pkt-line: annotate packet_writel with LAST_ARG_MUST_BE_NULL
[git/git.git] / pkt-line.h
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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);
81c634e9 23void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
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24void packet_buf_flush(struct strbuf *buf);
25void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
038ce90f 26int packet_flush_gently(int fd);
70428d1a 27int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
7e936842 28LAST_ARG_MUST_BE_NULL
c0c70f7a 29int packet_writel(int fd, const char *line, ...);
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30int write_packetized_from_fd(int fd_in, int fd_out);
31int write_packetized_from_buf(const char *src_in, size_t len, int fd_out);
f3a3214e 32
03809429 33/*
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34 * Read a packetized line into the buffer, which must be at least size bytes
35 * long. The return value specifies the number of bytes read into the buffer.
36 *
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37 * If src_buffer and *src_buffer are not NULL, it should point to a buffer
38 * containing the packet data to parse, of at least *src_len bytes. After the
39 * function returns, src_buf will be incremented and src_len decremented by the
40 * number of bytes consumed.
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41 *
42 * If src_buffer (or *src_buffer) is NULL, then data is read from the
43 * descriptor "fd".
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44 *
45 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
46 * of the following conditions:
47 *
48 * 1. Read error from descriptor.
49 *
50 * 2. Protocol error from the remote (e.g., bogus length characters).
51 *
52 * 3. Receiving a packet larger than "size" bytes.
53 *
54 * 4. Truncated output from the remote (e.g., we expected a packet but got
55 * EOF, or we got a partial packet followed by EOF).
56 *
57 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
58 * condition 4 (truncated input), but instead return -1. However, we will still
59 * die for the other 3 conditions.
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60 *
61 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
62 * present) is removed from the buffer before returning.
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63 */
64#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
819b929d 65#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
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66int packet_read(int fd, char **src_buffer, size_t *src_len, char
67 *buffer, unsigned size, int options);
03809429 68
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69/*
70 * Convenience wrapper for packet_read that is not gentle, and sets the
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71 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
72 * and otherwise points to a static buffer (that may be overwritten by
73 * subsequent calls). If the size parameter is not NULL, the length of the
74 * packet is written to it.
819b929d 75 */
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76char *packet_read_line(int fd, int *size);
77
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78/*
79 * Convenience wrapper for packet_read that sets the PACKET_READ_GENTLE_ON_EOF
80 * and CHOMP_NEWLINE options. The return value specifies the number of bytes
81 * read into the buffer or -1 on truncated input. If the *dst_line parameter
82 * is not NULL it will return NULL for a flush packet or when the number of
83 * bytes copied is zero and otherwise points to a static buffer (that may be
84 * overwritten by subsequent calls). If the size parameter is not NULL, the
85 * length of the packet is written to it.
86 */
87int packet_read_line_gently(int fd, int *size, char **dst_line);
88
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89/*
90 * Same as packet_read_line, but read from a buf rather than a descriptor;
91 * see packet_read for details on how src_* is used.
92 */
93char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
03809429 94
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95/*
96 * Reads a stream of variable sized packets until a flush packet is detected.
97 */
98ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out);
99
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100#define DEFAULT_PACKET_MAX 1000
101#define LARGE_PACKET_MAX 65520
bb643d8b 102#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
74543a04 103extern char packet_buffer[LARGE_PACKET_MAX];
047ec602 104
f3a3214e 105#endif