widget/GfxInfoCollector.h
author Chris H-C <chutten@mozilla.com>
Mon, 04 Jul 2016 11:16:05 -0400
changeset 312997 df28918fe2361f0b54ca9ce4773a29c4c0675d06
parent 252626 91d6e262b662a0b4e47358665e222d3927337af9
permissions -rw-r--r--
bug 1218576 - Support remote accumulation via JS histograms. r=gfritzsche The JS histograms, too, need to dispatch their accumulations from child to parent. JSHistograms_Add now only supports histograms that are in gHistogramsMap or that were created in the parent process. After bug 1288745, maybe we'll be able to change this to be less convoluted. MozReview-Commit-ID: 3qTH89YKbGP

/* 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