gecko-dev/widget/xpwidgets/GfxInfoCollector.h

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/* vim: se cin sw=2 ts=2 et : */
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
*
2012-05-21 11:12:37 +00:00
* 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 "jsapi.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 InfoObject
{
friend class GfxInfoBase;
public:
void DefineProperty(const char *name, int value)
{
if (!mOk)
return;
mOk = JS_DefineProperty(mCx, mObj, name, INT_TO_JSVAL(value), NULL, NULL, JSPROP_ENUMERATE);
}
void DefineProperty(const char *name, nsAString &value)
{
if (!mOk)
return;
const nsString &flat = PromiseFlatString(value);
JSString *string = JS_NewUCStringCopyN(mCx, static_cast<const jschar*>(flat.get()), flat.Length());
if (!string)
mOk = JS_FALSE;
if (!mOk)
return;
mOk = JS_DefineProperty(mCx, mObj, name, STRING_TO_JSVAL(string), NULL, NULL, JSPROP_ENUMERATE);
}
void DefineProperty(const char *name, const char *value)
{
nsAutoString string = NS_ConvertASCIItoUTF16(value);
DefineProperty(name, string);
}
private:
// We need to ensure that this object lives on the stack so that GC sees it properly
InfoObject(JSContext *aCx) : mCx(aCx), mOk(JS_TRUE)
{
mObj = JS_NewObject(mCx, NULL, NULL, NULL);
if (!mObj)
mOk = JS_FALSE;
}
InfoObject(InfoObject&);
JSContext *mCx;
JSObject *mObj;
JSBool 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) {
(mPointer->*mFunc)(obj);
}
protected:
T* mPointer;
void (T::*mFunc)(InfoObject &obj);
};
}
}
#endif