/*

 */

/*

 * Copyright 2001-2004 The Apache Software Foundation.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;

import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;

import com.sun.org.apache.bcel.internal.generic.InstructionList;

import com.sun.org.apache.bcel.internal.generic.PUSH;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;

import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;

import com.sun.org.apache.xml.internal.utils.XML11Char;

/**

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 * @author Morten Jorgensen

 * @author John Howard <JohnH@schemasoft.com>

 */

final class WithParam extends Instruction {

    /**

     * Parameter's name.

     */

    private QName _name;

    /**

     * The escaped qname of the with-param.

     */

    protected String _escapedName;

    /**

     * Parameter's default value.

     */

    private Expression _select;

    /**

     * %OPT% This is set to true when the WithParam is used in a CallTemplate

     * for a simple named template. If this is true, the parameters are

     * passed to the named template through method arguments rather than

     * using the expensive Translet.addParameter() call.

     */

    private boolean _doParameterOptimization = false;

    /**

     * Displays the contents of this element

     */

    public void display(int indent) {

        indent(indent);

        Util.println("with-param " + _name);

        if (_select != null) {

            indent(indent + IndentIncrement);

            Util.println("select " + _select.toString());

        }

        displayContents(indent + IndentIncrement);

    }

    /**

     * Returns the escaped qname of the parameter

     */

    public String getEscapedName() {

        return _escapedName;

    }

    /**

     * Return the name of this WithParam.

     */

    public QName getName() {

        return _name;

    }

    /**

     * Set the name of the variable or paremeter. Escape all special chars.

     */

    public void setName(QName name) {

        _name = name;

        _escapedName = Util.escape(name.getStringRep());

    }

    /**

     * Set the do parameter optimization flag

     */

    public void setDoParameterOptimization(boolean flag) {

        _doParameterOptimization = flag;

    }

    /**

     * The contents of a <xsl:with-param> elements are either in the element's

     * 'select' attribute (this has precedence) or in the element body.

     */

    public void parseContents(Parser parser) {

        final String name = getAttribute("name");

        if (name.length() > 0) {

            if (!XML11Char.isXML11ValidQName(name)) {

                ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, name,

                                            this);

                parser.reportError(Constants.ERROR, err);

            }

            setName(parser.getQNameIgnoreDefaultNs(name));

        }

        else {

            reportError(this, parser, ErrorMsg.REQUIRED_ATTR_ERR, "name");

        }

        final String select = getAttribute("select");

        if (select.length() > 0) {

            _select = parser.parseExpression(this, "select", null);

        }

        parseChildren(parser);

    }

    /**

     * Type-check either the select attribute or the element body, depending

     * on which is in use.

     */

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {

        if (_select != null) {

            final Type tselect = _select.typeCheck(stable);

            if (tselect instanceof ReferenceType == false) {

                _select = new CastExpr(_select, Type.Reference);

            }

        }

        else {

            typeCheckContents(stable);

        }

        return Type.Void;

    }

    /**

     * Compile the value of the parameter, which is either in an expression in

     * a 'select' attribute, or in the with-param element's body

     */

    public void translateValue(ClassGenerator classGen,

                               MethodGenerator methodGen) {

        // Compile expression is 'select' attribute if present

        if (_select != null) {

            _select.translate(classGen, methodGen);

            _select.startIterator(classGen, methodGen);

        }

        // If not, compile result tree from parameter body if present.

        else if (hasContents()) {

            compileResultTree(classGen, methodGen);

        }

        // If neither are present then store empty string in parameter slot

        else {

            final ConstantPoolGen cpg = classGen.getConstantPool();

            final InstructionList il = methodGen.getInstructionList();

            il.append(new PUSH(cpg, Constants.EMPTYSTRING));

        }

    }

    /**

     * This code generates a sequence of bytecodes that call the

     * addParameter() method in AbstractTranslet. The method call will add

     * (or update) the parameter frame with the new parameter value.

     */

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        // Translate the value and put it on the stack

        if (_doParameterOptimization) {

            translateValue(classGen, methodGen);

            return;

        }

        // Make name acceptable for use as field name in class

        String name = Util.escape(getEscapedName());

        // Load reference to the translet (method is in AbstractTranslet)

        il.append(classGen.loadTranslet());

        // Load the name of the parameter

        il.append(new PUSH(cpg, name)); // TODO: namespace ?

        // Generete the value of the parameter (use value in 'select' by def.)

        translateValue(classGen, methodGen);

        // Mark this parameter value is not being the default value

        il.append(new PUSH(cpg, false));

        // Pass the parameter to the template

        il.append(new INVOKEVIRTUAL(cpg.addMethodref(TRANSLET_CLASS,

                                                     ADD_PARAMETER,

                                                     ADD_PARAMETER_SIG)));

        il.append(POP); // cleanup stack

    }

}