/* vim: se cin sw=2 ts=2 et : */

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef __mozilla_widget_GfxInfoCollector_h__

#define __mozilla_widget_GfxInfoCollector_h__

#include "mozilla/Attributes.h"

#include "nsStringFwd.h"

#include "js/RootingAPI.h"

namespace mozilla {

namespace widget {

/* this is handy wrapper around JSAPI to make it more pleasant to use.

 * We collect the JSAPI errors and so that callers don't need to */

class MOZ_STACK_CLASS InfoObject

{

  friend class GfxInfoBase;

  public:

  void DefineProperty(const char *name, int value);

  void DefineProperty(const char *name, nsAString &value);

  void DefineProperty(const char *name, const char *value);

  private:

  // We need to ensure that this object lives on the stack so that GC sees it properly

  explicit InfoObject(JSContext *aCx);

  InfoObject(InfoObject&);

  JSContext *mCx;

  JS::Rooted<JSObject*> mObj;

  bool mOk;

};

/*

   Here's an example usage:

   class Foo {

   Foo::Foo() : mInfoCollector(this, &Foo::GetAweseomeness) {}

   void GetAwesomeness(InfoObject &obj) {

     obj.DefineProperty("awesome", mAwesome);

   }

   int mAwesome;

   GfxInfoCollector<Foo> mInfoCollector;

   }

   This will define a property on the object

   returned from calling getInfo() on a

   GfxInfo object. e.g.

       gfxInfo = Cc["@mozilla.org/gfx/info;1"].getService(Ci.nsIGfxInfo);

       info = gfxInfo.getInfo();

       if (info.awesome)

          alert(info.awesome);

*/

class GfxInfoCollectorBase

{

  public:

  GfxInfoCollectorBase();

  virtual void GetInfo(InfoObject &obj) = 0;

  virtual ~GfxInfoCollectorBase();

};

template<class T>

class GfxInfoCollector : public GfxInfoCollectorBase

{

  public:

  GfxInfoCollector(T* aPointer, void (T::*aFunc)(InfoObject &obj)) : mPointer(aPointer), mFunc(aFunc) {

  }

  virtual void GetInfo(InfoObject &obj) override {

    (mPointer->*mFunc)(obj);

  }

  protected:

  T* mPointer;

  void (T::*mFunc)(InfoObject &obj);

};

} // namespace widget

} // namespace mozilla

#endif