/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/*
 * 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.
 */
/*
 * $Id: ApplyImports.java,v 1.2.4.1 2005/09/13 12:22:02 pvedula Exp $
 */

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

import java.util.Enumeration;

import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
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.NEW;
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.xalan.internal.xsltc.compiler.util.Util;

final class ApplyImports extends Instruction {

    private QName      _modeName;
    private int        _precedence;

    public void display(int indent) {
        indent(indent);
        Util.println("ApplyTemplates");
        indent(indent + IndentIncrement);
        if (_modeName != null) {
            indent(indent + IndentIncrement);
            Util.println("mode " + _modeName);
        }
    }

    /**
     * Returns true if this <xsl:apply-imports/> element has parameters
     */
    public boolean hasWithParams() {
        return hasContents();
    }

    /**
     * Determine the lowest import precedence for any stylesheet imported
     * or included by the stylesheet in which this <xsl:apply-imports/>
     * element occured. The templates that are imported by the stylesheet in
     * which this element occured will all have higher import precedence than
     * the integer returned by this method.
     */
    private int getMinPrecedence(int max) {
        // Move to root of include tree
        Stylesheet includeRoot = getStylesheet();
        while (includeRoot._includedFrom != null) {
            includeRoot = includeRoot._includedFrom;
        }

        return includeRoot.getMinimumDescendantPrecedence();
    }

    /**
     * Parse the attributes and contents of an <xsl:apply-imports/> element.
     */
    public void parseContents(Parser parser) {
        // Indicate to the top-level stylesheet that all templates must be
        // compiled into separate methods.
        Stylesheet stylesheet = getStylesheet();
        stylesheet.setTemplateInlining(false);

        // Get the mode we are currently in (might not be any)
        Template template = getTemplate();
        _modeName = template.getModeName();
        _precedence = template.getImportPrecedence();

        // Get the method name for <xsl:apply-imports/> in this mode
        stylesheet = parser.getTopLevelStylesheet();

        parseChildren(parser);  // with-params
    }

    /**
     * Type-check the attributes/contents of an <xsl:apply-imports/> element.
     */
    public Type typeCheck(SymbolTable stable) throws TypeCheckError {
        typeCheckContents(stable);              // with-params
        return Type.Void;
    }

    /**
     * Translate call-template. A parameter frame is pushed only if
     * some template in the stylesheet uses parameters.
     */
    public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
        final Stylesheet stylesheet = classGen.getStylesheet();
        final ConstantPoolGen cpg = classGen.getConstantPool();
        final InstructionList il = methodGen.getInstructionList();
        final int current = methodGen.getLocalIndex("current");

        // Push the arguments that are passed to applyTemplates()
        il.append(classGen.loadTranslet());
        il.append(methodGen.loadDOM());
    il.append(methodGen.loadIterator());
        il.append(methodGen.loadHandler());
    il.append(methodGen.loadCurrentNode());

        // Push a new parameter frame in case imported template might expect
        // parameters.  The apply-imports has nothing that it can pass.
        if (stylesheet.hasLocalParams()) {
            il.append(classGen.loadTranslet());
            final int pushFrame = cpg.addMethodref(TRANSLET_CLASS,
                                                   PUSH_PARAM_FRAME,
                                                   PUSH_PARAM_FRAME_SIG);
            il.append(new INVOKEVIRTUAL(pushFrame));
        }

        // Get the [min,max> precedence of all templates imported under the
        // current stylesheet
        final int maxPrecedence = _precedence;
        final int minPrecedence = getMinPrecedence(maxPrecedence);
        final Mode mode = stylesheet.getMode(_modeName);

        // Get name of appropriate apply-templates function for this
        // xsl:apply-imports instruction
        String functionName = mode.functionName(minPrecedence, maxPrecedence);

        // Construct the translet class-name and the signature of the method
        final String className = classGen.getStylesheet().getClassName();
        final String signature = classGen.getApplyTemplatesSigForImport();
        final int applyTemplates = cpg.addMethodref(className,
                                                    functionName,
                                                    signature);
        il.append(new INVOKEVIRTUAL(applyTemplates));

        // Pop any parameter frame that was pushed above.
        if (stylesheet.hasLocalParams()) {
            il.append(classGen.loadTranslet());
            final int pushFrame = cpg.addMethodref(TRANSLET_CLASS,
                                                   POP_PARAM_FRAME,
                                                   POP_PARAM_FRAME_SIG);
            il.append(new INVOKEVIRTUAL(pushFrame));
        }
    }

}