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git/pager.c
Jeff King 6e9af863ee Support GIT_PAGER_IN_USE environment variable
When deciding whether or not to turn on automatic color
support, git_config_colorbool checks whether stdout is a
tty. However, because we run a pager, if stdout is not a
tty, we must check whether it is because we started the
pager. This used to be done by checking the pager_in_use
variable.

This variable was set only when the git program being run
started the pager; there was no way for an external program
running git indicate that it had already started a pager.
This patch allows a program to set GIT_PAGER_IN_USE to a
true value to indicate that even though stdout is not a tty,
it is because a pager is being used.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-12-11 00:42:05 -08:00

85 lines
1.4 KiB
C

#include "cache.h"
/*
* This is split up from the rest of git so that we might do
* something different on Windows, for example.
*/
static int spawned_pager;
static void run_pager(const char *pager)
{
/*
* Work around bug in "less" by not starting it until we
* have real input
*/
fd_set in;
FD_ZERO(&in);
FD_SET(0, &in);
select(1, &in, NULL, &in, NULL);
execlp(pager, pager, NULL);
execl("/bin/sh", "sh", "-c", pager, NULL);
}
void setup_pager(void)
{
pid_t pid;
int fd[2];
const char *pager = getenv("GIT_PAGER");
if (!isatty(1))
return;
if (!pager) {
if (!pager_program)
git_config(git_default_config);
pager = pager_program;
}
if (!pager)
pager = getenv("PAGER");
if (!pager)
pager = "less";
else if (!*pager || !strcmp(pager, "cat"))
return;
spawned_pager = 1; /* means we are emitting to terminal */
if (pipe(fd) < 0)
return;
pid = fork();
if (pid < 0) {
close(fd[0]);
close(fd[1]);
return;
}
/* return in the child */
if (!pid) {
dup2(fd[1], 1);
close(fd[0]);
close(fd[1]);
return;
}
/* The original process turns into the PAGER */
dup2(fd[0], 0);
close(fd[0]);
close(fd[1]);
setenv("LESS", "FRSX", 0);
run_pager(pager);
die("unable to execute pager '%s'", pager);
exit(255);
}
int pager_in_use(void)
{
const char *env;
if (spawned_pager)
return 1;
env = getenv("GIT_PAGER_IN_USE");
return env ? git_config_bool("GIT_PAGER_IN_USE", env) : 0;
}