Merge branch 'jk/fix-alias-pager-config-key-warnings'
[git/git.git] / pager.c
1 #include "cache.h"
2 #include "run-command.h"
3 #include "sigchain.h"
4
5 #ifndef DEFAULT_PAGER
6 #define DEFAULT_PAGER "less"
7 #endif
8
9 /*
10 * This is split up from the rest of git so that we can do
11 * something different on Windows.
12 */
13
14 static const char *pager_argv[] = { NULL, NULL };
15 static struct child_process pager_process = CHILD_PROCESS_INIT;
16
17 static void wait_for_pager(void)
18 {
19 fflush(stdout);
20 fflush(stderr);
21 /* signal EOF to pager */
22 close(1);
23 close(2);
24 finish_command(&pager_process);
25 }
26
27 static void wait_for_pager_signal(int signo)
28 {
29 wait_for_pager();
30 sigchain_pop(signo);
31 raise(signo);
32 }
33
34 const char *git_pager(int stdout_is_tty)
35 {
36 const char *pager;
37
38 if (!stdout_is_tty)
39 return NULL;
40
41 pager = getenv("GIT_PAGER");
42 if (!pager) {
43 if (!pager_program)
44 git_config(git_default_config, NULL);
45 pager = pager_program;
46 }
47 if (!pager)
48 pager = getenv("PAGER");
49 if (!pager)
50 pager = DEFAULT_PAGER;
51 if (!*pager || !strcmp(pager, "cat"))
52 pager = NULL;
53
54 return pager;
55 }
56
57 void setup_pager(void)
58 {
59 const char *pager = git_pager(isatty(1));
60
61 if (!pager)
62 return;
63
64 /*
65 * force computing the width of the terminal before we redirect
66 * the standard output to the pager.
67 */
68 (void) term_columns();
69
70 setenv("GIT_PAGER_IN_USE", "true", 1);
71
72 /* spawn the pager */
73 pager_argv[0] = pager;
74 pager_process.use_shell = 1;
75 pager_process.argv = pager_argv;
76 pager_process.in = -1;
77 if (!getenv("LESS"))
78 argv_array_push(&pager_process.env_array, "LESS=FRX");
79 if (!getenv("LV"))
80 argv_array_push(&pager_process.env_array, "LV=-c");
81 argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
82 if (start_command(&pager_process))
83 return;
84
85 /* original process continues, but writes to the pipe */
86 dup2(pager_process.in, 1);
87 if (isatty(2))
88 dup2(pager_process.in, 2);
89 close(pager_process.in);
90
91 /* this makes sure that the parent terminates after the pager */
92 sigchain_push_common(wait_for_pager_signal);
93 atexit(wait_for_pager);
94 }
95
96 int pager_in_use(void)
97 {
98 const char *env;
99 env = getenv("GIT_PAGER_IN_USE");
100 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
101 }
102
103 /*
104 * Return cached value (if set) or $COLUMNS environment variable (if
105 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
106 * and default to 80 if all else fails.
107 */
108 int term_columns(void)
109 {
110 static int term_columns_at_startup;
111
112 char *col_string;
113 int n_cols;
114
115 if (term_columns_at_startup)
116 return term_columns_at_startup;
117
118 term_columns_at_startup = 80;
119
120 col_string = getenv("COLUMNS");
121 if (col_string && (n_cols = atoi(col_string)) > 0)
122 term_columns_at_startup = n_cols;
123 #ifdef TIOCGWINSZ
124 else {
125 struct winsize ws;
126 if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
127 term_columns_at_startup = ws.ws_col;
128 }
129 #endif
130
131 return term_columns_at_startup;
132 }
133
134 /*
135 * How many columns do we need to show this number in decimal?
136 */
137 int decimal_width(uintmax_t number)
138 {
139 int width;
140
141 for (width = 1; number >= 10; width++)
142 number /= 10;
143 return width;
144 }
145
146 /* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
147 int check_pager_config(const char *cmd)
148 {
149 int want = -1;
150 struct strbuf key = STRBUF_INIT;
151 const char *value = NULL;
152 strbuf_addf(&key, "pager.%s", cmd);
153 if (git_config_key_is_valid(key.buf) &&
154 !git_config_get_value(key.buf, &value)) {
155 int b = git_config_maybe_bool(key.buf, value);
156 if (b >= 0)
157 want = b;
158 else {
159 want = 1;
160 pager_program = xstrdup(value);
161 }
162 }
163 strbuf_release(&key);
164 return want;
165 }