C++ txExprLexer::nextToken方法代码示例

nsresult
txExprParser::createFilterOrStep(txExprLexer& lexer, txIParseContext* aContext,
                                 Expr** aResult)
{
    *aResult = nsnull;

    nsresult rv = NS_OK;
    Token* tok = lexer.nextToken();

    nsAutoPtr<Expr> expr;
    switch (tok->mType) {
        case Token::FUNCTION_NAME_AND_PAREN:
            lexer.pushBack();
            rv = createFunctionCall(lexer, aContext, getter_Transfers(expr));
            NS_ENSURE_SUCCESS(rv, rv);
            break;
        case Token::VAR_REFERENCE :
            {
                nsCOMPtr<nsIAtom> prefix, lName;
                PRInt32 nspace;
                nsresult rv = resolveQName(tok->Value(), getter_AddRefs(prefix),
                                           aContext, getter_AddRefs(lName),
                                           nspace);
                NS_ENSURE_SUCCESS(rv, rv);
                expr = new VariableRefExpr(prefix, lName, nspace);
                NS_ENSURE_TRUE(expr, NS_ERROR_OUT_OF_MEMORY);
            }
            break;
        case Token::L_PAREN:
            rv = createExpr(lexer, aContext, getter_Transfers(expr));
            NS_ENSURE_SUCCESS(rv, rv);

            if (lexer.nextToken()->mType != Token::R_PAREN) {
                lexer.pushBack();
                return NS_ERROR_XPATH_PAREN_EXPECTED;
            }
            break;
        case Token::LITERAL :
            expr = new txLiteralExpr(tok->Value());
            NS_ENSURE_TRUE(expr, NS_ERROR_OUT_OF_MEMORY);
            break;
        case Token::NUMBER:
        {
            expr = new txLiteralExpr(Double::toDouble(tok->Value()));
            NS_ENSURE_TRUE(expr, NS_ERROR_OUT_OF_MEMORY);
            break;
        }
        default:
            lexer.pushBack();
            return createLocationStep(lexer, aContext, aResult);
    }

    if (lexer.peek()->mType == Token::L_BRACKET) {
        nsAutoPtr<FilterExpr> filterExpr(new FilterExpr(expr));
        NS_ENSURE_TRUE(filterExpr, NS_ERROR_OUT_OF_MEMORY);

        expr.forget();

        //-- handle predicates
        rv = parsePredicates(filterExpr, lexer, aContext);
        NS_ENSURE_SUCCESS(rv, rv);
        expr = filterExpr.forget();
    }

    *aResult = expr.forget();
    return NS_OK;
}

/**
 * Creates a PathExpr using the given txExprLexer
 * @param lexer the txExprLexer for retrieving Tokens
 */
nsresult
txExprParser::createPathExpr(txExprLexer& lexer, txIParseContext* aContext,
                             Expr** aResult)
{
    *aResult = nsnull;

    nsAutoPtr<Expr> expr;

    Token* tok = lexer.peek();

    // is this a root expression?
    if (tok->mType == Token::PARENT_OP) {
        lexer.nextToken();
        if (!isLocationStepToken(lexer.peek())) {
            *aResult = new RootExpr();
            NS_ENSURE_TRUE(*aResult, NS_ERROR_OUT_OF_MEMORY);
            return NS_OK;
        }
        lexer.pushBack();
    }

    // parse first step (possibly a FilterExpr)
    nsresult rv = NS_OK;
    if (tok->mType != Token::PARENT_OP &&
        tok->mType != Token::ANCESTOR_OP) {
        rv = createFilterOrStep(lexer, aContext, getter_Transfers(expr));
        NS_ENSURE_SUCCESS(rv, rv);

        // is this a singlestep path expression?
        tok = lexer.peek();
        if (tok->mType != Token::PARENT_OP &&
            tok->mType != Token::ANCESTOR_OP) {
            *aResult = expr.forget();
            return NS_OK;
        }
    }
    else {
        expr = new RootExpr();
        NS_ENSURE_TRUE(expr, NS_ERROR_OUT_OF_MEMORY);

#ifdef TX_TO_STRING
        static_cast<RootExpr*>(expr.get())->setSerialize(PR_FALSE);
#endif
    }
    
    // We have a PathExpr containing several steps
    nsAutoPtr<PathExpr> pathExpr(new PathExpr());
    NS_ENSURE_TRUE(pathExpr, NS_ERROR_OUT_OF_MEMORY);

    rv = pathExpr->addExpr(expr, PathExpr::RELATIVE_OP);
    NS_ENSURE_SUCCESS(rv, rv);

    expr.forget();

    // this is ugly
    while (1) {
        PathExpr::PathOperator pathOp;
        tok = lexer.nextToken();
        switch (tok->mType) {
            case Token::ANCESTOR_OP :
                pathOp = PathExpr::DESCENDANT_OP;
                break;
            case Token::PARENT_OP :
                pathOp = PathExpr::RELATIVE_OP;
                break;
            default:
                lexer.pushBack();
                *aResult = pathExpr.forget();
                return NS_OK;
        }
        
        rv = createLocationStep(lexer, aContext, getter_Transfers(expr));
        NS_ENSURE_SUCCESS(rv, rv);

        rv = pathExpr->addExpr(expr, pathOp);
        NS_ENSURE_SUCCESS(rv, rv);

        expr.forget();
    }
    NS_NOTREACHED("internal xpath parser error");
    return NS_ERROR_UNEXPECTED;
}

nsresult
txExprParser::createExpr(txExprLexer& lexer, txIParseContext* aContext,
                         Expr** aResult)
{
    *aResult = nsnull;

    nsresult rv = NS_OK;
    MBool done = MB_FALSE;

    nsAutoPtr<Expr> expr;

    txStack exprs;
    txStack ops;

    while (!done) {

        MBool unary = MB_FALSE;
        while (lexer.peek()->mType == Token::SUBTRACTION_OP) {
            unary = !unary;
            lexer.nextToken();
        }

        rv = createUnionExpr(lexer, aContext, getter_Transfers(expr));
        if (NS_FAILED(rv)) {
            break;
        }

        if (unary) {
            Expr* unaryExpr = new UnaryExpr(expr);
            if (!unaryExpr) {
                rv = NS_ERROR_OUT_OF_MEMORY;
                break;
            }
            
            expr.forget();
            expr = unaryExpr;
        }

        Token* tok = lexer.nextToken();
        short tokPrecedence = precedence(tok);
        if (tokPrecedence != 0) {
            while (!exprs.isEmpty() && tokPrecedence
                   <= precedence(static_cast<Token*>(ops.peek()))) {
                // can't use expr as argument due to order of evaluation
                nsAutoPtr<Expr> left(static_cast<Expr*>(exprs.pop()));
                nsAutoPtr<Expr> right(expr);
                rv = createBinaryExpr(left, right,
                                      static_cast<Token*>(ops.pop()),
                                      getter_Transfers(expr));
                if (NS_FAILED(rv)) {
                    done = PR_TRUE;
                    break;
                }
            }
            exprs.push(expr.forget());
            ops.push(tok);
        }
        else {
            lexer.pushBack();
            done = PR_TRUE;
        }
    }

    while (NS_SUCCEEDED(rv) && !exprs.isEmpty()) {
        nsAutoPtr<Expr> left(static_cast<Expr*>(exprs.pop()));
        nsAutoPtr<Expr> right(expr);
        rv = createBinaryExpr(left, right, static_cast<Token*>(ops.pop()),
                              getter_Transfers(expr));
    }
    // clean up on error
    while (!exprs.isEmpty()) {
        delete static_cast<Expr*>(exprs.pop());
    }
    NS_ENSURE_SUCCESS(rv, rv);

    *aResult = expr.forget();
    return NS_OK;
}

nsresult
txExprParser::createLocationStep(txExprLexer& lexer, txIParseContext* aContext,
                                 Expr** aExpr)
{
    *aExpr = nsnull;

    //-- child axis is default
    LocationStep::LocationStepType axisIdentifier = LocationStep::CHILD_AXIS;
    nsAutoPtr<txNodeTest> nodeTest;

    //-- get Axis Identifier or AbbreviatedStep, if present
    Token* tok = lexer.peek();
    switch (tok->mType) {
        case Token::AXIS_IDENTIFIER:
        {
            //-- eat token
            lexer.nextToken();
            nsCOMPtr<nsIAtom> axis = do_GetAtom(tok->Value());
            if (axis == txXPathAtoms::ancestor) {
                axisIdentifier = LocationStep::ANCESTOR_AXIS;
            }
            else if (axis == txXPathAtoms::ancestorOrSelf) {
                axisIdentifier = LocationStep::ANCESTOR_OR_SELF_AXIS;
            }
            else if (axis == txXPathAtoms::attribute) {
                axisIdentifier = LocationStep::ATTRIBUTE_AXIS;
            }
            else if (axis == txXPathAtoms::child) {
                axisIdentifier = LocationStep::CHILD_AXIS;
            }
            else if (axis == txXPathAtoms::descendant) {
                axisIdentifier = LocationStep::DESCENDANT_AXIS;
            }
            else if (axis == txXPathAtoms::descendantOrSelf) {
                axisIdentifier = LocationStep::DESCENDANT_OR_SELF_AXIS;
            }
            else if (axis == txXPathAtoms::following) {
                axisIdentifier = LocationStep::FOLLOWING_AXIS;
            }
            else if (axis == txXPathAtoms::followingSibling) {
                axisIdentifier = LocationStep::FOLLOWING_SIBLING_AXIS;
            }
            else if (axis == txXPathAtoms::_namespace) {
                axisIdentifier = LocationStep::NAMESPACE_AXIS;
            }
            else if (axis == txXPathAtoms::parent) {
                axisIdentifier = LocationStep::PARENT_AXIS;
            }
            else if (axis == txXPathAtoms::preceding) {
                axisIdentifier = LocationStep::PRECEDING_AXIS;
            }
            else if (axis == txXPathAtoms::precedingSibling) {
                axisIdentifier = LocationStep::PRECEDING_SIBLING_AXIS;
            }
            else if (axis == txXPathAtoms::self) {
                axisIdentifier = LocationStep::SELF_AXIS;
            }
            else {
                return NS_ERROR_XPATH_INVALID_AXIS;
            }
            break;
        }
        case Token::AT_SIGN:
            //-- eat token
            lexer.nextToken();
            axisIdentifier = LocationStep::ATTRIBUTE_AXIS;
            break;
        case Token::PARENT_NODE :
            //-- eat token
            lexer.nextToken();
            axisIdentifier = LocationStep::PARENT_AXIS;
            nodeTest = new txNodeTypeTest(txNodeTypeTest::NODE_TYPE);
            NS_ENSURE_TRUE(nodeTest, NS_ERROR_OUT_OF_MEMORY);
            break;
        case Token::SELF_NODE :
            //-- eat token
            lexer.nextToken();
            axisIdentifier = LocationStep::SELF_AXIS;
            nodeTest = new txNodeTypeTest(txNodeTypeTest::NODE_TYPE);
            NS_ENSURE_TRUE(nodeTest, NS_ERROR_OUT_OF_MEMORY);
            break;
        default:
            break;
    }

    //-- get NodeTest unless an AbbreviatedStep was found
    nsresult rv = NS_OK;
    if (!nodeTest) {
        tok = lexer.nextToken();

        if (tok->mType == Token::CNAME) {
            // resolve QName
            nsCOMPtr<nsIAtom> prefix, lName;
            PRInt32 nspace;
            rv = resolveQName(tok->Value(), getter_AddRefs(prefix),
                              aContext, getter_AddRefs(lName),
                              nspace, PR_TRUE);
            NS_ENSURE_SUCCESS(rv, rv);

            nodeTest =
//.........这里部分代码省略.........

nsresult txPatternParser::createUnionPattern(txExprLexer& aLexer,
                                             txIParseContext* aContext,
                                             txPattern*& aPattern)
{
    nsresult rv = NS_OK;
    txPattern* locPath = 0;

    rv = createLocPathPattern(aLexer, aContext, locPath);
    if (NS_FAILED(rv))
        return rv;

    Token::Type type = aLexer.peek()->mType;
    if (type == Token::END) {
        aPattern = locPath;
        return NS_OK;
    }

    if (type != Token::UNION_OP) {
        delete locPath;
        return NS_ERROR_XPATH_PARSE_FAILURE;
    }

    txUnionPattern* unionPattern = new txUnionPattern();
    if (!unionPattern) {
        delete locPath;
        return NS_ERROR_OUT_OF_MEMORY;
    }
    rv = unionPattern->addPattern(locPath);
#if 0 // XXX addPattern can't fail yet, it doesn't check for mem
    if (NS_FAILED(rv)) {
        delete unionPattern;
        delete locPath;
        return rv;
    }
#endif

    aLexer.nextToken();
    do {
        rv = createLocPathPattern(aLexer, aContext, locPath);
        if (NS_FAILED(rv)) {
            delete unionPattern;
            return rv;
        }
        rv = unionPattern->addPattern(locPath);
#if 0 // XXX addPattern can't fail yet, it doesn't check for mem
        if (NS_FAILED(rv)) {
            delete unionPattern;
            delete locPath;
            return rv;
        }
#endif
        type = aLexer.nextToken()->mType;
    } while (type == Token::UNION_OP);

    if (type != Token::END) {
        delete unionPattern;
        return NS_ERROR_XPATH_PARSE_FAILURE;
    }

    aPattern = unionPattern;
    return NS_OK;
}

nsresult txPatternParser::createStepPattern(txExprLexer& aLexer,
                                            txIParseContext* aContext,
                                            txPattern*& aPattern)
{
    nsresult rv = NS_OK;
    MBool isAttr = MB_FALSE;
    Token* tok = aLexer.peek();
    if (tok->mType == Token::AXIS_IDENTIFIER) {
        if (TX_StringEqualsAtom(tok->Value(), nsGkAtoms::attribute)) {
            isAttr = MB_TRUE;
        }
        else if (!TX_StringEqualsAtom(tok->Value(), nsGkAtoms::child)) {
            // all done already for CHILD_AXIS, for all others
            // XXX report unexpected axis error
            return NS_ERROR_XPATH_PARSE_FAILURE;
        }
        aLexer.nextToken();
    }
    else if (tok->mType == Token::AT_SIGN) {
        aLexer.nextToken();
        isAttr = MB_TRUE;
    }
    tok = aLexer.nextToken();

    txNodeTest* nodeTest;
    if (tok->mType == Token::CNAME) {
        // resolve QName
        nsCOMPtr<nsIAtom> prefix, lName;
        PRInt32 nspace;
        rv = resolveQName(tok->Value(), getter_AddRefs(prefix), aContext,
                          getter_AddRefs(lName), nspace, PR_TRUE);
        if (NS_FAILED(rv)) {
            // XXX error report namespace resolve failed
            return rv;
        }

        PRUint16 nodeType = isAttr ?
                            (PRUint16)txXPathNodeType::ATTRIBUTE_NODE :
                            (PRUint16)txXPathNodeType::ELEMENT_NODE;
        nodeTest = new txNameTest(prefix, lName, nspace, nodeType);
        if (!nodeTest) {
            return NS_ERROR_OUT_OF_MEMORY;
        }
    }
    else {
        aLexer.pushBack();
        rv = createNodeTypeTest(aLexer, &nodeTest);
        NS_ENSURE_SUCCESS(rv, rv);
    }

    nsAutoPtr<txStepPattern> step(new txStepPattern(nodeTest, isAttr));
    if (!step) {
        delete nodeTest;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    rv = parsePredicates(step, aLexer, aContext);
    NS_ENSURE_SUCCESS(rv, rv);

    aPattern = step.forget();

    return NS_OK;
}

nsresult txPatternParser::createLocPathPattern(txExprLexer& aLexer,
                                               txIParseContext* aContext,
                                               txPattern*& aPattern)
{
    nsresult rv = NS_OK;

    MBool isChild = MB_TRUE;
    MBool isAbsolute = MB_FALSE;
    txPattern* stepPattern = 0;
    txLocPathPattern* pathPattern = 0;

    Token::Type type = aLexer.peek()->mType;
    switch (type) {
        case Token::ANCESTOR_OP:
            isChild = MB_FALSE;
            isAbsolute = MB_TRUE;
            aLexer.nextToken();
            break;
        case Token::PARENT_OP:
            aLexer.nextToken();
            isAbsolute = MB_TRUE;
            if (aLexer.peek()->mType == Token::END || 
                aLexer.peek()->mType == Token::UNION_OP) {
                aPattern = new txRootPattern();

                return aPattern ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
            }
            break;
        case Token::FUNCTION_NAME_AND_PAREN:
            // id(Literal) or key(Literal, Literal)
            {
                nsCOMPtr<nsIAtom> nameAtom =
                    do_GetAtom(aLexer.nextToken()->Value());
                if (nameAtom == nsGkAtoms::id) {
                    rv = createIdPattern(aLexer, stepPattern);
                }
                else if (nameAtom == nsGkAtoms::key) {
                    rv = createKeyPattern(aLexer, aContext, stepPattern);
                }
                if (NS_FAILED(rv))
                    return rv;
            }
            break;
        default:
            break;
    }
    if (!stepPattern) {
        rv = createStepPattern(aLexer, aContext, stepPattern);
        if (NS_FAILED(rv))
            return rv;
    }

    type = aLexer.peek()->mType;
    if (!isAbsolute && type != Token::PARENT_OP
        && type != Token::ANCESTOR_OP) {
        aPattern = stepPattern;
        return NS_OK;
    }

    pathPattern = new txLocPathPattern();
    if (!pathPattern) {
        delete stepPattern;
        return NS_ERROR_OUT_OF_MEMORY;
    }

    if (isAbsolute) {
        txRootPattern* root = new txRootPattern();
        if (!root) {
            delete stepPattern;
            delete pathPattern;
            return NS_ERROR_OUT_OF_MEMORY;
        }

#ifdef TX_TO_STRING
        root->setSerialize(PR_FALSE);
#endif

        rv = pathPattern->addStep(root, isChild);
        if (NS_FAILED(rv)) {
            delete stepPattern;
            delete pathPattern;
            delete root;
            return NS_ERROR_OUT_OF_MEMORY;
        }
    }

    rv = pathPattern->addStep(stepPattern, isChild);
    if (NS_FAILED(rv)) {
        delete stepPattern;
        delete pathPattern;
        return NS_ERROR_OUT_OF_MEMORY;
    }
    stepPattern = 0; // stepPattern is part of pathPattern now

    while (type == Token::PARENT_OP || type == Token::ANCESTOR_OP) {
        isChild = type == Token::PARENT_OP;
        aLexer.nextToken();
        rv = createStepPattern(aLexer, aContext, stepPattern);
        if (NS_FAILED(rv)) {
            delete pathPattern;
//.........这里部分代码省略.........