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.Map;
28 import java.util.WeakHashMap;
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.ClassSymbol;
33 import com.sun.tools.javac.code.Symbol.Completer;
34 import com.sun.tools.javac.code.Symbol.CompletionFailure;
35 import com.sun.tools.javac.util.Context;
36
37 /** When a CompletionFailure is thrown when user code is running, it shouldn't be
38 * thrown out to the client code, but rather skipped, and then rethrown later if javac
39 * itself will complete the Symbol.
40 *
41 * On all places where javac invokes client code (e.g. TaskListeners, annotation
42 * Processors), the {@code userCodeHandler} should be set using
43 * {@link DeferredCompletionFailureHandler#setHandler}, and the original handler
44 * should be restored when the control returns back to javac.
45 *
46 * Implementations of API methods should use {@link Symbol#apiComplete()} instead of
47 * {@link Symbol#complete}, as the {@code apiComplete} method will invoke
48 * {@link DeferredCompletionFailureHandler#handleAPICompletionFailure }, which will
49 * catch the CompletionFailure and will either rethrow it or skip it, depending on
50 * the context.
51 */
52 public class DeferredCompletionFailureHandler {
53
54 protected static final Context.Key<DeferredCompletionFailureHandler> deferredCompletionFailureHandlerKey = new Context.Key<>();
55
56 public static DeferredCompletionFailureHandler instance(Context context) {
57 DeferredCompletionFailureHandler instance = context.get(deferredCompletionFailureHandlerKey);
58 if (instance == null)
59 instance = new DeferredCompletionFailureHandler(context);
60 return instance;
61 }
62
63 public final Handler userCodeHandler = new Handler() {
64 public void install() {
65 class2Flip.values().forEach(f -> f.flip());
66 }
67 public void handleAPICompletionFailure(CompletionFailure cf) {
68 //ignore
69 }
70 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
71 class2Flip.put(sym, new FlipSymbolDescription(sym, new DeferredCompleter(origCompleter)));
72 }
73 public void uninstall() {
74 class2Flip.values().forEach(f -> f.flip());
75 }
76 };
77
78 public final Handler javacCodeHandler = new Handler() {
79 public void install() {
80 }
81 public void handleAPICompletionFailure(CompletionFailure cf) {
82 throw cf;
83 }
84 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {}
85 public void uninstall() {
86 }
87 };
88
89 private Handler handler = javacCodeHandler;
90
91 private final Map<ClassSymbol, FlipSymbolDescription> class2Flip = new WeakHashMap<>();
92
93 protected DeferredCompletionFailureHandler(Context context) {
94 context.put(deferredCompletionFailureHandlerKey, this);
95 }
96
97 public Handler setHandler(Handler h) {
98 if (h == handler) return handler;
99
100 handler.uninstall();
101 Handler prev = handler;
102 handler = h;
103 handler.install();
104 return prev;
105 }
106
107 public void handleAPICompletionFailure(CompletionFailure cf) {
108 handler.handleAPICompletionFailure(cf);
109 }
110
111 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter) {
112 handler.classSymbolCompleteFailed(sym, origCompleter);
113 }
114
115 public boolean isDeferredCompleter(Completer c) {
116 return c instanceof DeferredCompleter;
117 }
118
119 public interface Handler {
120 public void install();
121 public void handleAPICompletionFailure(CompletionFailure cf);
122 public void classSymbolCompleteFailed(ClassSymbol sym, Completer origCompleter);
123 public void uninstall();
124 }
125
126 private class DeferredCompleter implements Completer {
127
128 private final Completer origCompleter;
129
130 public DeferredCompleter(Completer origCompleter) {
131 this.origCompleter = origCompleter;
132 }
133
134 @Override
135 public void complete(Symbol sym) throws CompletionFailure {
136 class2Flip.remove(sym);
137 origCompleter.complete(sym);
138 }
139 }
140
141 private static class FlipSymbolDescription {
142 public final ClassSymbol sym;
143 public Type type;
144 public Kind kind;
145 public WriteableScope members;
146 public Completer completer;
147
148 public FlipSymbolDescription(ClassSymbol sym, Completer completer) {
149 this.sym = sym;
150 this.type = sym.type;
151 this.kind = sym.kind;
152 this.members = null;
153 this.completer = completer;
154 }
155
156 public void flip() {
157 Type prevType = sym.type;
158 sym.type = type;
159 this.type = prevType;
160 Kind prevKind = sym.kind;
161 sym.kind = kind;
162 this.kind = prevKind;
163 Completer prevCompleter = sym.completer;
164 sym.completer = completer;
165 this.completer = prevCompleter;
166 WriteableScope prevMembers = sym.members_field;
167 sym.members_field = members;
168 this.members = prevMembers;
169 }
170
171 }
172 }