1 | // Copyright (c) 2009, Google Inc. |
2 | // All rights reserved. |
3 | // |
4 | // Redistribution and use in source and binary forms, with or without |
5 | // modification, are permitted provided that the following conditions are |
6 | // met: |
7 | // |
8 | // * Redistributions of source code must retain the above copyright |
9 | // notice, this list of conditions and the following disclaimer. |
10 | // * Redistributions in binary form must reproduce the above |
11 | // copyright notice, this list of conditions and the following disclaimer |
12 | // in the documentation and/or other materials provided with the |
13 | // distribution. |
14 | // * Neither the name of Google Inc. nor the names of its |
15 | // contributors may be used to endorse or promote products derived from |
16 | // this software without specific prior written permission. |
17 | // |
18 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
19 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
20 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
21 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
22 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
23 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
24 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
25 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
26 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
27 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
28 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
29 | |
30 | #ifndef CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_ |
31 | #define CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_ |
32 | |
33 | #include <stdint.h> |
34 | #include <assert.h> |
35 | #include <string.h> |
36 | |
37 | #include "common/linux/linux_libc_support.h" |
38 | #include "third_party/lss/linux_syscall_support.h" |
39 | |
40 | namespace google_breakpad { |
41 | |
42 | // A class for reading a file, line by line, without using fopen/fgets or other |
43 | // functions which may allocate memory. |
44 | class LineReader { |
45 | public: |
46 | LineReader(int fd) |
47 | : fd_(fd), |
48 | hit_eof_(false), |
49 | buf_used_(0) { |
50 | } |
51 | |
52 | // The maximum length of a line. |
53 | static const size_t kMaxLineLen = 512; |
54 | |
55 | // Return the next line from the file. |
56 | // line: (output) a pointer to the start of the line. The line is NUL |
57 | // terminated. |
58 | // len: (output) the length of the line (not inc the NUL byte) |
59 | // |
60 | // Returns true iff successful (false on EOF). |
61 | // |
62 | // One must call |PopLine| after this function, otherwise you'll continue to |
63 | // get the same line over and over. |
64 | bool GetNextLine(const char** line, unsigned* len) { |
65 | for (;;) { |
66 | if (buf_used_ == 0 && hit_eof_) |
67 | return false; |
68 | |
69 | for (unsigned i = 0; i < buf_used_; ++i) { |
70 | if (buf_[i] == '\n' || buf_[i] == 0) { |
71 | buf_[i] = 0; |
72 | *len = i; |
73 | *line = buf_; |
74 | return true; |
75 | } |
76 | } |
77 | |
78 | if (buf_used_ == sizeof(buf_)) { |
79 | // we scanned the whole buffer and didn't find an end-of-line marker. |
80 | // This line is too long to process. |
81 | return false; |
82 | } |
83 | |
84 | // We didn't find any end-of-line terminators in the buffer. However, if |
85 | // this is the last line in the file it might not have one: |
86 | if (hit_eof_) { |
87 | assert(buf_used_); |
88 | // There's room for the NUL because of the buf_used_ == sizeof(buf_) |
89 | // check above. |
90 | buf_[buf_used_] = 0; |
91 | *len = buf_used_; |
92 | buf_used_ += 1; // since we appended the NUL. |
93 | *line = buf_; |
94 | return true; |
95 | } |
96 | |
97 | // Otherwise, we should pull in more data from the file |
98 | const ssize_t n = sys_read(fd_, buf_ + buf_used_, |
99 | sizeof(buf_) - buf_used_); |
100 | if (n < 0) { |
101 | return false; |
102 | } else if (n == 0) { |
103 | hit_eof_ = true; |
104 | } else { |
105 | buf_used_ += n; |
106 | } |
107 | |
108 | // At this point, we have either set the hit_eof_ flag, or we have more |
109 | // data to process... |
110 | } |
111 | } |
112 | |
113 | void PopLine(unsigned len) { |
114 | // len doesn't include the NUL byte at the end. |
115 | |
116 | assert(buf_used_ >= len + 1); |
117 | buf_used_ -= len + 1; |
118 | my_memmove(buf_, buf_ + len + 1, buf_used_); |
119 | } |
120 | |
121 | private: |
122 | const int fd_; |
123 | |
124 | bool hit_eof_; |
125 | unsigned buf_used_; |
126 | char buf_[kMaxLineLen]; |
127 | }; |
128 | |
129 | } // namespace google_breakpad |
130 | |
131 | #endif // CLIENT_LINUX_MINIDUMP_WRITER_LINE_READER_H_ |
132 | |