зеркало из https://github.com/mozilla/gecko-dev.git
94 строки
2.5 KiB
C++
94 строки
2.5 KiB
C++
/* -*- 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 nsDOMScriptObjectHolder_h__
|
|
#define nsDOMScriptObjectHolder_h__
|
|
|
|
#include "nsIScriptContext.h"
|
|
#include "nsIDOMScriptObjectFactory.h"
|
|
|
|
#include "jspubtd.h"
|
|
|
|
// A thin class used to help with script object memory management. No virtual
|
|
// functions and a fully inline implementation should keep the cost down.
|
|
// [Note that a fully inline implementation is necessary for use by other
|
|
// languages, which do not link against the layout component module]
|
|
template<class T>
|
|
class NS_STACK_CLASS nsScriptObjectHolder {
|
|
public:
|
|
// A constructor that will cause a reference to |ctx| to be stored in
|
|
// the object. Only use for short-lived object holders.
|
|
nsScriptObjectHolder<T>(nsIScriptContext *ctx, T* aObject = nullptr) :
|
|
mObject(aObject), mContext(ctx) {
|
|
NS_ASSERTION(ctx, "Must provide a valid context");
|
|
}
|
|
|
|
// copy constructor
|
|
nsScriptObjectHolder<T>(const nsScriptObjectHolder<T>& other) :
|
|
mObject(other.mObject),
|
|
mContext(other.mContext)
|
|
{
|
|
// New hold the script object and new reference on the script context.
|
|
if (mObject)
|
|
mContext->HoldScriptObject(mObject);
|
|
}
|
|
|
|
~nsScriptObjectHolder<T>() {
|
|
if (mObject)
|
|
mContext->DropScriptObject(mObject);
|
|
}
|
|
|
|
// misc operators
|
|
nsScriptObjectHolder<T> &operator=(const nsScriptObjectHolder<T> &other) {
|
|
set(other);
|
|
return *this;
|
|
}
|
|
bool operator!() const {
|
|
return !mObject;
|
|
}
|
|
operator bool() const {
|
|
return !!mObject;
|
|
}
|
|
T* get() const {
|
|
return mObject;
|
|
}
|
|
|
|
// Drop the script object - but *not* the nsIScriptContext.
|
|
nsresult drop() {
|
|
nsresult rv = NS_OK;
|
|
if (mObject) {
|
|
rv = mContext->DropScriptObject(mObject);
|
|
mObject = nullptr;
|
|
}
|
|
return rv;
|
|
}
|
|
|
|
nsresult set(T* object) {
|
|
nsresult rv = drop();
|
|
if (NS_FAILED(rv))
|
|
return rv;
|
|
if (object) {
|
|
rv = mContext->HoldScriptObject(object);
|
|
// don't store the pointer if we failed to lock it.
|
|
if (NS_SUCCEEDED(rv)) {
|
|
mObject = object;
|
|
}
|
|
}
|
|
return rv;
|
|
}
|
|
nsresult set(const nsScriptObjectHolder<T> &other) {
|
|
nsresult rv = drop();
|
|
if (NS_FAILED(rv))
|
|
return rv;
|
|
return set(other.mObject);
|
|
}
|
|
|
|
protected:
|
|
T* mObject;
|
|
nsCOMPtr<nsIScriptContext> mContext;
|
|
};
|
|
|
|
#endif // nsDOMScriptObjectHolder_h__
|