diff -r 000000000000 -r 6474c204b198 dom/xslt/xpath/txResultRecycler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/xslt/xpath/txResultRecycler.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,250 @@
+/* -*- 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/. */
+
+#include "txResultRecycler.h"
+#include "txExprResult.h"
+#include "txNodeSet.h"
+
+txResultRecycler::txResultRecycler()
+    : mEmptyStringResult(nullptr),
+      mTrueResult(nullptr),
+      mFalseResult(nullptr)
+{
+}
+
+txResultRecycler::~txResultRecycler()
+{
+    txStackIterator stringIter(&mStringResults);
+    while (stringIter.hasNext()) {
+        delete static_cast<StringResult*>(stringIter.next());
+    }
+    txStackIterator nodesetIter(&mNodeSetResults);
+    while (nodesetIter.hasNext()) {
+        delete static_cast<txNodeSet*>(nodesetIter.next());
+    }
+    txStackIterator numberIter(&mNumberResults);
+    while (numberIter.hasNext()) {
+        delete static_cast<NumberResult*>(numberIter.next());
+    }
+
+    NS_IF_RELEASE(mEmptyStringResult);
+    NS_IF_RELEASE(mTrueResult);
+    NS_IF_RELEASE(mFalseResult);
+}
+
+
+nsresult
+txResultRecycler::init()
+{
+    NS_ASSERTION(!mEmptyStringResult && !mTrueResult && !mFalseResult,
+                 "Already inited");
+    mEmptyStringResult = new StringResult(nullptr);
+    NS_ENSURE_TRUE(mEmptyStringResult, NS_ERROR_OUT_OF_MEMORY);
+
+    NS_ADDREF(mEmptyStringResult);
+
+    mTrueResult = new BooleanResult(true);
+    NS_ENSURE_TRUE(mTrueResult, NS_ERROR_OUT_OF_MEMORY);
+
+    NS_ADDREF(mTrueResult);
+
+    mFalseResult = new BooleanResult(false);
+    NS_ENSURE_TRUE(mFalseResult, NS_ERROR_OUT_OF_MEMORY);
+
+    NS_ADDREF(mFalseResult);
+
+    return NS_OK;
+}
+
+
+void
+txResultRecycler::recycle(txAExprResult* aResult)
+{
+    NS_ASSERTION(aResult->mRefCnt == 0, "In-use txAExprResult recycled");
+    nsRefPtr<txResultRecycler> kungFuDeathGrip;
+    aResult->mRecycler.swap(kungFuDeathGrip);
+
+    nsresult rv = NS_OK;
+    switch (aResult->getResultType()) {
+        case txAExprResult::STRING:
+        {
+            rv = mStringResults.push(static_cast<StringResult*>(aResult));
+            if (NS_FAILED(rv)) {
+                delete aResult;
+            }
+            return;
+        }
+        case txAExprResult::NODESET:
+        {
+            static_cast<txNodeSet*>(aResult)->clear();
+            rv = mNodeSetResults.push(static_cast<txNodeSet*>(aResult));
+            if (NS_FAILED(rv)) {
+                delete aResult;
+            }
+            return;
+        }
+        case txAExprResult::NUMBER:
+        {
+            rv = mNumberResults.push(static_cast<NumberResult*>(aResult));
+            if (NS_FAILED(rv)) {
+                delete aResult;
+            }
+            return;
+        }
+        default:
+        {
+            delete aResult;
+        }
+    }
+}
+
+nsresult
+txResultRecycler::getStringResult(StringResult** aResult)
+{
+    if (mStringResults.isEmpty()) {
+        *aResult = new StringResult(this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        *aResult = static_cast<StringResult*>(mStringResults.pop());
+        (*aResult)->mValue.Truncate();
+        (*aResult)->mRecycler = this;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+nsresult
+txResultRecycler::getStringResult(const nsAString& aValue,
+                                  txAExprResult** aResult)
+{
+    if (mStringResults.isEmpty()) {
+        *aResult = new StringResult(aValue, this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        StringResult* strRes =
+            static_cast<StringResult*>(mStringResults.pop());
+        strRes->mValue = aValue;
+        strRes->mRecycler = this;
+        *aResult = strRes;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+void
+txResultRecycler::getEmptyStringResult(txAExprResult** aResult)
+{
+    *aResult = mEmptyStringResult;
+    NS_ADDREF(*aResult);
+}
+
+nsresult
+txResultRecycler::getNodeSet(txNodeSet** aResult)
+{
+    if (mNodeSetResults.isEmpty()) {
+        *aResult = new txNodeSet(this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        *aResult = static_cast<txNodeSet*>(mNodeSetResults.pop());
+        (*aResult)->mRecycler = this;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+nsresult
+txResultRecycler::getNodeSet(txNodeSet* aNodeSet, txNodeSet** aResult)
+{
+    if (mNodeSetResults.isEmpty()) {
+        *aResult = new txNodeSet(*aNodeSet, this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        *aResult = static_cast<txNodeSet*>(mNodeSetResults.pop());
+        (*aResult)->append(*aNodeSet);
+        (*aResult)->mRecycler = this;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+nsresult
+txResultRecycler::getNodeSet(const txXPathNode& aNode, txAExprResult** aResult)
+{
+    if (mNodeSetResults.isEmpty()) {
+        *aResult = new txNodeSet(aNode, this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        txNodeSet* nodes = static_cast<txNodeSet*>(mNodeSetResults.pop());
+        nodes->append(aNode);
+        nodes->mRecycler = this;
+        *aResult = nodes;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+nsresult
+txResultRecycler::getNumberResult(double aValue, txAExprResult** aResult)
+{
+    if (mNumberResults.isEmpty()) {
+        *aResult = new NumberResult(aValue, this);
+        NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
+    }
+    else {
+        NumberResult* numRes =
+            static_cast<NumberResult*>(mNumberResults.pop());
+        numRes->value = aValue;
+        numRes->mRecycler = this;
+        *aResult = numRes;
+    }
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+void
+txResultRecycler::getBoolResult(bool aValue, txAExprResult** aResult)
+{
+    *aResult = aValue ? mTrueResult : mFalseResult;
+    NS_ADDREF(*aResult);
+}
+
+nsresult
+txResultRecycler::getNonSharedNodeSet(txNodeSet* aNodeSet, txNodeSet** aResult)
+{
+    if (aNodeSet->mRefCnt > 1) {
+        return getNodeSet(aNodeSet, aResult);
+    }
+
+    *aResult = aNodeSet;
+    NS_ADDREF(*aResult);
+
+    return NS_OK;
+}
+
+void
+txAExprResult::Release()
+{
+    --mRefCnt;
+    NS_LOG_RELEASE(this, mRefCnt, "txAExprResult");
+    if (mRefCnt == 0) {
+        if (mRecycler) {
+            mRecycler->recycle(this);
+        }
+        else {
+            delete this;
+        }
+    }
+}