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16 package com.google.gwt.dev.jjs.ast;
17
18 import com.google.gwt.dev.jjs.InternalCompilerException;
19
20 import java.util.ArrayList  ;
21 import java.util.List ;
22
23
26 public class JModVisitor extends JVisitor {
27
28 private interface ContextFactory {
29 Context create();
30 }
31
32 private class ContextPool extends ArrayList {
33
34 private ContextFactory factory;
35 private int pos = 0;
36
37 public ContextPool(ContextFactory factory) {
38 this.factory = factory;
39 }
40
41 public void release(Context ctx) {
42 if (get(--pos) != ctx) {
43 throw new InternalCompilerException(
44 "Tried to release the wrong context");
45 }
46 }
47
48 public Context take() {
49 if (pos == size()) {
50 add(factory.create());
51 }
52 return (Context) get(pos++);
53 }
54 }
55
56 private class ListContext implements Context {
57 private int index;
58 private List list;
59 private boolean removed;
60 private boolean replaced;
61
62 public boolean canInsert() {
63 return true;
64 }
65
66 public boolean canRemove() {
67 return true;
68 }
69
70 public void insertAfter(JNode node) {
71 checkRemoved();
72 list.add(index + 1, node);
73 didChange = true;
74 }
75
76 public void insertBefore(JNode node) {
77 checkRemoved();
78 list.add(index++, node);
79 didChange = true;
80 }
81
82 public void removeMe() {
83 checkState();
84 list.remove(index--);
85 didChange = removed = true;
86 }
87
88 public void replaceMe(JNode node) {
89 checkState();
90 checkReplacement((JNode) list.get(index), node);
91 list.set(index, node);
92 didChange = replaced = true;
93 }
94
95 protected void doReplace(Class targetClass, JNode x) {
96 checkState();
97 checkReplacement((JNode) list.get(index), x);
98 list.set(index, x);
99 didChange = replaced = true;
100 }
101
102 protected void traverse(List list) {
103 this.list = list;
104 for (index = 0; index < list.size(); ++index) {
105 removed = replaced = false;
106 doTraverse((JNode) list.get(index), this);
107 }
108 }
109
110 private void checkRemoved() {
111 if (removed) {
112 throw new InternalCompilerException("Node was already removed");
113 }
114 }
115
116 private void checkState() {
117 checkRemoved();
118 if (replaced) {
119 throw new InternalCompilerException("Node was already replaced");
120 }
121 }
122 }
123
124 private class NodeContext implements Context {
125 private JNode node;
126 private boolean replaced;
127
128 public boolean canInsert() {
129 return false;
130 }
131
132 public boolean canRemove() {
133 return false;
134 }
135
136 public void insertAfter(JNode node) {
137 throw new UnsupportedOperationException ();
138 }
139
140 public void insertBefore(JNode node) {
141 throw new UnsupportedOperationException ();
142 }
143
144 public void removeMe() {
145 throw new UnsupportedOperationException ();
146 }
147
148 public void replaceMe(JNode node) {
149 if (replaced) {
150 throw new InternalCompilerException("Node was already replaced");
151 }
152 checkReplacement(this.node, node);
153 this.node = node;
154 didChange = replaced = true;
155 }
156
157 protected JNode traverse(JNode node) {
158 this.node = node;
159 replaced = false;
160 doTraverse(node, this);
161 return this.node;
162 }
163 }
164
165 protected static void checkReplacement(JNode origNode, JNode newNode) {
166 if (newNode == null) {
167 throw new InternalCompilerException("Cannot replace with null");
168 }
169 if (newNode == origNode) {
170 throw new InternalCompilerException(
171 "The replacement is the same as the original");
172 }
173 }
174
175 protected boolean didChange = false;
176
177 private final ContextPool listContextPool = new ContextPool(
178 new ContextFactory() {
179 public Context create() {
180 return new ListContext();
181 }
182 });
183
184 private final ContextPool nodeContextPool = new ContextPool(
185 new ContextFactory() {
186 public Context create() {
187 return new NodeContext();
188 }
189 });
190
191 public boolean didChange() {
192 return didChange;
193 }
194
195 protected JNode doAccept(JNode node) {
196 NodeContext ctx = (NodeContext) nodeContextPool.take();
197 try {
198 return ctx.traverse(node);
199 } finally {
200 nodeContextPool.release(ctx);
201 }
202 }
203
204 protected void doAccept(List list) {
205 NodeContext ctx = (NodeContext) nodeContextPool.take();
206 try {
207 for (int i = 0, c = list.size(); i < c; ++i) {
208 list.set(i, ctx.traverse((JNode) list.get(i)));
209 }
210 } finally {
211 nodeContextPool.release(ctx);
212 }
213 }
214
215 protected void doAcceptWithInsertRemove(List list) {
216 ListContext ctx = (ListContext) listContextPool.take();
217 try {
218 ctx.traverse(list);
219 } finally {
220 listContextPool.release(ctx);
221 }
222 }
223
224 }
225 |
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