1 /*
2 * Copyright (c) 2015, 2019, 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.api;
27
28 import java.io.PrintStream;
29 import java.io.Writer;
30 import java.util.ArrayDeque;
31 import java.util.ArrayList;
32 import java.util.Collection;
33 import java.util.HashMap;
34 import java.util.HashSet;
35 import java.util.List;
36 import java.util.Map;
37 import java.util.Queue;
38 import java.util.Set;
39 import java.util.stream.Collectors;
40 import java.util.stream.StreamSupport;
41
42 import javax.tools.Diagnostic;
43 import javax.tools.DiagnosticListener;
44 import javax.tools.JavaFileManager;
45 import javax.tools.JavaFileObject;
46
47 import com.sun.source.tree.ClassTree;
48 import com.sun.source.tree.CompilationUnitTree;
49 import com.sun.source.tree.Tree;
50 import com.sun.source.util.JavacTask;
51 import com.sun.source.util.TaskEvent;
52 import com.sun.source.util.TaskEvent.Kind;
53 import com.sun.source.util.TaskListener;
54 import com.sun.source.util.TreeScanner;
55 import com.sun.tools.javac.code.Kinds;
56 import com.sun.tools.javac.code.Preview;
57 import com.sun.tools.javac.code.Symbol;
58 import com.sun.tools.javac.code.Symtab;
59 import com.sun.tools.javac.code.Type;
60 import com.sun.tools.javac.code.Type.ClassType;
61 import com.sun.tools.javac.code.TypeTag;
62 import com.sun.tools.javac.code.Types;
63 import com.sun.tools.javac.comp.Annotate;
64 import com.sun.tools.javac.comp.Check;
65 import com.sun.tools.javac.comp.CompileStates;
66 import com.sun.tools.javac.comp.Enter;
67 import com.sun.tools.javac.comp.Modules;
68 import com.sun.tools.javac.main.Arguments;
69 import com.sun.tools.javac.main.JavaCompiler;
70 import com.sun.tools.javac.model.JavacElements;
71 import com.sun.tools.javac.tree.JCTree.JCClassDecl;
72 import com.sun.tools.javac.tree.JCTree.LetExpr;
73 import com.sun.tools.javac.util.Context;
74 import com.sun.tools.javac.util.DefinedBy;
75 import com.sun.tools.javac.util.DefinedBy.Api;
76 import com.sun.tools.javac.util.Log;
77
78 /**
79 * A pool of reusable JavacTasks. When a task is no valid anymore, it is returned to the pool,
80 * and its Context may be reused for future processing in some cases. The reuse is achieved
81 * by replacing some components (most notably JavaCompiler and Log) with reusable counterparts,
82 * and by cleaning up leftovers from previous compilation.
83 * <p>
84 * For each combination of options, a separate task/context is created and kept, as most option
85 * values are cached inside components themselves.
86 * <p>
87 * When the compilation redefines sensitive classes (e.g. classes in the the java.* packages), the
88 * task/context is not reused.
89 * <p>
90 * When the task is reused, then packages that were already listed won't be listed again.
91 * <p>
92 * Care must be taken to only return tasks that won't be used by the original caller.
93 * <p>
94 * Care must also be taken when custom components are installed, as those are not cleaned when the
95 * task/context is reused, and subsequent getTask may return a task based on a context with these
96 * custom components.
97 *
98 * <p><b>This is NOT part of any supported API.
99 * If you write code that depends on this, you do so at your own risk.
100 * This code and its internal interfaces are subject to change or
101 * deletion without notice.</b>
102 */
103 public class JavacTaskPool {
104
105 private static final JavacTool systemProvider = JavacTool.create();
106 private static final Queue<ReusableContext> EMPTY_QUEUE = new ArrayDeque<>(0);
107
108 private final int maxPoolSize;
109 private final Map<List<String>, Queue<ReusableContext>> options2Contexts = new HashMap<>();
110 private int id;
111
112 private int statReused = 0;
113 private int statNew = 0;
114 private int statPolluted = 0;
115 private int statRemoved = 0;
116
117 /**Creates the pool.
118 *
119 * @param maxPoolSize maximum number of tasks/context that will be kept in the pool.
120 */
121 public JavacTaskPool(int maxPoolSize) {
122 this.maxPoolSize = maxPoolSize;
123 }
124
125 /**Creates a new task as if by {@link javax.tools.JavaCompiler#getTask} and runs the provided
126 * worker with it. The task is only valid while the worker is running. The internal structures
127 * may be reused from some previous compilation.
128 *
129 * @param out a Writer for additional output from the compiler;
130 * use {@code System.err} if {@code null}
131 * @param fileManager a file manager; if {@code null} use the
132 * compiler's standard file manager
133 * @param diagnosticListener a diagnostic listener; if {@code
134 * null} use the compiler's default method for reporting
135 * diagnostics
136 * @param options compiler options, {@code null} means no options
137 * @param classes names of classes to be processed by annotation
138 * processing, {@code null} means no class names
139 * @param compilationUnits the compilation units to compile, {@code
140 * null} means no compilation units
141 * @param worker that should be run with the task
142 * @return an object representing the compilation
143 * @throws RuntimeException if an unrecoverable error
144 * occurred in a user supplied component. The
145 * {@linkplain Throwable#getCause() cause} will be the error in
146 * user code.
147 * @throws IllegalArgumentException if any of the options are invalid,
148 * or if any of the given compilation units are of other kind than
149 * {@linkplain JavaFileObject.Kind#SOURCE source}
150 */
151 public <Z> Z getTask(Writer out,
152 JavaFileManager fileManager,
153 DiagnosticListener<? super JavaFileObject> diagnosticListener,
154 Iterable<String> options,
155 Iterable<String> classes,
156 Iterable<? extends JavaFileObject> compilationUnits,
157 Worker<Z> worker) {
158 List<String> opts =
159 StreamSupport.stream(options.spliterator(), false)
160 .collect(Collectors.toCollection(ArrayList::new));
161
162 ReusableContext ctx;
163
164 synchronized (this) {
165 Queue<ReusableContext> cached =
166 options2Contexts.getOrDefault(opts, EMPTY_QUEUE);
167
168 if (cached.isEmpty()) {
169 ctx = new ReusableContext(opts);
170 statNew++;
171 } else {
172 ctx = cached.remove();
173 statReused++;
174 }
175 }
176
177 ctx.useCount++;
178
179 JavacTaskImpl task =
180 (JavacTaskImpl) systemProvider.getTask(out, fileManager, diagnosticListener,
181 opts, classes, compilationUnits, ctx);
182
183 task.addTaskListener(ctx);
184
185 Z result = worker.withTask(task);
186
187 //not returning the context to the pool if task crashes with an exception
188 //the task/context may be in a broken state
189 ctx.clear();
190 if (ctx.polluted) {
191 statPolluted++;
192 } else {
193 task.cleanup();
194 synchronized (this) {
195 while (cacheSize() + 1 > maxPoolSize) {
196 ReusableContext toRemove =
197 options2Contexts.values()
198 .stream()
199 .flatMap(Collection::stream)
200 .sorted((c1, c2) -> c1.timeStamp < c2.timeStamp ? -1 : 1)
201 .findFirst()
202 .get();
203 options2Contexts.get(toRemove.arguments).remove(toRemove);
204 statRemoved++;
205 }
206 options2Contexts.computeIfAbsent(ctx.arguments, x -> new ArrayDeque<>()).add(ctx);
207 ctx.timeStamp = id++;
208 }
209 }
210
211 return result;
212 }
213 //where:
214 private long cacheSize() {
215 return options2Contexts.values().stream().flatMap(Collection::stream).count();
216 }
217
218 public void printStatistics(PrintStream out) {
219 out.println(statReused + " reused Contexts");
220 out.println(statNew + " newly created Contexts");
221 out.println(statPolluted + " polluted Contexts");
222 out.println(statRemoved + " removed Contexts");
223 }
224
225 public interface Worker<Z> {
226 public Z withTask(JavacTask task);
227 }
228
229 static class ReusableContext extends Context implements TaskListener {
230
231 Set<CompilationUnitTree> roots = new HashSet<>();
232
233 List<String> arguments;
234 boolean polluted = false;
235
236 int useCount;
237 long timeStamp;
238
239 ReusableContext(List<String> arguments) {
240 super();
241 this.arguments = arguments;
242 put(Log.logKey, ReusableLog.factory);
243 put(JavaCompiler.compilerKey, ReusableJavaCompiler.factory);
244 }
245
246 void clear() {
247 drop(Arguments.argsKey);
248 drop(DiagnosticListener.class);
249 drop(Log.outKey);
250 drop(Log.errKey);
251 drop(JavaFileManager.class);
252 drop(JavacTask.class);
253 drop(JavacTrees.class);
254 drop(JavacElements.class);
255
256 if (ht.get(Log.logKey) instanceof ReusableLog) {
257 //log already inited - not first round
258 ((ReusableLog)Log.instance(this)).clear();
259 Enter.instance(this).newRound();
260 ((ReusableJavaCompiler)ReusableJavaCompiler.instance(this)).clear();
261 Types.instance(this).newRound();
262 Check.instance(this).newRound();
263 Check.instance(this).clear(); //clear mandatory warning handlers
264 Preview.instance(this).clear(); //clear mandatory warning handlers
265 Modules.instance(this).newRound();
266 Annotate.instance(this).newRound();
267 CompileStates.instance(this).clear();
268 MultiTaskListener.instance(this).clear();
269
270 //find if any of the roots have redefined java.* classes
271 Symtab syms = Symtab.instance(this);
272 pollutionScanner.scan(roots, syms);
273 roots.clear();
274 }
275 }
276
277 /**
278 * This scanner detects as to whether the shared context has been polluted. This happens
279 * whenever a compiled program redefines a core class (in 'java.*' package) or when
280 * (typically because of cyclic inheritance) the symbol kind of a core class has been touched.
281 */
282 TreeScanner<Void, Symtab> pollutionScanner = new TreeScanner<Void, Symtab>() {
283 @Override @DefinedBy(Api.COMPILER_TREE)
284 public Void scan(Tree tree, Symtab syms) {
285 if (tree instanceof LetExpr) {
286 LetExpr le = (LetExpr) tree;
287 scan(le.defs, syms);
288 scan(le.expr, syms);
289 return null;
290 } else {
291 return super.scan(tree, syms);
292 }
293 }
294
295 @Override @DefinedBy(Api.COMPILER_TREE)
296 public Void visitClass(ClassTree node, Symtab syms) {
297 Symbol sym = ((JCClassDecl)node).sym;
298 if (sym != null) {
299 syms.removeClass(sym.packge().modle, sym.flatName());
300 Type sup = supertype(sym);
301 if (isCoreClass(sym) ||
302 (sup != null && isCoreClass(sup.tsym) && sup.tsym.kind != Kinds.Kind.TYP)) {
303 polluted = true;
304 }
305 }
306 return super.visitClass(node, syms);
307 }
308
309 private boolean isCoreClass(Symbol s) {
310 return s.flatName().toString().startsWith("java.");
311 }
312
313 private Type supertype(Symbol s) {
314 if (s.type == null ||
315 !s.type.hasTag(TypeTag.CLASS)) {
316 return null;
317 } else {
318 ClassType ct = (ClassType)s.type;
319 return ct.supertype_field;
320 }
321 }
322 };
323
324 @Override @DefinedBy(Api.COMPILER_TREE)
325 public void finished(TaskEvent e) {
326 if (e.getKind() == Kind.PARSE) {
327 roots.add(e.getCompilationUnit());
328 }
329 }
330
331 @Override @DefinedBy(Api.COMPILER_TREE)
332 public void started(TaskEvent e) {
333 //do nothing
334 }
335
336 <T> void drop(Key<T> k) {
337 ht.remove(k);
338 }
339
340 <T> void drop(Class<T> c) {
341 ht.remove(key(c));
342 }
343
344 /**
345 * Reusable JavaCompiler; exposes a method to clean up the component from leftovers associated with
346 * previous compilations.
347 */
348 static class ReusableJavaCompiler extends JavaCompiler {
349
350 final static Factory<JavaCompiler> factory = ReusableJavaCompiler::new;
351
352 ReusableJavaCompiler(Context context) {
353 super(context);
354 }
355
356 @Override
357 public void close() {
358 //do nothing
359 }
360
361 void clear() {
362 newRound();
363 }
364
365 @Override
366 protected void checkReusable() {
367 //do nothing - it's ok to reuse the compiler
368 }
369 }
370
371 /**
372 * Reusable Log; exposes a method to clean up the component from leftovers associated with
373 * previous compilations.
374 */
375 static class ReusableLog extends Log {
376
377 final static Factory<Log> factory = ReusableLog::new;
378
379 Context context;
380
381 ReusableLog(Context context) {
382 super(context);
383 this.context = context;
384 }
385
386 void clear() {
387 recorded.clear();
388 sourceMap.clear();
389 nerrors = 0;
390 nwarnings = 0;
391 //Set a fake listener that will lazily lookup the context for the 'real' listener. Since
392 //this field is never updated when a new task is created, we cannot simply reset the field
393 //or keep old value. This is a hack to workaround the limitations in the current infrastructure.
394 diagListener = new DiagnosticListener<JavaFileObject>() {
395 DiagnosticListener<JavaFileObject> cachedListener;
396
397 @Override @DefinedBy(Api.COMPILER)
398 @SuppressWarnings("unchecked")
399 public void report(Diagnostic<? extends JavaFileObject> diagnostic) {
400 if (cachedListener == null) {
401 cachedListener = context.get(DiagnosticListener.class);
402 }
403 cachedListener.report(diagnostic);
404 }
405 };
406 }
407 }
408 }
409 }