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.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "v8.h"

#include "api.h"
#include "execution.h"
#include "spaces-inl.h"
#include "top.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);
  }
}


void MessageHandler::ReportMessage(const char* msg) {
  PrintF("%s\n", msg);
}


Handle<Object> MessageHandler::MakeMessageObject(
    const char* type,
    MessageLocation* loc,
    Vector< Handle<Object> > args,
    Handle<String> stack_trace) {
  // Build error message object
  v8::HandleScope scope;  // Instantiate a closeable HandleScope for EscapeFrom.
  Handle<Object> type_str = Factory::LookupAsciiSymbol(type);
  Handle<Object> array = Factory::NewJSArray(args.length());
  for (int i = 0; i < args.length(); i++)
    SetElement(Handle<JSArray>::cast(array), i, args[i]);

  Handle<JSFunction> fun(Top::global_context()->make_message_fun());
  int start, end;
  Handle<Object> script;
  if (loc) {
    start = loc->start_pos();
    end = loc->end_pos();
    script = GetScriptWrapper(loc->script());
  } else {
    start = end = 0;
    script = Factory::undefined_value();
  }
  Handle<Object> start_handle(Smi::FromInt(start));
  Handle<Object> end_handle(Smi::FromInt(end));
  Handle<Object> stack_trace_val = stack_trace.is_null()
    ? Factory::undefined_value()
    : Handle<Object>::cast(stack_trace);
  const int argc = 6;
  Object** argv[argc] = { type_str.location(),
                          array.location(),
                          start_handle.location(),
                          end_handle.location(),
                          script.location(),
                          stack_trace_val.location() };

  // Setup a catch handler to catch exceptions in creating the message. This
  // handler is non-verbose to avoid calling MakeMessage recursively in case of
  // an exception.
  v8::TryCatch catcher;
  catcher.SetVerbose(false);
  catcher.SetCaptureMessage(false);

  // Format the message.
  bool caught_exception = false;
  Handle<Object> message =
      Execution::Call(fun, Factory::undefined_value(), argc, argv,
                      &caught_exception);

  // If creating the message (in JS code) resulted in an exception, we
  // skip doing the callback. This usually only happens in case of
  // stack overflow exceptions being thrown by the parser when the
  // stack is almost full.
  if (caught_exception) return Handle<Object>();

  return message.EscapeFrom(&scope);
}


void MessageHandler::ReportMessage(MessageLocation* loc,
                                   Handle<Object> message) {
  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);
  } 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));
      callback(api_message_obj, v8::Utils::ToLocal(callback_data));
    }
  }
}


Handle<String> MessageHandler::GetMessage(Handle<Object> data) {
  Handle<String> fmt_str = Factory::LookupAsciiSymbol("FormatMessage");
  Handle<JSFunction> fun =
      Handle<JSFunction>(
          JSFunction::cast(Top::builtins()->GetProperty(*fmt_str)));
  Object** argv[1] = { data.location() };

  bool caught_exception;
  Handle<Object> result =
      Execution::TryCall(fun, Top::builtins(), 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