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![SZEDER Gábor](/assets/img/avatar_default.png)
There are a couple of places where we want to clear the last line on the terminal, e.g. when a progress bar line is overwritten by a shorter line, then the end of that progress line would remain visible, unless we cover it up. In 'progress.c' we did this by always appending a fixed number of space characters to the next line (even if it was not shorter than the previous), but as it turned out that fixed number was not quite large enough, see the fix in9f1fd84e15
(progress: clear previous progress update dynamically, 2019-04-12). From then on we've been keeping track of the length of the last displayed progress line and appending the appropriate number of space characters to the next line, if necessary, but, alas, this approach turned out to be error prone, see the fix in1aed1a5f25
(progress: avoid empty line when breaking the progress line, 2019-05-19). The next patch in this series is about to fix a case where we don't clear the last line, and on occasion do end up with such garbage at the end of the line. It would be great if we could do that without the need to deal with that without meticulously computing the necessary number of space characters. So add a helper function to clear the last line on the terminal using an ANSI escape sequence, which has the advantage to clear the whole line no matter how wide it is, even after the terminal width changed. Such an escape sequence is not available on dumb terminals, though, so in that case fall back to simply print a whole terminal width (as reported by term_columns()) worth of space characters. In 'editor.c' launch_specified_editor() already used this ANSI escape sequence, so replace it with a call to this function. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
251 lines
5.1 KiB
C
251 lines
5.1 KiB
C
#include "cache.h"
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#include "config.h"
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#include "run-command.h"
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#include "sigchain.h"
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#include "alias.h"
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#ifndef DEFAULT_PAGER
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#define DEFAULT_PAGER "less"
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#endif
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static struct child_process pager_process = CHILD_PROCESS_INIT;
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static const char *pager_program;
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static void wait_for_pager(int in_signal)
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{
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if (!in_signal) {
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fflush(stdout);
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fflush(stderr);
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}
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/* signal EOF to pager */
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close(1);
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close(2);
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if (in_signal)
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finish_command_in_signal(&pager_process);
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else
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finish_command(&pager_process);
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}
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static void wait_for_pager_atexit(void)
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{
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wait_for_pager(0);
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}
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static void wait_for_pager_signal(int signo)
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{
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wait_for_pager(1);
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sigchain_pop(signo);
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raise(signo);
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}
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static int core_pager_config(const char *var, const char *value, void *data)
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{
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if (!strcmp(var, "core.pager"))
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return git_config_string(&pager_program, var, value);
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return 0;
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}
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const char *git_pager(int stdout_is_tty)
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{
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const char *pager;
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if (!stdout_is_tty)
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return NULL;
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pager = getenv("GIT_PAGER");
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if (!pager) {
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if (!pager_program)
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read_early_config(core_pager_config, NULL);
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pager = pager_program;
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}
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if (!pager)
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pager = getenv("PAGER");
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if (!pager)
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pager = DEFAULT_PAGER;
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if (!*pager || !strcmp(pager, "cat"))
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pager = NULL;
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return pager;
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}
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static void setup_pager_env(struct argv_array *env)
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{
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const char **argv;
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int i;
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char *pager_env = xstrdup(PAGER_ENV);
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int n = split_cmdline(pager_env, &argv);
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if (n < 0)
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die("malformed build-time PAGER_ENV: %s",
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split_cmdline_strerror(n));
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for (i = 0; i < n; i++) {
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char *cp = strchr(argv[i], '=');
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if (!cp)
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die("malformed build-time PAGER_ENV");
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*cp = '\0';
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if (!getenv(argv[i])) {
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*cp = '=';
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argv_array_push(env, argv[i]);
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}
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}
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free(pager_env);
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free(argv);
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}
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void prepare_pager_args(struct child_process *pager_process, const char *pager)
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{
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argv_array_push(&pager_process->args, pager);
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pager_process->use_shell = 1;
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setup_pager_env(&pager_process->env_array);
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pager_process->trace2_child_class = "pager";
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}
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void setup_pager(void)
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{
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const char *pager = git_pager(isatty(1));
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if (!pager)
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return;
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/*
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* After we redirect standard output, we won't be able to use an ioctl
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* to get the terminal size. Let's grab it now, and then set $COLUMNS
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* to communicate it to any sub-processes.
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*/
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{
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char buf[64];
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xsnprintf(buf, sizeof(buf), "%d", term_columns());
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setenv("COLUMNS", buf, 0);
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}
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setenv("GIT_PAGER_IN_USE", "true", 1);
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/* spawn the pager */
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prepare_pager_args(&pager_process, pager);
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pager_process.in = -1;
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argv_array_push(&pager_process.env_array, "GIT_PAGER_IN_USE");
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if (start_command(&pager_process))
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return;
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/* original process continues, but writes to the pipe */
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dup2(pager_process.in, 1);
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if (isatty(2))
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dup2(pager_process.in, 2);
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close(pager_process.in);
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/* this makes sure that the parent terminates after the pager */
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sigchain_push_common(wait_for_pager_signal);
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atexit(wait_for_pager_atexit);
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}
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int pager_in_use(void)
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{
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return git_env_bool("GIT_PAGER_IN_USE", 0);
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}
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/*
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* Return cached value (if set) or $COLUMNS environment variable (if
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* set and positive) or ioctl(1, TIOCGWINSZ).ws_col (if positive),
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* and default to 80 if all else fails.
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*/
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int term_columns(void)
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{
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static int term_columns_at_startup;
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char *col_string;
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int n_cols;
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if (term_columns_at_startup)
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return term_columns_at_startup;
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term_columns_at_startup = 80;
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col_string = getenv("COLUMNS");
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if (col_string && (n_cols = atoi(col_string)) > 0)
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term_columns_at_startup = n_cols;
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#ifdef TIOCGWINSZ
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else {
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struct winsize ws;
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if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_col)
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term_columns_at_startup = ws.ws_col;
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}
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#endif
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return term_columns_at_startup;
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}
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/*
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* Clear the entire line, leave cursor in first column.
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*/
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void term_clear_line(void)
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{
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if (is_terminal_dumb())
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/*
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* Fall back to print a terminal width worth of space
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* characters (hoping that the terminal is still as wide
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* as it was upon the first call to term_columns()).
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*/
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fprintf(stderr, "\r%*s\r", term_columns(), "");
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else
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/*
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* On non-dumb terminals use an escape sequence to clear
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* the whole line, no matter how wide the terminal.
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*/
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fputs("\r\033[K", stderr);
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}
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/*
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* How many columns do we need to show this number in decimal?
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*/
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int decimal_width(uintmax_t number)
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{
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int width;
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for (width = 1; number >= 10; width++)
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number /= 10;
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return width;
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}
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struct pager_command_config_data {
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const char *cmd;
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int want;
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char *value;
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};
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static int pager_command_config(const char *var, const char *value, void *vdata)
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{
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struct pager_command_config_data *data = vdata;
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const char *cmd;
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if (skip_prefix(var, "pager.", &cmd) && !strcmp(cmd, data->cmd)) {
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int b = git_parse_maybe_bool(value);
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if (b >= 0)
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data->want = b;
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else {
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data->want = 1;
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data->value = xstrdup(value);
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}
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}
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return 0;
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}
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/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
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int check_pager_config(const char *cmd)
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{
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struct pager_command_config_data data;
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data.cmd = cmd;
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data.want = -1;
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data.value = NULL;
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read_early_config(pager_command_config, &data);
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if (data.value)
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pager_program = data.value;
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return data.want;
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}
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