git/sideband.c
Shawn O. Pearce de1a2fdd38 Smart push over HTTP: client side
The git-remote-curl backend detects if the remote server supports
the git-receive-pack service, and if so, runs git-send-pack in a
pipe to dump the command and pack data as a single POST request.

The advertisements from the server that were obtained during the
discovery are passed into git-send-pack before the POST request
starts.  This permits git-send-pack to operate largely unmodified.

For smaller packs (those under 1 MiB) a HTTP/1.0 POST with a
Content-Length is used, permitting interaction with any server.
The 1 MiB limit is arbitrary, but is sufficent to fit most deltas
created by human authors against text sources with the occasional
small binary file (e.g. few KiB icon image).  The configuration
option http.postBuffer can be used to increase (or shink) this
buffer if the default is not sufficient.

For larger packs which cannot be spooled entirely into the helper's
memory space (due to http.postBuffer being too small), the POST
request requires HTTP/1.1 and sets "Transfer-Encoding: chunked".
This permits the client to upload an unknown amount of data in one
HTTP transaction without needing to pregenerate the entire pack
file locally.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
CC: Daniel Barkalow <barkalow@iabervon.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-11-04 17:58:15 -08:00

152 lines
3.4 KiB
C

#include "pkt-line.h"
#include "sideband.h"
/*
* Receive multiplexed output stream over git native protocol.
* in_stream is the input stream from the remote, which carries data
* in pkt_line format with band designator. Demultiplex it into out
* and err and return error appropriately. Band #1 carries the
* primary payload. Things coming over band #2 is not necessarily
* error; they are usually informative message on the standard error
* stream, aka "verbose"). A message over band #3 is a signal that
* the remote died unexpectedly. A flush() concludes the stream.
*/
#define PREFIX "remote:"
#define ANSI_SUFFIX "\033[K"
#define DUMB_SUFFIX " "
#define FIX_SIZE 10 /* large enough for any of the above */
int recv_sideband(const char *me, int in_stream, int out)
{
unsigned pf = strlen(PREFIX);
unsigned sf;
char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
char *suffix, *term;
int skip_pf = 0;
memcpy(buf, PREFIX, pf);
term = getenv("TERM");
if (term && strcmp(term, "dumb"))
suffix = ANSI_SUFFIX;
else
suffix = DUMB_SUFFIX;
sf = strlen(suffix);
while (1) {
int band, len;
len = packet_read_line(in_stream, buf + pf, LARGE_PACKET_MAX);
if (len == 0)
break;
if (len < 1) {
fprintf(stderr, "%s: protocol error: no band designator\n", me);
return SIDEBAND_PROTOCOL_ERROR;
}
band = buf[pf] & 0xff;
len--;
switch (band) {
case 3:
buf[pf] = ' ';
buf[pf+1+len] = '\0';
fprintf(stderr, "%s\n", buf);
return SIDEBAND_REMOTE_ERROR;
case 2:
buf[pf] = ' ';
do {
char *b = buf;
int brk = 0;
/*
* If the last buffer didn't end with a line
* break then we should not print a prefix
* this time around.
*/
if (skip_pf) {
b += pf+1;
} else {
len += pf+1;
brk += pf+1;
}
/* Look for a line break. */
for (;;) {
brk++;
if (brk > len) {
brk = 0;
break;
}
if (b[brk-1] == '\n' ||
b[brk-1] == '\r')
break;
}
/*
* Let's insert a suffix to clear the end
* of the screen line if a line break was
* found. Also, if we don't skip the
* prefix, then a non-empty string must be
* present too.
*/
if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
char save[FIX_SIZE];
memcpy(save, b + brk, sf);
b[brk + sf - 1] = b[brk - 1];
memcpy(b + brk - 1, suffix, sf);
fprintf(stderr, "%.*s", brk + sf, b);
memcpy(b + brk, save, sf);
len -= brk;
} else {
int l = brk ? brk : len;
fprintf(stderr, "%.*s", l, b);
len -= l;
}
skip_pf = !brk;
memmove(buf + pf+1, b + brk, len);
} while (len);
continue;
case 1:
safe_write(out, buf + pf+1, len);
continue;
default:
fprintf(stderr, "%s: protocol error: bad band #%d\n",
me, band);
return SIDEBAND_PROTOCOL_ERROR;
}
}
return 0;
}
/*
* fd is connected to the remote side; send the sideband data
* over multiplexed packet stream.
*/
ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
{
ssize_t ssz = sz;
const char *p = data;
while (sz) {
unsigned n;
char hdr[5];
n = sz;
if (packet_max - 5 < n)
n = packet_max - 5;
if (0 <= band) {
sprintf(hdr, "%04x", n + 5);
hdr[4] = band;
safe_write(fd, hdr, 5);
} else {
sprintf(hdr, "%04x", n + 4);
safe_write(fd, hdr, 4);
}
safe_write(fd, p, n);
p += n;
sz -= n;
}
return ssz;
}