Fix 'git var' usage synopsis
[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
JH
5#ifndef DEFAULT_PAGER
6#define DEFAULT_PAGER "less"
7#endif
8
f67b45f8 9/*
bfdd9ffd
JS
10 * This is split up from the rest of git so that we can do
11 * something different on Windows.
f67b45f8
LT
12 */
13
6e9af863
JK
14static int spawned_pager;
15
71064e3f 16#ifndef WIN32
ea27a18c 17static void pager_preexec(void)
f67b45f8 18{
35ce8622
LT
19 /*
20 * Work around bug in "less" by not starting it until we
21 * have real input
22 */
23 fd_set in;
24
25 FD_ZERO(&in);
26 FD_SET(0, &in);
27 select(1, &in, NULL, &in, NULL);
f67b45f8 28}
ea27a18c 29#endif
bfdd9ffd 30
ac0ba18d 31static const char *pager_argv[] = { NULL, NULL };
ea27a18c
JK
32static struct child_process pager_process;
33
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JS
34static void wait_for_pager(void)
35{
36 fflush(stdout);
37 fflush(stderr);
38 /* signal EOF to pager */
39 close(1);
40 close(2);
41 finish_command(&pager_process);
42}
f67b45f8 43
a3da8821
JK
44static void wait_for_pager_signal(int signo)
45{
46 wait_for_pager();
47 sigchain_pop(signo);
48 raise(signo);
49}
50
63618245 51const char *git_pager(void)
f67b45f8 52{
63618245 53 const char *pager;
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54
55 if (!isatty(1))
63618245
JN
56 return NULL;
57
58 pager = getenv("GIT_PAGER");
cad3a205
JH
59 if (!pager) {
60 if (!pager_program)
ef90d6d4 61 git_config(git_default_config, NULL);
54adf370 62 pager = pager_program;
cad3a205 63 }
c27d205a
ML
64 if (!pager)
65 pager = getenv("PAGER");
402461aa 66 if (!pager)
a3d023d0 67 pager = DEFAULT_PAGER;
caef71a5 68 else if (!*pager || !strcmp(pager, "cat"))
63618245
JN
69 pager = NULL;
70
71 return pager;
72}
73
74void setup_pager(void)
75{
76 const char *pager = git_pager();
77
78 if (!pager)
402461aa
JS
79 return;
80
6e9af863 81 spawned_pager = 1; /* means we are emitting to terminal */
85fb65ed 82
bfdd9ffd 83 /* spawn the pager */
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84 pager_argv[0] = pager;
85 pager_process.use_shell = 1;
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86 pager_process.argv = pager_argv;
87 pager_process.in = -1;
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88 if (!getenv("LESS")) {
89 static const char *env[] = { "LESS=FRSX", NULL };
90 pager_process.env = env;
91 }
71064e3f 92#ifndef WIN32
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93 pager_process.preexec_cb = pager_preexec;
94#endif
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95 if (start_command(&pager_process))
96 return;
97
98 /* original process continues, but writes to the pipe */
99 dup2(pager_process.in, 1);
a8335024
JH
100 if (isatty(2))
101 dup2(pager_process.in, 2);
bfdd9ffd
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102 close(pager_process.in);
103
104 /* this makes sure that the parent terminates after the pager */
a3da8821 105 sigchain_push_common(wait_for_pager_signal);
bfdd9ffd 106 atexit(wait_for_pager);
f67b45f8 107}
6e9af863
JK
108
109int pager_in_use(void)
110{
111 const char *env;
112
113 if (spawned_pager)
114 return 1;
115
116 env = getenv("GIT_PAGER_IN_USE");
117 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
118}