gecko-dev/dom/xslt/xpath/txResultRecycler.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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 txResultRecycler_h__
#define txResultRecycler_h__

#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "txStack.h"

class txAExprResult;
class StringResult;
class txNodeSet;
class txXPathNode;
class NumberResult;
class BooleanResult;

class txResultRecycler
{
public:
    txResultRecycler();
    ~txResultRecycler();

    void AddRef()
    {
        ++mRefCnt;
        NS_LOG_ADDREF(this, mRefCnt, "txResultRecycler", sizeof(*this));
    }
    void Release()
    {
        --mRefCnt;
        NS_LOG_RELEASE(this, mRefCnt, "txResultRecycler");
        if (mRefCnt == 0) {
            mRefCnt = 1; //stabilize
            delete this;
        }
    }

    /**
     * Returns an txAExprResult to this recycler for reuse.
     * @param aResult  result to recycle
     */
    void recycle(txAExprResult* aResult);

    /**
     * Functions to return results that will be fully used by the caller.
     * Returns nullptr on out-of-memory and an inited result otherwise.
     */
    nsresult getStringResult(StringResult** aResult);
    nsresult getStringResult(const nsAString& aValue, txAExprResult** aResult);
    nsresult getNodeSet(txNodeSet** aResult);
    nsresult getNodeSet(txNodeSet* aNodeSet, txNodeSet** aResult);
    nsresult getNodeSet(const txXPathNode& aNode, txAExprResult** aResult);
    nsresult getNumberResult(double aValue, txAExprResult** aResult);

    /**
     * Functions to return a txAExprResult that is shared across several
     * clients and must not be modified. Never returns nullptr.
     */
    void getEmptyStringResult(txAExprResult** aResult);
    void getBoolResult(bool aValue, txAExprResult** aResult);

    /**
     * Functions that return non-shared resultsobjects
     */
    nsresult getNonSharedNodeSet(txNodeSet* aNodeSet, txNodeSet** aResult);

private:
    nsAutoRefCnt mRefCnt;
    txStack mStringResults;
    txStack mNodeSetResults;
    txStack mNumberResults;
    RefPtr<StringResult> mEmptyStringResult;
    RefPtr<BooleanResult> mTrueResult;
    RefPtr<BooleanResult> mFalseResult;
};

#endif //txResultRecycler_h__