Start preparing for 1.8.4.2
[alt-git.git] / pkt-line.h
blob0a838d1656171019c07fe802d615ecaf78412003
1 #ifndef PKTLINE_H
2 #define PKTLINE_H
4 #include "git-compat-util.h"
5 #include "strbuf.h"
7 /*
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).
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).
19 * The writing side could use stdio, but since the reading
20 * side can't, we stay with pure read/write interfaces.
22 void packet_flush(int fd);
23 void packet_write(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
24 void packet_buf_flush(struct strbuf *buf);
25 void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
28 * Read a packetized line into the buffer, which must be at least size bytes
29 * long. The return value specifies the number of bytes read into the buffer.
31 * If src_buffer is not NULL (and nor is *src_buffer), it should point to a
32 * buffer containing the packet data to parse, of at least *src_len bytes.
33 * After the function returns, src_buf will be incremented and src_len
34 * decremented by the number of bytes consumed.
36 * If src_buffer (or *src_buffer) is NULL, then data is read from the
37 * descriptor "fd".
39 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
40 * of the following conditions:
42 * 1. Read error from descriptor.
44 * 2. Protocol error from the remote (e.g., bogus length characters).
46 * 3. Receiving a packet larger than "size" bytes.
48 * 4. Truncated output from the remote (e.g., we expected a packet but got
49 * EOF, or we got a partial packet followed by EOF).
51 * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
52 * condition 4 (truncated input), but instead return -1. However, we will still
53 * die for the other 3 conditions.
55 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
56 * present) is removed from the buffer before returning.
58 #define PACKET_READ_GENTLE_ON_EOF (1u<<0)
59 #define PACKET_READ_CHOMP_NEWLINE (1u<<1)
60 int packet_read(int fd, char **src_buffer, size_t *src_len, char
61 *buffer, unsigned size, int options);
64 * Convenience wrapper for packet_read that is not gentle, and sets the
65 * CHOMP_NEWLINE option. The return value is NULL for a flush packet,
66 * and otherwise points to a static buffer (that may be overwritten by
67 * subsequent calls). If the size parameter is not NULL, the length of the
68 * packet is written to it.
70 char *packet_read_line(int fd, int *size);
73 * Same as packet_read_line, but read from a buf rather than a descriptor;
74 * see packet_read for details on how src_* is used.
76 char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
78 #define DEFAULT_PACKET_MAX 1000
79 #define LARGE_PACKET_MAX 65520
80 extern char packet_buffer[LARGE_PACKET_MAX];
82 #endif