sideband.c: small optimization of strbuf usage
[git/git.git] / sideband.c
CommitLineData
cdf4fb8e 1#include "cache.h"
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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 */
ebe8fa73 15
5e5be9e2 16#define PREFIX "remote: "
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17
18#define ANSI_SUFFIX "\033[K"
19#define DUMB_SUFFIX " "
20
34df8aba 21int recv_sideband(const char *me, int in_stream, int out)
49a52b1d 22{
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23 const char *term, *suffix;
24 char buf[LARGE_PACKET_MAX + 1];
25 struct strbuf outbuf = STRBUF_INIT;
26 int retval = 0;
13e4760a 27
13e4760a 28 term = getenv("TERM");
38de156a 29 if (isatty(2) && term && strcmp(term, "dumb"))
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30 suffix = ANSI_SUFFIX;
31 else
32 suffix = DUMB_SUFFIX;
13e4760a 33
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34 while (!retval) {
35 const char *b, *brk;
9ac13ec9 36 int band, len;
5e5be9e2 37 len = packet_read(in_stream, NULL, NULL, buf, LARGE_PACKET_MAX, 0);
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38 if (len == 0)
39 break;
40 if (len < 1) {
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41 strbuf_addf(&outbuf,
42 "%s%s: protocol error: no band designator",
43 outbuf.len ? "\n" : "", me);
44 retval = SIDEBAND_PROTOCOL_ERROR;
45 break;
49a52b1d 46 }
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47 band = buf[0] & 0xff;
48 buf[len] = '\0';
49a52b1d 49 len--;
9ac13ec9 50 switch (band) {
49a52b1d 51 case 3:
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52 strbuf_addf(&outbuf, "%s%s%s", outbuf.len ? "\n" : "",
53 PREFIX, buf + 1);
54 retval = SIDEBAND_REMOTE_ERROR;
55 break;
49a52b1d 56 case 2:
5e5be9e2 57 b = buf + 1;
ebe8fa73 58
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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;
ebe8fa73 69
5e5be9e2 70 if (!outbuf.len)
c61b2af7 71 strbuf_addstr(&outbuf, PREFIX);
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72 if (linelen > 0) {
73 strbuf_addf(&outbuf, "%.*s%s%c",
74 linelen, b, suffix, *brk);
6b9c42b4 75 } else {
c61b2af7 76 strbuf_addch(&outbuf, *brk);
6b9c42b4 77 }
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78 xwrite(2, outbuf.buf, outbuf.len);
79 strbuf_reset(&outbuf);
ebe8fa73 80
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81 b = brk + 1;
82 }
83
84 if (*b)
85 strbuf_addf(&outbuf, "%s%s",
86 outbuf.len ? "" : PREFIX, b);
87 break;
49a52b1d 88 case 1:
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89 write_or_die(out, buf + 1, len);
90 break;
49a52b1d 91 default:
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92 strbuf_addf(&outbuf, "%s%s: protocol error: bad band #%d",
93 outbuf.len ? "\n" : "", me, band);
94 retval = SIDEBAND_PROTOCOL_ERROR;
95 break;
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96 }
97 }
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98
99 if (outbuf.len) {
c61b2af7 100 strbuf_addch(&outbuf, '\n');
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101 xwrite(2, outbuf.buf, outbuf.len);
102 }
103 strbuf_release(&outbuf);
104 return retval;
49a52b1d 105}
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106
107/*
108 * fd is connected to the remote side; send the sideband data
109 * over multiplexed packet stream.
110 */
111ssize_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;
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123 if (0 <= band) {
124 sprintf(hdr, "%04x", n + 5);
125 hdr[4] = band;
cdf4fb8e 126 write_or_die(fd, hdr, 5);
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127 } else {
128 sprintf(hdr, "%04x", n + 4);
cdf4fb8e 129 write_or_die(fd, hdr, 4);
de1a2fdd 130 }
cdf4fb8e 131 write_or_die(fd, p, n);
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132 p += n;
133 sz -= n;
134 }
135 return ssz;
136}