Use packet_reader instead of packet_read_line
[git/git.git] / pkt-line.h
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f3a3214e
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1#ifndef PKTLINE_H
2#define PKTLINE_H
3
07d68930 4#include "git-compat-util.h"
f5615d24 5#include "strbuf.h"
07d68930 6
f3a3214e 7/*
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8 * Write a packetized stream, where each line is preceded by
9 * its length (including the header) as a 4-byte hex number.
10 * A length of 'zero' means end of stream (and a length of 1-3
11 * would be an error).
12 *
13 * This is all pretty stupid, but we use this packetized line
14 * format to make a streaming format possible without ever
15 * over-running the read buffers. That way we'll never read
16 * into what might be the pack data (which should go to another
17 * process entirely).
18 *
19 * The writing side could use stdio, but since the reading
20 * side can't, we stay with pure read/write interfaces.
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21 */
22void packet_flush(int fd);
a4cfd41c 23void packet_delim(int fd);
81c634e9 24void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
f5615d24 25void packet_buf_flush(struct strbuf *buf);
a4cfd41c 26void packet_buf_delim(struct strbuf *buf);
5d2124b3 27void packet_write(int fd_out, const char *buf, size_t size);
f5615d24 28void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
f1f4d8ac 29void packet_buf_write_len(struct strbuf *buf, const char *data, size_t len);
038ce90f 30int packet_flush_gently(int fd);
70428d1a 31int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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32int write_packetized_from_fd(int fd_in, int fd_out);
33int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
f3a3214e 34
03809429 35/*
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36 * Read a packetized line into the buffer, which must be at least size bytes
37 * long. The return value specifies the number of bytes read into the buffer.
38 *
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39 * If src_buffer and *src_buffer are not NULL, it should point to a buffer
40 * containing the packet data to parse, of at least *src_len bytes. After the
41 * function returns, src_buf will be incremented and src_len decremented by the
42 * number of bytes consumed.
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43 *
44 * If src_buffer (or *src_buffer) is NULL, then data is read from the
45 * descriptor "fd".
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46 *
47 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
48 * of the following conditions:
49 *
50 * 1. Read error from descriptor.
51 *
52 * 2. Protocol error from the remote (e.g., bogus length characters).
53 *
54 * 3. Receiving a packet larger than "size" bytes.
55 *
56 * 4. Truncated output from the remote (e.g., we expected a packet but got
57 * EOF, or we got a partial packet followed by EOF).
58 *
59 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
60 * condition 4 (truncated input), but instead return -1. However, we will still
61 * die for the other 3 conditions.
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62 *
63 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
64 * present) is removed from the buffer before returning.
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65 */
66#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
819b929d 67#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
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68int packet_read(int fd, char **src_buffer, size_t *src_len, char
69 *buffer, unsigned size, int options);
03809429 70
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71/*
72 * Read a packetized line into a buffer like the 'packet_read()' function but
73 * returns an 'enum packet_read_status' which indicates the status of the read.
74 * The number of bytes read will be assigined to *pktlen if the status of the
75 * read was 'PACKET_READ_NORMAL'.
76 */
77enum packet_read_status {
78 PACKET_READ_EOF,
79 PACKET_READ_NORMAL,
80 PACKET_READ_FLUSH,
a4cfd41c 81 PACKET_READ_DELIM,
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82};
83enum packet_read_status packet_read_with_status(int fd, char **src_buffer,
84 size_t *src_len, char *buffer,
85 unsigned size, int *pktlen,
86 int options);
87
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88/*
89 * Convenience wrapper for packet_read that is not gentle, and sets the
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90 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
91 * and otherwise points to a static buffer (that may be overwritten by
92 * subsequent calls). If the size parameter is not NULL, the length of the
93 * packet is written to it.
819b929d 94 */
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95char *packet_read_line(int fd, int *size);
96
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97/*
98 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
99 * and CHOMP_NEWLINE options. The return value specifies the number of bytes
100 * read into the buffer or -1 on truncated input. If the *dst_line parameter
101 * is not NULL it will return NULL for a flush packet or when the number of
102 * bytes copied is zero and otherwise points to a static buffer (that may be
103 * overwritten by subsequent calls). If the size parameter is not NULL, the
104 * length of the packet is written to it.
105 */
106int packet_read_line_gently(int fd, int *size, char **dst_line);
107
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108/*
109 * Same as packet_read_line, but read from a buf rather than a descriptor;
110 * see packet_read for details on how src_* is used.
111 */
112char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
03809429 113
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114/*
115 * Reads a stream of variable sized packets until a flush packet is detected.
116 */
117ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
118
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119struct packet_reader {
120 /* source file descriptor */
121 int fd;
122
123 /* source buffer and its size */
124 char *src_buffer;
125 size_t src_len;
126
127 /* buffer that pkt-lines are read into and its size */
128 char *buffer;
129 unsigned buffer_size;
130
131 /* options to be used during reads */
132 int options;
133
134 /* status of the last read */
135 enum packet_read_status status;
136
137 /* length of data read during the last read */
138 int pktlen;
139
140 /* the last line read */
141 const char *line;
142
143 /* indicates if a line has been peeked */
144 int line_peeked;
145};
146
147/*
148 * Initialize a 'struct packet_reader' object which is an
149 * abstraction around the 'packet_read_with_status()' function.
150 */
151extern void packet_reader_init(struct packet_reader *reader, int fd,
152 char *src_buffer, size_t src_len,
153 int options);
154
155/*
156 * Perform a packet read and return the status of the read.
157 * The values of 'pktlen' and 'line' are updated based on the status of the
158 * read as follows:
159 *
160 * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL
161 * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read
162 * 'line' is set to point at the read line
163 * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL
164 */
165extern enum packet_read_status packet_reader_read(struct packet_reader *reader);
166
167/*
168 * Peek the next packet line without consuming it and return the status.
169 * The next call to 'packet_reader_read()' will perform a read of the same line
170 * that was peeked, consuming the line.
171 *
172 * Peeking multiple times without calling 'packet_reader_read()' will return
173 * the same result.
174 */
175extern enum packet_read_status packet_reader_peek(struct packet_reader *reader);
176
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177#define DEFAULT_PACKET_MAX 1000
178#define LARGE_PACKET_MAX 65520
bb643d8b 179#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
74543a04 180extern char packet_buffer[LARGE_PACKET_MAX];
047ec602 181
f3a3214e 182#endif