Andrew's git - gitweb.git/blob

   1#ifndef PKTLINE_H
   2#define PKTLINE_H
   3
   4#include "git-compat-util.h"
   5#include "strbuf.h"
   6
   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).
  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.
  21 */
  22void packet_flush(int fd);
  23void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
  24void packet_buf_flush(struct strbuf *buf);
  25void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
  26int packet_flush_gently(int fd);
  27int packet_write_fmt_gently(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3)));
  28LAST_ARG_MUST_BE_NULL
  29int packet_writel(int fd, const char *line, ...);
  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);
  32
  33/*
  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 *
  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.
  41 *
  42 * If src_buffer (or *src_buffer) is NULL, then data is read from the
  43 * descriptor "fd".
  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.
  60 *
  61 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
  62 * present) is removed from the buffer before returning.
  63 */
  64#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
  65#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
  66int packet_read(int fd, char **src_buffer, size_t *src_len, char
  67                *buffer, unsigned size, int options);
  68
  69/*
  70 * Convenience wrapper for packet_read that is not gentle, and sets the
  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.
  75 */
  76char *packet_read_line(int fd, int *size);
  77
  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
  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);
  94
  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
 100#define DEFAULT_PACKET_MAX 1000
 101#define LARGE_PACKET_MAX 65520
 102#define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4)
 103extern char packet_buffer[LARGE_PACKET_MAX];
 104
 105#endif