src/messages.cc

// Copyright 2006-2008 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
//       with the distribution.
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//       from this software without specific prior written permission.
//
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "v8.h"

#include "api.h"
#include "execution.h"
#include "messages.h"
#include "spaces-inl.h"

namespace v8 {
namespace internal {


// If no message listeners have been registered this one is called
// by default.
void MessageHandler::DefaultMessageReport(const MessageLocation* loc,
                                          Handle<Object> message_obj) {
  SmartPointer<char> str = GetLocalizedMessage(message_obj);
  if (loc == NULL) {
    PrintF("%s\n", *str);
  } else {
    HandleScope scope;
    Handle<Object> data(loc->script()->name());
    SmartPointer<char> data_str;
    if (data->IsString())
      data_str = Handle<String>::cast(data)->ToCString(DISALLOW_NULLS);
    PrintF("%s:%i: %s\n", *data_str ? *data_str : "<unknown>",
           loc->start_pos(), *str);
  }
}


Handle<JSMessageObject> MessageHandler::MakeMessageObject(
    const char* type,
    MessageLocation* loc,
    Vector< Handle<Object> > args,
    Handle<String> stack_trace,
    Handle<JSArray> stack_frames) {
  Handle<String> type_handle = FACTORY->LookupAsciiSymbol(type);
  Handle<FixedArray> arguments_elements =
      FACTORY->NewFixedArray(args.length());
  for (int i = 0; i < args.length(); i++) {
    arguments_elements->set(i, *args[i]);
  }
  Handle<JSArray> arguments_handle =
      FACTORY->NewJSArrayWithElements(arguments_elements);

  int start = 0;
  int end = 0;
  Handle<Object> script_handle = FACTORY->undefined_value();
  if (loc) {
    start = loc->start_pos();
    end = loc->end_pos();
    script_handle = GetScriptWrapper(loc->script());
  }

  Handle<Object> stack_trace_handle = stack_trace.is_null()
      ? FACTORY->undefined_value()
      : Handle<Object>::cast(stack_trace);

  Handle<Object> stack_frames_handle = stack_frames.is_null()
      ? FACTORY->undefined_value()
      : Handle<Object>::cast(stack_frames);

  Handle<JSMessageObject> message =
      FACTORY->NewJSMessageObject(type_handle,
                                  arguments_handle,
                                  start,
                                  end,
                                  script_handle,
                                  stack_trace_handle,
                                  stack_frames_handle);

  return message;
}


void MessageHandler::ReportMessage(Isolate* isolate,
                                   MessageLocation* loc,
                                   Handle<Object> message) {
  // We are calling into embedder's code which can throw exceptions.
  // Thus we need to save current exception state, reset it to the clean one
  // and ignore scheduled exceptions callbacks can throw.
  Isolate::ExceptionScope exception_scope(isolate);
  isolate->clear_pending_exception();
  isolate->set_external_caught_exception(false);

  v8::Local<v8::Message> api_message_obj = v8::Utils::MessageToLocal(message);

  v8::NeanderArray global_listeners(FACTORY->message_listeners());
  int global_length = global_listeners.length();
  if (global_length == 0) {
    DefaultMessageReport(loc, message);
    if (isolate->has_scheduled_exception()) {
      isolate->clear_scheduled_exception();
    }
  } else {
    for (int i = 0; i < global_length; i++) {
      HandleScope scope;
      if (global_listeners.get(i)->IsUndefined()) continue;
      v8::NeanderObject listener(JSObject::cast(global_listeners.get(i)));
      Handle<Proxy> callback_obj(Proxy::cast(listener.get(0)));
      v8::MessageCallback callback =
          FUNCTION_CAST<v8::MessageCallback>(callback_obj->proxy());
      Handle<Object> callback_data(listener.get(1));
      {
        // Do not allow exceptions to propagate.
        v8::TryCatch tryCatch;
        callback(api_message_obj, v8::Utils::ToLocal(callback_data));
      }
      if (isolate->has_scheduled_exception()) {
        isolate->clear_scheduled_exception();
      }
    }
  }
}


Handle<String> MessageHandler::GetMessage(Handle<Object> data) {
  Handle<String> fmt_str = FACTORY->LookupAsciiSymbol("FormatMessage");
  Handle<JSFunction> fun =
      Handle<JSFunction>(
          JSFunction::cast(
              Isolate::Current()->js_builtins_object()->
              GetPropertyNoExceptionThrown(*fmt_str)));
  Object** argv[1] = { data.location() };

  bool caught_exception;
  Handle<Object> result =
      Execution::TryCall(fun,
          Isolate::Current()->js_builtins_object(), 1, argv, &caught_exception);

  if (caught_exception || !result->IsString()) {
    return FACTORY->LookupAsciiSymbol("<error>");
  }
  Handle<String> result_string = Handle<String>::cast(result);
  // A string that has been obtained from JS code in this way is
  // likely to be a complicated ConsString of some sort.  We flatten it
  // here to improve the efficiency of converting it to a C string and
  // other operations that are likely to take place (see GetLocalizedMessage
  // for example).
  FlattenString(result_string);
  return result_string;
}


SmartPointer<char> MessageHandler::GetLocalizedMessage(Handle<Object> data) {
  HandleScope scope;
  return GetMessage(data)->ToCString(DISALLOW_NULLS);
}


} }  // namespace v8::internal