The current fetch/upload protocol works like this: - client sends revs it wants to have via "want" messages - client sends a flush message (message with len 0) - client sends revs it has via "have" messages - after one window (32 revs), a flush is sent - after each subsequent window, a flush is sent, and an ACK/NAK is received. (NAK means that server does not have any of the transmitted revs; ACK sends also the sha1 of the rev server has) - when the first ACK is received, client sends "done", and does not expect any further messages One special case, though: - if no ACK is received (only NAK's), and client runs out of revs to send, "done" is sent, and server sends just one more "NAK" A smarter scheme, which actually has a chance to detect more than one common rev, would be to send more than just one ACK. This patch implements the server side of the following extension to the protocol: - client sends at least one "want" message with "multi_ack" appended, like "want 1234567890123456789012345678901234567890 multi_ack" - if the server understands that extension, it will send ACK messages for all revs it has, not just the first one - server appends "continue" to the ACK messages like "ACK 1234567890123456789012345678901234567890 continue" until it has MAX_HAS-1 revs. In this manner, client knows when to stop sending revs by checking for the substring "continue" (and further knows that server understands multi_ack) In this manner, the protocol stays backwards compatible, since both client must send "want ... multi_ack" and server must answer with "ACK ... continue" to enable the extension. Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> --- upload-pack.c | 37 +++++++++++++++---------------------- 1 files changed, 15 insertions(+), 22 deletions(-) applies-to: 95634a3973bbc1eb8cc626fd6fd67bb773caf7ab 89df3fb3bb65e37c33b478b66c76adc46cf22cd7 diff --git a/upload-pack.c b/upload-pack.c index ab1981c..c3abf7b 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -10,7 +10,7 @@ static const char upload_pack_usage[] = #define THEY_HAVE (1U << 0) #define MAX_HAS 256 #define MAX_NEEDS 256 -static int nr_has = 0, nr_needs = 0; +static int nr_has = 0, nr_needs = 0, multi_ack = 0; static unsigned char has_sha1[MAX_HAS][20]; static unsigned char needs_sha1[MAX_NEEDS][20]; static unsigned int timeout = 0; @@ -124,39 +124,28 @@ static int get_common_commits(void) reset_timeout(); if (!len) { - packet_write(1, "NAK\n"); + if (multi_ack || nr_has == 0) + packet_write(1, "NAK\n"); continue; } len = strip(line, len); if (!strncmp(line, "have ", 5)) { - if (got_sha1(line+5, sha1)) { - packet_write(1, "ACK %s\n", sha1_to_hex(sha1)); - break; - } + if (got_sha1(line+5, sha1) && + (multi_ack || nr_has == 1)) + packet_write(1, "ACK %s%s\n", + sha1_to_hex(sha1), + multi_ack && nr_has < MAX_HAS ? + " continue" : ""); continue; } if (!strcmp(line, "done")) { + if (nr_has > 0) + return 0; packet_write(1, "NAK\n"); return -1; } die("git-upload-pack: expected SHA1 list, got '%s'", line); } - - for (;;) { - len = packet_read_line(0, line, sizeof(line)); - reset_timeout(); - if (!len) - continue; - len = strip(line, len); - if (!strncmp(line, "have ", 5)) { - got_sha1(line+5, sha1); - continue; - } - if (!strcmp(line, "done")) - break; - die("git-upload-pack: expected SHA1 list, got '%s'", line); - } - return 0; } static int receive_needs(void) @@ -185,6 +174,10 @@ static int receive_needs(void) if (strncmp("want ", line, 5) || get_sha1_hex(line+5, sha1_buf)) die("git-upload-pack: protocol error, " "expected to get sha, not '%s'", line); + + if (strstr(line+45, "multi_ack")) + multi_ack = 1; + needs++; } } --- 0.99.8.GIT - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.htmlReceived on Sun Oct 23 11:38:19 2005
This archive was generated by hypermail 2.1.8 : 2005-10-23 11:38:23 EST