From 77dabc14c497d2498b814967bf21a3ed1618207f Mon Sep 17 00:00:00 2001 From: Brandon Williams Date: Wed, 14 Mar 2018 11:31:39 -0700 Subject: pkt-line: allow peeking a packet line without consuming it Sometimes it is advantageous to be able to peek the next packet line without consuming it (e.g. to be able to determine the protocol version a server is speaking). In order to do that introduce 'struct packet_reader' which is an abstraction around the normal packet reading logic. This enables a caller to be able to peek a single line at a time using 'packet_reader_peek()' and having a caller consume a line by calling 'packet_reader_read()'. Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano --- pkt-line.h | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 58 insertions(+) (limited to 'pkt-line.h') diff --git a/pkt-line.h b/pkt-line.h index 099b26b95f..11b04f026f 100644 --- a/pkt-line.h +++ b/pkt-line.h @@ -112,6 +112,64 @@ char *packet_read_line_buf(char **src_buf, size_t *src_len, int *size); */ ssize_t read_packetized_to_strbuf(int fd_in, struct strbuf *sb_out); +struct packet_reader { + /* source file descriptor */ + int fd; + + /* source buffer and its size */ + char *src_buffer; + size_t src_len; + + /* buffer that pkt-lines are read into and its size */ + char *buffer; + unsigned buffer_size; + + /* options to be used during reads */ + int options; + + /* status of the last read */ + enum packet_read_status status; + + /* length of data read during the last read */ + int pktlen; + + /* the last line read */ + const char *line; + + /* indicates if a line has been peeked */ + int line_peeked; +}; + +/* + * Initialize a 'struct packet_reader' object which is an + * abstraction around the 'packet_read_with_status()' function. + */ +extern void packet_reader_init(struct packet_reader *reader, int fd, + char *src_buffer, size_t src_len, + int options); + +/* + * Perform a packet read and return the status of the read. + * The values of 'pktlen' and 'line' are updated based on the status of the + * read as follows: + * + * PACKET_READ_ERROR: 'pktlen' is set to '-1' and 'line' is set to NULL + * PACKET_READ_NORMAL: 'pktlen' is set to the number of bytes read + * 'line' is set to point at the read line + * PACKET_READ_FLUSH: 'pktlen' is set to '0' and 'line' is set to NULL + */ +extern enum packet_read_status packet_reader_read(struct packet_reader *reader); + +/* + * Peek the next packet line without consuming it and return the status. + * The next call to 'packet_reader_read()' will perform a read of the same line + * that was peeked, consuming the line. + * + * Peeking multiple times without calling 'packet_reader_read()' will return + * the same result. + */ +extern enum packet_read_status packet_reader_peek(struct packet_reader *reader); + #define DEFAULT_PACKET_MAX 1000 #define LARGE_PACKET_MAX 65520 #define LARGE_PACKET_DATA_MAX (LARGE_PACKET_MAX - 4) -- cgit v1.2.3