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    1   /*
    2    $Id: VariableScope.java,v 1.3 2004/07/10 03:31:38 bran Exp $
    3
    4    Copyright 2003 (C) James Strachan and Bob Mcwhirter. All Rights Reserved.
    5
    6    Redistribution and use of this software and associated documentation
    7    ("Software"), with or without modification, are permitted provided
    8    that the following conditions are met:
    9
    10   1. Redistributions of source code must retain copyright
    11      statements and notices.  Redistributions must also contain a
    12      copy of this document.
    13
    14   2. Redistributions in binary form must reproduce the
    15      above copyright notice, this list of conditions and the
    16      following disclaimer in the documentation and/or other
    17      materials provided with the distribution.
    18
    19   3. The name "groovy" must not be used to endorse or promote
    20      products derived from this Software without prior written
    21      permission of The Codehaus.  For written permission,
    22      please contact info@codehaus.org.
    23
    24   4. Products derived from this Software may not be called "groovy"
    25      nor may "groovy" appear in their names without prior written
    26      permission of The Codehaus. "groovy" is a registered
    27      trademark of The Codehaus.
    28
    29   5. Due credit should be given to The Codehaus -
    30      http://groovy.codehaus.org/
    31
    32   THIS SOFTWARE IS PROVIDED BY THE CODEHAUS AND CONTRIBUTORS
    33   ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
    34   NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
    35   FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
    36   THE CODEHAUS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
    37   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    38   (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
    39   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
    40   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
    41   STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
    42   ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
    43   OF THE POSSIBILITY OF SUCH DAMAGE.
    44
    45   */
    46  package org.codehaus.groovy.ast;
    47
    48  import java.util.ArrayList;
    49  import java.util.HashSet;
    50  import java.util.Iterator;
    51  import java.util.List;
    52  import java.util.Set;
    53
    54  /***
    55   * Represents a variable scope. This is primarily used to determine variable sharing
    56   * across method and closure boundaries.
    57   *
    58   * @author <a href="mailto:james@coredevelopers.net">James Strachan</a>
    59   * @version $Revision: 1.3 $
    60   */
    61  public class VariableScope  {
    62  	static int i = 0;
    63      private Set declaredVariables = new HashSet(); // contain var names
    64      private Set referencedVariables = new HashSet(); // contain var names
    65
    66      /***
    67       *  br contain vars really declared and defined in the current scope.
    68       * to be filler later by comparing with parent scope all the ancestors.
    69       */
    70      private Set varsDeclaredHere = null;
    71      // each var should really have a scope decarator
    72      // for now it's a naked name, which has the problem of name clashing with parameters
    73      // and ancesters' vars with the same name. Effectively this means we cannot have a
    74      // local var defined with the same name with any parameters or vars in any of the
    75      // ancestors.
    76      // we need to reengineer the scope and vars framework.
    77
    78      private VariableScope parent;
    79      private List children = new ArrayList();
    80      String name = null;
    81
    82      public VariableScope() {
    83      	name = String.valueOf(i++);  // should give it a more meaningful name, w/ class, methed, blockstatement etc.
    84      }
    85
    86      public VariableScope(VariableScope parent) {
    87          this.parent = parent;
    88          parent.children.add(this);
    89          name = String.valueOf(i);
    90      }
    91
    92      public Set getDeclaredVariables() {
    93          return declaredVariables;
    94      }
    95
    96      public Set getReferencedVariables() {
    97          return referencedVariables;
    98      }
    99
    100     /***
    101      * @return all the child scopes
    102      */
    103     public List getChildren() {
    104         return children;
    105     }
    106
    107     /***
    108      * Creates a composite variable scope combining all the variable references
    109      * and declarations from all the child scopes not including this scope
    110      *
    111      * @return
    112      */
    113     public VariableScope createCompositeChildScope() {
    114         VariableScope answer = new VariableScope();
    115         for (Iterator iter = children.iterator(); iter.hasNext(); ) {
    116             answer.appendRecursive((VariableScope) iter.next());
    117         }
    118         answer.parent = this;  // shall we cache this for better performance?
    119         return answer;
    120     }
    121
    122     /***
    123      * Creates a scope including this scope and all nested scopes combined together
    124      *
    125      * @return
    126      */
    127     public VariableScope createRecursiveChildScope() {
    128         VariableScope answer = createCompositeChildScope();
    129         answer.referencedVariables.addAll(referencedVariables);
    130         answer.declaredVariables.addAll(declaredVariables);
    131         return answer;
    132     }
    133
    134     /***
    135      * Creates a scope including this scope and all parent scopes combined together
    136      *
    137      * @return
    138      */
    139     public VariableScope createRecursiveParentScope() {
    140         VariableScope answer = new VariableScope();
    141         VariableScope node = this;
    142         do {
    143             answer.append(node);
    144             node = node.parent;
    145         }
    146         while (node != null);
    147         return answer;
    148     }
    149
    150     /***
    151      * Appends all of the references and declarations from the given scope
    152      * to this one
    153      *
    154      * @param scope
    155      */
    156     protected void append(VariableScope scope) {
    157         referencedVariables.addAll(scope.referencedVariables);
    158         declaredVariables.addAll(scope.declaredVariables);
    159     }
    160
    161     /***
    162      * Appends all of the references and declarations from the given scope
    163      * and all its children to this one
    164      *
    165      * @param scope
    166      */
    167     protected void appendRecursive(VariableScope scope) {
    168         append(scope);
    169
    170         // now lets traverse the children
    171         for (Iterator iter = scope.children.iterator(); iter.hasNext(); ) {
    172             appendRecursive((VariableScope) iter.next());
    173         }
    174      }
    175
    176     /*
    177      * compute the real declares in the current scope
    178      * @author bran
    179      *
    180      * To change the template for this generated type comment go to
    181      * Window - Preferences - Java - Code Generation - Code and Comments
    182      */
    183     public void computeRealDeclares() {
    184     	if (this.varsDeclaredHere == null) this.varsDeclaredHere = new HashSet();
    185     	Set decls = this.declaredVariables;
    186     	for (Iterator iter = decls.iterator(); iter.hasNext();) {
    187 			String var = (String) iter.next();
    188 			// simplistic way of determing declares by simple name matching
    189 			if (!createRecursiveParentScope().getDeclaredVariables().contains(var)) {
    190 				this.varsDeclaredHere.add(var);
    191 			}
    192 		}
    193     }
    194 	/***
    195 	 * @return Returns the varsDeclaredHere.
    196 	 */
    197 	public Set getVarsDeclaredHere() {
    198 		if (this.varsDeclaredHere == null) computeRealDeclares();
    199 		return varsDeclaredHere;
    200 	}
    201 	/***
    202 	 * @param varsDeclaredHere The varsDeclaredHere to set.
    203 	 */
    204 	public void setVarsDeclaredHere(Set varsDeclaredHere) {
    205 		this.varsDeclaredHere = varsDeclaredHere;
    206 	}
    207 }