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1   /*
2    * Copyright (c) 2009, 2013, 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 genstubs;
27  
28  import java.io.*;
29  import java.util.*;
30  import javax.tools.JavaFileObject;
31  import javax.tools.StandardJavaFileManager;
32  import javax.tools.StandardLocation;
33  
34  import com.sun.source.tree.CompilationUnitTree;
35  import com.sun.source.util.JavacTask;
36  import com.sun.tools.javac.api.JavacTool;
37  import com.sun.tools.javac.code.Flags;
38  import com.sun.tools.javac.code.TypeTag;
39  import com.sun.tools.javac.tree.JCTree;
40  import com.sun.tools.javac.tree.JCTree.JCClassDecl;
41  import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
42  import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
43  import com.sun.tools.javac.tree.JCTree.JCIdent;
44  import com.sun.tools.javac.tree.JCTree.JCImport;
45  import com.sun.tools.javac.tree.JCTree.JCLiteral;
46  import com.sun.tools.javac.tree.JCTree.JCMethodDecl;
47  import com.sun.tools.javac.tree.JCTree.JCModifiers;
48  import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
49  import com.sun.tools.javac.tree.Pretty;
50  import com.sun.tools.javac.tree.TreeMaker;
51  import com.sun.tools.javac.tree.TreeScanner;
52  import com.sun.tools.javac.tree.TreeTranslator;
53  import com.sun.tools.javac.util.Context;
54  import com.sun.tools.javac.util.ListBuffer;
55  import com.sun.tools.javac.util.Name;
56  import javax.tools.JavaFileManager;
57  
58  /**
59   * Generate stub source files by removing implementation details from input files.
60   *
61   * This is a special purpose stub generator, specific to the needs of generating
62   * stub files for JDK 7 API that are needed to compile langtools files that depend
63   * on that API. The stub generator works by removing as much of the API source code
64   * as possible without affecting the public signature, in order to reduce the
65   * transitive closure of the API being referenced. The resulting stubs can be
66   * put on the langtools sourcepath with -implicit:none to compile the langtools
67   * files that depend on the JDK 7 API.
68   *
69   * Usage:
70   *  genstubs -s <outdir> -sourcepath <path> <classnames>
71   *
72   * The specified class names are looked up on the sourcepath, and corresponding
73   * stubs are written to the source output directory.
74   *
75   * Classes are parsed into javac ASTs, then processed with a javac TreeTranslator
76   * to remove implementation details, and written out in the source output directory.
77   * Documentation comments and annotations are removed. Method bodies are removed
78   * and methods are marked native. Private and package-private field definitions
79   * have their initializers replace with 0, 0.0, false, null as appropriate.
80   */
81  
82  public class GenStubs {
83      static class Fault extends Exception {
84          private static final long serialVersionUID = 0;
85          Fault(String message) {
86              super(message);
87          }
88          Fault(String message, Throwable cause) {
89              super(message);
90              initCause(cause);
91          }
92      }
93  
94      public static void main(String[] args) {
95          boolean ok = new GenStubs().run(args);
96          if (!ok)
97              System.exit(1);
98      }
99  
100     public boolean run(String... args) {
101         File outdir = null;
102         String sourcepath = null;
103         List<String> classes = new ArrayList<String>();
104         for (ListIterator<String> iter = Arrays.asList(args).listIterator(); iter.hasNext(); ) {
105             String arg = iter.next();
106             if (arg.equals("-s") && iter.hasNext())
107                 outdir = new File(iter.next());
108             else if (arg.equals("-sourcepath") && iter.hasNext())
109                 sourcepath = iter.next();
110             else if (arg.startsWith("-"))
111                 throw new IllegalArgumentException(arg);
112             else {
113                 classes.add(arg);
114                 while (iter.hasNext())
115                     classes.add(iter.next());
116             }
117         }
118 
119         return run(sourcepath, outdir, classes);
120     }
121 
122     public boolean run(String sourcepath, File outdir, List<String> classes) {
123         //System.err.println("run: sourcepath:" + sourcepath + " outdir:" + outdir + " classes:" + classes);
124         if (sourcepath == null)
125             throw new IllegalArgumentException("sourcepath not set");
126         if (outdir == null)
127             throw new IllegalArgumentException("source output dir not set");
128 
129         JavacTool tool = JavacTool.create();
130         StandardJavaFileManager fm = tool.getStandardFileManager(null, null, null);
131 
132         try {
133             fm.setLocation(StandardLocation.SOURCE_OUTPUT, Collections.singleton(outdir));
134             fm.setLocation(StandardLocation.SOURCE_PATH, splitPath(sourcepath));
135             List<JavaFileObject> files = new ArrayList<JavaFileObject>();
136             for (String c: classes) {
137                 JavaFileObject fo = fm.getJavaFileForInput(
138                         StandardLocation.SOURCE_PATH, c, JavaFileObject.Kind.SOURCE);
139                 if (fo == null)
140                     error("class not found: " + c);
141                 else
142                     files.add(fo);
143             }
144 
145             JavacTask t = tool.getTask(null, fm, null, null, null, files);
146             Iterable<? extends CompilationUnitTree> trees = t.parse();
147             for (CompilationUnitTree tree: trees) {
148                 makeStub(fm, tree);
149             }
150         } catch (IOException e) {
151             error("IO error " + e, e);
152         }
153 
154         return (errors == 0);
155     }
156 
157     void makeStub(StandardJavaFileManager fm, CompilationUnitTree tree) throws IOException {
158         CompilationUnitTree tree2 = new StubMaker().translate(tree);
159         CompilationUnitTree tree3 = new ImportCleaner(fm).removeRedundantImports(tree2);
160 
161         String className = fm.inferBinaryName(StandardLocation.SOURCE_PATH, tree.getSourceFile());
162         JavaFileObject fo = fm.getJavaFileForOutput(StandardLocation.SOURCE_OUTPUT,
163                 className, JavaFileObject.Kind.SOURCE, null);
164         // System.err.println("Writing " + className + " to " + fo.getName());
165         Writer out = fo.openWriter();
166         try {
167             new Pretty(out, true).printExpr((JCTree) tree3);
168         } finally {
169             out.close();
170         }
171     }
172 
173     List<File> splitPath(String path) {
174         List<File> list = new ArrayList<File>();
175         for (String p: path.split(File.pathSeparator)) {
176             if (p.length() > 0)
177                 list.add(new File(p));
178         }
179         return list;
180     }
181 
182     void error(String message) {
183         System.err.println(message);
184         errors++;
185     }
186 
187     void error(String message, Throwable cause) {
188         error(message);
189     }
190 
191     int errors;
192 
193     class StubMaker extends TreeTranslator {
194         CompilationUnitTree translate(CompilationUnitTree tree) {
195             return super.translate((JCCompilationUnit) tree);
196         }
197 
198         /**
199          * compilation units: remove javadoc comments
200          * -- required, in order to remove @deprecated tags, since we
201          * (separately) remove all annotations, including @Deprecated
202          */
203         public void visitTopLevel(JCCompilationUnit tree) {
204             super.visitTopLevel(tree);
205             tree.docComments = null;
206         }
207 
208         /**
209          * methods: remove method bodies, make methods native
210          */
211         @Override
212         public void visitClassDef(JCClassDecl tree) {
213             long prevClassMods = currClassMods;
214             currClassMods = tree.mods.flags;
215             try {
216                 super.visitClassDef(tree);;
217             } finally {
218                 currClassMods = prevClassMods;
219             }
220         }
221         private long currClassMods = 0;
222 
223         /**
224          * methods: remove method bodies, make methods native
225          */
226         @Override
227         public void visitMethodDef(JCMethodDecl tree) {
228             tree.mods = translate(tree.mods);
229             tree.restype = translate(tree.restype);
230             tree.typarams = translateTypeParams(tree.typarams);
231             tree.params = translateVarDefs(tree.params);
232             tree.thrown = translate(tree.thrown);
233             if (tree.body != null) {
234                 if ((currClassMods & Flags.INTERFACE) != 0) {
235                     tree.mods.flags &= ~(Flags.DEFAULT | Flags.STATIC);
236                 } else {
237                     tree.mods.flags |= Flags.NATIVE;
238                 }
239                 tree.body = null;
240             }
241             result = tree;
242         }
243 
244         /**
245          * modifiers: remove annotations
246          */
247         @Override
248         public void visitModifiers(JCModifiers tree) {
249             tree.annotations = com.sun.tools.javac.util.List.nil();
250             result = tree;
251         }
252 
253         /**
254          * field definitions: replace initializers with 0, 0.0, false etc
255          * when possible -- i.e. leave public, protected initializers alone
256          */
257         @Override
258         public void visitVarDef(JCVariableDecl tree) {
259             tree.mods = translate(tree.mods);
260             tree.vartype = translate(tree.vartype);
261             if (tree.init != null) {
262                 if ((tree.mods.flags & (Flags.PUBLIC | Flags.PROTECTED)) != 0)
263                     tree.init = translate(tree.init);
264                 else {
265                     String t = tree.vartype.toString();
266                     if (t.equals("boolean"))
267                         tree.init = new JCLiteral(TypeTag.BOOLEAN, 0) { };
268                     else if (t.equals("byte"))
269                         tree.init = new JCLiteral(TypeTag.BYTE, 0) { };
270                     else if (t.equals("char"))
271                         tree.init = new JCLiteral(TypeTag.CHAR, 0) { };
272                     else if (t.equals("double"))
273                         tree.init = new JCLiteral(TypeTag.DOUBLE, 0.d) { };
274                     else if (t.equals("float"))
275                         tree.init = new JCLiteral(TypeTag.FLOAT, 0.f) { };
276                     else if (t.equals("int"))
277                         tree.init = new JCLiteral(TypeTag.INT, 0) { };
278                     else if (t.equals("long"))
279                         tree.init = new JCLiteral(TypeTag.LONG, 0) { };
280                     else if (t.equals("short"))
281                         tree.init = new JCLiteral(TypeTag.SHORT, 0) { };
282                     else
283                         tree.init = new JCLiteral(TypeTag.BOT, null) { };
284                 }
285             }
286             result = tree;
287         }
288     }
289 
290     class ImportCleaner extends TreeScanner {
291         private Set<Name> names = new HashSet<Name>();
292         private TreeMaker m;
293 
294         ImportCleaner(JavaFileManager fm) {
295             // ImportCleaner itself doesn't require a filemanager, but instantiating
296             // a TreeMaker does, indirectly (via ClassReader, sigh)
297             Context c = new Context();
298             c.put(JavaFileManager.class, fm);
299             m = TreeMaker.instance(c);
300         }
301 
302         CompilationUnitTree removeRedundantImports(CompilationUnitTree t) {
303             JCCompilationUnit tree = (JCCompilationUnit) t;
304             tree.accept(this);
305             ListBuffer<JCTree> defs = new ListBuffer<JCTree>();
306             for (JCTree def: tree.defs) {
307                 if (def.getTag() == JCTree.Tag.IMPORT) {
308                     JCImport imp = (JCImport) def;
309                     if (imp.qualid.getTag() == JCTree.Tag.SELECT) {
310                         JCFieldAccess qualid = (JCFieldAccess) imp.qualid;
311                         if (!qualid.name.toString().equals("*")
312                                 && !names.contains(qualid.name)) {
313                             continue;
314                         }
315                     }
316                 }
317                 defs.add(def);
318             }
319             return m.TopLevel(tree.packageAnnotations, tree.pid, defs.toList());
320         }
321 
322         @Override
323         public void visitImport(JCImport tree) { } // ignore names found in imports
324 
325         @Override
326         public void visitIdent(JCIdent tree) {
327             names.add(tree.name);
328         }
329 
330         @Override
331         public void visitSelect(JCFieldAccess tree) {
332             super.visitSelect(tree);
333             names.add(tree.name);
334         }
335     }
336 }