1 /*
2 * Copyright (C) 2010 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 #define LOG_TAG "Tokenizer"
18
19 #include <utils/Tokenizer.h>
20 #include <fcntl.h>
21 #include <sys/stat.h>
22 #include <utils/Log.h>
23
24 // Enables debug output for the tokenizer.
25 #define DEBUG_TOKENIZER 0
26
27
28 namespace android {
29
isDelimiter(char ch,const char * delimiters)30 static inline bool isDelimiter(char ch, const char* delimiters) {
31 return strchr(delimiters, ch) != nullptr;
32 }
33
Tokenizer(const String8 & filename,FileMap * fileMap,char * buffer,bool ownBuffer,size_t length)34 Tokenizer::Tokenizer(const String8& filename, FileMap* fileMap, char* buffer,
35 bool ownBuffer, size_t length) :
36 mFilename(filename), mFileMap(fileMap),
37 mBuffer(buffer), mOwnBuffer(ownBuffer), mLength(length),
38 mCurrent(buffer), mLineNumber(1) {
39 }
40
~Tokenizer()41 Tokenizer::~Tokenizer() {
42 delete mFileMap;
43 if (mOwnBuffer) {
44 delete[] mBuffer;
45 }
46 }
47
open(const String8 & filename,Tokenizer ** outTokenizer)48 status_t Tokenizer::open(const String8& filename, Tokenizer** outTokenizer) {
49 *outTokenizer = nullptr;
50
51 int result = OK;
52 int fd = ::open(filename.string(), O_RDONLY);
53 if (fd < 0) {
54 result = -errno;
55 ALOGE("Error opening file '%s': %s", filename.string(), strerror(errno));
56 } else {
57 struct stat stat;
58 if (fstat(fd, &stat)) {
59 result = -errno;
60 ALOGE("Error getting size of file '%s': %s", filename.string(), strerror(errno));
61 } else {
62 size_t length = size_t(stat.st_size);
63
64 FileMap* fileMap = new FileMap();
65 bool ownBuffer = false;
66 char* buffer;
67 if (fileMap->create(nullptr, fd, 0, length, true)) {
68 fileMap->advise(FileMap::SEQUENTIAL);
69 buffer = static_cast<char*>(fileMap->getDataPtr());
70 } else {
71 delete fileMap;
72 fileMap = nullptr;
73
74 // Fall back to reading into a buffer since we can't mmap files in sysfs.
75 // The length we obtained from stat is wrong too (it will always be 4096)
76 // so we must trust that read will read the entire file.
77 buffer = new char[length];
78 ownBuffer = true;
79 ssize_t nrd = read(fd, buffer, length);
80 if (nrd < 0) {
81 result = -errno;
82 ALOGE("Error reading file '%s': %s", filename.string(), strerror(errno));
83 delete[] buffer;
84 buffer = nullptr;
85 } else {
86 length = size_t(nrd);
87 }
88 }
89
90 if (!result) {
91 *outTokenizer = new Tokenizer(filename, fileMap, buffer, ownBuffer, length);
92 }
93 }
94 close(fd);
95 }
96 return result;
97 }
98
fromContents(const String8 & filename,const char * contents,Tokenizer ** outTokenizer)99 status_t Tokenizer::fromContents(const String8& filename,
100 const char* contents, Tokenizer** outTokenizer) {
101 *outTokenizer = new Tokenizer(filename, nullptr,
102 const_cast<char*>(contents), false, strlen(contents));
103 return OK;
104 }
105
getLocation() const106 String8 Tokenizer::getLocation() const {
107 String8 result;
108 result.appendFormat("%s:%d", mFilename.string(), mLineNumber);
109 return result;
110 }
111
peekRemainderOfLine() const112 String8 Tokenizer::peekRemainderOfLine() const {
113 const char* end = getEnd();
114 const char* eol = mCurrent;
115 while (eol != end) {
116 char ch = *eol;
117 if (ch == '\n') {
118 break;
119 }
120 eol += 1;
121 }
122 return String8(mCurrent, eol - mCurrent);
123 }
124
nextToken(const char * delimiters)125 String8 Tokenizer::nextToken(const char* delimiters) {
126 #if DEBUG_TOKENIZER
127 ALOGD("nextToken");
128 #endif
129 const char* end = getEnd();
130 const char* tokenStart = mCurrent;
131 while (mCurrent != end) {
132 char ch = *mCurrent;
133 if (ch == '\n' || isDelimiter(ch, delimiters)) {
134 break;
135 }
136 mCurrent += 1;
137 }
138 return String8(tokenStart, mCurrent - tokenStart);
139 }
140
nextLine()141 void Tokenizer::nextLine() {
142 #if DEBUG_TOKENIZER
143 ALOGD("nextLine");
144 #endif
145 const char* end = getEnd();
146 while (mCurrent != end) {
147 char ch = *(mCurrent++);
148 if (ch == '\n') {
149 mLineNumber += 1;
150 break;
151 }
152 }
153 }
154
skipDelimiters(const char * delimiters)155 void Tokenizer::skipDelimiters(const char* delimiters) {
156 #if DEBUG_TOKENIZER
157 ALOGD("skipDelimiters");
158 #endif
159 const char* end = getEnd();
160 while (mCurrent != end) {
161 char ch = *mCurrent;
162 if (ch == '\n' || !isDelimiter(ch, delimiters)) {
163 break;
164 }
165 mCurrent += 1;
166 }
167 }
168
169 } // namespace android
170