Merge branch 'dl/cocci-everywhere'
[git/git.git] / pkt-line.h
1 #ifndef PKTLINE_H
2 #define PKTLINE_H
3
4 #include "git-compat-util.h"
5 #include "strbuf.h"
6 #include "sideband.h"
7
8 /*
9 * Write a packetized stream, where each line is preceded by
10 * its length (including the header) as a 4-byte hex number.
11 * A length of 'zero' means end of stream (and a length of 1-3
12 * would be an error).
13 *
14 * This is all pretty stupid, but we use this packetized line
15 * format to make a streaming format possible without ever
16 * over-running the read buffers. That way we'll never read
17 * into what might be the pack data (which should go to another
18 * process entirely).
19 *
20 * The writing side could use stdio, but since the reading
21 * side can't, we stay with pure read/write interfaces.
22 */
23 void packet_flush(int fd);
24 void packet_delim(int fd);
25 void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
26 void packet_buf_flush(struct strbuf *buf);
27 void packet_buf_delim(struct strbuf *buf);
28 void set_packet_header(char *buf, int size);
29 void packet_write(int fd_out, const char *buf, size_t size);
30 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
31 void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
32 int packet_flush_gently(int fd);
33 int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
34 int write_packetized_from_fd(int fd_in, int fd_out);
35 int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
36
37 /*
38 * Read a packetized line into the buffer, which must be at least size bytes
39 * long. The return value specifies the number of bytes read into the buffer.
40 *
41 * If src_buffer and *src_buffer are not NULL, it should point to a buffer
42 * containing the packet data to parse, of at least *src_len bytes. After the
43 * function returns, src_buf will be incremented and src_len decremented by the
44 * number of bytes consumed.
45 *
46 * If src_buffer (or *src_buffer) is NULL, then data is read from the
47 * descriptor "fd".
48 *
49 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
50 * of the following conditions:
51 *
52 * 1. Read error from descriptor.
53 *
54 * 2. Protocol error from the remote (e.g., bogus length characters).
55 *
56 * 3. Receiving a packet larger than "size" bytes.
57 *
58 * 4. Truncated output from the remote (e.g., we expected a packet but got
59 * EOF, or we got a partial packet followed by EOF).
60 *
61 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
62 * condition 4 (truncated input), but instead return -1. However, we will still
63 * die for the other 3 conditions.
64 *
65 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
66 * present) is removed from the buffer before returning.
67 *
68 * If options contains PACKET_READ_DIE_ON_ERR_PACKET, it dies when it sees an
69 * ERR packet.
70 */
71 #define PACKET_READ_GENTLE_ON_EOF (1u<<0)
72 #define PACKET_READ_CHOMP_NEWLINE (1u<<1)
73 #define PACKET_READ_DIE_ON_ERR_PACKET (1u<<2)
74 int packet_read(int fd, char **src_buffer, size_t *src_len, char
75 *buffer, unsigned size, int options);
76
77 /*
78 * Read a packetized line into a buffer like the 'packet_read()' function but
79 * returns an 'enum packet_read_status' which indicates the status of the read.
80 * The number of bytes read will be assigined to *pktlen if the status of the
81 * read was 'PACKET_READ_NORMAL'.
82 */
83 enum packet_read_status {
84 PACKET_READ_EOF,
85 PACKET_READ_NORMAL,
86 PACKET_READ_FLUSH,
87 PACKET_READ_DELIM,
88 };
89 enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
90 size_t *src_len, char *buffer,
91 unsigned size, int *pktlen,
92 int options);
93
94 /*
95 * Convenience wrapper for packet_read that is not gentle, and sets the
96 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
97 * and otherwise points to a static buffer (that may be overwritten by
98 * subsequent calls). If the size parameter is not NULL, the length of the
99 * packet is written to it.
100 */
101 char *packet_read_line(int fd, int *size);
102
103 /*
104 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
105 * and CHOMP_NEWLINE options. The return value specifies the number of bytes
106 * read into the buffer or -1 on truncated input. If the *dst_line parameter
107 * is not NULL it will return NULL for a flush packet or when the number of
108 * bytes copied is zero and otherwise points to a static buffer (that may be
109 * overwritten by subsequent calls). If the size parameter is not NULL, the
110 * length of the packet is written to it.
111 */
112 int packet_read_line_gently(int fd, int *size, char **dst_line);
113
114 /*
115 * Same as packet_read_line, but read from a buf rather than a descriptor;
116 * see packet_read for details on how src_* is used.
117 */
118 char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
119
120 /*
121 * Reads a stream of variable sized packets until a flush packet is detected.
122 */
123 ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
124
125 /*
126 * Receive multiplexed output stream over git native protocol.
127 * in_stream is the input stream from the remote, which carries data
128 * in pkt_line format with band designator. Demultiplex it into out
129 * and err and return error appropriately. Band #1 carries the
130 * primary payload. Things coming over band #2 is not necessarily
131 * error; they are usually informative message on the standard error
132 * stream, aka "verbose"). A message over band #3 is a signal that
133 * the remote died unexpectedly. A flush() concludes the stream.
134 *
135 * Returns SIDEBAND_FLUSH upon a normal conclusion, and SIDEBAND_PROTOCOL_ERROR
136 * or SIDEBAND_REMOTE_ERROR if an error occurred.
137 */
138 int recv_sideband(const char *me, int in_stream, int out);
139
140 struct packet_reader {
141 /* source file descriptor */
142 int fd;
143
144 /* source buffer and its size */
145 char *src_buffer;
146 size_t src_len;
147
148 /* buffer that pkt-lines are read into and its size */
149 char *buffer;
150 unsigned buffer_size;
151
152 /* options to be used during reads */
153 int options;
154
155 /* status of the last read */
156 enum packet_read_status status;
157
158 /* length of data read during the last read */
159 int pktlen;
160
161 /* the last line read */
162 const char *line;
163
164 /* indicates if a line has been peeked */
165 int line_peeked;
166
167 unsigned use_sideband : 1;
168 const char *me;
169 };
170
171 /*
172 * Initialize a 'struct packet_reader' object which is an
173 * abstraction around the 'packet_read_with_status()' function.
174 */
175 void packet_reader_init(struct packet_reader *reader, int fd,
176 char *src_buffer, size_t src_len,
177 int options);
178
179 /*
180 * Perform a packet read and return the status of the read.
181 * The values of 'pktlen' and 'line' are updated based on the status of the
182 * read as follows:
183 *
184 * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL
185 * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read
186 * 'line' is set to point at the read line
187 * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL
188 */
189 enum packet_read_status packet_reader_read(struct packet_reader *reader);
190
191 /*
192 * Peek the next packet line without consuming it and return the status.
193 * The next call to 'packet_reader_read()' will perform a read of the same line
194 * that was peeked, consuming the line.
195 *
196 * Peeking multiple times without calling 'packet_reader_read()' will return
197 * the same result.
198 */
199 enum packet_read_status packet_reader_peek(struct packet_reader *reader);
200
201 #define DEFAULT_PACKET_MAX 1000
202 #define LARGE_PACKET_MAX 65520
203 #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
204 extern char packet_buffer[LARGE_PACKET_MAX];
205
206 struct packet_writer {
207 int dest_fd;
208 unsigned use_sideband : 1;
209 };
210
211 void packet_writer_init(struct packet_writer *writer, int dest_fd);
212
213 /* These functions die upon failure. */
214 __attribute__((format (printf, 2, 3)))
215 void packet_writer_write(struct packet_writer *writer, const char *fmt, ...);
216 __attribute__((format (printf, 2, 3)))
217 void packet_writer_error(struct packet_writer *writer, const char *fmt, ...);
218 void packet_writer_delim(struct packet_writer *writer);
219 void packet_writer_flush(struct packet_writer *writer);
220
221 #endif