File: pager.c

package info (click to toggle)
git 1:2.20.1-2+deb10u3
  • links: PTS, VCS
  • area: main
  • in suites:
  • size: 45,676 kB
  • sloc: ansic: 210,769; sh: 180,432; perl: 29,102; tcl: 21,663; python: 6,143; makefile: 3,700; sed: 189; php: 120; asm: 98; csh: 45; ruby: 24; lisp: 12
file content (229 lines) | stat: -rw-r--r-- 4,651 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
#include "cache.h"
#include "config.h"
#include "run-command.h"
#include "sigchain.h"
#include "alias.h"

#ifndef DEFAULT_PAGER
#define DEFAULT_PAGER "less"
#endif

static struct child_process pager_process = CHILD_PROCESS_INIT;
static const char *pager_program;

static void wait_for_pager(int in_signal)
{
	if (!in_signal) {
		fflush(stdout);
		fflush(stderr);
	}
	/* signal EOF to pager */
	close(1);
	close(2);
	if (in_signal)
		finish_command_in_signal(&pager_process);
	else
		finish_command(&pager_process);
}

static void wait_for_pager_atexit(void)
{
	wait_for_pager(0);
}

static void wait_for_pager_signal(int signo)
{
	wait_for_pager(1);
	sigchain_pop(signo);
	raise(signo);
}

static int core_pager_config(const char *var, const char *value, void *data)
{
	if (!strcmp(var, "core.pager"))
		return git_config_string(&pager_program, var, value);
	return 0;
}

const char *git_pager(int stdout_is_tty)
{
	const char *pager;

	if (!stdout_is_tty)
		return NULL;

	pager = getenv("GIT_PAGER");
	if (!pager) {
		if (!pager_program)
			read_early_config(core_pager_config, NULL);
		pager = pager_program;
	}
	if (!pager)
		pager = getenv("PAGER");
	if (!pager)
		pager = DEFAULT_PAGER;
	if (!*pager || !strcmp(pager, "cat"))
		pager = NULL;

	return pager;
}

static void setup_pager_env(struct argv_array *env)
{
	const char **argv;
	int i;
	char *pager_env = xstrdup(PAGER_ENV);
	int n = split_cmdline(pager_env, &argv);

	if (n < 0)
		die("malformed build-time PAGER_ENV: %s",
			split_cmdline_strerror(n));

	for (i = 0; i < n; i++) {
		char *cp = strchr(argv[i], '=');

		if (!cp)
			die("malformed build-time PAGER_ENV");

		*cp = '\0';
		if (!getenv(argv[i])) {
			*cp = '=';
			argv_array_push(env, argv[i]);
		}
	}
	free(pager_env);
	free(argv);
}

void prepare_pager_args(struct child_process *pager_process, const char *pager)
{
	argv_array_push(&pager_process->args, pager);
	pager_process->use_shell = 1;
	setup_pager_env(&pager_process->env_array);
}

void setup_pager(void)
{
	const char *pager = git_pager(isatty(1));

	if (!pager)
		return;

	/*
	 * After we redirect standard output, we won't be able to use an ioctl
	 * to get the terminal size. Let's grab it now, and then set $COLUMNS
	 * to communicate it to any sub-processes.
	 */
	{
		char buf[64];
		xsnprintf(buf, sizeof(buf), "%d", term_columns());
		setenv("COLUMNS", buf, 0);
	}

	setenv("GIT_PAGER_IN_USE", "true", 1);

	/* spawn the pager */
	prepare_pager_args(&pager_process, pager);
	pager_process.in = -1;
	argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
	if (start_command(&pager_process))
		return;

	/* original process continues, but writes to the pipe */
	dup2(pager_process.in, 1);
	if (isatty(2))
		dup2(pager_process.in, 2);
	close(pager_process.in);

	/* this makes sure that the parent terminates after the pager */
	sigchain_push_common(wait_for_pager_signal);
	atexit(wait_for_pager_atexit);
}

int pager_in_use(void)
{
	return git_env_bool("GIT_PAGER_IN_USE", 0);
}

/*
 * Return cached value (if set) or $COLUMNS environment variable (if
 * set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
 * and default to 80 if all else fails.
 */
int term_columns(void)
{
	static int term_columns_at_startup;

	char *col_string;
	int n_cols;

	if (term_columns_at_startup)
		return term_columns_at_startup;

	term_columns_at_startup = 80;

	col_string = getenv("COLUMNS");
	if (col_string && (n_cols = atoi(col_string)) > 0)
		term_columns_at_startup = n_cols;
#ifdef TIOCGWINSZ
	else {
		struct winsize ws;
		if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
			term_columns_at_startup = ws.ws_col;
	}
#endif

	return term_columns_at_startup;
}

/*
 * How many columns do we need to show this number in decimal?
 */
int decimal_width(uintmax_t number)
{
	int width;

	for (width = 1; number >= 10; width++)
		number /= 10;
	return width;
}

struct pager_command_config_data {
	const char *cmd;
	int want;
	char *value;
};

static int pager_command_config(const char *var, const char *value, void *vdata)
{
	struct pager_command_config_data *data = vdata;
	const char *cmd;

	if (skip_prefix(var, "pager.", &cmd) && !strcmp(cmd, data->cmd)) {
		int b = git_parse_maybe_bool(value);
		if (b >= 0)
			data->want = b;
		else {
			data->want = 1;
			data->value = xstrdup(value);
		}
	}

	return 0;
}

/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
int check_pager_config(const char *cmd)
{
	struct pager_command_config_data data;

	data.cmd = cmd;
	data.want = -1;
	data.value = NULL;

	read_early_config(pager_command_config, &data);

	if (data.value)
		pager_program = data.value;
	return data.want;
}