binidngs: Make callInternalFunction return MaybeLocal

Source/bindings/core/v8/ScriptDebugServer.cpp

 /*
  * Copyright (c) 2010-2011 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
@@ skipping 50 matching lines @@
 
 const char stepIntoV8MethodName[] = "stepIntoStatement";
 const char stepOutV8MethodName[] = "stepOutOfFunction";
 }
 
 v8::Local<v8::Value> ScriptDebugServer::callDebuggerMethod(const char* functionName, int argc, v8::Local<v8::Value> argv[])
 {
     v8::Local<v8::Object> debuggerScript = debuggerScriptLocal();
     v8::Local<v8::Function> function = v8::Local<v8::Function>::Cast(debuggerScript->Get(v8InternalizedString(functionName)));
     ASSERT(m_isolate->InContext());
-    return V8ScriptRunner::callInternalFunction(function, debuggerScript, argc, argv, m_isolate);
+    return V8ScriptRunner::callInternalFunction(function, debuggerScript, argc, argv, m_isolate).ToLocalChecked();

[haraken, 2015/03/25 12:05:22]

How is it guaranteed that this callInternalFunction does not erturn an empty
handle?

[yurys, 2015/03/25 12:25:06]

In fact it is expected to throw in some cases. See 
ScriptDebugServer::setScriptSource where the exception is handled explicitly. In
most of the cases debugger code must not throw and if it does we have no better
option than to crash.

[bashi, 2015/03/27 00:39:50]

In other places, I changed the return value to MaybeLocal, but I'd prefer using
ToLocalChecked() here as yurys@ says there is no better option than crash.

 }
 
 ScriptDebugServer::ScriptDebugServer(v8::Isolate* isolate)
     : m_isolate(isolate)
     , m_breakpointsActivated(true)
     , m_compiledScripts(isolate)
     , m_runningNestedMessageLoop(false)
 {
 }
 
@@ skipping 29 matching lines @@
 void ScriptDebugServer::reportCompiledScripts(const String& contextDebugDataSubstring, ScriptDebugListener* listener)
 {
     v8::HandleScope scope(m_isolate);
     v8::Local<v8::Context> debuggerContext = v8::Debug::GetDebugContext();
     v8::Context::Scope contextScope(debuggerContext);
 
     v8::Local<v8::Object> debuggerScript = debuggerScriptLocal();
     ASSERT(!debuggerScript->IsUndefined());
     v8::Local<v8::Function> getScriptsFunction = v8::Local<v8::Function>::Cast(debuggerScript->Get(v8AtomicString(m_isolate, "getScripts")));
     v8::Local<v8::Value> argv[] = { v8String(m_isolate, contextDebugDataSubstring) };
-    v8::Local<v8::Value> value = V8ScriptRunner::callInternalFunction(getScriptsFunction, debuggerScript, WTF_ARRAY_LENGTH(argv), argv, m_isolate);
-    if (value.IsEmpty())
+    v8::Local<v8::Value> value;
+    if (!V8ScriptRunner::callInternalFunction(getScriptsFunction, debuggerScript, WTF_ARRAY_LENGTH(argv), argv, m_isolate).ToLocal(&value))
         return;
     ASSERT(value->IsArray());
     v8::Local<v8::Array> scriptsArray = v8::Local<v8::Array>::Cast(value);
     for (unsigned i = 0; i < scriptsArray->Length(); ++i)
         dispatchDidParseSource(listener, v8::Local<v8::Object>::Cast(scriptsArray->Get(v8::Integer::New(m_isolate, i))), CompileSuccess);
 }
 
 String ScriptDebugServer::setBreakpoint(const String& sourceID, const ScriptBreakpoint& scriptBreakpoint, int* actualLineNumber, int* actualColumnNumber, bool interstatementLocation)
 {
     v8::HandleScope scope(m_isolate);
@@ skipping 405 matching lines @@
 void ScriptDebugServer::v8DebugEventCallback(const v8::Debug::EventDetails& eventDetails)
 {
     ScriptDebugServer* thisPtr = toScriptDebugServer(eventDetails.GetCallbackData());
     thisPtr->handleV8DebugEvent(eventDetails);
 }
 
 static v8::Local<v8::Value> callInternalGetterFunction(v8::Local<v8::Object> object, const char* functionName, v8::Isolate* isolate)
 {
     v8::Local<v8::Value> getterValue = object->Get(v8AtomicString(isolate, functionName));
     ASSERT(!getterValue.IsEmpty() && getterValue->IsFunction());
-    return V8ScriptRunner::callInternalFunction(v8::Local<v8::Function>::Cast(getterValue), object, 0, 0, isolate);
+    return V8ScriptRunner::callInternalFunction(v8::Local<v8::Function>::Cast(getterValue), object, 0, 0, isolate).ToLocalChecked();
 }
 
 void ScriptDebugServer::handleV8DebugEvent(const v8::Debug::EventDetails& eventDetails)
 {
     v8::DebugEvent event = eventDetails.GetEvent();
 
     if (event == v8::BreakForCommand) {
         ClientDataImpl* data = static_cast<ClientDataImpl*>(eventDetails.GetClientData());
         data->task()->run();
         return;
@@ skipping 231 matching lines @@
             *lineNumber = message->GetLineNumber();
             *columnNumber = message->GetStartColumn();
             v8::Local<v8::StackTrace> messageStackTrace = message->GetStackTrace();
             if (!messageStackTrace.IsEmpty() && messageStackTrace->GetFrameCount() > 0)
                 *stackTrace = createScriptCallStack(m_isolate, messageStackTrace, messageStackTrace->GetFrameCount());
         }
     }
 }
 
 } // namespace blink