git/pager.c
Junio C Hamano a3d023d0a3 Provide a build time default-pager setting
Provide a DEFAULT_PAGER knob so packagers can set the fallback
pager to something appropriate during the build.

Examples:

On (old) solaris systems, /usr/bin/less (typically the first less
found) doesn't understand the default arguments (FXRS), which
forces users to alter their environment (PATH, GIT_PAGER, LESS,
etc) or have a local or global gitconfig before paging works as
expected.

On Debian systems, by policy packages must fall back to the
'pager' command, so that changing the target of the
/usr/bin/pager symlink changes the default pager for all packages
at once.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-11-13 12:20:56 -08:00

118 lines
2.1 KiB
C

#include "cache.h"
#include "run-command.h"
#include "sigchain.h"
#ifndef DEFAULT_PAGER
#define DEFAULT_PAGER "less"
#endif
/*
* This is split up from the rest of git so that we can do
* something different on Windows.
*/
static int spawned_pager;
#ifndef WIN32
static void pager_preexec(void)
{
/*
* 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);
}
#endif
static const char *pager_argv[] = { "sh", "-c", NULL, NULL };
static struct child_process pager_process;
static void wait_for_pager(void)
{
fflush(stdout);
fflush(stderr);
/* signal EOF to pager */
close(1);
close(2);
finish_command(&pager_process);
}
static void wait_for_pager_signal(int signo)
{
wait_for_pager();
sigchain_pop(signo);
raise(signo);
}
const char *git_pager(void)
{
const char *pager;
if (!isatty(1))
return NULL;
pager = getenv("GIT_PAGER");
if (!pager) {
if (!pager_program)
git_config(git_default_config, NULL);
pager = pager_program;
}
if (!pager)
pager = getenv("PAGER");
if (!pager)
pager = DEFAULT_PAGER;
else if (!*pager || !strcmp(pager, "cat"))
pager = NULL;
return pager;
}
void setup_pager(void)
{
const char *pager = git_pager();
if (!pager)
return;
spawned_pager = 1; /* means we are emitting to terminal */
/* spawn the pager */
pager_argv[2] = pager;
pager_process.argv = pager_argv;
pager_process.in = -1;
if (!getenv("LESS")) {
static const char *env[] = { "LESS=FRSX", NULL };
pager_process.env = env;
}
#ifndef WIN32
pager_process.preexec_cb = pager_preexec;
#endif
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);
}
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;
}