Merge branch 'mg/mailmap-update'
[git] / sideband.c
1 #include "pkt-line.h"
2 #include "sideband.h"
3
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.
13  */
14
15 #define PREFIX "remote:"
16
17 #define ANSI_SUFFIX "\033[K"
18 #define DUMB_SUFFIX "        "
19
20 #define FIX_SIZE 10  /* large enough for any of the above */
21
22 int recv_sideband(const char *me, int in_stream, int out)
23 {
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;
29
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);
37
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                         fprintf(stderr, "%s: protocol error: no band designator\n", me);
45                         return SIDEBAND_PROTOCOL_ERROR;
46                 }
47                 band = buf[pf] & 0xff;
48                 len--;
49                 switch (band) {
50                 case 3:
51                         buf[pf] = ' ';
52                         buf[pf+1+len] = '\0';
53                         fprintf(stderr, "%s\n", buf);
54                         return SIDEBAND_REMOTE_ERROR;
55                 case 2:
56                         buf[pf] = ' ';
57                         do {
58                                 char *b = buf;
59                                 int brk = 0;
60
61                                 /*
62                                  * If the last buffer didn't end with a line
63                                  * break then we should not print a prefix
64                                  * this time around.
65                                  */
66                                 if (skip_pf) {
67                                         b += pf+1;
68                                 } else {
69                                         len += pf+1;
70                                         brk += pf+1;
71                                 }
72
73                                 /* Look for a line break. */
74                                 for (;;) {
75                                         brk++;
76                                         if (brk > len) {
77                                                 brk = 0;
78                                                 break;
79                                         }
80                                         if (b[brk-1] == '\n' ||
81                                             b[brk-1] == '\r')
82                                                 break;
83                                 }
84
85                                 /*
86                                  * Let's insert a suffix to clear the end
87                                  * of the screen line if a line break was
88                                  * found.  Also, if we don't skip the
89                                  * prefix, then a non-empty string must be
90                                  * present too.
91                                  */
92                                 if (brk > (skip_pf ? 0 : (pf+1 + 1))) {
93                                         char save[FIX_SIZE];
94                                         memcpy(save, b + brk, sf);
95                                         b[brk + sf - 1] = b[brk - 1];
96                                         memcpy(b + brk - 1, suffix, sf);
97                                         fprintf(stderr, "%.*s", brk + sf, b);
98                                         memcpy(b + brk, save, sf);
99                                         len -= brk;
100                                 } else {
101                                         int l = brk ? brk : len;
102                                         fprintf(stderr, "%.*s", l, b);
103                                         len -= l;
104                                 }
105
106                                 skip_pf = !brk;
107                                 memmove(buf + pf+1, b + brk, len);
108                         } while (len);
109                         continue;
110                 case 1:
111                         safe_write(out, buf + pf+1, len);
112                         continue;
113                 default:
114                         fprintf(stderr, "%s: protocol error: bad band #%d\n",
115                                 me, band);
116                         return SIDEBAND_PROTOCOL_ERROR;
117                 }
118         }
119         return 0;
120 }
121
122 /*
123  * fd is connected to the remote side; send the sideband data
124  * over multiplexed packet stream.
125  */
126 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
127 {
128         ssize_t ssz = sz;
129         const char *p = data;
130
131         while (sz) {
132                 unsigned n;
133                 char hdr[5];
134
135                 n = sz;
136                 if (packet_max - 5 < n)
137                         n = packet_max - 5;
138                 if (0 <= band) {
139                         sprintf(hdr, "%04x", n + 5);
140                         hdr[4] = band;
141                         safe_write(fd, hdr, 5);
142                 } else {
143                         sprintf(hdr, "%04x", n + 4);
144                         safe_write(fd, hdr, 4);
145                 }
146                 safe_write(fd, p, n);
147                 p += n;
148                 sz -= n;
149         }
150         return ssz;
151 }