1 /*
2 * Copyright (c) 2018, 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
26 package com.sun.tools.javac.code;
27
28 import com.sun.tools.javac.code.Lint.LintCategory;
29 import com.sun.tools.javac.code.Source.Feature;
30 import com.sun.tools.javac.comp.Infer;
31 import com.sun.tools.javac.jvm.Target;
32 import com.sun.tools.javac.resources.CompilerProperties.Errors;
33 import com.sun.tools.javac.resources.CompilerProperties.Warnings;
34 import com.sun.tools.javac.util.Assert;
35 import com.sun.tools.javac.util.Context;
36 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
37 import com.sun.tools.javac.util.JCDiagnostic.Error;
38 import com.sun.tools.javac.util.JCDiagnostic.SimpleDiagnosticPosition;
39 import com.sun.tools.javac.util.Log;
40 import com.sun.tools.javac.util.MandatoryWarningHandler;
41 import com.sun.tools.javac.util.Name;
42 import com.sun.tools.javac.util.Options;
43
44 import javax.tools.JavaFileObject;
45 import java.util.HashMap;
46 import java.util.HashSet;
47 import java.util.Map;
48 import java.util.Optional;
49 import java.util.Set;
50
51 import static com.sun.tools.javac.main.Option.PREVIEW;
52
53 /**
54 * Helper class to handle preview language features. This class maps certain language features
55 * (see {@link Feature} into 'preview' features; the mapping is completely ad-hoc, so as to allow
56 * for maximum flexibility, which allows to migrate preview feature into supported features with ease.
57 *
58 * This class acts as a centralized point against which usages of preview features are reported by
59 * clients (e.g. other javac classes). Internally, this class collects all such usages and generates
60 * diagnostics to inform the user of such usages. Such diagnostics can be enabled using the
61 * {@link LintCategory#PREVIEW} lint category, and are suppressible by usual means.
62 */
63 public class Preview {
64
65 /** flag: are preview featutres enabled */
66 private final boolean enabled;
67
68 /** the diag handler to manage preview feature usage diagnostics */
69 private final MandatoryWarningHandler previewHandler;
70
71 /** test flag: should all features be considered as preview features? */
72 private final boolean forcePreview;
73
74 /** a mapping from classfile numbers to Java SE versions */
75 private final Map<Integer, Source> majorVersionToSource;
76
77
78 private final Lint lint;
79 private final Log log;
80
81 private static final Context.Key<Preview> previewKey = new Context.Key<>();
82
83 public static Preview instance(Context context) {
84 Preview instance = context.get(previewKey);
85 if (instance == null) {
86 instance = new Preview(context);
87 }
88 return instance;
89 }
90
91 Preview(Context context) {
92 context.put(previewKey, this);
93 Options options = Options.instance(context);
94 enabled = options.isSet(PREVIEW);
95 log = Log.instance(context);
96 lint = Lint.instance(context);
97 this.previewHandler =
98 new MandatoryWarningHandler(log, lint.isEnabled(LintCategory.PREVIEW), true, "preview", LintCategory.PREVIEW);
99 forcePreview = options.isSet("forcePreview");
100 majorVersionToSource = initMajorVersionToSourceMap();
101 }
102
103 private Map<Integer, Source> initMajorVersionToSourceMap() {
104 Map<Integer, Source> majorVersionToSource = new HashMap<>();
105 for (Target t : Target.values()) {
106 int major = t.majorVersion;
107 Source source = Source.lookup(t.name);
108 if (source != null) {
109 majorVersionToSource.put(major, source);
110 }
111 }
112 return majorVersionToSource;
113 }
114
115 /**
116 * Report usage of a preview feature. Usages reported through this method will affect the
117 * set of sourcefiles with dependencies on preview features.
118 * @param pos the position at which the preview feature was used.
119 * @param feature the preview feature used.
120 */
121 public void warnPreview(int pos, Feature feature) {
122 warnPreview(new SimpleDiagnosticPosition(pos), feature);
123 }
124
125 /**
126 * Report usage of a preview feature. Usages reported through this method will affect the
127 * set of sourcefiles with dependencies on preview features.
128 * @param pos the position at which the preview feature was used.
129 * @param feature the preview feature used.
130 */
131 public void warnPreview(DiagnosticPosition pos, Feature feature) {
132 Assert.check(isEnabled());
133 Assert.check(isPreview(feature));
134 if (!lint.isSuppressed(LintCategory.PREVIEW)) {
135 previewHandler.report(pos, feature.isPlural() ?
136 Warnings.PreviewFeatureUsePlural(feature.nameFragment()) :
137 Warnings.PreviewFeatureUse(feature.nameFragment()));
138 }
139 }
140
141 /**
142 * Report usage of a preview feature in classfile.
143 * @param classfile the name of the classfile with preview features enabled
144 * @param majorVersion the major version found in the classfile.
145 */
146 public void warnPreview(JavaFileObject classfile, int majorVersion) {
147 Assert.check(isEnabled());
148 if (!lint.isSuppressed(LintCategory.PREVIEW)) {
149 previewHandler.report(null,
150 Warnings.PreviewFeatureUseClassfile(classfile, majorVersionToSource.get(majorVersion).name));
151 }
152 }
153
154 /**
155 * Are preview features enabled?
156 * @return true, if preview features are enabled.
157 */
158 public boolean isEnabled() {
159 return enabled;
160 }
161
162 /**
163 * Is given feature a preview feature?
164 * @param feature the feature to be tested.
165 * @return true, if given feature is a preview feature.
166 */
167 public boolean isPreview(Feature feature) {
168 //Note: this is a backdoor which allows to optionally treat all features as 'preview' (for testing).
169 //When real preview features will be added, this method can be implemented to return 'true'
170 //for those selected features, and 'false' for all the others.
171 return forcePreview;
172 }
173
174 /**
175 * Generate an error key which captures the fact that a given preview feature could not be used
176 * due to the preview feature support being disabled.
177 * @param feature the feature for which the diagnostic has to be generated.
178 * @return the diagnostic.
179 */
180 public Error disabledError(Feature feature) {
181 Assert.check(!isEnabled());
182 return feature.isPlural() ?
183 Errors.PreviewFeatureDisabledPlural(feature.nameFragment()) :
184 Errors.PreviewFeatureDisabled(feature.nameFragment());
185 }
186
187 /**
188 * Generate an error key which captures the fact that a preview classfile cannot be loaded
189 * due to the preview feature support being disabled.
190 * @param classfile the name of the classfile with preview features enabled
191 * @param majorVersion the major version found in the classfile.
192 */
193 public Error disabledError(JavaFileObject classfile, int majorVersion) {
194 Assert.check(!isEnabled());
195 return Errors.PreviewFeatureDisabledClassfile(classfile, majorVersionToSource.get(majorVersion).name);
196 }
197
198 /**
199 * Report any deferred diagnostics.
200 */
201 public void reportDeferredDiagnostics() {
202 previewHandler.reportDeferredDiagnostic();
203 }
204 }