t0050: Use TAB for indentation
[git/jnareb-git.git] / pager.c
blob4dcb08d9674c252cbe2c2725f92eca2a0350dc93
1 #include "cache.h"
2 #include "run-command.h"
3 #include "sigchain.h"
5 #ifndef DEFAULT_PAGER
6 #define DEFAULT_PAGER "less"
7 #endif
9 /*
10 * This is split up from the rest of git so that we can do
11 * something different on Windows.
14 #ifndef WIN32
15 static void pager_preexec(void)
18 * Work around bug in "less" by not starting it until we
19 * have real input
21 fd_set in;
23 FD_ZERO(&in);
24 FD_SET(0, &in);
25 select(1, &in, NULL, &in, NULL);
27 #endif
29 static const char *pager_argv[] = { NULL, NULL };
30 static struct child_process pager_process;
32 static void wait_for_pager(void)
34 fflush(stdout);
35 fflush(stderr);
36 /* signal EOF to pager */
37 close(1);
38 close(2);
39 finish_command(&pager_process);
42 static void wait_for_pager_signal(int signo)
44 wait_for_pager();
45 sigchain_pop(signo);
46 raise(signo);
49 const char *git_pager(int stdout_is_tty)
51 const char *pager;
53 if (!stdout_is_tty)
54 return NULL;
56 pager = getenv("GIT_PAGER");
57 if (!pager) {
58 if (!pager_program)
59 git_config(git_default_config, NULL);
60 pager = pager_program;
62 if (!pager)
63 pager = getenv("PAGER");
64 if (!pager)
65 pager = DEFAULT_PAGER;
66 else if (!*pager || !strcmp(pager, "cat"))
67 pager = NULL;
69 return pager;
72 void setup_pager(void)
74 const char *pager = git_pager(isatty(1));
76 if (!pager || pager_in_use())
77 return;
80 * force computing the width of the terminal before we redirect
81 * the standard output to the pager.
83 (void) term_columns();
85 setenv("GIT_PAGER_IN_USE", "true", 1);
87 /* spawn the pager */
88 pager_argv[0] = pager;
89 pager_process.use_shell = 1;
90 pager_process.argv = pager_argv;
91 pager_process.in = -1;
92 if (!getenv("LESS")) {
93 static const char *env[] = { "LESS=FRSX", NULL };
94 pager_process.env = env;
96 #ifndef WIN32
97 pager_process.preexec_cb = pager_preexec;
98 #endif
99 if (start_command(&pager_process))
100 return;
102 /* original process continues, but writes to the pipe */
103 dup2(pager_process.in, 1);
104 if (isatty(2))
105 dup2(pager_process.in, 2);
106 close(pager_process.in);
108 /* this makes sure that the parent terminates after the pager */
109 sigchain_push_common(wait_for_pager_signal);
110 atexit(wait_for_pager);
113 int pager_in_use(void)
115 const char *env;
116 env = getenv("GIT_PAGER_IN_USE");
117 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
121 * Return cached value (if set) or $COLUMNS environment variable (if
122 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
123 * and default to 80 if all else fails.
125 int term_columns(void)
127 static int term_columns_at_startup;
129 char *col_string;
130 int n_cols;
132 if (term_columns_at_startup)
133 return term_columns_at_startup;
135 term_columns_at_startup = 80;
137 col_string = getenv("COLUMNS");
138 if (col_string && (n_cols = atoi(col_string)) > 0)
139 term_columns_at_startup = n_cols;
140 #ifdef TIOCGWINSZ
141 else {
142 struct winsize ws;
143 if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
144 term_columns_at_startup = ws.ws_col;
146 #endif
148 return term_columns_at_startup;
152 * How many columns do we need to show this number in decimal?
154 int decimal_width(int number)
156 int i, width;
158 for (width = 1, i = 10; i <= number; width++)
159 i *= 10;
160 return width;