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 javacCodeHandler = new Handler() {
90 public void install() {
91 }
92 public void handleAPICompletionFailure(CompletionFailure cf) {
93 throw cf;
94 }
95 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {}
96 public void classSymbolRemoved(ClassSymbol sym) {}
97 public void uninstall() {
98 }
99 };
100
101 private Handler handler = javacCodeHandler;
102
103 protected DeferredCompletionFailureHandler(Context context) {
104 context.put(deferredCompletionFailureHandlerKey, this);
105 }
106
107 public Handler setHandler(Handler h) {
108 if (h == handler) return handler;
109
110 handler.uninstall();
111 Handler prev = handler;
112 handler = h;
113 handler.install();
114 return prev;
115 }
116
117 public void handleAPICompletionFailure(CompletionFailure cf) {
118 handler.handleAPICompletionFailure(cf);
119 }
120
121 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
122 handler.classSymbolCompleteFailed(sym, origCompleter);
123 }
124
125 public void classSymbolRemoved(ClassSymbol sym) {
126 handler.classSymbolRemoved(sym);
127 }
128
129 public boolean isDeferredCompleter(Completer c) {
130 return c instanceof DeferredCompleter;
131 }
132
133 public interface Handler {
134 public void install();
135 public void handleAPICompletionFailure(CompletionFailure cf);
136 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter);
137 public void classSymbolRemoved(ClassSymbol sym);
138 public void uninstall();
139 }
140
141 private class DeferredCompleter implements Completer {
142
143 private final Completer origCompleter;
144
145 public DeferredCompleter(Completer origCompleter) {
146 this.origCompleter = origCompleter;
147 }
148
149 @Override
150 public void complete(Symbol sym) throws CompletionFailure {
151 origCompleter.complete(sym);
152 }
153 }
154
155 private static class FlipSymbolDescription {
156 public final ClassSymbol sym;
157 public Type type;
158 public Kind kind;
159 public WriteableScope members;
160 public Completer completer;
161
162 public FlipSymbolDescription(ClassSymbol sym, Completer completer) {
163 this.sym = sym;
164 this.type = sym.type;
165 this.kind = sym.kind;
166 this.members = null;
167 this.completer = completer;
168 }
169
170 public void flip() {
171 Type prevType = sym.type;
172 sym.type = type;
173 this.type = prevType;
174 Kind prevKind = sym.kind;
175 sym.kind = kind;
176 this.kind = prevKind;
177 Completer prevCompleter = sym.completer;
178 sym.completer = completer;
179 this.completer = prevCompleter;
180 WriteableScope prevMembers = sym.members_field;
181 sym.members_field = members;
182 this.members = prevMembers;
183 }
184
185 }
186 }