ShortestUsagePrinter


1   /*
2    * ProGuard -- shrinking, optimization, obfuscation, and preverification
3    *             of Java bytecode.
4    *
5    * Copyright (c) 2002-2007 Eric Lafortune (eric@graphics.cornell.edu)
6    *
7    * This program is free software; you can redistribute it and/or modify it
8    * under the terms of the GNU General Public License as published by the Free
9    * Software Foundation; either version 2 of the License, or (at your option)
10   * any later version.
11   *
12   * This program is distributed in the hope that it will be useful, but WITHOUT
13   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14   * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15   * more details.
16   *
17   * You should have received a copy of the GNU General Public License along
18   * with this program; if not, write to the Free Software Foundation, Inc.,
19   * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20   */
21  package proguard.shrink;
22  
23  import proguard.classfile.*;
24  import proguard.classfile.util.*;
25  import proguard.classfile.visitor.*;
26  
27  import java.io.*;
28  
29  
30  /**
31   * This ClassVisitor     and MemberVisitor prints out the reasons why
32   * classes and class members have been marked as being used.
33   *
34   * @see UsageMarker
35   *
36   * @author Eric Lafortune
37   */
38  public class ShortestUsagePrinter
39  implements   ClassVisitor,
40               MemberVisitor
41  {
42      private ShortestUsageMarker shortestUsageMarker;
43      private boolean             verbose;
44      private PrintStream         ps;
45  
46  
47      /**
48       * Creates a new UsagePrinter that prints verbosely to <code>System.out</code>.
49       * @param shortestUsageMarker the usage marker that was used to mark the
50       *                            classes and class members.
51       */
52      public ShortestUsagePrinter(ShortestUsageMarker shortestUsageMarker)
53      {
54          this(shortestUsageMarker, true);
55      }
56  
57  
58      /**
59       * Creates a new UsagePrinter that prints to the given stream.
60       * @param shortestUsageMarker the usage marker that was used to mark the
61       *                            classes and class members.
62       * @param verbose             specifies whether the output should be verbose.
63       */
64      public ShortestUsagePrinter(ShortestUsageMarker shortestUsageMarker,
65                                  boolean             verbose)
66      {
67          this(shortestUsageMarker, verbose, System.out);
68      }
69  
70      /**
71       * Creates a new UsagePrinter that prints to the given stream.
72       * @param shortestUsageMarker the usage marker that was used to mark the
73       *                            classes and class members.
74       * @param verbose             specifies whether the output should be verbose.
75       * @param printStream         the stream to which to print.
76       */
77      public ShortestUsagePrinter(ShortestUsageMarker shortestUsageMarker,
78                                  boolean             verbose,
79                                  PrintStream         printStream)
80      {
81          this.shortestUsageMarker = shortestUsageMarker;
82          this.verbose             = verbose;
83          this.ps                  = printStream;
84      }
85  
86  
87      // Implementations for ClassVisitor.
88  
89      public void visitProgramClass(ProgramClass programClass)
90      {
91          // Print the name of this class.
92          ps.println(ClassUtil.externalClassName(programClass.getName()));
93  
94          // Print the reason for keeping this class.
95          printReason(programClass);
96      }
97  
98  
99      public void visitLibraryClass(LibraryClass libraryClass)
100     {
101         // Print the name of this class.
102         ps.println(ClassUtil.externalClassName(libraryClass.getName()));
103 
104         // Print the reason for keeping this class.
105         ps.println("  is a library class.\n");
106     }
107 
108 
109     // Implementations for MemberVisitor.
110 
111     public void visitProgramField(ProgramClass programClass, ProgramField programField)
112     {
113         // Print the name of this field.
114         String   name = programField.getName(programClass);
115         String   type = programField.getDescriptor(programClass);
116 
117         ps.println(ClassUtil.externalClassName(programClass.getName()) +
118                    (verbose ?
119                         ": " + ClassUtil.externalFullFieldDescription(0, name, type):
120                         "."  + name) +
121                    lineNumberRange(programClass, programField));
122 
123         // Print the reason for keeping this method.
124         printReason(programField);
125     }
126 
127 
128     public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod)
129     {
130         // Print the name of this method.
131         String   name = programMethod.getName(programClass);
132         String   type = programMethod.getDescriptor(programClass);
133 
134         ps.println(ClassUtil.externalClassName(programClass.getName()) +
135                    (verbose ?
136                         ": " + ClassUtil.externalFullMethodDescription(programClass.getName(), 0, name, type):
137                         "."  + name) +
138                    lineNumberRange(programClass, programMethod));
139 
140         // Print the reason for keeping this method.
141         printReason(programMethod);
142     }
143 
144 
145     public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField)
146     {
147         // Print the name of this field.
148         String   name = libraryField.getName(libraryClass);
149         String   type = libraryField.getDescriptor(libraryClass);
150 
151         ps.println(ClassUtil.externalClassName(libraryClass.getName()) +
152                    (verbose ?
153                         ": " + ClassUtil.externalFullFieldDescription(0, name, type):
154                         "."  + name));
155 
156         // Print the reason for keeping this field.
157         ps.println("  is a library field.\n");
158     }
159 
160 
161     public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod)
162     {
163         // Print the name of this method.
164         String   name = libraryMethod.getName(libraryClass);
165         String   type = libraryMethod.getDescriptor(libraryClass);
166 
167         ps.println(ClassUtil.externalClassName(libraryClass.getName()) +
168                    (verbose ?
169                         ": " + ClassUtil.externalFullMethodDescription(libraryClass.getName(), 0, name, type):
170                         "."  + name));
171 
172         // Print the reason for keeping this method.
173         ps.println("  is a library method.\n");
174     }
175 
176 
177     // Small utility methods.
178 
179     private void printReason(VisitorAccepter visitorAccepter)
180     {
181         if (shortestUsageMarker.isUsed(visitorAccepter))
182         {
183             ShortestUsageMark shortestUsageMark = shortestUsageMarker.getShortestUsageMark(visitorAccepter);
184 
185             // Print the reason for keeping this class.
186             ps.print("  " + shortestUsageMark.getReason());
187 
188             // Print the class or method that is responsible, with its reasons.
189             shortestUsageMark.acceptClassVisitor(this);
190             shortestUsageMark.acceptMethodVisitor(this);
191         }
192         else
193         {
194             ps.println("  is not being kept.\n");
195         }
196     }
197 
198 
199     /**
200      * Returns the line number range of the given class member, followed by a
201      * colon, or just an empty String if no range is available.
202      */
203     private static String   lineNumberRange(ProgramClass programClass, ProgramMember programMember)
204     {
205         String   range = programMember.getLineNumberRange(programClass);
206         return range != null ?
207             (" (" + range + ")") :
208             "";
209     }
210 }
211
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