| 1 | /* |
| 2 | * Copyright 1999-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package com.sun.tools.javac.comp; |
| 27 | |
| 28 | import com.sun.tools.javac.util.*; |
| 29 | import com.sun.tools.javac.tree.*; |
| 30 | import java.util.Iterator; |
| 31 | import java.util.NoSuchElementException; |
| 32 | |
| 33 | /** A class for environments, instances of which are passed as |
| 34 | * arguments to tree visitors. Environments refer to important ancestors |
| 35 | * of the subtree that's currently visited, such as the enclosing method, |
| 36 | * the enclosing class, or the enclosing toplevel node. They also contain |
| 37 | * a generic component, represented as a type parameter, to carry further |
| 38 | * information specific to individual passes. |
| 39 | * |
| 40 | * <p><b>This is NOT part of any API supported by Sun Microsystems. If |
| 41 | * you write code that depends on this, you do so at your own risk. |
| 42 | * This code and its internal interfaces are subject to change or |
| 43 | * deletion without notice.</b> |
| 44 | */ |
| 45 | public class Env<A> implements Iterable<Env<A>> { |
| 46 | |
| 47 | /** The next enclosing environment. |
| 48 | */ |
| 49 | public Env<A> next; |
| 50 | |
| 51 | /** The environment enclosing the current class. |
| 52 | */ |
| 53 | public Env<A> outer; |
| 54 | |
| 55 | /** The tree with which this environment is associated. |
| 56 | */ |
| 57 | public JCTree tree; |
| 58 | |
| 59 | /** The enclosing toplevel tree. |
| 60 | */ |
| 61 | public JCTree.JCCompilationUnit toplevel; |
| 62 | |
| 63 | /** The next enclosing class definition. |
| 64 | */ |
| 65 | public JCTree.JCClassDecl enclClass; |
| 66 | |
| 67 | /** The next enclosing method definition. |
| 68 | */ |
| 69 | public JCTree.JCMethodDecl enclMethod; |
| 70 | |
| 71 | /** A generic field for further information. |
| 72 | */ |
| 73 | public A info; |
| 74 | |
| 75 | /** Is this an environment for evaluating a base clause? |
| 76 | */ |
| 77 | public boolean baseClause = false; |
| 78 | |
| 79 | /** Create an outermost environment for a given (toplevel)tree, |
| 80 | * with a given info field. |
| 81 | */ |
| 82 | public Env(JCTree tree, A info) { |
| 83 | this.next = null; |
| 84 | this.outer = null; |
| 85 | this.tree = tree; |
| 86 | this.toplevel = null; |
| 87 | this.enclClass = null; |
| 88 | this.enclMethod = null; |
| 89 | this.info = info; |
| 90 | } |
| 91 | |
| 92 | /** Duplicate this environment, updating with given tree and info, |
| 93 | * and copying all other fields. |
| 94 | */ |
| 95 | public Env<A> dup(JCTree tree, A info) { |
| 96 | return dupto(new Env<A>(tree, info)); |
| 97 | } |
| 98 | |
| 99 | /** Duplicate this environment into a given Environment, |
| 100 | * using its tree and info, and copying all other fields. |
| 101 | */ |
| 102 | public Env<A> dupto(Env<A> that) { |
| 103 | that.next = this; |
| 104 | that.outer = this.outer; |
| 105 | that.toplevel = this.toplevel; |
| 106 | that.enclClass = this.enclClass; |
| 107 | that.enclMethod = this.enclMethod; |
| 108 | return that; |
| 109 | } |
| 110 | |
| 111 | /** Duplicate this environment, updating with given tree, |
| 112 | * and copying all other fields. |
| 113 | */ |
| 114 | public Env<A> dup(JCTree tree) { |
| 115 | return dup(tree, this.info); |
| 116 | } |
| 117 | |
| 118 | /** Return closest enclosing environment which points to a tree with given tag. |
| 119 | */ |
| 120 | public Env<A> enclosing(int tag) { |
| 121 | Env<A> env1 = this; |
| 122 | while (env1 != null && env1.tree.getTag() != tag) env1 = env1.next; |
| 123 | return env1; |
| 124 | } |
| 125 | |
| 126 | public String toString() { |
| 127 | return "Env[" + info + (outer == null ? "" : ",outer=" + outer) + "]"; |
| 128 | } |
| 129 | |
| 130 | public Iterator<Env<A>> iterator() { |
| 131 | return new Iterator<Env<A>>() { |
| 132 | Env<A> next = Env.this; |
| 133 | public boolean hasNext() { |
| 134 | return next.outer != null; |
| 135 | } |
| 136 | public Env<A> next() { |
| 137 | if (hasNext()) { |
| 138 | Env<A> current = next; |
| 139 | next = current.outer; |
| 140 | return current; |
| 141 | } |
| 142 | throw new NoSuchElementException(); |
| 143 | |
| 144 | } |
| 145 | public void remove() { |
| 146 | throw new UnsupportedOperationException(); |
| 147 | } |
| 148 | }; |
| 149 | } |
| 150 | } |