pkt-line.h

   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  */
  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)));
  26
  27 /*
  28  * Read a packetized line from the descriptor into the buffer, which must be at
  29  * least size bytes long. The return value specifies the number of bytes read
  30  * into the buffer.
  31  *
  32  * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any
  33  * of the following conditions:
  34  *
  35  *   1. Read error from descriptor.
  36  *
  37  *   2. Protocol error from the remote (e.g., bogus length characters).
  38  *
  39  *   3. Receiving a packet larger than "size" bytes.
  40  *
  41  *   4. Truncated output from the remote (e.g., we expected a packet but got
  42  *      EOF, or we got a partial packet followed by EOF).
  43  *
  44  * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on
  45  * condition 4 (truncated input), but instead return -1. However, we will still
  46  * die for the other 3 conditions.
  47  */
  48 #define PACKET_READ_GENTLE_ON_EOF (1u<<0)
  49 int packet_read(int fd, char *buffer, unsigned size, int options);
  50
  51 /* Historical convenience wrapper for packet_read that sets no options */
  52 int packet_read_line(int fd, char *buffer, unsigned size);
  53
  54 int packet_get_line(struct strbuf *out, char **src_buf, size_t *src_len);
  55
  56 #endif