1 /*
2  * Copyright (C) 2009 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.mkstubs;
18 
19 import com.android.mkstubs.Main.Logger;
20 
21 import org.objectweb.asm.ClassReader;
22 
23 import java.io.IOException;
24 import java.util.Enumeration;
25 import java.util.Iterator;
26 import java.util.Map;
27 import java.util.Set;
28 import java.util.TreeMap;
29 import java.util.zip.ZipEntry;
30 import java.util.zip.ZipFile;
31 
32 /**
33  * Analyzes an input Jar to get all the relevant classes according to the given filter.
34  * <p/>
35  * This is mostly a helper extracted for convenience. Callers will want to use
36  * {@link #parseInputJar(String)} followed by {@link #filter(Map, Filter, Logger)}.
37  */
38 class AsmAnalyzer {
39 
40     /**
41      * Parses a JAR file and returns a list of all classes founds using a map
42      * class name => ASM ClassReader. Class names are in the form "android.view.View".
43      */
parseInputJar(String inputJarPath)44     Map<String,ClassReader> parseInputJar(String inputJarPath) throws IOException {
45         TreeMap<String, ClassReader> classes = new TreeMap<>();
46 
47         ZipFile zip = new ZipFile(inputJarPath);
48         Enumeration<? extends ZipEntry> entries = zip.entries();
49         ZipEntry entry;
50         while (entries.hasMoreElements()) {
51             entry = entries.nextElement();
52             if (entry.getName().endsWith(".class")) {
53                 ClassReader cr = new ClassReader(zip.getInputStream(entry));
54                 String className = classReaderToAsmName(cr);
55                 classes.put(className, cr);
56             }
57         }
58 
59         return classes;
60     }
61 
62     /**
63      * Utility that returns the fully qualified ASM class name for a ClassReader.
64      * E.g. it returns something like android/view/View.
65      */
classReaderToAsmName(ClassReader classReader)66     static String classReaderToAsmName(ClassReader classReader) {
67         if (classReader == null) {
68             return null;
69         } else {
70             return classReader.getClassName();
71         }
72     }
73 
74     /**
75      * Filters the set of classes. Removes all classes that should not be included in the
76      * filter or that should be excluded. This modifies the map in-place.
77      *
78      * @param classes The in-out map of classes to examine and filter. The map is filtered
79      *                in-place.
80      * @param filter  A filter describing which classes to include and which ones to exclude.
81      * @param log
82      */
filter(Map<String, ClassReader> classes, Filter filter, Logger log)83     void filter(Map<String, ClassReader> classes, Filter filter, Logger log) {
84 
85         Set<String> keys = classes.keySet();
86         for(Iterator<String> it = keys.iterator(); it.hasNext(); ) {
87             String key = it.next();
88 
89             // TODO: We *could* filter out all private classes here: classes.get(key).getAccess().
90 
91             // remove if we don't keep it
92             if (!filter.accept(key)) {
93                 log.debug("- Remove class " + key);
94                 it.remove();
95             }
96         }
97     }
98 
99 }
100