[WIP 03/15] pkt-line: add delim packet support
- From
- Brandon Williams <bmwill@google.com>
- Date
- Dec 4, 2017, 23:58 UTC
- Message-ID
- <20171204235823.63299-4-bmwill@google.com>
- In-Reply-To
- <20171204235823.63299-1-bmwill@google.com>
One of the design goals of protocol-v2 is to improve the semantics of flush packets. Currently in protocol-v1, flush packets are used both to indicate a break in a list of packet lines as well as an indication that one side has finished speaking. This makes it particularly difficult to implement proxies as a proxy would need to completely understand git protocol instead of simply looking for a flush packet.
To do this, introduce the special deliminator packet '0001'. A delim packet can then be used as a deliminator between lists of packet lines while flush packets can be reserved to indicate the end of a response.
Signed-off-by: Brandon Williams <bmwill@google.com> --- pkt-line.c | 19 ++++++++++++++++++- pkt-line.h | 3 +++ 2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/pkt-line.c b/pkt-line.c index 518109bbe..222e1e310 100644 --- a/pkt-line.c +++ b/pkt-line.c @@ -91,6 +91,12 @@ void packet_flush(int fd) write_or_die(fd, "0000", 4); } +void packet_delim(int fd) +{ + packet_trace("0001", 4, 1); + write_or_die(fd, "0001", 4); +} + int packet_flush_gently(int fd) { packet_trace("0000", 4, 1); @@ -105,6 +111,12 @@ void packet_buf_flush(struct strbuf *buf) strbuf_add(buf, "0000", 4); } +void packet_buf_delim(struct strbuf *buf) +{ + packet_trace("0001", 4, 1); + strbuf_add(buf, "0001", 4); +} + static void set_packet_header(char *buf, const int size) { static char hexchar[] = "0123456789abcdef"; @@ -297,7 +309,10 @@ enum packet_read_status packet_read_with_status(int fd, char **src_buffer, size_ if (len == 0) { packet_trace("0000", 4, 0); return PACKET_READ_FLUSH; - } else if (len >= 1 && len <= 3) { + } else if (len == 1) { + packet_trace("0001", 4, 0); + return PACKET_READ_DELIM; + } else if (len >= 2 && len <= 3) { die("protocol error: bad line length character: %.4s", linelen); } @@ -333,6 +348,7 @@ int packet_read(int fd, char **src_buffer, size_t *src_len, break; case PACKET_READ_NORMAL: break; + case PACKET_READ_DELIM: case PACKET_READ_FLUSH: pktlen = 0; break; @@ -447,6 +463,7 @@ enum packet_read_status packet_reader_read(struct packet_reader *reader) case PACKET_READ_NORMAL: reader->line = reader->buffer; break; + case PACKET_READ_DELIM: case PACKET_READ_FLUSH: reader->pktlen = 0; reader->line = NULL; diff --git a/pkt-line.h b/pkt-line.h index 2b5c7cf11..49ec80c80 100644 --- a/pkt-line.h +++ b/pkt-line.h @@ -20,8 +20,10 @@ * side can't, we stay with pure read/write interfaces. */ void packet_flush(int fd); +void packet_delim(int fd); void packet_write_fmt(int fd, const char *fmt, ...) __attribute__((format (printf, 2, 3))); void packet_buf_flush(struct strbuf *buf); +void packet_buf_delim(struct strbuf *buf); void packet_write(int fd_out, const char *buf, size_t size); void packet_buf_write(struct strbuf *buf, const char *fmt, ...) __attribute__((format (printf, 2, 3))); int packet_flush_gently(int fd); @@ -64,6 +66,7 @@ enum packet_read_status { PACKET_READ_ERROR = -1, PACKET_READ_NORMAL, PACKET_READ_FLUSH, + PACKET_READ_DELIM, }; #define PACKET_READ_GENTLE_ON_EOF (1u<<0) #define PACKET_READ_CHOMP_NEWLINE (1u<<1)
-- 2.15.1.424.g9478a66081-goog