[Blink-in-JS] 'Import' function to load sub-modules and other resources for private scripts (Part-3)

Source/bindings/core/v8/PrivateScriptRunner.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "bindings/core/v8/PrivateScriptRunner.h"
 
 #include "bindings/core/v8/DOMWrapperWorld.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8Binding.h"
@@ skipping 22 matching lines @@
     message->GetLineNumber();
 
     v8::Handle<v8::Value> resourceName = message->GetScriptOrigin().ResourceName();
     String fileName = "Unknown JavaScript file";
     if (!resourceName.IsEmpty() && resourceName->IsString())
         fileName = toCoreString(v8::Handle<v8::String>::Cast(resourceName));
     int lineNumber = message->GetLineNumber();
     v8::Handle<v8::String> errorMessage = message->Get();
     fprintf(stderr, "%s (line %d): %s\n", fileName.utf8().data(), lineNumber, toCoreString(errorMessage).utf8().data());
 }
+static void functionImport(const v8::FunctionCallbackInfo<v8::Value>& args);
 
 static v8::Handle<v8::Value> compileAndRunPrivateScript(v8::Isolate* isolate, String scriptClassName, const char* source, size_t size)
 {
     v8::TryCatch block;
     String sourceString(source, size);
     String fileName = scriptClassName + ".js";
+
+    v8::Handle<v8::Context> context = isolate->GetCurrentContext();
+    v8::Handle<v8::Object> global = context->Global();
+
+    v8::Handle<v8::Value> functionImportObject = global->Get(v8String(isolate, "Import"));
+    if (isUndefinedOrNull(functionImportObject))

[haraken, 2014/11/25 09:41:41]

RELEASE_ASSERT(functionImportObject.IsEmpty() ||
functionImportObject->IsFunction());
if (functionImportObject.IsEmpty())
  global->Set(...);

[vivekg, 2014/11/25 11:30:32]

If I change to 

RELEASE_ASSERT(functionImportObject.IsEmpty() ||
functionImportObject->IsFunction());

the code is asserting immediately for the first time for
functionImportObject.IsEmpty() being false. 

Does IsEmpty() return "True" in such case as I am seeing the result otherwise?

+        global->Set(v8String(isolate, "Import"), v8::FunctionTemplate::New(isolate, functionImport)->GetFunction());
+
     v8::Handle<v8::Script> script = V8ScriptRunner::compileScript(v8String(isolate, sourceString), fileName, TextPosition::minimumPosition(), 0, 0, isolate, NotSharableCrossOrigin);
     if (block.HasCaught()) {
         fprintf(stderr, "Private script error: Compile failed. (Class name = %s)\n", scriptClassName.utf8().data());
         dumpV8Message(block.Message());
         RELEASE_ASSERT_NOT_REACHED();
     }
 
     v8::Handle<v8::Value> result = V8ScriptRunner::runCompiledInternalScript(isolate, script);
     if (block.HasCaught()) {
         fprintf(stderr, "Private script error: installClass() failed. (Class name = %s)\n", scriptClassName.utf8().data());
         dumpV8Message(block.Message());
         RELEASE_ASSERT_NOT_REACHED();
     }
     return result;
 }
 
+void functionImport(const v8::FunctionCallbackInfo<v8::Value>& args)
+{
+    v8::Isolate* isolate = args.GetIsolate();
+    RELEASE_ASSERT(isolate && (args.Length() == 1));
+
+    String resourceFileName = toCoreString(args[0]->ToString());
+    String resourceData = loadResourceAsASCIIString(resourceFileName.utf8().data());
+    RELEASE_ASSERT(resourceData.length());
+
+    if (resourceFileName.endsWith(".js")) {
+        compileAndRunPrivateScript(isolate, resourceFileName.replace(".js", ""), resourceData.utf8().data(), resourceData.length());
+    } else if (resourceFileName.endsWith(".css")) {
+        v8::Handle<v8::Object> global = isolate->GetCurrentContext()->Global();
+        global->Set(v8String(isolate, "css" + resourceFileName.replace(".css", "")), v8String(isolate, resourceData));
+    }
+}
+
 // FIXME: If we have X.js, XPartial-1.js and XPartial-2.js, currently all of the JS files
 // are compiled when any of the JS files is requested. Ideally we should avoid compiling
 // unrelated JS files. For example, if a method in XPartial-1.js is requested, we just
 // need to compile X.js and XPartial-1.js, and don't need to compile XPartial-2.js.
 static void installPrivateScript(v8::Isolate* isolate, String className)
 {
     int compiledScriptCount = 0;
     // |kPrivateScriptSourcesForTesting| is defined in V8PrivateScriptSources.h, which is auto-generated
     // by make_private_script_source.py.
 #ifndef NDEBUG
@@ skipping 219 matching lines @@
     v8::Handle<v8::Value> result = V8ScriptRunner::callFunction(v8::Handle<v8::Function>::Cast(method), scriptState->executionContext(), holder, argc, argv, scriptState->isolate());
     if (block.HasCaught()) {
         rethrowExceptionInPrivateScript(scriptState->isolate(), block, scriptStateInUserScript, ExceptionState::ExecutionContext, methodName, className);
         block.ReThrow();
         return v8::Handle<v8::Value>();
     }
     return result;
 }
 
 } // namespace blink