/*
 * Copyright 2014 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_GLOBAL_OBJECT_PROXY_H_
#define COBALT_SCRIPT_GLOBAL_OBJECT_PROXY_H_

#include <string>
#include <vector>

#include "base/memory/ref_counted.h"
#include "base/optional.h"
#include "cobalt/script/opaque_handle.h"
#include "cobalt/script/script_object.h"
#include "cobalt/script/stack_frame.h"
#include "cobalt/script/wrappable.h"

namespace cobalt {
namespace script {

class EnvironmentSettings;
class JavaScriptEngine;
class SourceCode;

// Manages a handle to a JavaScript engine's global object. The lifetime of
// the global object is not necessarily tied to the lifetime of the proxy.
class GlobalObjectProxy : public base::RefCounted<GlobalObjectProxy> {
 public:
  // Create a new global object with bindings as defined for the definition of
  // the GlobalInterface type. The IDL for this interface must have the
  // PrimaryGlobal or Global extended attribute.
  //
  // Specializations of this template function are implemented in the
  // generated bindings code for each JavaScript engine.
  template <typename GlobalInterface>
  void CreateGlobalObject(
      const scoped_refptr<GlobalInterface>& global_interface,
      EnvironmentSettings* environment_settings);

  // Create a new global object with no bindings.
  virtual void CreateGlobalObject() = 0;

  // Evaluate the JavaScript source code. Returns true on success,
  // false if there is an exception.
  // If out_result is non-NULL, it will be set to hold the result of the script
  // evaluation if the script succeeds, or an exception message if it fails.
  virtual bool EvaluateScript(const scoped_refptr<SourceCode>& script_utf8,
                              std::string* out_result_utf8) = 0;

  // Evaluate the JavaScript source code. Returns true on success,
  // false if there is an exception.
  // Set |out_opaque_handle| to be a reference to the result of the evaluation
  // of the script that is owned by |owner|.
  virtual bool EvaluateScript(
      const scoped_refptr<SourceCode>& script_utf8,
      const scoped_refptr<Wrappable>& owning_object,
      base::optional<OpaqueHandleHolder::Reference>* out_opaque_handle) = 0;

  // Returns the stack trace as a vector of individual frames.
  // Set |max_frames| to 0 to retrieve all available frames. Otherwise
  // return at most |max_frames|.
  virtual std::vector<StackFrame> GetStackTrace(int max_frames = 0) = 0;

  // Prevent this wrappable's associated JS wrapper object from being garbage
  // collected. AllowGarbageCollection must be called some time afterwards or
  // else both the JS wrapper object and Wrappable will leak.
  virtual void PreventGarbageCollection(
      const scoped_refptr<Wrappable>& wrappable) = 0;

  // Allow this wrappable's associated JS wrapper object to be garbage
  // collected.
  virtual void AllowGarbageCollection(
      const scoped_refptr<Wrappable>& wrappable) = 0;

  // Disable eval() and specify the message to report in the exception.
  virtual void DisableEval(const std::string& message) = 0;

  // Allow eval().
  virtual void EnableEval() = 0;

  // Set a callback that will be fired whenever eval() or a Function()
  // constructor is used.
  virtual void SetReportEvalCallback(const base::Closure& report_eval) = 0;

  // Dynamically bind a cpp object to the javascript global object with the
  // supplied identifier.
  // This method is useful for testing and debug purposes, as well as for
  // dynamically injecting an API into a JavaScript environment.
  //
  // This static function must be implemented by the JavaScriptEngine
  // implementation
  virtual void Bind(const std::string& identifier,
                    const scoped_refptr<Wrappable>& impl) = 0;

 protected:
  virtual ~GlobalObjectProxy() {}
  friend class base::RefCounted<GlobalObjectProxy>;
};

}  // namespace script
}  // namespace cobalt

#endif  // COBALT_SCRIPT_GLOBAL_OBJECT_PROXY_H_