mirror of
https://github.com/git/git
synced 2024-08-25 02:35:46 +00:00
git-upload-pack: Support sending multiple ACK messages
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> Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
parent
794f9fe7db
commit
0f8fdc3958
|
@ -10,7 +10,7 @@ static const char upload_pack_usage[] = "git-upload-pack [--strict] [--timeout=n
|
|||
#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++;
|
||||
}
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue