debian/git-email: use perl instead of perl-modules in dependency
[git/debian.git] / pager.c
blobc113d898a4ab184cf5ad5ea04dc66365fdf8a8f8
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 static struct child_process pager_process = CHILD_PROCESS_INIT;
10 static const char *pager_program;
12 static void wait_for_pager(int in_signal)
14 if (!in_signal) {
15 fflush(stdout);
16 fflush(stderr);
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);
27 static void wait_for_pager_atexit(void)
29 wait_for_pager(0);
32 static void wait_for_pager_signal(int signo)
34 wait_for_pager(1);
35 sigchain_pop(signo);
36 raise(signo);
39 static int core_pager_config(const char *var, const char *value, void *data)
41 if (!strcmp(var, "core.pager"))
42 return git_config_string(&pager_program, var, value);
43 return 0;
46 const char *git_pager(int stdout_is_tty)
48 const char *pager;
50 if (!stdout_is_tty)
51 return NULL;
53 pager = getenv("GIT_PAGER");
54 if (!pager) {
55 if (!pager_program)
56 read_early_config(core_pager_config, NULL);
57 pager = pager_program;
59 if (!pager)
60 pager = getenv("PAGER");
61 if (!pager)
62 pager = DEFAULT_PAGER;
63 if (!*pager || !strcmp(pager, "cat"))
64 pager = NULL;
66 return pager;
69 static void setup_pager_env(struct argv_array *env)
71 const char **argv;
72 int i;
73 char *pager_env = xstrdup(PAGER_ENV);
74 int n = split_cmdline(pager_env, &argv);
76 if (n < 0)
77 die("malformed build-time PAGER_ENV: %s",
78 split_cmdline_strerror(n));
80 for (i = 0; i < n; i++) {
81 char *cp = strchr(argv[i], '=');
83 if (!cp)
84 die("malformed build-time PAGER_ENV");
86 *cp = '\0';
87 if (!getenv(argv[i])) {
88 *cp = '=';
89 argv_array_push(env, argv[i]);
92 free(pager_env);
93 free(argv);
96 void prepare_pager_args(struct child_process *pager_process, const char *pager)
98 argv_array_push(&pager_process->args, pager);
99 pager_process->use_shell = 1;
100 setup_pager_env(&pager_process->env_array);
103 void setup_pager(void)
105 const char *pager = git_pager(isatty(1));
107 if (!pager)
108 return;
111 * force computing the width of the terminal before we redirect
112 * the standard output to the pager.
114 (void) term_columns();
116 setenv("GIT_PAGER_IN_USE", "true", 1);
118 /* spawn the pager */
119 prepare_pager_args(&pager_process, pager);
120 pager_process.in = -1;
121 argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
122 if (start_command(&pager_process))
123 return;
125 /* original process continues, but writes to the pipe */
126 dup2(pager_process.in, 1);
127 if (isatty(2))
128 dup2(pager_process.in, 2);
129 close(pager_process.in);
131 /* this makes sure that the parent terminates after the pager */
132 sigchain_push_common(wait_for_pager_signal);
133 atexit(wait_for_pager_atexit);
136 int pager_in_use(void)
138 return git_env_bool("GIT_PAGER_IN_USE", 0);
142 * Return cached value (if set) or $COLUMNS environment variable (if
143 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
144 * and default to 80 if all else fails.
146 int term_columns(void)
148 static int term_columns_at_startup;
150 char *col_string;
151 int n_cols;
153 if (term_columns_at_startup)
154 return term_columns_at_startup;
156 term_columns_at_startup = 80;
158 col_string = getenv("COLUMNS");
159 if (col_string && (n_cols = atoi(col_string)) > 0)
160 term_columns_at_startup = n_cols;
161 #ifdef TIOCGWINSZ
162 else {
163 struct winsize ws;
164 if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
165 term_columns_at_startup = ws.ws_col;
167 #endif
169 return term_columns_at_startup;
173 * How many columns do we need to show this number in decimal?
175 int decimal_width(uintmax_t number)
177 int width;
179 for (width = 1; number >= 10; width++)
180 number /= 10;
181 return width;
184 struct pager_command_config_data {
185 const char *cmd;
186 int want;
187 char *value;
190 static int pager_command_config(const char *var, const char *value, void *vdata)
192 struct pager_command_config_data *data = vdata;
193 const char *cmd;
195 if (skip_prefix(var, "pager.", &cmd) && !strcmp(cmd, data->cmd)) {
196 int b = git_config_maybe_bool(var, value);
197 if (b >= 0)
198 data->want = b;
199 else {
200 data->want = 1;
201 data->value = xstrdup(value);
205 return 0;
208 /* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
209 int check_pager_config(const char *cmd)
211 struct pager_command_config_data data;
213 data.cmd = cmd;
214 data.want = -1;
215 data.value = NULL;
217 read_early_config(pager_command_config, &data);
219 if (data.value)
220 pager_program = data.value;
221 return data.want;