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1 /*
2  * Copyright (C) 2018 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 package android.signature.cts;
17 
18 import java.io.BufferedReader;
19 import java.io.InputStream;
20 import java.io.InputStreamReader;
21 import java.nio.ByteBuffer;
22 import java.util.Arrays;
23 import java.util.function.BiFunction;
24 import java.util.function.Function;
25 import java.util.regex.Matcher;
26 import java.util.regex.Pattern;
27 import java.util.stream.Stream;
28 import java.util.stream.StreamSupport;
29 import java.text.ParseException;
30 
31 /**
32  * Parses an API definition given as a text file with DEX signatures of class
33  * members. Constructs a {@link DexApiDocumentParser.DexMember} for every class
34  * member.
35  *
36  * <p>The definition file is converted into a {@link Stream} of
37  * {@link DexApiDocumentParser.DexMember}.
38  */
39 public class DexApiDocumentParser {
40 
41     // Regex patterns which match DEX signatures of methods and fields.
42     // See comment by next() for more details.
43     private static final Pattern REGEX_FIELD = Pattern.compile("^(L[^>]*;)->(.*):(.*)$");
44     private static final Pattern REGEX_METHOD =
45             Pattern.compile("^(L[^>]*;)->(.*)(\\(.*\\).*)$");
46 
47     // Estimate of the length of a line.
48     private static final int LINE_LENGTH_ESTIMATE = 100;
49 
50     // Converter from String to DexMember. Cached here.
51     private static final Function<String, DexMember> DEX_MEMBER_CONVERTER = str -> {
52         try {
53             return parseLine(str, /* lineNum= */ -1); // No line info available.
54         } catch (ParseException e) {
55             throw new RuntimeException(e);
56         }
57     };
58     private static final BiFunction<String, Integer, DexMember> DEX_MEMBER_LINE_NUM_CONVERTER = (
59             str, lineNum) -> {
60         try {
61             return parseLine(str, lineNum);
62         } catch (ParseException e) {
63             throw new RuntimeException(e);
64         }
65     };
66 
parseAsStream(Object o)67     public Stream<DexMember> parseAsStream(Object o) {
68         if (o instanceof ByteBuffer) {
69             return parseAsStream((ByteBuffer) o);
70         } else {
71             return parseAsStream((InputStream) o);
72         }
73     }
74 
parseAsStream(InputStream inputStream)75     public Stream<DexMember> parseAsStream(InputStream inputStream) {
76         BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
77         return StreamSupport.stream(
78                 new BufferedReaderLineSpliterator<DexMember>(reader, DEX_MEMBER_LINE_NUM_CONVERTER),
79                 false);
80     }
81 
parseAsStream(ByteBuffer buffer)82     public Stream<DexMember> parseAsStream(ByteBuffer buffer) {
83         return parseAsStream(buffer, LINE_LENGTH_ESTIMATE);
84     }
parseAsStream(ByteBuffer buffer, int lineLengthEstimate)85     public Stream<DexMember> parseAsStream(ByteBuffer buffer, int lineLengthEstimate) {
86         // TODO: Ensurance that the input conforms to ByteBufferLineSpliterator requirements.
87         return StreamSupport.stream(new ByteBufferLineSpliterator<DexMember>(buffer,
88                 lineLengthEstimate, DEX_MEMBER_CONVERTER), true);
89     }
90 
parseLine(String line, int lineNum)91     private static DexMember parseLine(String line, int lineNum) throws ParseException {
92         // Split the CSV line.
93         String[] splitLine = line.split(",");
94         String signature = splitLine[0];
95         String[] flags = Arrays.copyOfRange(splitLine, 1, splitLine.length);
96 
97         // Match line against regex patterns.
98         Matcher matchField = REGEX_FIELD.matcher(signature);
99         Matcher matchMethod = REGEX_METHOD.matcher(signature);
100 
101         // Check that *exactly* one pattern matches.
102         int matchCount = (matchField.matches() ? 1 : 0) + (matchMethod.matches() ? 1 : 0);
103         if (matchCount == 0) {
104             throw new ParseException("Could not parse: \"" + line + "\"", lineNum);
105         } else if (matchCount > 1) {
106             throw new ParseException("Ambiguous parse: \"" + line + "\"", lineNum);
107         }
108 
109         // Extract information from the signature.
110         if (matchField.matches()) {
111             return new DexField(
112                     matchField.group(1), matchField.group(2), matchField.group(3), flags);
113         } else if (matchMethod.matches()) {
114             return new DexMethod(
115                     matchMethod.group(1),matchMethod.group(2), matchMethod.group(3), flags);
116         }
117         throw new IllegalStateException();
118     }
119 }
120