setup_pager: set GIT_PAGER_IN_USE
[git/git.git] / pager.c
CommitLineData
f67b45f8 1#include "cache.h"
ea27a18c 2#include "run-command.h"
a3da8821 3#include "sigchain.h"
f67b45f8 4
a3d023d0
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5#ifndef DEFAULT_PAGER
6#define DEFAULT_PAGER "less"
7#endif
8
f67b45f8 9/*
bfdd9ffd
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10 * This is split up from the rest of git so that we can do
11 * something different on Windows.
f67b45f8
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12 */
13
71064e3f 14#ifndef WIN32
ea27a18c 15static void pager_preexec(void)
f67b45f8 16{
35ce8622
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17 /*
18 * Work around bug in "less" by not starting it until we
19 * have real input
20 */
21 fd_set in;
22
23 FD_ZERO(&in);
24 FD_SET(0, &in);
25 select(1, &in, NULL, &in, NULL);
f67b45f8 26}
ea27a18c 27#endif
bfdd9ffd 28
ac0ba18d 29static const char *pager_argv[] = { NULL, NULL };
ea27a18c
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30static struct child_process pager_process;
31
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32static void wait_for_pager(void)
33{
34 fflush(stdout);
35 fflush(stderr);
36 /* signal EOF to pager */
37 close(1);
38 close(2);
39 finish_command(&pager_process);
40}
f67b45f8 41
a3da8821
JK
42static void wait_for_pager_signal(int signo)
43{
44 wait_for_pager();
45 sigchain_pop(signo);
46 raise(signo);
47}
48
64778d24 49const char *git_pager(int stdout_is_tty)
f67b45f8 50{
63618245 51 const char *pager;
f67b45f8 52
64778d24 53 if (!stdout_is_tty)
63618245
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54 return NULL;
55
56 pager = getenv("GIT_PAGER");
cad3a205
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57 if (!pager) {
58 if (!pager_program)
ef90d6d4 59 git_config(git_default_config, NULL);
54adf370 60 pager = pager_program;
cad3a205 61 }
c27d205a
ML
62 if (!pager)
63 pager = getenv("PAGER");
402461aa 64 if (!pager)
a3d023d0 65 pager = DEFAULT_PAGER;
caef71a5 66 else if (!*pager || !strcmp(pager, "cat"))
63618245
JN
67 pager = NULL;
68
69 return pager;
70}
71
72void setup_pager(void)
73{
64778d24 74 const char *pager = git_pager(isatty(1));
63618245
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75
76 if (!pager)
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77 return;
78
2e6c012e 79 setenv("GIT_PAGER_IN_USE", "true", 1);
85fb65ed 80
bfdd9ffd 81 /* spawn the pager */
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82 pager_argv[0] = pager;
83 pager_process.use_shell = 1;
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84 pager_process.argv = pager_argv;
85 pager_process.in = -1;
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86 if (!getenv("LESS")) {
87 static const char *env[] = { "LESS=FRSX", NULL };
88 pager_process.env = env;
89 }
71064e3f 90#ifndef WIN32
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91 pager_process.preexec_cb = pager_preexec;
92#endif
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93 if (start_command(&pager_process))
94 return;
95
96 /* original process continues, but writes to the pipe */
97 dup2(pager_process.in, 1);
a8335024
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98 if (isatty(2))
99 dup2(pager_process.in, 2);
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100 close(pager_process.in);
101
102 /* this makes sure that the parent terminates after the pager */
a3da8821 103 sigchain_push_common(wait_for_pager_signal);
bfdd9ffd 104 atexit(wait_for_pager);
f67b45f8 105}
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106
107int pager_in_use(void)
108{
109 const char *env;
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110 env = getenv("GIT_PAGER_IN_USE");
111 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
112}