Clean up Debugger::NotifyMessageHandler.

src/debug.cc

 // Copyright 2012 the V8 project 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 "v8.h"
 
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "code-stubs.h"
@@ skipping 31 matching lines @@
       isolate_(isolate) {
   memset(registers_, 0, sizeof(JSCallerSavedBuffer));
   ThreadInit();
 }
 
 
 Debug::~Debug() {
 }
 
 
-static void PrintLn(v8::Local<v8::Value> value) {
-  v8::Local<v8::String> s = value->ToString();
-  ScopedVector<char> data(s->Utf8Length() + 1);
-  if (data.start() == NULL) {
-    V8::FatalProcessOutOfMemory("PrintLn");
-    return;
-  }
-  s->WriteUtf8(data.start());
-  PrintF("%s\n", data.start());
-}
-
-
 static v8::Handle<v8::Context> GetDebugEventContext(Isolate* isolate) {
   Handle<Context> context = isolate->debug()->debugger_entry()->GetContext();
   // Isolate::context() may have been NULL when "script collected" event
   // occured.
   if (context.is_null()) return v8::Local<v8::Context>();
   Handle<Context> native_context(context->native_context());
   return v8::Utils::ToLocal(native_context);
 }
 
 
@@ skipping 2985 matching lines @@
 
   // Clear the flag indicating that the debugger should be unloaded.
   debugger_unload_pending_ = false;
 }
 
 
 void Debugger::NotifyMessageHandler(v8::DebugEvent event,
                                     Handle<JSObject> exec_state,
                                     Handle<JSObject> event_data,
                                     bool auto_continue) {
-  v8::Isolate* isolate = reinterpret_cast<v8::Isolate*>(isolate_);
   HandleScope scope(isolate_);
 
   if (!isolate_->debug()->Load()) return;
 
   // Process the individual events.
   bool sendEventMessage = false;
   switch (event) {
     case v8::Break:
     case v8::BreakForCommand:
       sendEventMessage = !auto_continue;
@@ skipping 33 matching lines @@
   }
 
   // If auto continue don't make the event cause a break, but process messages
   // in the queue if any. For script collected events don't even process
   // messages in the queue as the execution state might not be what is expected
   // by the client.
   if ((auto_continue && !HasCommands()) || event == v8::ScriptCollected) {
     return;
   }
 
-  v8::TryCatch try_catch;
-
   // DebugCommandProcessor goes here.
-  v8::Local<v8::Object> cmd_processor;
-  {
-    v8::Local<v8::Object> api_exec_state =
-        v8::Utils::ToLocal(Handle<JSObject>::cast(exec_state));
-    v8::Local<v8::String> fun_name = v8::String::NewFromUtf8(
-        isolate, "debugCommandProcessor");
-    v8::Local<v8::Function> fun =
-        v8::Local<v8::Function>::Cast(api_exec_state->Get(fun_name));
-
-    v8::Handle<v8::Boolean> running = v8::Boolean::New(isolate, auto_continue);
-    static const int kArgc = 1;
-    v8::Handle<Value> argv[kArgc] = { running };
-    cmd_processor = v8::Local<v8::Object>::Cast(
-        fun->Call(api_exec_state, kArgc, argv));
-    if (try_catch.HasCaught()) {
-      PrintLn(try_catch.Exception());
-      return;
-    }
-  }
-
   bool running = auto_continue;
 
+  Handle<Object> cmd_processor_ctor = Object::GetProperty(
+      isolate_, exec_state, "debugCommandProcessor").ToHandleChecked();
+  Handle<Object> ctor_args[] = { isolate_->factory()->ToBoolean(running) };
+  Handle<Object> cmd_processor = Execution::Call(
+      isolate_, cmd_processor_ctor, exec_state, 1, ctor_args).ToHandleChecked();

[ulan, 2014/05/09 08:10:34]

Why did you remove v8::TryCatch try_catch here and below?

[Yang, 2014/05/09 08:36:14]

We don't expect this to fail. If it indeed does, something terrible happened and
we are better off crashing in ToHandleChecked().

Judging from the old code, I'm not surprised about anything anymore, even a
stray try-catch.

+  Handle<JSFunction> process_debug_request = Handle<JSFunction>::cast(
+      Object::GetProperty(
+          isolate_, cmd_processor, "processDebugRequest").ToHandleChecked());
+  Handle<Object> is_running = Object::GetProperty(
+      isolate_, cmd_processor, "isRunning").ToHandleChecked();
+
   // Process requests from the debugger.
-  while (true) {
+  do {
     // Wait for new command in the queue.
     command_received_.Wait();
 
     // Get the command from the queue.
     CommandMessage command = command_queue_.Get();
     isolate_->logger()->DebugTag(
         "Got request from command queue, in interactive loop.");
     if (!Debugger::IsDebuggerActive()) {
       // Delete command text and user data.
       command.Dispose();
       return;
     }
 
-    // Invoke JavaScript to process the debug request.
-    v8::Local<v8::String> fun_name;
-    v8::Local<v8::Function> fun;
-    v8::Local<v8::Value> request;
-    v8::TryCatch try_catch;
-    fun_name = v8::String::NewFromUtf8(isolate, "processDebugRequest");
-    fun = v8::Local<v8::Function>::Cast(cmd_processor->Get(fun_name));
+    Vector<const uc16> command_text(
+        const_cast<const uc16*>(command.text().start()),
+        command.text().length());
+    Handle<String> request_text = isolate_->factory()->NewStringFromTwoByte(
+        command_text).ToHandleChecked();
+    Handle<Object> request_args[] = { request_text };
+    Handle<Object> exception;
+    Handle<Object> answer_value;
+    Handle<String> answer;
+    MaybeHandle<Object> maybe_result = Execution::TryCall(
+        process_debug_request, cmd_processor, 1, request_args, &exception);
 
-    request = v8::String::NewFromTwoByte(isolate, command.text().start(),
-                                         v8::String::kNormalString,
-                                         command.text().length());
-    static const int kArgc = 1;
-    v8::Handle<Value> argv[kArgc] = { request };
-    v8::Local<v8::Value> response_val = fun->Call(cmd_processor, kArgc, argv);
-
-    // Get the response.
-    v8::Local<v8::String> response;
-    if (!try_catch.HasCaught()) {
-      // Get response string.
-      if (!response_val->IsUndefined()) {
-        response = v8::Local<v8::String>::Cast(response_val);
+    if (maybe_result.ToHandle(&answer_value)) {
+      if (answer_value->IsUndefined()) {
+        answer = isolate_->factory()->empty_string();
       } else {
-        response = v8::String::NewFromUtf8(isolate, "");
+        answer = Handle<String>::cast(answer_value);
       }
 
       // Log the JSON request/response.
       if (FLAG_trace_debug_json) {
-        PrintLn(request);
-        PrintLn(response);
+        request_text->PrintLn();

[ulan, 2014/05/09 08:10:34]

Will this compile with release without object-printing enabled?

[Yang, 2014/05/09 08:36:14]

You are right. Fixed that.

+        answer->PrintLn();
       }
 
-      // Get the running state.
-      fun_name = v8::String::NewFromUtf8(isolate, "isRunning");
-      fun = v8::Local<v8::Function>::Cast(cmd_processor->Get(fun_name));
-      static const int kArgc = 1;
-      v8::Handle<Value> argv[kArgc] = { response };
-      v8::Local<v8::Value> running_val = fun->Call(cmd_processor, kArgc, argv);
-      if (!try_catch.HasCaught()) {
-        running = running_val->ToBoolean()->Value();
-      }
+      Handle<Object> is_running_args[] = { answer };
+      maybe_result = Execution::Call(
+          isolate_, is_running, cmd_processor, 1, is_running_args);
+      running = maybe_result.ToHandleChecked()->IsTrue();
     } else {
-      // In case of failure the result text is the exception text.
-      response = try_catch.Exception()->ToString();
+      answer = Handle<String>::cast(
+          Execution::ToString(isolate_, exception).ToHandleChecked());
     }
 
     // Return the result.
     MessageImpl message = MessageImpl::NewResponse(
-        event,
-        running,
-        Handle<JSObject>::cast(exec_state),
-        Handle<JSObject>::cast(event_data),
-        Handle<String>(Utils::OpenHandle(*response)),
-        command.client_data());
+        event, running, exec_state, event_data, answer, command.client_data());
     InvokeMessageHandler(message);
     command.Dispose();
 
     // Return from debug event processing if either the VM is put into the
     // running state (through a continue command) or auto continue is active
     // and there are no more commands queued.
-    if (running && !HasCommands()) {
-      return;
-    }
-  }
+  } while (!running || HasCommands());
 }
 
 
 void Debugger::SetEventListener(Handle<Object> callback,
                                 Handle<Object> data) {
   HandleScope scope(isolate_);
   GlobalHandles* global_handles = isolate_->global_handles();
 
   // Clear the global handles for the event listener and the event listener data
   // object.
@@ skipping 592 matching lines @@
       already_signalled_ = false;
     }
     {
       Locker locker(reinterpret_cast<v8::Isolate*>(isolate_));
       isolate_->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 } }  // namespace v8::internal