diff options
Diffstat (limited to 'pkt-line.h')
| -rw-r--r-- | pkt-line.h | 71 |
1 files changed, 67 insertions, 4 deletions
@@ -5,15 +5,78 @@ #include "strbuf.h" /* - * Silly packetized line writing interface + * Write a packetized stream, where each line is preceded by + * its length (including the header) as a 4-byte hex number. + * A length of 'zero' means end of stream (and a length of 1-3 + * would be an error). + * + * This is all pretty stupid, but we use this packetized line + * format to make a streaming format possible without ever + * over-running the read buffers. That way we'll never read + * into what might be the pack data (which should go to another + * process entirely). + * + * The writing side could use stdio, but since the reading + * side can't, we stay with pure read/write interfaces. */ void packet_flush(int fd); void packet_write(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); void packet_buf_flush(struct strbuf *buf); void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3))); -int packet_read_line(int fd, char *buffer, unsigned size); -int packet_get_line(struct strbuf *out, char **src_buf, size_t *src_len); -ssize_t safe_write(int, const void *, ssize_t); +/* + * Read a packetized line into the buffer, which must be at least size bytes + * long. The return value specifies the number of bytes read into the buffer. + * + * If src_buffer and *src_buffer are not NULL, it should point to a buffer + * containing the packet data to parse, of at least *src_len bytes. After the + * function returns, src_buf will be incremented and src_len decremented by the + * number of bytes consumed. + * + * If src_buffer (or *src_buffer) is NULL, then data is read from the + * descriptor "fd". + * + * If options does not contain PACKET_READ_GENTLE_ON_EOF, we will die under any + * of the following conditions: + * + * 1. Read error from descriptor. + * + * 2. Protocol error from the remote (e.g., bogus length characters). + * + * 3. Receiving a packet larger than "size" bytes. + * + * 4. Truncated output from the remote (e.g., we expected a packet but got + * EOF, or we got a partial packet followed by EOF). + * + * If options does contain PACKET_READ_GENTLE_ON_EOF, we will not die on + * condition 4 (truncated input), but instead return -1. However, we will still + * die for the other 3 conditions. + * + * If options contains PACKET_READ_CHOMP_NEWLINE, a trailing newline (if + * present) is removed from the buffer before returning. + */ +#define PACKET_READ_GENTLE_ON_EOF (1u<<0) +#define PACKET_READ_CHOMP_NEWLINE (1u<<1) +int packet_read(int fd, char **src_buffer, size_t *src_len, char + *buffer, unsigned size, int options); + +/* + * Convenience wrapper for packet_read that is not gentle, and sets the + * CHOMP_NEWLINE option. The return value is NULL for a flush packet, + * and otherwise points to a static buffer (that may be overwritten by + * subsequent calls). If the size parameter is not NULL, the length of the + * packet is written to it. + */ +char *packet_read_line(int fd, int *size); + +/* + * Same as packet_read_line, but read from a buf rather than a descriptor; + * see packet_read for details on how src_* is used. + */ +char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); + +#define DEFAULT_PACKET_MAX 1000 +#define LARGE_PACKET_MAX 65520 +extern char packet_buffer[LARGE_PACKET_MAX]; #endif |