GenStubs.java revision 1304:9d47f4850714 
1/*
2 * Copyright (c) 2009, 2012, 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
26package genstubs;
27
28import java.io.*;
29import java.util.*;
30import javax.tools.JavaFileObject;
31import javax.tools.StandardJavaFileManager;
32import javax.tools.StandardLocation;
33
34import com.sun.source.tree.CompilationUnitTree;
35import com.sun.source.util.JavacTask;
36import com.sun.tools.javac.api.JavacTool;
37import com.sun.tools.javac.code.Flags;
38import com.sun.tools.javac.code.TypeTags;
39import com.sun.tools.javac.tree.JCTree;
40import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
41import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
42import com.sun.tools.javac.tree.JCTree.JCIdent;
43import com.sun.tools.javac.tree.JCTree.JCImport;
44import com.sun.tools.javac.tree.JCTree.JCLiteral;
45import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
46import com.sun.tools.javac.tree.JCTree.JCModifiers;
47import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
48import com.sun.tools.javac.tree.Pretty;
49import com.sun.tools.javac.tree.TreeMaker;
50import com.sun.tools.javac.tree.TreeScanner;
51import com.sun.tools.javac.tree.TreeTranslator;
52import com.sun.tools.javac.util.Context;
53import com.sun.tools.javac.util.ListBuffer;
54import com.sun.tools.javac.util.Name;
55import javax.tools.JavaFileManager;
56
57/**
58 * Generate stub source files by removing implementation details from input files.
59 *
60 * This is a special purpose stub generator, specific to the needs of generating
61 * stub files for JDK 7 API that are needed to compile langtools files that depend
62 * on that API. The stub generator works by removing as much of the API source code
63 * as possible without affecting the public signature, in order to reduce the
64 * transitive closure of the API being referenced. The resulting stubs can be
65 * put on the langtools sourcepath with -implicit:none to compile the langtools
66 * files that depend on the JDK 7 API.
67 *
68 * Usage:
69 *  genstubs -s <outdir> -sourcepath <path> <classnames>
70 *
71 * The specified class names are looked up on the sourcepath, and corresponding
72 * stubs are written to the source output directory.
73 *
74 * Classes are parsed into javac ASTs, then processed with a javac TreeTranslator
75 * to remove implementation details, and written out in the source output directory.
76 * Documentation comments and annotations are removed. Method bodies are removed
77 * and methods are marked native. Private and package-private field definitions
78 * have their initializers replace with 0, 0.0, false, null as appropriate.
79 */
80
81public class GenStubs {
82    static class Fault extends Exception {
83        private static final long serialVersionUID = 0;
84        Fault(String message) {
85            super(message);
86        }
87        Fault(String message, Throwable cause) {
88            super(message);
89            initCause(cause);
90        }
91    }
92
93    public static void main(String[] args) {
94        boolean ok = new GenStubs().run(args);
95        if (!ok)
96            System.exit(1);
97    }
98
99    public boolean run(String... args) {
100        File outdir = null;
101        String sourcepath = null;
102        List<String> classes = new ArrayList<String>();
103        for (ListIterator<String> iter = Arrays.asList(args).listIterator(); iter.hasNext(); ) {
104            String arg = iter.next();
105            if (arg.equals("-s") && iter.hasNext())
106                outdir = new File(iter.next());
107            else if (arg.equals("-sourcepath") && iter.hasNext())
108                sourcepath = iter.next();
109            else if (arg.startsWith("-"))
110                throw new IllegalArgumentException(arg);
111            else {
112                classes.add(arg);
113                while (iter.hasNext())
114                    classes.add(iter.next());
115            }
116        }
117
118        return run(sourcepath, outdir, classes);
119    }
120
121    public boolean run(String sourcepath, File outdir, List<String> classes) {
122        //System.err.println("run: sourcepath:" + sourcepath + " outdir:" + outdir + " classes:" + classes);
123        if (sourcepath == null)
124            throw new IllegalArgumentException("sourcepath not set");
125        if (outdir == null)
126            throw new IllegalArgumentException("source output dir not set");
127
128        JavacTool tool = JavacTool.create();
129        StandardJavaFileManager fm = tool.getStandardFileManager(null, null, null);
130
131        try {
132            fm.setLocation(StandardLocation.SOURCE_OUTPUT, Collections.singleton(outdir));
133            fm.setLocation(StandardLocation.SOURCE_PATH, splitPath(sourcepath));
134            List<JavaFileObject> files = new ArrayList<JavaFileObject>();
135            for (String c: classes) {
136                JavaFileObject fo = fm.getJavaFileForInput(
137                        StandardLocation.SOURCE_PATH, c, JavaFileObject.Kind.SOURCE);
138                if (fo == null)
139                    error("class not found: " + c);
140                else
141                    files.add(fo);
142            }
143
144            JavacTask t = tool.getTask(null, fm, null, null, null, files);
145            Iterable<? extends CompilationUnitTree> trees = t.parse();
146            for (CompilationUnitTree tree: trees) {
147                makeStub(fm, tree);
148            }
149        } catch (IOException e) {
150            error("IO error " + e, e);
151        }
152
153        return (errors == 0);
154    }
155
156    void makeStub(StandardJavaFileManager fm, CompilationUnitTree tree) throws IOException {
157        CompilationUnitTree tree2 = new StubMaker().translate(tree);
158        CompilationUnitTree tree3 = new ImportCleaner(fm).removeRedundantImports(tree2);
159
160        String className = fm.inferBinaryName(StandardLocation.SOURCE_PATH, tree.getSourceFile());
161        JavaFileObject fo = fm.getJavaFileForOutput(StandardLocation.SOURCE_OUTPUT,
162                className, JavaFileObject.Kind.SOURCE, null);
163        // System.err.println("Writing " + className + " to " + fo.getName());
164        Writer out = fo.openWriter();
165        try {
166            new Pretty(out, true).printExpr((JCTree) tree3);
167        } finally {
168            out.close();
169        }
170    }
171
172    List<File> splitPath(String path) {
173        List<File> list = new ArrayList<File>();
174        for (String p: path.split(File.pathSeparator)) {
175            if (p.length() > 0)
176                list.add(new File(p));
177        }
178        return list;
179    }
180
181    void error(String message) {
182        System.err.println(message);
183        errors++;
184    }
185
186    void error(String message, Throwable cause) {
187        error(message);
188    }
189
190    int errors;
191
192    class StubMaker extends TreeTranslator {
193        CompilationUnitTree translate(CompilationUnitTree tree) {
194            return super.translate((JCCompilationUnit) tree);
195        }
196
197        /**
198         * compilation units: remove javadoc comments
199         * -- required, in order to remove @deprecated tags, since we
200         * (separately) remove all annotations, including @Deprecated
201         */
202        public void visitTopLevel(JCCompilationUnit tree) {
203            super.visitTopLevel(tree);
204            tree.docComments = null;
205        }
206
207        /**
208         * methods: remove method bodies, make methods native
209         */
210        @Override
211        public void visitMethodDef(JCMethodDecl tree) {
212            tree.mods = translate(tree.mods);
213            tree.restype = translate(tree.restype);
214            tree.typarams = translateTypeParams(tree.typarams);
215            tree.params = translateVarDefs(tree.params);
216            tree.thrown = translate(tree.thrown);
217            if (tree.restype != null && tree.body != null) {
218                tree.mods.flags |= Flags.NATIVE;
219                tree.body = null;
220            }
221            result = tree;
222        }
223
224        /**
225         * modifiers: remove annotations
226         */
227        @Override
228        public void visitModifiers(JCModifiers tree) {
229            tree.annotations = com.sun.tools.javac.util.List.nil();
230            result = tree;
231        }
232
233        /**
234         * field definitions: replace initializers with 0, 0.0, false etc
235         * when possible -- i.e. leave public, protected initializers alone
236         */
237        @Override
238        public void visitVarDef(JCVariableDecl tree) {
239            tree.mods = translate(tree.mods);
240            tree.vartype = translate(tree.vartype);
241            if (tree.init != null) {
242                if ((tree.mods.flags & (Flags.PUBLIC | Flags.PROTECTED)) != 0)
243                    tree.init = translate(tree.init);
244                else {
245                    String t = tree.vartype.toString();
246                    if (t.equals("boolean"))
247                        tree.init = new JCLiteral(TypeTags.BOOLEAN, 0) { };
248                    else if (t.equals("byte"))
249                        tree.init = new JCLiteral(TypeTags.BYTE, 0) { };
250                    else if (t.equals("char"))
251                        tree.init = new JCLiteral(TypeTags.CHAR, 0) { };
252                    else if (t.equals("double"))
253                        tree.init = new JCLiteral(TypeTags.DOUBLE, 0.d) { };
254                    else if (t.equals("float"))
255                        tree.init = new JCLiteral(TypeTags.FLOAT, 0.f) { };
256                    else if (t.equals("int"))
257                        tree.init = new JCLiteral(TypeTags.INT, 0) { };
258                    else if (t.equals("long"))
259                        tree.init = new JCLiteral(TypeTags.LONG, 0) { };
260                    else if (t.equals("short"))
261                        tree.init = new JCLiteral(TypeTags.SHORT, 0) { };
262                    else
263                        tree.init = new JCLiteral(TypeTags.BOT, null) { };
264                }
265            }
266            result = tree;
267        }
268    }
269
270    class ImportCleaner extends TreeScanner {
271        private Set<Name> names = new HashSet<Name>();
272        private TreeMaker m;
273
274        ImportCleaner(JavaFileManager fm) {
275            // ImportCleaner itself doesn't require a filemanager, but instantiating
276            // a TreeMaker does, indirectly (via ClassReader, sigh)
277            Context c = new Context();
278            c.put(JavaFileManager.class, fm);
279            m = TreeMaker.instance(c);
280        }
281
282        CompilationUnitTree removeRedundantImports(CompilationUnitTree t) {
283            JCCompilationUnit tree = (JCCompilationUnit) t;
284            tree.accept(this);
285            ListBuffer<JCTree> defs = new ListBuffer<JCTree>();
286            for (JCTree def: tree.defs) {
287                if (def.getTag() == JCTree.Tag.IMPORT) {
288                    JCImport imp = (JCImport) def;
289                    if (imp.qualid.getTag() == JCTree.Tag.SELECT) {
290                        JCFieldAccess qualid = (JCFieldAccess) imp.qualid;
291                        if (!qualid.name.toString().equals("*")
292                                && !names.contains(qualid.name)) {
293                            continue;
294                        }
295                    }
296                }
297                defs.add(def);
298            }
299            return m.TopLevel(tree.packageAnnotations, tree.pid, defs.toList());
300        }
301
302        @Override
303        public void visitImport(JCImport tree) { } // ignore names found in imports
304
305        @Override
306        public void visitIdent(JCIdent tree) {
307            names.add(tree.name);
308        }
309
310        @Override
311        public void visitSelect(JCFieldAccess tree) {
312            super.visitSelect(tree);
313            names.add(tree.name);
314        }
315    }
316}
317