Return MaybeHandle from Invoke.

src/debug.cc

 // Copyright 2012 the V8 project authors. 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
@@ skipping 756 matching lines @@
                                           NATIVES_CODE);
 
   // Silently ignore stack overflows during compilation.
   if (function_info.is_null()) {
     ASSERT(isolate->has_pending_exception());
     isolate->clear_pending_exception();
     return false;
   }
 
   // Execute the shared function in the debugger context.
-  bool caught_exception;
   Handle<JSFunction> function =
       factory->NewFunctionFromSharedFunctionInfo(function_info, context);
 
-  Handle<Object> exception =
-      Execution::TryCall(function,
-                         Handle<Object>(context->global_object(), isolate),
-                         0,
-                         NULL,
-                         &caught_exception);
+  bool caught_exception = false;
+  Handle<Object> exception = Execution::TryCall(
+      function,
+      Handle<Object>(context->global_object(), isolate),
+      0,
+      NULL,
+      &caught_exception);
 
   // Check for caught exceptions.
   if (caught_exception) {
     ASSERT(!isolate->has_pending_exception());
     MessageLocation computed_location;
     isolate->ComputeLocation(&computed_location);
     Handle<Object> message = MessageHandler::MakeMessageObject(
         isolate, "error_loading_debugger", &computed_location,
         Vector<Handle<Object> >::empty(), Handle<JSArray>());
     ASSERT(!isolate->has_pending_exception());
@@ skipping 321 matching lines @@
           STATIC_ASCII_VECTOR("IsBreakPointTriggered"));
   Handle<GlobalObject> debug_global(debug_context()->global_object());
   Handle<JSFunction> check_break_point =
     Handle<JSFunction>::cast(GlobalObject::GetPropertyNoExceptionThrown(
         debug_global, is_break_point_triggered_string));
 
   // Get the break id as an object.
   Handle<Object> break_id = factory->NewNumberFromInt(Debug::break_id());
 
   // Call HandleBreakPointx.
-  bool caught_exception;
   Handle<Object> argv[] = { break_id, break_point_object };
+  bool caught_exception = false;
   Handle<Object> result = Execution::TryCall(check_break_point,
                                              isolate_->js_builtins_object(),
                                              ARRAY_SIZE(argv),
                                              argv,
                                              &caught_exception);
 
   // If exception or non boolean result handle as not triggered
   if (caught_exception || !result->IsBoolean()) {
     return false;
   }
 
   // Return whether the break point is triggered.
-  ASSERT(!result.is_null());
-  return (*result)->IsTrue();
+  return result->IsTrue();
 }
 
 
 // Check whether the function has debug information.
 bool Debug::HasDebugInfo(Handle<SharedFunctionInfo> shared) {
   return !shared->debug_info()->IsUndefined();
 }
 
 
 // Return the debug info for this function. EnsureDebugInfo must be called
@@ skipping 1305 matching lines @@
   PostponeInterruptsScope postpone(isolate_);
   HandleScope scope(isolate_);
   ASSERT(isolate_->context() == *Debug::debug_context());
 
   // Clear the mirror cache.
   Handle<String> function_name = isolate_->factory()->InternalizeOneByteString(
       STATIC_ASCII_VECTOR("ClearMirrorCache"));
   Handle<Object> fun = GlobalObject::GetPropertyNoExceptionThrown(
       isolate_->global_object(), function_name);
   ASSERT(fun->IsJSFunction());
-  bool caught_exception;
-  Execution::TryCall(Handle<JSFunction>::cast(fun),
+  bool caught_exception = false;
+  Execution::TryCall(
+      Handle<JSFunction>::cast(fun),
       Handle<JSObject>(Debug::debug_context()->global_object()),
-      0, NULL, &caught_exception);
+      0,
+      NULL,
+      &caught_exception);
 }
 
 
 void Debug::CreateScriptCache() {
   Heap* heap = isolate_->heap();
   HandleScope scope(isolate_);
 
   // Perform two GCs to get rid of all unreferenced scripts. The first GC gets
   // rid of all the cached script wrappers and the second gets rid of the
   // scripts which are no longer referenced.  The second also sweeps precisely,
@@ skipping 100 matching lines @@
       command_queue_(isolate->logger(), kQueueInitialSize),
       command_received_(0),
       event_command_queue_(isolate->logger(), kQueueInitialSize),
       isolate_(isolate) {
 }
 
 
 Debugger::~Debugger() {}
 
 
-Handle<Object> Debugger::MakeJSObject(Vector<const char> constructor_name,
-                                      int argc,
-                                      Handle<Object> argv[],
-                                      bool* caught_exception) {
+MaybeHandle<Object> Debugger::MakeJSObject(
+    Vector<const char> constructor_name,
+    int argc,
+    Handle<Object> argv[]) {
   ASSERT(isolate_->context() == *isolate_->debug()->debug_context());
 
   // Create the execution state object.
   Handle<String> constructor_str =
       isolate_->factory()->InternalizeUtf8String(constructor_name);
   ASSERT(!constructor_str.is_null());
   Handle<Object> constructor = GlobalObject::GetPropertyNoExceptionThrown(
       isolate_->global_object(), constructor_str);
   ASSERT(constructor->IsJSFunction());
-  if (!constructor->IsJSFunction()) {
-    *caught_exception = true;
-    return isolate_->factory()->undefined_value();
-  }
-  Handle<Object> js_object = Execution::TryCall(
+  if (!constructor->IsJSFunction()) return MaybeHandle<Object>();
+  bool caught_exception = false;
+  return Execution::TryCall(
       Handle<JSFunction>::cast(constructor),
       Handle<JSObject>(isolate_->debug()->debug_context()->global_object()),
       argc,
       argv,
-      caught_exception);
-  return js_object;
+      &caught_exception);

[Igor Sheludko, 2014/04/10 21:34:30]

I think we should write here and in all other places where TryCall() is used
something like this:
  if (caught_exception) return MaybeHandle<Object>();
  return result;
Because callers of MakeJSObject() expect empty handle on exception.

 }
 
 
-Handle<Object> Debugger::MakeExecutionState(bool* caught_exception) {
+MaybeHandle<Object> Debugger::MakeExecutionState() {
   // Create the execution state object.
   Handle<Object> break_id = isolate_->factory()->NewNumberFromInt(
       isolate_->debug()->break_id());
   Handle<Object> argv[] = { break_id };
-  return MakeJSObject(CStrVector("MakeExecutionState"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
+  return MakeJSObject(CStrVector("MakeExecutionState"), ARRAY_SIZE(argv), argv);
 }
 
 
-Handle<Object> Debugger::MakeBreakEvent(Handle<Object> exec_state,
-                                        Handle<Object> break_points_hit,
-                                        bool* caught_exception) {
+MaybeHandle<Object> Debugger::MakeBreakEvent(Handle<Object> break_points_hit) {
+  Handle<Object> exec_state;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate_, exec_state, MakeExecutionState(), Object);
   // Create the new break event object.
   Handle<Object> argv[] = { exec_state, break_points_hit };
-  return MakeJSObject(CStrVector("MakeBreakEvent"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
+  return MakeJSObject(CStrVector("MakeBreakEvent"), ARRAY_SIZE(argv), argv);
 }
 
 
-Handle<Object> Debugger::MakeExceptionEvent(Handle<Object> exec_state,
-                                            Handle<Object> exception,
-                                            bool uncaught,
-                                            bool* caught_exception) {
-  Factory* factory = isolate_->factory();
+MaybeHandle<Object> Debugger::MakeExceptionEvent(Handle<Object> exception,
+                                                 bool uncaught) {
+  Handle<Object> exec_state;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate_, exec_state, MakeExecutionState(), Object);
   // Create the new exception event object.
   Handle<Object> argv[] = { exec_state,
                             exception,
-                            factory->ToBoolean(uncaught) };
-  return MakeJSObject(CStrVector("MakeExceptionEvent"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
+                            isolate_->factory()->ToBoolean(uncaught) };
+  return MakeJSObject(CStrVector("MakeExceptionEvent"), ARRAY_SIZE(argv), argv);
 }
 
 
-Handle<Object> Debugger::MakeNewFunctionEvent(Handle<Object> function,
-                                              bool* caught_exception) {
-  // Create the new function event object.
-  Handle<Object> argv[] = { function };
-  return MakeJSObject(CStrVector("MakeNewFunctionEvent"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
-}
-
-
-Handle<Object> Debugger::MakeCompileEvent(Handle<Script> script,
-                                          bool before,
-                                          bool* caught_exception) {
+MaybeHandle<Object> Debugger::MakeCompileEvent(Handle<Script> script,
+                                               bool before) {
   Factory* factory = isolate_->factory();
   // Create the compile event object.
-  Handle<Object> exec_state = MakeExecutionState(caught_exception);
+  Handle<Object> exec_state;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate_, exec_state, MakeExecutionState(), Object);
   Handle<Object> script_wrapper = GetScriptWrapper(script);
   Handle<Object> argv[] = { exec_state,
                             script_wrapper,
                             factory->ToBoolean(before) };
-  return MakeJSObject(CStrVector("MakeCompileEvent"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
+  return MakeJSObject(CStrVector("MakeCompileEvent"), ARRAY_SIZE(argv), argv);
 }
 
 
-Handle<Object> Debugger::MakeScriptCollectedEvent(int id,
-                                                  bool* caught_exception) {
+MaybeHandle<Object> Debugger::MakeScriptCollectedEvent(int id) {
   // Create the script collected event object.
-  Handle<Object> exec_state = MakeExecutionState(caught_exception);
+  Handle<Object> exec_state;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate_, exec_state, MakeExecutionState(), Object);
   Handle<Object> id_object = Handle<Smi>(Smi::FromInt(id), isolate_);
   Handle<Object> argv[] = { exec_state, id_object };
 
-  return MakeJSObject(CStrVector("MakeScriptCollectedEvent"),
-                      ARRAY_SIZE(argv),
-                      argv,
-                      caught_exception);
+  return MakeJSObject(
+      CStrVector("MakeScriptCollectedEvent"), ARRAY_SIZE(argv), argv);
 }
 
 
 void Debugger::OnException(Handle<Object> exception, bool uncaught) {
   HandleScope scope(isolate_);
   Debug* debug = isolate_->debug();
 
   // Bail out based on state or if there is no listener for this event
   if (debug->InDebugger()) return;
   if (!Debugger::EventActive(v8::Exception)) return;
 
   // Bail out if exception breaks are not active
   if (uncaught) {
     // Uncaught exceptions are reported by either flags.
     if (!(debug->break_on_uncaught_exception() ||
           debug->break_on_exception())) return;
   } else {
     // Caught exceptions are reported is activated.
     if (!debug->break_on_exception()) return;
   }
 
   // Enter the debugger.
   EnterDebugger debugger(isolate_);
   if (debugger.FailedToEnter()) return;
 
   // Clear all current stepping setup.
   debug->ClearStepping();
   // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
   Handle<Object> event_data;
-  if (!caught_exception) {
-    event_data = MakeExceptionEvent(exec_state, exception, uncaught,
-                                    &caught_exception);
-  }
   // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, event_data, MakeExceptionEvent(exception, uncaught),
+      /* void */ ;);
 
   // Process debug event.
   ProcessDebugEvent(v8::Exception, Handle<JSObject>::cast(event_data), false);
   // Return to continue execution from where the exception was thrown.
 }
 
 
 void Debugger::OnDebugBreak(Handle<Object> break_points_hit,
                             bool auto_continue) {
   HandleScope scope(isolate_);
 
   // Debugger has already been entered by caller.
   ASSERT(isolate_->context() == *isolate_->debug()->debug_context());
 
   // Bail out if there is no listener for this event
   if (!Debugger::EventActive(v8::Break)) return;
 
   // Debugger must be entered in advance.
   ASSERT(isolate_->context() == *isolate_->debug()->debug_context());
 
   // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
   Handle<Object> event_data;
-  if (!caught_exception) {
-    event_data = MakeBreakEvent(exec_state, break_points_hit,
-                                &caught_exception);
-  }
   // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, event_data, MakeBreakEvent(break_points_hit), /* void */ ;);
 
   // Process debug event.
   ProcessDebugEvent(v8::Break,
                     Handle<JSObject>::cast(event_data),
                     auto_continue);
 }
 
 
 void Debugger::OnBeforeCompile(Handle<Script> script) {
   HandleScope scope(isolate_);
 
   // Bail out based on state or if there is no listener for this event
   if (isolate_->debug()->InDebugger()) return;
   if (compiling_natives()) return;
   if (!EventActive(v8::BeforeCompile)) return;
 
   // Enter the debugger.
   EnterDebugger debugger(isolate_);
   if (debugger.FailedToEnter()) return;
 
   // Create the event data object.
-  bool caught_exception = false;
-  Handle<Object> event_data = MakeCompileEvent(script, true, &caught_exception);
+  Handle<Object> event_data;
   // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, event_data, MakeCompileEvent(script, true), /* void */ ;);
 
   // Process debug event.
   ProcessDebugEvent(v8::BeforeCompile,
                     Handle<JSObject>::cast(event_data),
                     true);
 }
 
 
 // Handle debugger actions when a new script is compiled.
 void Debugger::OnAfterCompile(Handle<Script> script,
@@ skipping 31 matching lines @@
   if (!update_script_break_points->IsJSFunction()) {
     return;
   }
   ASSERT(update_script_break_points->IsJSFunction());
 
   // Wrap the script object in a proper JS object before passing it
   // to JavaScript.
   Handle<JSValue> wrapper = GetScriptWrapper(script);
 
   // Call UpdateScriptBreakPoints expect no exceptions.
-  bool caught_exception;
   Handle<Object> argv[] = { wrapper };
+  bool caught_exception = false;
   Execution::TryCall(Handle<JSFunction>::cast(update_script_break_points),
                      isolate_->js_builtins_object(),
                      ARRAY_SIZE(argv),
                      argv,
                      &caught_exception);
-  if (caught_exception) {
-    return;
-  }
+  if (caught_exception) return;
   // Bail out based on state or if there is no listener for this event
   if (in_debugger && (after_compile_flags & SEND_WHEN_DEBUGGING) == 0) return;
   if (!Debugger::EventActive(v8::AfterCompile)) return;
 
   // Create the compile state object.
-  Handle<Object> event_data = MakeCompileEvent(script,
-                                               false,
-                                               &caught_exception);
+  Handle<Object> event_data;
   // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, event_data, MakeCompileEvent(script, false), /* void */ ;);
+
   // Process debug event.
-  ProcessDebugEvent(v8::AfterCompile,
-                    Handle<JSObject>::cast(event_data),
-                    true);
+  ProcessDebugEvent(v8::AfterCompile, Handle<JSObject>::cast(event_data), true);
 }
 
 
 void Debugger::OnScriptCollected(int id) {
   HandleScope scope(isolate_);
 
   // No more to do if not debugging.
   if (isolate_->debug()->InDebugger()) return;
   if (!IsDebuggerActive()) return;
   if (!Debugger::EventActive(v8::ScriptCollected)) return;
 
   // Enter the debugger.
   EnterDebugger debugger(isolate_);
   if (debugger.FailedToEnter()) return;
 
   // Create the script collected state object.
-  bool caught_exception = false;
-  Handle<Object> event_data = MakeScriptCollectedEvent(id,
-                                                       &caught_exception);
+  Handle<Object> event_data;
   // Bail out and don't call debugger if exception.
-  if (caught_exception) {
-    return;
-  }
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, event_data, MakeScriptCollectedEvent(id), /* void */ ;);
 
   // Process debug event.
   ProcessDebugEvent(v8::ScriptCollected,
                     Handle<JSObject>::cast(event_data),
                     true);
 }
 
 
 void Debugger::ProcessDebugEvent(v8::DebugEvent event,
                                  Handle<JSObject> event_data,
                                  bool auto_continue) {
   HandleScope scope(isolate_);
 
   // Clear any pending debug break if this is a real break.
   if (!auto_continue) {
     isolate_->debug()->clear_interrupt_pending(DEBUGBREAK);
   }
 
   // Create the execution state.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  if (caught_exception) {
-    return;
-  }
+  Handle<Object> exec_state;
+  // Bail out and don't call debugger if exception.
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, exec_state, MakeExecutionState(), /* void */ ;);
   // First notify the message handler if any.
   if (message_handler_ != NULL) {
     NotifyMessageHandler(event,
                          Handle<JSObject>::cast(exec_state),
                          event_data,
                          auto_continue);
   }
   // Notify registered debug event listener. This can be either a C or
   // a JavaScript function. Don't call event listener for v8::Break
   // here, if it's only a debug command -- they will be processed later.
@@ skipping 50 matching lines @@
                                    Handle<Object> exec_state,
                                    Handle<Object> event_data) {
   ASSERT(event_listener_->IsJSFunction());
   Handle<JSFunction> fun(Handle<JSFunction>::cast(event_listener_));
 
   // Invoke the JavaScript debug event listener.
   Handle<Object> argv[] = { Handle<Object>(Smi::FromInt(event), isolate_),
                             exec_state,
                             event_data,
                             event_listener_data_ };
-  bool caught_exception;
+  bool caught_exception = false;
   Execution::TryCall(fun,
                      isolate_->global_object(),
                      ARRAY_SIZE(argv),
                      argv,
                      &caught_exception);
   // Silently ignore exceptions from debug event listeners.
 }
 
 
 Handle<Context> Debugger::GetDebugContext() {
@@ skipping 338 matching lines @@
 
 bool Debugger::IsDebuggerActive() {
   LockGuard<RecursiveMutex> with(debugger_access_);
 
   return message_handler_ != NULL ||
       !event_listener_.is_null() ||
       force_debugger_active_;
 }
 
 
-Handle<Object> Debugger::Call(Handle<JSFunction> fun,
-                              Handle<Object> data,
-                              bool* pending_exception) {
+MaybeHandle<Object> Debugger::Call(Handle<JSFunction> fun,
+                                   Handle<Object> data) {
   // When calling functions in the debugger prevent it from beeing unloaded.
   Debugger::never_unload_debugger_ = true;
 
   // Enter the debugger.
   EnterDebugger debugger(isolate_);
   if (debugger.FailedToEnter()) {
     return isolate_->factory()->undefined_value();
   }
 
   // Create the execution state.
-  bool caught_exception = false;
-  Handle<Object> exec_state = MakeExecutionState(&caught_exception);
-  if (caught_exception) {
-    return isolate_->factory()->undefined_value();
-  }
+  Handle<Object> exec_state;
+  ASSIGN_RETURN_ON_EXCEPTION_VALUE(
+      isolate_, exec_state,
+      MakeExecutionState(),
+      isolate_->factory()->undefined_value());
 
   Handle<Object> argv[] = { exec_state, data };
-  Handle<Object> result = Execution::Call(
+  return Execution::Call(
       isolate_,
       fun,
       Handle<Object>(isolate_->debug()->debug_context_->global_proxy(),
                      isolate_),
       ARRAY_SIZE(argv),
-      argv,
-      pending_exception);
-  return result;
+      argv);
 }
 
 
 static void StubMessageHandler2(const v8::Debug::Message& message) {
   // Simply ignore message.
 }
 
 
 bool Debugger::StartAgent(const char* name, int port,
                           bool wait_for_connection) {
@@ skipping 208 matching lines @@
   v8::EscapableHandleScope scope(
       reinterpret_cast<v8::Isolate*>(event_data_->GetIsolate()));
 
   if (IsEvent()) {
     // Call toJSONProtocol on the debug event object.
     Handle<Object> fun =
         GetProperty(event_data_, "toJSONProtocol").ToHandleChecked();
     if (!fun->IsJSFunction()) {
       return v8::Handle<v8::String>();
     }
-    bool caught_exception;
-    Handle<Object> json = Execution::TryCall(Handle<JSFunction>::cast(fun),
-                                             event_data_,
-                                             0, NULL, &caught_exception);
+    Handle<Object> json;
+    bool caught_exception = false;
+    Execution::TryCall(Handle<JSFunction>::cast(fun),
+                       event_data_,
+                       0,
+                       NULL,
+                       &caught_exception);
     if (caught_exception || !json->IsString()) {
       return v8::Handle<v8::String>();
     }
     return scope.Escape(v8::Utils::ToLocal(Handle<String>::cast(json)));
   } else {
     return v8::Utils::ToLocal(response_json_);
   }
 }
 
 
@@ skipping 188 matching lines @@
     {
       Locker locker(reinterpret_cast<v8::Isolate*>(isolate_));
       isolate_->debugger()->CallMessageDispatchHandler();
     }
   }
 }
 
 #endif  // ENABLE_DEBUGGER_SUPPORT
 
 } }  // namespace v8::internal