sideband.c: small optimization of strbuf usage
[git/git.git] / sideband.c
1 #include "cache.h"
2 #include "pkt-line.h"
3 #include "sideband.h"
4
5 /*
6 * Receive multiplexed output stream over git native protocol.
7 * in_stream is the input stream from the remote, which carries data
8 * in pkt_line format with band designator. Demultiplex it into out
9 * and err and return error appropriately. Band #1 carries the
10 * primary payload. Things coming over band #2 is not necessarily
11 * error; they are usually informative message on the standard error
12 * stream, aka "verbose"). A message over band #3 is a signal that
13 * the remote died unexpectedly. A flush() concludes the stream.
14 */
15
16 #define PREFIX "remote: "
17
18 #define ANSI_SUFFIX "\033[K"
19 #define DUMB_SUFFIX " "
20
21 int recv_sideband(const char *me, int in_stream, int out)
22 {
23 const char *term, *suffix;
24 char buf[LARGE_PACKET_MAX + 1];
25 struct strbuf outbuf = STRBUF_INIT;
26 int retval = 0;
27
28 term = getenv("TERM");
29 if (isatty(2) && term && strcmp(term, "dumb"))
30 suffix = ANSI_SUFFIX;
31 else
32 suffix = DUMB_SUFFIX;
33
34 while (!retval) {
35 const char *b, *brk;
36 int band, len;
37 len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
38 if (len == 0)
39 break;
40 if (len < 1) {
41 strbuf_addf(&outbuf,
42 "%s%s: protocol error: no band designator",
43 outbuf.len ? "\n" : "", me);
44 retval = SIDEBAND_PROTOCOL_ERROR;
45 break;
46 }
47 band = buf[0] & 0xff;
48 buf[len] = '\0';
49 len--;
50 switch (band) {
51 case 3:
52 strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
53 PREFIX, buf + 1);
54 retval = SIDEBAND_REMOTE_ERROR;
55 break;
56 case 2:
57 b = buf + 1;
58
59 /*
60 * Append a suffix to each nonempty line to clear the
61 * end of the screen line.
62 *
63 * The output is accumulated in a buffer and
64 * each line is printed to stderr using
65 * write(2) to ensure inter-process atomicity.
66 */
67 while ((brk = strpbrk(b, "\n\r"))) {
68 int linelen = brk - b;
69
70 if (!outbuf.len)
71 strbuf_addstr(&outbuf, PREFIX);
72 if (linelen > 0) {
73 strbuf_addf(&outbuf, "%.*s%s%c",
74 linelen, b, suffix, *brk);
75 } else {
76 strbuf_addch(&outbuf, *brk);
77 }
78 xwrite(2, outbuf.buf, outbuf.len);
79 strbuf_reset(&outbuf);
80
81 b = brk + 1;
82 }
83
84 if (*b)
85 strbuf_addf(&outbuf, "%s%s",
86 outbuf.len ? "" : PREFIX, b);
87 break;
88 case 1:
89 write_or_die(out, buf + 1, len);
90 break;
91 default:
92 strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d",
93 outbuf.len ? "\n" : "", me, band);
94 retval = SIDEBAND_PROTOCOL_ERROR;
95 break;
96 }
97 }
98
99 if (outbuf.len) {
100 strbuf_addch(&outbuf, '\n');
101 xwrite(2, outbuf.buf, outbuf.len);
102 }
103 strbuf_release(&outbuf);
104 return retval;
105 }
106
107 /*
108 * fd is connected to the remote side; send the sideband data
109 * over multiplexed packet stream.
110 */
111 ssize_t send_sideband(int fd, int band, const char *data, ssize_t sz, int packet_max)
112 {
113 ssize_t ssz = sz;
114 const char *p = data;
115
116 while (sz) {
117 unsigned n;
118 char hdr[5];
119
120 n = sz;
121 if (packet_max - 5 < n)
122 n = packet_max - 5;
123 if (0 <= band) {
124 sprintf(hdr, "%04x", n + 5);
125 hdr[4] = band;
126 write_or_die(fd, hdr, 5);
127 } else {
128 sprintf(hdr, "%04x", n + 4);
129 write_or_die(fd, hdr, 4);
130 }
131 write_or_die(fd, p, n);
132 p += n;
133 sz -= n;
134 }
135 return ssz;
136 }