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