1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package com.sun.tools.javac.code;
26
27 import java.util.HashMap;
28 import java.util.Map;
29
30 import com.sun.tools.javac.code.Kinds.Kind;
31 import com.sun.tools.javac.code.Scope.WriteableScope;
32 import com.sun.tools.javac.code.Symbol;
33 import com.sun.tools.javac.code.Symbol.ClassSymbol;
34 import com.sun.tools.javac.code.Symbol.Completer;
35 import com.sun.tools.javac.code.Symbol.CompletionFailure;
36 import com.sun.tools.javac.util.Context;
37
38 /** When a CompletionFailure is thrown when user code is running, it shouldn't be
39 * thrown out to the client code, but rather skipped, and then rethrown later if javac
40 * itself will complete the Symbol.
41 *
42 * On all places where javac invokes client code (e.g. TaskListeners, annotation
43 * Processors), the {@code userCodeHandler} should be set using
44 * {@link DeferredCompletionFailureHandler#setHandler}, and the original handler
45 * should be restored when the control returns back to javac.
46 *
47 * Implementations of API methods should use {@link Symbol#apiComplete()} instead of
48 * {@link Symbol#complete}, as the {@code apiComplete} method will invoke
49 * {@link DeferredCompletionFailureHandler#handleAPICompletionFailure }, which will
50 * catch the CompletionFailure and will either rethrow it or skip it, depending on
51 * the context.
52 */
53 public class DeferredCompletionFailureHandler {
54
55 protected static final Context.Key<DeferredCompletionFailureHandler> deferredCompletionFailureHandlerKey = new Context.Key<>();
56
57 public static DeferredCompletionFailureHandler instance(Context context) {
58 DeferredCompletionFailureHandler instance = context.get(deferredCompletionFailureHandlerKey);
59 if (instance == null)
60 instance = new DeferredCompletionFailureHandler(context);
61 return instance;
62 }
63
64 public final Handler userCodeHandler = new Handler() {
65 private final Map<ClassSymbol, FlipSymbolDescription> class2Flip = new HashMap<>();
66
67 public void install() {
68 class2Flip.values().forEach(f -> f.flip());
69 }
70 public void handleAPICompletionFailure(CompletionFailure cf) {
71 //ignore
72 }
73 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
74 class2Flip.put(sym, new FlipSymbolDescription(sym, new DeferredCompleter(origCompleter) {
75 @Override public void complete(Symbol sym) throws CompletionFailure {
76 class2Flip.remove(sym);
77 super.complete(sym);
78 }
79 }));
80 }
81 public void classSymbolRemoved(ClassSymbol sym) {
82 class2Flip.remove(sym);
83 }
84 public void uninstall() {
85 class2Flip.values().forEach(f -> f.flip());
86 }
87 };
88
89 public final Handler speculativeCodeHandler = new Handler() {
90 private final Map<ClassSymbol, FlipSymbolDescription> class2Flip = new HashMap<>();
91
92 public void install() {
93 }
94 public void handleAPICompletionFailure(CompletionFailure cf) {
95 throw cf;
96 }
97 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
98 class2Flip.put(sym, new FlipSymbolDescription(sym, new DeferredCompleter(origCompleter)));
99 }
100 public void classSymbolRemoved(ClassSymbol sym) {
101 class2Flip.remove(sym);
102 }
103 public void uninstall() {
104 class2Flip.values().forEach(f -> f.flip());
105 class2Flip.clear();
106 }
107 };
108
109 public final Handler javacCodeHandler = new Handler() {
110 public void install() {
111 }
112 public void handleAPICompletionFailure(CompletionFailure cf) {
113 throw cf;
114 }
115 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {}
116 public void classSymbolRemoved(ClassSymbol sym) {}
117 public void uninstall() {
118 }
119 };
120
121 private Handler handler = javacCodeHandler;
122
123 protected DeferredCompletionFailureHandler(Context context) {
124 context.put(deferredCompletionFailureHandlerKey, this);
125 }
126
127 public Handler setHandler(Handler h) {
128 if (h == handler) return handler;
129
130 handler.uninstall();
131 Handler prev = handler;
132 handler = h;
133 handler.install();
134 return prev;
135 }
136
137 public void handleAPICompletionFailure(CompletionFailure cf) {
138 handler.handleAPICompletionFailure(cf);
139 }
140
141 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
142 handler.classSymbolCompleteFailed(sym, origCompleter);
143 }
144
145 public void classSymbolRemoved(ClassSymbol sym) {
146 handler.classSymbolRemoved(sym);
147 }
148
149 public boolean isDeferredCompleter(Completer c) {
150 return c instanceof DeferredCompleter;
151 }
152
153 public interface Handler {
154 public void install();
155 public void handleAPICompletionFailure(CompletionFailure cf);
156 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter);
157 public void classSymbolRemoved(ClassSymbol sym);
158 public void uninstall();
159 }
160
161 private class DeferredCompleter implements Completer {
162
163 private final Completer origCompleter;
164
165 public DeferredCompleter(Completer origCompleter) {
166 this.origCompleter = origCompleter;
167 }
168
169 @Override
170 public void complete(Symbol sym) throws CompletionFailure {
171 origCompleter.complete(sym);
172 }
173 }
174
175 private static class FlipSymbolDescription {
176 public final ClassSymbol sym;
177 public Type type;
178 public Kind kind;
179 public WriteableScope members;
180 public Completer completer;
181
182 public FlipSymbolDescription(ClassSymbol sym, Completer completer) {
183 this.sym = sym;
184 this.type = sym.type;
185 this.kind = sym.kind;
186 this.members = null;
187 this.completer = completer;
188 }
189
190 public void flip() {
191 Type prevType = sym.type;
192 sym.type = type;
193 this.type = prevType;
194 Kind prevKind = sym.kind;
195 sym.kind = kind;
196 this.kind = prevKind;
197 Completer prevCompleter = sym.completer;
198 sym.completer = completer;
199 this.completer = prevCompleter;
200 WriteableScope prevMembers = sym.members_field;
201 sym.members_field = members;
202 this.members = prevMembers;
203 }
204
205 }
206 }