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(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)));
  26
  27/*
  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.
  30 *
  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.
  35 *
  36 * If src_buffer (or *src_buffer) is NULL, then data is read from the
  37 * descriptor "fd".
  38 *
  39 * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
  40 * of the following conditions:
  41 *
  42 *   1. Read error from descriptor.
  43 *
  44 *   2. Protocol error from the remote (e.g., bogus length characters).
  45 *
  46 *   3. Receiving a packet larger than "size" bytes.
  47 *
  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).
  50 *
  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.
  54 *
  55 * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if
  56 * present) is removed from the buffer before returning.
  57 */
  58#define PACKET_READ_GENTLE_ON_EOF (1u<<0)
  59#define PACKET_READ_CHOMP_NEWLINE (1u<<1)
  60int packet_read(int fd, char **src_buffer, size_t *src_len, char
  61                *buffer, unsigned size, int options);
  62
  63/*
  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.
  69 */
  70char *packet_read_line(int fd, int *size);
  71
  72/*
  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.
  75 */
  76char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size);
  77
  78#define DEFAULT_PACKET_MAX 1000
  79#define LARGE_PACKET_MAX 65520
  80extern char packet_buffer[LARGE_PACKET_MAX];
  81
  82#endif