src/org/apache/xalan/xsltc/compiler/TestSeq.java - xalan-j - Git at Google

 /*
  * @(#)$Id$
  *
  * The Apache Software License, Version 1.1
  *
  *
  * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
  * reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. The end-user documentation included with the redistribution,
  *    if any, must include the following acknowledgment:
  *       "This product includes software developed by the
  *        Apache Software Foundation (http://www.apache.org/)."
  *    Alternately, this acknowledgment may appear in the software itself,
  *    if and wherever such third-party acknowledgments normally appear.
  *
  * 4. The names "Xalan" and "Apache Software Foundation" must
  *    not be used to endorse or promote products derived from this
  *    software without prior written permission. For written
  *    permission, please contact apache@apache.org.
  *
  * 5. Products derived from this software may not be called "Apache",
  *    nor may "Apache" appear in their name, without prior written
  *    permission of the Apache Software Foundation.
  *
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  * ====================================================================
  *
  * This software consists of voluntary contributions made by many
  * individuals on behalf of the Apache Software Foundation and was
  * originally based on software copyright (c) 2001, Sun
  * Microsystems., http://www.sun.com.  For more
  * information on the Apache Software Foundation, please see
  * <http://www.apache.org/>.
  *
  * @author Jacek Ambroziak
  * @author Santiago Pericas-Geertsen
  * @author Erwin Bolwidt <ejb@klomp.org>
  * @author Morten Jorgensen <morten.jorgensen@sun.com>
  *
  */

 package org.apache.xalan.xsltc.compiler;

 import java.util.Vector;
 import java.util.Hashtable;
 import java.util.Dictionary;
 import java.util.Enumeration;
 import java.util.Iterator;

 import org.apache.bcel.generic.*;
 import org.apache.xalan.xsltc.compiler.util.*;

 /**
  * A test sequence is a sequence of patterns that
  *
  *  (1) occured in templates in the same mode
  *  (2) share the same kernel node type (e.g. A/B and C/C/B)
  *  (3) may also contain patterns matching "*" and "node()"
  *      (element sequence only) or matching "@*" (attribute
  *      sequence only).
  *
  * A test sequence may have a default template, which will be
  * instantiated if none of the other patterns match.
  */
 final class TestSeq {

     /**
      * Integer code for the kernel type of this test sequence
      */
     private int _kernelType;

     /**
      * Vector of all patterns in the test sequence. May include
      * patterns with "*", "@*" or "node()" kernel.
      */
     private Vector _patterns = null;

     /**
      * A reference to the Mode object.
      */
     private Mode _mode = null;

     /**
      * Default template for this test sequence
      */
     private Template _default = null;

     /**
      * Instruction list representing this test sequence.
      */
     private InstructionList _instructionList;

     /**
      * Cached handle to avoid compiling more than once.
      */
     private InstructionHandle _start = null;

     /**
      * Creates a new test sequence given a set of patterns and a mode.
      */
     public TestSeq(Vector patterns, Mode mode) {
 	this(patterns, -2, mode);
     }

     public TestSeq(Vector patterns, int kernelType, Mode mode) {
 	_patterns = patterns;
 	_kernelType = kernelType;
 	_mode = mode;
     }

     /**
      * Returns a string representation of this test sequence. Notice
      * that test sequences are mutable, so the value returned by this
      * method is different before and after calling reduce().
      */
     public String toString() {
 	final int count = _patterns.size();
 	final StringBuffer result = new StringBuffer();

 	for (int i = 0; i < count; i++) {
 	    final LocationPathPattern pattern =
 		(LocationPathPattern) _patterns.elementAt(i);

 	    if (i == 0) {
 		result.append("Testseq for kernel " + _kernelType)
 		      .append('\n');
 	    }
 	    result.append("   pattern " + i + ": ")
 	          .append(pattern.toString())
 		  .append('\n');
 	}
 	return result.toString();
     }

     /**
      * Returns the instruction list for this test sequence
      */
     public InstructionList getInstructionList() {
 	return _instructionList;
     }

     /**
      * Return the highest priority for a pattern in this test
      * sequence. This is either the priority of the first or
      * of the default pattern.
      */
     public double getPriority() {
 	final Template template = (_patterns.size() == 0) ? _default
 	    : ((Pattern) _patterns.elementAt(0)).getTemplate();
 	return template.getPriority();
     }

     /**
      * Returns the position of the highest priority pattern in
      * this test sequence.
      */
     public int getPosition() {
 	final Template template = (_patterns.size() == 0) ? _default
 	    : ((Pattern) _patterns.elementAt(0)).getTemplate();
 	return template.getPosition();
     }

     /**
      * Reduce the patterns in this test sequence. Creates a new
      * vector of patterns and sets the default pattern if it
      * finds a patterns that is fully reduced.
      */
     public void reduce() {
 	final Vector newPatterns = new Vector();

 	final int count = _patterns.size();
 	for (int i = 0; i < count; i++) {
 	    final LocationPathPattern pattern =
 		(LocationPathPattern)_patterns.elementAt(i);

 	    // Reduce this pattern
 	    pattern.reduceKernelPattern();

 	    // Is this pattern fully reduced?
 	    if (pattern.isWildcard()) {
 		_default = pattern.getTemplate();
 		break; 		// Ignore following patterns
 	    }
 	    else {
 		newPatterns.addElement(pattern);
 	    }
 	}
 	_patterns = newPatterns;
     }

     /**
      * Returns, by reference, the templates that are included in
      * this test sequence. Note that a single template can occur
      * in several test sequences if its pattern is a union.
      */
     public void findTemplates(Dictionary templates) {
 	if (_default != null) {
 	    templates.put(_default, this);
 	}
 	for (int i = 0; i < _patterns.size(); i++) {
 	    final LocationPathPattern pattern =
 		(LocationPathPattern)_patterns.elementAt(i);
 	    templates.put(pattern.getTemplate(), this);
 	}
     }

     /**
      * Get the instruction handle to a template's code. This is
      * used when a single template occurs in several test
      * sequences; that is, if its pattern is a union of patterns
      * (e.g. match="A/B | A/C").
      */
     private InstructionHandle getTemplateHandle(Template template) {
 	return (InstructionHandle)_mode.getTemplateInstructionHandle(template);
     }

     /**
      * Returns pattern n in this test sequence
      */
     private LocationPathPattern getPattern(int n) {
 	return (LocationPathPattern)_patterns.elementAt(n);
     }

     /**
      * Compile the code for this test sequence. Compile patterns
      * from highest to lowest priority. Note that since patterns
      * can be share by multiple test sequences, instruction lists
      * must be copied before backpatching.
      */
     public InstructionHandle compile(ClassGenerator classGen,
 				     MethodGenerator methodGen,
 				     InstructionHandle continuation)
     {
 	// Returned cached value if already compiled
 	if (_start != null) {
 	    return _start;
 	}

 	// If not patterns, then return handle for default template
 	final int count = _patterns.size();
 	if (count == 0) {
 	    return (_start = getTemplateHandle(_default));
 	}

 	// Init handle to jump when all patterns failed
 	InstructionHandle fail = (_default == null) ? continuation
 	    : getTemplateHandle(_default);

 	// Compile all patterns in reverse order
 	for (int n = count - 1; n >= 0; n--) {
 	    final LocationPathPattern pattern = getPattern(n);
 	    final Template template = pattern.getTemplate();
 	    final InstructionList il = new InstructionList();

 	    // Patterns expect current node on top of stack
 	    il.append(methodGen.loadCurrentNode());

 	    // Apply the test-code compiled for the pattern
 	    InstructionList ilist = _mode.getInstructionList(pattern);
 	    if (ilist == null) {
 		ilist = pattern.compile(classGen, methodGen);
 		_mode.addInstructionList(pattern, ilist);
 	    }

 	    // Make a copy of the instruction list for backpatching
 	    InstructionList copyOfilist = ilist.copy();

 	    FlowList trueList = pattern.getTrueList();
 	    if (trueList != null) {
 		trueList = trueList.copyAndRedirect(ilist, copyOfilist);
 	    }
 	    FlowList falseList = pattern.getFalseList();
 	    if (falseList != null) {
 		falseList = falseList.copyAndRedirect(ilist, copyOfilist);
 	    }

 	    il.append(copyOfilist);

 	    // On success branch to the template code
 	    final InstructionHandle gtmpl = getTemplateHandle(template);
 	    final InstructionHandle success = il.append(new GOTO_W(gtmpl));

 	    if (trueList != null) {
 		trueList.backPatch(success);
 	    }
 	    if (falseList != null) {
 		falseList.backPatch(fail);
 	    }

 	    // Next pattern's 'fail' target is this pattern's first instruction
 	    fail = il.getStart();

 	    // Append existing instruction list to the end of this one
 	    if (_instructionList != null) {
 		il.append(_instructionList);
 	    }

 	    // Set current instruction list to be this one
 	    _instructionList = il;
 	}
 	return (_start = fail);
     }
 }
	/*
	* @(#)$Id$
	*
	* The Apache Software License, Version 1.1
	*
	*
	* Copyright (c) 2001-2003 The Apache Software Foundation. All rights
	* reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. The end-user documentation included with the redistribution,
	* if any, must include the following acknowledgment:
	* "This product includes software developed by the
	* Apache Software Foundation (http://www.apache.org/)."
	* Alternately, this acknowledgment may appear in the software itself,
	* if and wherever such third-party acknowledgments normally appear.
	*
	* 4. The names "Xalan" and "Apache Software Foundation" must
	* not be used to endorse or promote products derived from this
	* software without prior written permission. For written
	* permission, please contact apache@apache.org.
	*
	* 5. Products derived from this software may not be called "Apache",
	* nor may "Apache" appear in their name, without prior written
	* permission of the Apache Software Foundation.
	*
	* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
	* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
	* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
	* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	* ====================================================================
	*
	* This software consists of voluntary contributions made by many
	* individuals on behalf of the Apache Software Foundation and was
	* originally based on software copyright (c) 2001, Sun
	* Microsystems., http://www.sun.com. For more
	* information on the Apache Software Foundation, please see
	* <http://www.apache.org/>.
	*
	* @author Jacek Ambroziak
	* @author Santiago Pericas-Geertsen
	* @author Erwin Bolwidt <ejb@klomp.org>
	* @author Morten Jorgensen <morten.jorgensen@sun.com>
	*
	*/

	package org.apache.xalan.xsltc.compiler;

	import java.util.Vector;
	import java.util.Hashtable;
	import java.util.Dictionary;
	import java.util.Enumeration;
	import java.util.Iterator;

	import org.apache.bcel.generic.*;
	import org.apache.xalan.xsltc.compiler.util.*;

	/**
	* A test sequence is a sequence of patterns that
	*
	* (1) occured in templates in the same mode
	* (2) share the same kernel node type (e.g. A/B and C/C/B)
	* (3) may also contain patterns matching "*" and "node()"
	* (element sequence only) or matching "@*" (attribute
	* sequence only).
	*
	* A test sequence may have a default template, which will be
	* instantiated if none of the other patterns match.
	*/
	final class TestSeq {

	/**
	* Integer code for the kernel type of this test sequence
	*/
	private int _kernelType;

	/**
	* Vector of all patterns in the test sequence. May include
	* patterns with "", "@" or "node()" kernel.
	*/
	private Vector _patterns = null;

	/**
	* A reference to the Mode object.
	*/
	private Mode _mode = null;

	/**
	* Default template for this test sequence
	*/
	private Template _default = null;

	/**
	* Instruction list representing this test sequence.
	*/
	private InstructionList _instructionList;

	/**
	* Cached handle to avoid compiling more than once.
	*/
	private InstructionHandle _start = null;

	/**
	* Creates a new test sequence given a set of patterns and a mode.
	*/
	public TestSeq(Vector patterns, Mode mode) {
	this(patterns, -2, mode);
	}

	public TestSeq(Vector patterns, int kernelType, Mode mode) {
	_patterns = patterns;
	_kernelType = kernelType;
	_mode = mode;
	}

	/**
	* Returns a string representation of this test sequence. Notice
	* that test sequences are mutable, so the value returned by this
	* method is different before and after calling reduce().
	*/
	public String toString() {
	final int count = _patterns.size();
	final StringBuffer result = new StringBuffer();

	for (int i = 0; i < count; i++) {
	final LocationPathPattern pattern =
	(LocationPathPattern) _patterns.elementAt(i);

	if (i == 0) {
	result.append("Testseq for kernel " + _kernelType)
	.append('\n');
	}
	result.append(" pattern " + i + ": ")
	.append(pattern.toString())
	.append('\n');
	}
	return result.toString();
	}

	/**
	* Returns the instruction list for this test sequence
	*/
	public InstructionList getInstructionList() {
	return _instructionList;
	}

	/**
	* Return the highest priority for a pattern in this test
	* sequence. This is either the priority of the first or
	* of the default pattern.
	*/
	public double getPriority() {
	final Template template = (_patterns.size() == 0) ? _default
	: ((Pattern) _patterns.elementAt(0)).getTemplate();
	return template.getPriority();
	}

	/**
	* Returns the position of the highest priority pattern in
	* this test sequence.
	*/
	public int getPosition() {
	final Template template = (_patterns.size() == 0) ? _default
	: ((Pattern) _patterns.elementAt(0)).getTemplate();
	return template.getPosition();
	}

	/**
	* Reduce the patterns in this test sequence. Creates a new
	* vector of patterns and sets the default pattern if it
	* finds a patterns that is fully reduced.
	*/
	public void reduce() {
	final Vector newPatterns = new Vector();

	final int count = _patterns.size();
	for (int i = 0; i < count; i++) {
	final LocationPathPattern pattern =
	(LocationPathPattern)_patterns.elementAt(i);

	// Reduce this pattern
	pattern.reduceKernelPattern();

	// Is this pattern fully reduced?
	if (pattern.isWildcard()) {
	_default = pattern.getTemplate();
	break; // Ignore following patterns
	}
	else {
	newPatterns.addElement(pattern);
	}
	}
	_patterns = newPatterns;
	}

	/**
	* Returns, by reference, the templates that are included in
	* this test sequence. Note that a single template can occur
	* in several test sequences if its pattern is a union.
	*/
	public void findTemplates(Dictionary templates) {
	if (_default != null) {
	templates.put(_default, this);
	}
	for (int i = 0; i < _patterns.size(); i++) {
	final LocationPathPattern pattern =
	(LocationPathPattern)_patterns.elementAt(i);
	templates.put(pattern.getTemplate(), this);
	}
	}

	/**
	* Get the instruction handle to a template's code. This is
	* used when a single template occurs in several test
	* sequences; that is, if its pattern is a union of patterns
	* (e.g. match="A/B \| A/C").
	*/
	private InstructionHandle getTemplateHandle(Template template) {
	return (InstructionHandle)_mode.getTemplateInstructionHandle(template);
	}

	/**
	* Returns pattern n in this test sequence
	*/
	private LocationPathPattern getPattern(int n) {
	return (LocationPathPattern)_patterns.elementAt(n);
	}

	/**
	* Compile the code for this test sequence. Compile patterns
	* from highest to lowest priority. Note that since patterns
	* can be share by multiple test sequences, instruction lists
	* must be copied before backpatching.
	*/
	public InstructionHandle compile(ClassGenerator classGen,
	MethodGenerator methodGen,
	InstructionHandle continuation)
	{
	// Returned cached value if already compiled
	if (_start != null) {
	return _start;
	}

	// If not patterns, then return handle for default template
	final int count = _patterns.size();
	if (count == 0) {
	return (_start = getTemplateHandle(_default));
	}

	// Init handle to jump when all patterns failed
	InstructionHandle fail = (_default == null) ? continuation
	: getTemplateHandle(_default);

	// Compile all patterns in reverse order
	for (int n = count - 1; n >= 0; n--) {
	final LocationPathPattern pattern = getPattern(n);
	final Template template = pattern.getTemplate();
	final InstructionList il = new InstructionList();

	// Patterns expect current node on top of stack
	il.append(methodGen.loadCurrentNode());

	// Apply the test-code compiled for the pattern
	InstructionList ilist = _mode.getInstructionList(pattern);
	if (ilist == null) {
	ilist = pattern.compile(classGen, methodGen);
	_mode.addInstructionList(pattern, ilist);
	}

	// Make a copy of the instruction list for backpatching
	InstructionList copyOfilist = ilist.copy();

	FlowList trueList = pattern.getTrueList();
	if (trueList != null) {
	trueList = trueList.copyAndRedirect(ilist, copyOfilist);
	}
	FlowList falseList = pattern.getFalseList();
	if (falseList != null) {
	falseList = falseList.copyAndRedirect(ilist, copyOfilist);
	}

	il.append(copyOfilist);

	// On success branch to the template code
	final InstructionHandle gtmpl = getTemplateHandle(template);
	final InstructionHandle success = il.append(new GOTO_W(gtmpl));

	if (trueList != null) {
	trueList.backPatch(success);
	}
	if (falseList != null) {
	falseList.backPatch(fail);
	}

	// Next pattern's 'fail' target is this pattern's first instruction
	fail = il.getStart();

	// Append existing instruction list to the end of this one
	if (_instructionList != null) {
	il.append(_instructionList);
	}

	// Set current instruction list to be this one
	_instructionList = il;
	}
	return (_start = fail);
	}
	}