/*

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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.BranchHandle;

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

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

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

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

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

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

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

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.MethodGenerator;

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.xml.internal.dtm.Axis;

import com.sun.org.apache.xml.internal.dtm.DTM;

/**

 * @author Morten Jorgensen

 */

final class ProcessingInstructionPattern extends StepPattern {

    private String _name = null;

    private boolean _typeChecked = false;

    /**

     * Handles calls with no parameter (current node is implicit parameter).

     */

    public ProcessingInstructionPattern(String name) {

        super(Axis.CHILD, DTM.PROCESSING_INSTRUCTION_NODE, null);

        _name = name;

        //if (_name.equals("*")) _typeChecked = true; no wildcard allowed!

    }

    /**

     *

     */

     public double getDefaultPriority() {

        return (_name != null) ? 0.0 : -0.5;

     }

    public String toString() {

        if (_predicates == null)

            return "processing-instruction("+_name+")";

        else

            return "processing-instruction("+_name+")"+_predicates;

    }

    public void reduceKernelPattern() {

        _typeChecked = true;

    }

    public boolean isWildcard() {

        return false;

    }

    public Type typeCheck(SymbolTable stable) throws TypeCheckError {

        if (hasPredicates()) {

            // Type check all the predicates (e -> position() = e)

            final int n = _predicates.size();

            for (int i = 0; i < n; i++) {

                pred.typeCheck(stable);

            }

        }

        return Type.NodeSet;

    }

    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        // context node is on the stack

        int gname = cpg.addInterfaceMethodref(DOM_INTF,

                                              "getNodeName",

                                              "(I)Ljava/lang/String;");

        int cmp = cpg.addMethodref(STRING_CLASS,

                                   "equals", "(Ljava/lang/Object;)Z");

        // Push current node on the stack

        il.append(methodGen.loadCurrentNode());

        il.append(SWAP);

        // Overwrite current node with matching node

        il.append(methodGen.storeCurrentNode());

        // If pattern not reduced then check kernel

        if (!_typeChecked) {

            il.append(methodGen.loadCurrentNode());

            final int getType = cpg.addInterfaceMethodref(DOM_INTF,

                                                          "getExpandedTypeID",

                                                          "(I)I");

            il.append(methodGen.loadDOM());

            il.append(methodGen.loadCurrentNode());

            il.append(new INVOKEINTERFACE(getType, 2));

            il.append(new PUSH(cpg, DTM.PROCESSING_INSTRUCTION_NODE));

            _falseList.add(il.append(new IF_ICMPEQ(null)));

        }

        // Load the requested processing instruction name

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

        // Load the current processing instruction's name

        il.append(methodGen.loadDOM());

        il.append(methodGen.loadCurrentNode());

        il.append(new INVOKEINTERFACE(gname, 2));

        // Compare the two strings

        il.append(new INVOKEVIRTUAL(cmp));

        _falseList.add(il.append(new IFEQ(null)));

        // Compile the expressions within the predicates

        if (hasPredicates()) {

            final int n = _predicates.size();

            for (int i = 0; i < n; i++) {

                Expression exp = pred.getExpr();

                exp.translateDesynthesized(classGen, methodGen);

                _trueList.append(exp._trueList);

                _falseList.append(exp._falseList);

            }

        }

        // Backpatch true list and restore current iterator/node

        InstructionHandle restore;

        restore = il.append(methodGen.storeCurrentNode());

        backPatchTrueList(restore);

        BranchHandle skipFalse = il.append(new GOTO(null));

        // Backpatch false list and restore current iterator/node

        restore = il.append(methodGen.storeCurrentNode());

        backPatchFalseList(restore);

        _falseList.add(il.append(new GOTO(null)));

        // True list falls through

        skipFalse.setTarget(il.append(NOP));

    }

}