCallStack>())
+    {
+        v8::Context::Scope contextScope(m_controller->mainWorldContext());
+        getScriptExecutionContext()->reportException(m_creationError, lineNumber, sourceName, callStack);
+    }
+
+    String preprocessSourceCode(const String& sourceCode, const String& sourceName)
+    {
+        v8::HandleScope handleScope(m_isolate);
+        if (m_preprocessorFunction.isEmpty())
+            return sourceCode;
+
+        v8::Local<v8::Context> context = v8::Local<v8::Context>::New(m_utilityContext.get());

[abarth-chromium, 2013/06/04 06:50:23]

I think we have a new pattern for this sort of code that avoids calling the
v8::Persistent copy constructor.  We're trying to get rid of all calls to the
v8::Persistent copy constructor.

[johnjbarton, 2013/06/04 18:41:22]

I've changed this code and I will ask Marja to review the use of
ScopedPersistent.

+        v8::Context::Scope contextScope(context);
+
+        v8::Handle<v8::String> sourceCodeString = v8::String::New(sourceCode.utf8().data(), sourceCode.utf8().length());
+
+        v8::Handle<v8::String> sourceNameString = v8::String::New(sourceName.utf8().data(), sourceName.utf8().length());
+        v8::Handle<v8::Value> argv[] = { sourceCodeString, sourceNameString };
+
+        v8::TryCatch tryCatch;
+        v8::Handle<v8::Value> resultValue =
+            V8ScriptRunner::callAsFunction(m_preprocessorFunction.newLocal(m_isolate), context->Global(), 2, argv);
+
+        if (tryCatch.HasCaught()) {
+            reportException(tryCatch, sourceName);
+            return sourceCode;
+        }
+
+        if (resultValue->IsString()) {
+            v8::String::Utf8Value utf8Value(resultValue);
+            return String::fromUTF8(*utf8Value, utf8Value.length());

[abarth-chromium, 2013/06/04 06:50:23]

This isn't the way we create WTFStrings from v8::Strings.

[johnjbarton, 2013/06/04 18:41:22]

Done.

+        }
+        return sourceCode;
+    }
+
+    bool hadCreationError()
+    {
+        return !m_creationError.isEmpty();
+    }
+
+    ~ScriptPreprocessor()
+    {
+    }
+
+private:
+    ScopedPersistent<v8::Context> m_utilityContext;
+    String m_preprocessorBody;
+    ScopedPersistent<v8::Function> m_preprocessorFunction;
+    ScriptController* m_controller;
+    v8::Isolate* m_isolate;
+    String m_creationError;
+};
+
+void ScriptController::setScriptPreprocessor(const String& preprocessorBody)
+{
+    // The preprocessor will be created the first time it is needed.
+    m_scriptPreprocessor.clear();
+    m_preprocessorSource = preprocessorBody;
+}
+
+String ScriptController::preprocess(const String& scriptSource, const String& scriptName)
+{
+    if (m_preprocessorSource.isEmpty())
+        return scriptSource;
+
+    if (!m_scriptPreprocessor)
+        m_scriptPreprocessor = adoptPtr(new ScriptPreprocessor(m_preprocessorSource, this));
+
+    if (m_scriptPreprocessor->hadCreationError())
+        return scriptSource;
+
+    return m_scriptPreprocessor->preprocessSourceCode(scriptSource, scriptName);
+}
+
+
 } // namespace WebCore