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