duke@1: /*
xdono@117:  * Copyright 1999-2008 Sun Microsystems, Inc.  All Rights Reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
duke@1:  * published by the Free Software Foundation.  Sun designates this
duke@1:  * particular file as subject to the "Classpath" exception as provided
duke@1:  * by Sun in the LICENSE file that accompanied this code.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
duke@1:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@1:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@1:  * have any questions.
duke@1:  */
duke@1: 
duke@1: package com.sun.tools.javac.comp;
duke@1: 
duke@1: import com.sun.tools.javac.tree.*;
duke@1: import java.util.Iterator;
duke@1: import java.util.NoSuchElementException;
duke@1: 
duke@1: /** A class for environments, instances of which are passed as
duke@1:  *  arguments to tree visitors.  Environments refer to important ancestors
duke@1:  *  of the subtree that's currently visited, such as the enclosing method,
duke@1:  *  the enclosing class, or the enclosing toplevel node. They also contain
duke@1:  *  a generic component, represented as a type parameter, to carry further
duke@1:  *  information specific to individual passes.
duke@1:  *
duke@1:  *  <p><b>This is NOT part of any API supported by Sun Microsystems.  If
duke@1:  *  you write code that depends on this, you do so at your own risk.
duke@1:  *  This code and its internal interfaces are subject to change or
duke@1:  *  deletion without notice.</b>
duke@1:  */
duke@1: public class Env<A> implements Iterable<Env<A>> {
duke@1: 
duke@1:     /** The next enclosing environment.
duke@1:      */
duke@1:     public Env<A> next;
duke@1: 
duke@1:     /** The environment enclosing the current class.
duke@1:      */
duke@1:     public Env<A> outer;
duke@1: 
duke@1:     /** The tree with which this environment is associated.
duke@1:      */
duke@1:     public JCTree tree;
duke@1: 
duke@1:     /** The enclosing toplevel tree.
duke@1:      */
duke@1:     public JCTree.JCCompilationUnit toplevel;
duke@1: 
duke@1:     /** The next enclosing class definition.
duke@1:      */
duke@1:     public JCTree.JCClassDecl enclClass;
duke@1: 
duke@1:     /** The next enclosing method definition.
duke@1:      */
duke@1:     public JCTree.JCMethodDecl enclMethod;
duke@1: 
duke@1:     /** A generic field for further information.
duke@1:      */
duke@1:     public A info;
duke@1: 
duke@1:     /** Is this an environment for evaluating a base clause?
duke@1:      */
duke@1:     public boolean baseClause = false;
duke@1: 
duke@1:     /** Create an outermost environment for a given (toplevel)tree,
duke@1:      *  with a given info field.
duke@1:      */
duke@1:     public Env(JCTree tree, A info) {
duke@1:         this.next = null;
duke@1:         this.outer = null;
duke@1:         this.tree = tree;
duke@1:         this.toplevel = null;
duke@1:         this.enclClass = null;
duke@1:         this.enclMethod = null;
duke@1:         this.info = info;
duke@1:     }
duke@1: 
duke@1:     /** Duplicate this environment, updating with given tree and info,
duke@1:      *  and copying all other fields.
duke@1:      */
duke@1:     public Env<A> dup(JCTree tree, A info) {
duke@1:         return dupto(new Env<A>(tree, info));
duke@1:     }
duke@1: 
duke@1:     /** Duplicate this environment into a given Environment,
duke@1:      *  using its tree and info, and copying all other fields.
duke@1:      */
duke@1:     public Env<A> dupto(Env<A> that) {
duke@1:         that.next = this;
duke@1:         that.outer = this.outer;
duke@1:         that.toplevel = this.toplevel;
duke@1:         that.enclClass = this.enclClass;
duke@1:         that.enclMethod = this.enclMethod;
duke@1:         return that;
duke@1:     }
duke@1: 
duke@1:     /** Duplicate this environment, updating with given tree,
duke@1:      *  and copying all other fields.
duke@1:      */
duke@1:     public Env<A> dup(JCTree tree) {
duke@1:         return dup(tree, this.info);
duke@1:     }
duke@1: 
duke@1:     /** Return closest enclosing environment which points to a tree with given tag.
duke@1:      */
duke@1:     public Env<A> enclosing(int tag) {
duke@1:         Env<A> env1 = this;
duke@1:         while (env1 != null && env1.tree.getTag() != tag) env1 = env1.next;
duke@1:         return env1;
duke@1:     }
duke@1: 
duke@1:     public String toString() {
duke@1:         return "Env[" + info + (outer == null ? "" : ",outer=" + outer) + "]";
duke@1:     }
duke@1: 
duke@1:     public Iterator<Env<A>> iterator() {
duke@1:         return new Iterator<Env<A>>() {
duke@1:             Env<A> next = Env.this;
duke@1:             public boolean hasNext() {
duke@1:                 return next.outer != null;
duke@1:             }
duke@1:             public Env<A> next() {
duke@1:                 if (hasNext()) {
duke@1:                     Env<A> current = next;
duke@1:                     next = current.outer;
duke@1:                     return current;
duke@1:                 }
duke@1:                 throw new NoSuchElementException();
duke@1: 
duke@1:             }
duke@1:             public void remove() {
duke@1:                 throw new UnsupportedOperationException();
duke@1:             }
duke@1:         };
duke@1:     }
duke@1: }