src/cobalt/script/javascriptcore/jsc_callback_function.h.pump

$$ This is a pump file for generating file templates.  Pump is a python
$$ script that is part of the Google Test suite of utilities.  Description
$$ can be found here:
$$
$$ http://code.google.com/p/googletest/wiki/PumpManual
$$

$$ This should be no larger than MAX_ARITY in base/bind.h.pump.
$var MAX_ARITY = 7
/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef COBALT_SCRIPT_JAVASCRIPTCORE_JSC_CALLBACK_FUNCTION_H_
#define COBALT_SCRIPT_JAVASCRIPTCORE_JSC_CALLBACK_FUNCTION_H_

#include "base/debug/trace_event.h"
#include "base/logging.h"
#include "cobalt/script/callback_function.h"
#include "cobalt/script/javascriptcore/jsc_global_object.h"
#include "cobalt/script/javascriptcore/util/exception_helpers.h"
#include "cobalt/script/logging_exception_state.h"
#include "cobalt/script/script_object.h"
#include "third_party/WebKit/Source/JavaScriptCore/runtime/JSFunction.h"

// The JSCCallbackFunction type is used to represent IDL callback functions.
// Create a new JSCCallbackFunction by specifying the base CallbackFunction
// as a template parameter to the constructor.
//
// Constructor parameters:
//     callable: A handle that keeps keeps alive the JSC::JSFunction that
//         will be called when the callback is fired.
//     callback: A base::Callback that will be executed when the Run(...)
//         function is executed. It will take as parameters a JSC::JSFunction
//         followed by any arguments that are defined on the callback type.

namespace cobalt {
namespace script {
namespace javascriptcore {
namespace internal {
// Helper template functions for Callback functions' return values before being
// returned to Cobalt.
// Converts the return value from JavaScript into the correct Cobalt type, or
// sets the exception bit if conversion fails.
template <typename R>
inline CallbackResult<R> ConvertReturnValue(JSC::ExecState* exec_state,
                                            JSC::JSValue jsvalue);
}
// First, we forward declare the Callback class template. This informs the
// compiler that the template only has 1 type parameter which is the base
// CallbackFunction template class with parameters.
//
// See base/callback.h.pump for further discussion on this pattern.
template <typename Sig>
class JSCCallbackFunction;

$range ARITY 0..MAX_ARITY
$for ARITY [[
$range ARG 1..ARITY


$if ARITY == 0 [[
template <typename R>
class JSCCallbackFunction<R(void)>
    : public CallbackFunction<R(void)> {
]] $else [[
template <typename R, $for ARG , [[typename A$(ARG)]]>
class JSCCallbackFunction<R($for ARG , [[A$(ARG)]])>
    : public CallbackFunction<R($for ARG , [[A$(ARG)]])> {
]]

 public:
  explicit JSCCallbackFunction(JSC::JSFunction* callable)
      : callable_(callable) { DCHECK(callable_); }

  CallbackResult<R> Run($for ARG , [[

      typename base::internal::CallbackParamTraits<A$(ARG)>::ForwardType a$(ARG)]])
      const OVERRIDE {
    TRACE_EVENT0("cobalt::script::javascriptcore", "JSCCallbackFunction::Run");
    DCHECK(callable_);
    JSCGlobalObject* global_object =
        JSC::jsCast<JSCGlobalObject*>(callable_->globalObject());
    JSC::JSLockHolder lock(global_object->globalData());

    // https://www.w3.org/TR/WebIDL/#es-invoking-callback-functions
    // Callback 'this' is set to null, unless overridden by other specifications
    JSC::JSValue this_value = JSC::jsNull();
    JSC::MarkedArgumentBuffer args;
    $for ARG [[args.append(ToJSValue(global_object, a$(ARG)));
    ]]

    JSC::CallData call_data;
    JSC::CallType call_type =
        JSC::JSFunction::getCallData(callable_, call_data);
    JSC::ExecState* exec_state = global_object->globalExec();
    JSC::JSGlobalData& global_data = global_object->globalData();
    JSC::JSValue retval =
        JSC::call(exec_state, callable_, call_type, call_data, this_value, args);
    CallbackResult<R> callback_result;
    if (exec_state->hadException()) {
      DLOG(WARNING) << "Exception in callback: "
                    << util::GetExceptionString(exec_state);

      exec_state->clearException();
      callback_result.exception = true;
    } else {
      callback_result = internal::ConvertReturnValue<R>(exec_state, retval);
    }
    return callback_result;
  }

  JSC::JSFunction* callable() const { return callable_; }

 private:
  JSC::JSFunction* callable_;
};

]]

}  // namespace javascriptcore
}  // namespace script
}  // namespace cobalt

#endif  // COBALT_SCRIPT_JAVASCRIPTCORE_JSC_CALLBACK_FUNCTION_H_