00c8baace0f9bf73c8f809639babce775310237b
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
9static struct child_process pager_process = CHILD_PROCESS_INIT;
10static const char *pager_program;
11
12static void wait_for_pager(int in_signal)
13{
14 if (!in_signal) {
15 fflush(stdout);
16 fflush(stderr);
17 }
18 /* signal EOF to pager */
19 close(1);
20 close(2);
21 if (in_signal)
22 finish_command_in_signal(&pager_process);
23 else
24 finish_command(&pager_process);
25}
26
27static void wait_for_pager_atexit(void)
28{
29 wait_for_pager(0);
30}
31
32static void wait_for_pager_signal(int signo)
33{
34 wait_for_pager(1);
35 sigchain_pop(signo);
36 raise(signo);
37}
38
39static int core_pager_config(const char *var, const char *value, void *data)
40{
41 if (!strcmp(var, "core.pager"))
42 return git_config_string(&pager_program, var, value);
43 return 0;
44}
45
46const char *git_pager(int stdout_is_tty)
47{
48 const char *pager;
49
50 if (!stdout_is_tty)
51 return NULL;
52
53 pager = getenv("GIT_PAGER");
54 if (!pager) {
55 if (!pager_program)
56 git_config(core_pager_config, NULL);
57 pager = pager_program;
58 }
59 if (!pager)
60 pager = getenv("PAGER");
61 if (!pager)
62 pager = DEFAULT_PAGER;
63 if (!*pager || !strcmp(pager, "cat"))
64 pager = NULL;
65
66 return pager;
67}
68
69void prepare_pager_args(struct child_process *pager_process, const char *pager)
70{
71 argv_array_push(&pager_process->args, pager);
72 pager_process->use_shell = 1;
73 if (!getenv("LESS"))
74 argv_array_push(&pager_process->env_array, "LESS=FRX");
75 if (!getenv("LV"))
76 argv_array_push(&pager_process->env_array, "LV=-c");
77}
78
79void setup_pager(void)
80{
81 const char *pager = git_pager(isatty(1));
82
83 if (!pager)
84 return;
85
86 /*
87 * force computing the width of the terminal before we redirect
88 * the standard output to the pager.
89 */
90 (void) term_columns();
91
92 setenv("GIT_PAGER_IN_USE", "true", 1);
93
94 /* spawn the pager */
95 prepare_pager_args(&pager_process, pager);
96 pager_process.in = -1;
97 argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
98 if (start_command(&pager_process))
99 return;
100
101 /* original process continues, but writes to the pipe */
102 dup2(pager_process.in, 1);
103 if (isatty(2))
104 dup2(pager_process.in, 2);
105 close(pager_process.in);
106
107 /* this makes sure that the parent terminates after the pager */
108 sigchain_push_common(wait_for_pager_signal);
109 atexit(wait_for_pager_atexit);
110}
111
112int pager_in_use(void)
113{
114 const char *env;
115 env = getenv("GIT_PAGER_IN_USE");
116 return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
117}
118
119/*
120 * Return cached value (if set) or $COLUMNS environment variable (if
121 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
122 * and default to 80 if all else fails.
123 */
124int term_columns(void)
125{
126 static int term_columns_at_startup;
127
128 char *col_string;
129 int n_cols;
130
131 if (term_columns_at_startup)
132 return term_columns_at_startup;
133
134 term_columns_at_startup = 80;
135
136 col_string = getenv("COLUMNS");
137 if (col_string && (n_cols = atoi(col_string)) > 0)
138 term_columns_at_startup = n_cols;
139#ifdef TIOCGWINSZ
140 else {
141 struct winsize ws;
142 if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
143 term_columns_at_startup = ws.ws_col;
144 }
145#endif
146
147 return term_columns_at_startup;
148}
149
150/*
151 * How many columns do we need to show this number in decimal?
152 */
153int decimal_width(uintmax_t number)
154{
155 int width;
156
157 for (width = 1; number >= 10; width++)
158 number /= 10;
159 return width;
160}
161
162/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
163int check_pager_config(const char *cmd)
164{
165 int want = -1;
166 struct strbuf key = STRBUF_INIT;
167 const char *value = NULL;
168 strbuf_addf(&key, "pager.%s", cmd);
169 if (git_config_key_is_valid(key.buf) &&
170 !git_config_get_value(key.buf, &value)) {
171 int b = git_config_maybe_bool(key.buf, value);
172 if (b >= 0)
173 want = b;
174 else {
175 want = 1;
176 pager_program = xstrdup(value);
177 }
178 }
179 strbuf_release(&key);
180 return want;
181}