gecko/dom/xslt/xslt/txXSLTPatterns.cpp

/* -*- 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 "mozilla/FloatingPoint.h"

#include "nsReadableUtils.h"
#include "txExecutionState.h"
#include "txXSLTPatterns.h"
#include "txNodeSetContext.h"
#include "txForwardContext.h"
#include "txXMLUtils.h"
#include "txXSLTFunctions.h"
#include "nsWhitespaceTokenizer.h"
#include "nsIContent.h"

/*
 * Returns the default priority of this Pattern.
 * UnionPatterns don't like this.
 * This should be called on the simple patterns.
 */
double txUnionPattern::getDefaultPriority()
{
    NS_ERROR("Don't call getDefaultPriority on txUnionPattern");
    return mozilla::UnspecifiedNaN();
}

/*
 * Determines whether this Pattern matches the given node within
 * the given context
 * This should be called on the simple patterns for xsl:template,
 * but is fine for xsl:key and xsl:number
 */
bool txUnionPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    uint32_t i, len = mLocPathPatterns.Length();
    for (i = 0; i < len; ++i) {
        if (mLocPathPatterns[i]->matches(aNode, aContext)) {
            return true;
        }
    }
    return false;
}

txPattern::Type
txUnionPattern::getType()
{
  return UNION_PATTERN;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_EXPR(txUnionPattern)
txPattern*
txUnionPattern::getSubPatternAt(uint32_t aPos)
{
    return mLocPathPatterns.SafeElementAt(aPos);
}

void
txUnionPattern::setSubPatternAt(uint32_t aPos, txPattern* aPattern)
{
    NS_ASSERTION(aPos < mLocPathPatterns.Length(),
                 "setting bad subexpression index");
    mLocPathPatterns[aPos] = aPattern;
}


#ifdef TX_TO_STRING
void
txUnionPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txUnionPattern{");
#endif
    for (uint32_t i = 0; i < mLocPathPatterns.Length(); ++i) {
        if (i != 0)
            aDest.AppendLiteral(" | ");
        mLocPathPatterns[i]->toString(aDest);
    }
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif


/*
 * LocationPathPattern
 *
 * a list of step patterns, can start with id or key
 * (dealt with by the parser)
 */

nsresult txLocPathPattern::addStep(txPattern* aPattern, bool isChild)
{
    Step* step = mSteps.AppendElement();
    if (!step)
        return NS_ERROR_OUT_OF_MEMORY;

    step->pattern = aPattern;
    step->isChild = isChild;

    return NS_OK;
}

bool txLocPathPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    NS_ASSERTION(mSteps.Length() > 1, "Internal error");

    /*
     * The idea is to split up a path into blocks separated by descendant
     * operators. For example "foo/bar//baz/bop//ying/yang" is split up into
     * three blocks. The "ying/yang" block is handled by the first while-loop
     * and the "foo/bar" and "baz/bop" blocks are handled by the second
     * while-loop.
     * A block is considered matched when we find a list of ancestors that
     * match the block. If there are more than one list of ancestors that
     * match a block we only need to find the one furthermost down in the
     * tree.
     */

    uint32_t pos = mSteps.Length();
    Step* step = &mSteps[--pos];
    if (!step->pattern->matches(aNode, aContext))
        return false;

    txXPathTreeWalker walker(aNode);
    bool hasParent = walker.moveToParent();

    while (step->isChild) {
        if (!pos)
            return true; // all steps matched
        step = &mSteps[--pos];
        if (!hasParent || !step->pattern->matches(walker.getCurrentPosition(), aContext))
            return false; // no more ancestors or no match

        hasParent = walker.moveToParent();
    }

    // We have at least one // path separator
    txXPathTreeWalker blockWalker(walker);
    uint32_t blockPos = pos;

    while (pos) {
        if (!hasParent)
            return false; // There are more steps in the current block 
                             // than ancestors of the tested node

        step = &mSteps[--pos];
        if (!step->pattern->matches(walker.getCurrentPosition(), aContext)) {
            // Didn't match. We restart at beginning of block using a new
            // start node
            pos = blockPos;
            hasParent = blockWalker.moveToParent();
            walker.moveTo(blockWalker);
        }
        else {
            hasParent = walker.moveToParent();
            if (!step->isChild) {
                // We've matched an entire block. Set new start pos and start node
                blockPos = pos;
                blockWalker.moveTo(walker);
            }
        }
    }

    return true;
} // txLocPathPattern::matches

double txLocPathPattern::getDefaultPriority()
{
    NS_ASSERTION(mSteps.Length() > 1, "Internal error");

    return 0.5;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_EXPR(txLocPathPattern)
txPattern*
txLocPathPattern::getSubPatternAt(uint32_t aPos)
{
    return aPos < mSteps.Length() ? mSteps[aPos].pattern.get() : nullptr;
}

void
txLocPathPattern::setSubPatternAt(uint32_t aPos, txPattern* aPattern)
{
    NS_ASSERTION(aPos < mSteps.Length(), "setting bad subexpression index");
    Step* step = &mSteps[aPos];
    step->pattern.forget();
    step->pattern = aPattern;
}

#ifdef TX_TO_STRING
void
txLocPathPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txLocPathPattern{");
#endif
    for (uint32_t i = 0; i < mSteps.Length(); ++i) {
        if (i != 0) {
            if (mSteps[i].isChild)
                aDest.Append(char16_t('/'));
            else
                aDest.AppendLiteral("//");
        }
        mSteps[i].pattern->toString(aDest);
    }
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif

/*
 * txRootPattern
 *
 * a txPattern matching the document node, or '/'
 */

bool txRootPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    return txXPathNodeUtils::isRoot(aNode);
}

double txRootPattern::getDefaultPriority()
{
    return 0.5;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_EXPR(txRootPattern)
TX_IMPL_PATTERN_STUBS_NO_SUB_PATTERN(txRootPattern)

#ifdef TX_TO_STRING
void
txRootPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txRootPattern{");
#endif
    if (mSerialize)
        aDest.Append(char16_t('/'));
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif

/*
 * txIdPattern
 *
 * txIdPattern matches if the given node has a ID attribute with one
 * of the space delimited values.
 * This looks like the id() function, but may only have LITERALs as
 * argument.
 */
txIdPattern::txIdPattern(const nsSubstring& aString)
{
    nsWhitespaceTokenizer tokenizer(aString);
    while (tokenizer.hasMoreTokens()) {
        // this can fail, XXX move to a Init(aString) method
        nsCOMPtr<nsIAtom> atom = do_GetAtom(tokenizer.nextToken());
        mIds.AppendObject(atom);
    }
}

bool txIdPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    if (!txXPathNodeUtils::isElement(aNode)) {
        return false;
    }

    // Get a ID attribute, if there is
    nsIContent* content = txXPathNativeNode::getContent(aNode);
    NS_ASSERTION(content, "a Element without nsIContent");

    nsIAtom* id = content->GetID();
    return id && mIds.IndexOf(id) > -1;
}

double txIdPattern::getDefaultPriority()
{
    return 0.5;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_EXPR(txIdPattern)
TX_IMPL_PATTERN_STUBS_NO_SUB_PATTERN(txIdPattern)

#ifdef TX_TO_STRING
void
txIdPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txIdPattern{");
#endif
    aDest.AppendLiteral("id('");
    uint32_t k, count = mIds.Count() - 1;
    for (k = 0; k < count; ++k) {
        nsAutoString str;
        mIds[k]->ToString(str);
        aDest.Append(str);
        aDest.Append(char16_t(' '));
    }
    nsAutoString str;
    mIds[count]->ToString(str);
    aDest.Append(str);
    aDest.Append(NS_LITERAL_STRING("')"));
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif

/*
 * txKeyPattern
 *
 * txKeyPattern matches if the given node is in the evalation of 
 * the key() function
 * This resembles the key() function, but may only have LITERALs as
 * argument.
 */

bool txKeyPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    txExecutionState* es = (txExecutionState*)aContext->getPrivateContext();
    nsAutoPtr<txXPathNode> contextDoc(txXPathNodeUtils::getOwnerDocument(aNode));
    NS_ENSURE_TRUE(contextDoc, false);

    nsRefPtr<txNodeSet> nodes;
    nsresult rv = es->getKeyNodes(mName, *contextDoc, mValue, true,
                                  getter_AddRefs(nodes));
    NS_ENSURE_SUCCESS(rv, false);

    return nodes->contains(aNode);
}

double txKeyPattern::getDefaultPriority()
{
    return 0.5;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_EXPR(txKeyPattern)
TX_IMPL_PATTERN_STUBS_NO_SUB_PATTERN(txKeyPattern)

#ifdef TX_TO_STRING
void
txKeyPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txKeyPattern{");
#endif
    aDest.AppendLiteral("key('");
    nsAutoString tmp;
    if (mPrefix) {
        mPrefix->ToString(tmp);
        aDest.Append(tmp);
        aDest.Append(char16_t(':'));
    }
    mName.mLocalName->ToString(tmp);
    aDest.Append(tmp);
    aDest.AppendLiteral(", ");
    aDest.Append(mValue);
    aDest.Append(NS_LITERAL_STRING("')"));
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif

/*
 * txStepPattern
 *
 * a txPattern to hold the NodeTest and the Predicates of a StepPattern
 */

bool txStepPattern::matches(const txXPathNode& aNode, txIMatchContext* aContext)
{
    NS_ASSERTION(mNodeTest, "Internal error");

    if (!mNodeTest->matches(aNode, aContext))
        return false;

    txXPathTreeWalker walker(aNode);
    if ((!mIsAttr &&
         txXPathNodeUtils::isAttribute(walker.getCurrentPosition())) ||
        !walker.moveToParent()) {
        return false;
    }
    if (isEmpty()) {
        return true;
    }

    /*
     * Evaluate Predicates
     *
     * Copy all siblings/attributes matching mNodeTest to nodes
     * Up to the last Predicate do
     *  Foreach node in nodes
     *   evaluate Predicate with node as context node
     *   if the result is a number, check the context position,
     *    otherwise convert to bool
     *   if result is true, copy node to newNodes
     *  if aNode is not member of newNodes, return false
     *  nodes = newNodes
     *
     * For the last Predicate, evaluate Predicate with aNode as
     *  context node, if the result is a number, check the position,
     *  otherwise return the result converted to boolean
     */

    // Create the context node set for evaluating the predicates
    nsRefPtr<txNodeSet> nodes;
    nsresult rv = aContext->recycler()->getNodeSet(getter_AddRefs(nodes));
    NS_ENSURE_SUCCESS(rv, false);

    bool hasNext = mIsAttr ? walker.moveToFirstAttribute() :
                               walker.moveToFirstChild();
    while (hasNext) {
        if (mNodeTest->matches(walker.getCurrentPosition(), aContext)) {
            nodes->append(walker.getCurrentPosition());
        }
        hasNext = mIsAttr ? walker.moveToNextAttribute() :
                            walker.moveToNextSibling();
    }

    Expr* predicate = mPredicates[0];
    nsRefPtr<txNodeSet> newNodes;
    rv = aContext->recycler()->getNodeSet(getter_AddRefs(newNodes));
    NS_ENSURE_SUCCESS(rv, false);

    uint32_t i, predLen = mPredicates.Length();
    for (i = 1; i < predLen; ++i) {
        newNodes->clear();
        bool contextIsInPredicate = false;
        txNodeSetContext predContext(nodes, aContext);
        while (predContext.hasNext()) {
            predContext.next();
            nsRefPtr<txAExprResult> exprResult;
            rv = predicate->evaluate(&predContext, getter_AddRefs(exprResult));
            NS_ENSURE_SUCCESS(rv, false);

            switch(exprResult->getResultType()) {
                case txAExprResult::NUMBER:
                    // handle default, [position() == numberValue()]
                    if ((double)predContext.position() ==
                        exprResult->numberValue()) {
                        const txXPathNode& tmp = predContext.getContextNode();
                        if (tmp == aNode)
                            contextIsInPredicate = true;
                        newNodes->append(tmp);
                    }
                    break;
                default:
                    if (exprResult->booleanValue()) {
                        const txXPathNode& tmp = predContext.getContextNode();
                        if (tmp == aNode)
                            contextIsInPredicate = true;
                        newNodes->append(tmp);
                    }
                    break;
            }
        }
        // Move new NodeSet to the current one
        nodes->clear();
        nodes->append(*newNodes);
        if (!contextIsInPredicate) {
            return false;
        }
        predicate = mPredicates[i];
    }
    txForwardContext evalContext(aContext, aNode, nodes);
    nsRefPtr<txAExprResult> exprResult;
    rv = predicate->evaluate(&evalContext, getter_AddRefs(exprResult));
    NS_ENSURE_SUCCESS(rv, false);

    if (exprResult->getResultType() == txAExprResult::NUMBER)
        // handle default, [position() == numberValue()]
        return ((double)evalContext.position() == exprResult->numberValue());

    return exprResult->booleanValue();
} // matches

double txStepPattern::getDefaultPriority()
{
    if (isEmpty())
        return mNodeTest->getDefaultPriority();
    return 0.5;
}

txPattern::Type
txStepPattern::getType()
{
  return STEP_PATTERN;
}

TX_IMPL_PATTERN_STUBS_NO_SUB_PATTERN(txStepPattern)
Expr*
txStepPattern::getSubExprAt(uint32_t aPos)
{
    return PredicateList::getSubExprAt(aPos);
}

void
txStepPattern::setSubExprAt(uint32_t aPos, Expr* aExpr)
{
    PredicateList::setSubExprAt(aPos, aExpr);
}

#ifdef TX_TO_STRING
void
txStepPattern::toString(nsAString& aDest)
{
#ifdef DEBUG
    aDest.AppendLiteral("txStepPattern{");
#endif
    if (mIsAttr)
        aDest.Append(char16_t('@'));
    if (mNodeTest)
        mNodeTest->toString(aDest);

    PredicateList::toString(aDest);
#ifdef DEBUG
    aDest.Append(char16_t('}'));
#endif
}
#endif