git-archive: work in bare repos
[git/dscho.git] / sideband.c
blobcca3360546dabf9f018b882f690bd1dea9de534d
1 #include "pkt-line.h"
2 #include "sideband.h"
4 /*
5 * Receive multiplexed output stream over git native protocol.
6 * in_stream is the input stream from the remote, which carries data
7 * in pkt_line format with band designator. Demultiplex it into out
8 * and err and return error appropriately. Band #1 carries the
9 * primary payload. Things coming over band #2 is not necessarily
10 * error; they are usually informative message on the standard error
11 * stream, aka "verbose"). A message over band #3 is a signal that
12 * the remote died unexpectedly. A flush() concludes the stream.
15 #define PREFIX "remote:"
17 #define ANSI_SUFFIX "\033[K"
18 #define DUMB_SUFFIX " "
20 #define FIX_SIZE 10 /* large enough for any of the above */
22 int recv_sideband(const char *me, int in_stream, int out, int err)
24 unsigned pf = strlen(PREFIX);
25 unsigned sf;
26 char buf[LARGE_PACKET_MAX + 2*FIX_SIZE];
27 char *suffix, *term;
28 int skip_pf = 0;
30 memcpy(buf, PREFIX, pf);
31 term = getenv("TERM");
32 if (term && strcmp(term, "dumb"))
33 suffix = ANSI_SUFFIX;
34 else
35 suffix = DUMB_SUFFIX;
36 sf = strlen(suffix);
38 while (1) {
39 int band, len;
40 len = packet_read_line(in_stream, buf + pf, LARGE_PACKET_MAX);
41 if (len == 0)
42 break;
43 if (len < 1) {
44 len = sprintf(buf, "%s: protocol error: no band designator\n", me);
45 safe_write(err, buf, len);
46 return SIDEBAND_PROTOCOL_ERROR;
48 band = buf[pf] & 0xff;
49 len--;
50 switch (band) {
51 case 3:
52 buf[pf] = ' ';
53 buf[pf+1+len] = '\n';
54 safe_write(err, buf, pf+1+len+1);
55 return SIDEBAND_REMOTE_ERROR;
56 case 2:
57 buf[pf] = ' ';
58 do {
59 char *b = buf;
60 int brk = 0;
63 * If the last buffer didn't end with a line
64 * break then we should not print a prefix
65 * this time around.
67 if (skip_pf) {
68 b += pf+1;
69 } else {
70 len += pf+1;
71 brk += pf+1;
74 /* Look for a line break. */
75 for (;;) {
76 brk++;
77 if (brk > len) {
78 brk = 0;
79 break;
81 if (b[brk-1] == '\n' ||
82 b[brk-1] == '\r')
83 break;
87 * Let's insert a suffix to clear the end
88 * of the screen line if a line break was
89 * found. Also, if we don't skip the
90 * prefix, then a non-empty string must be
91 * present too.
93 if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
94 char save[FIX_SIZE];
95 memcpy(save, b + brk, sf);
96 b[brk + sf - 1] = b[brk - 1];
97 memcpy(b + brk - 1, suffix, sf);
98 safe_write(err, b, brk + sf);
99 memcpy(b + brk, save, sf);
100 len -= brk;
101 } else {
102 int l = brk ? brk : len;
103 safe_write(err, b, l);
104 len -= l;
107 skip_pf = !brk;
108 memmove(buf + pf+1, b + brk, len);
109 } while (len);
110 continue;
111 case 1:
112 safe_write(out, buf + pf+1, len);
113 continue;
114 default:
115 len = sprintf(buf,
116 "%s: protocol error: bad band #%d\n",
117 me, band);
118 safe_write(err, buf, len);
119 return SIDEBAND_PROTOCOL_ERROR;
122 return 0;
126 * fd is connected to the remote side; send the sideband data
127 * over multiplexed packet stream.
129 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
131 ssize_t ssz = sz;
132 const char *p = data;
134 while (sz) {
135 unsigned n;
136 char hdr[5];
138 n = sz;
139 if (packet_max - 5 < n)
140 n = packet_max - 5;
141 sprintf(hdr, "%04x", n + 5);
142 hdr[4] = band;
143 safe_write(fd, hdr, 5);
144 safe_write(fd, p, n);
145 p += n;
146 sz -= n;
148 return ssz;