Since f67b45f862 (Introduce trivial new pager.c helper infrastructure,
2006-02-28) we have the machinery to send our output to a pager.
That machinery, once set up, does not allow us to regain the original
stdio streams.
In the interactive commands (i.e.: add -p) we want to use the pager for
some output, while maintaining the interaction with the user.
Modify the pager machinery so that we can use `setup_pager()` and, once
we've finished sending the desired output for the pager, wait for the
pager termination using a new function `wait_for_pager()`. Make this
function reset the pager machinery before returning.
One specific point to note is that we avoid forking the pager in
`setup_pager()` if the configured pager is an empty string [*1*] or
simply "cat" [*2*]. In these cases, `setup_pager()` does nothing and
therefore `wait_for_pager()` should not be called.
We could modify `setup_pager()` to return an indication of these
situations, so we could avoid calling `wait_for_pager()`.
However, let's avoid transferring that responsibility to the caller and
instead treat the call to `wait_for_pager()` as a no-op when we know we
haven't forked the pager.
1.- 402461aab1 (pager: do not fork a pager if PAGER is set to empty.,
2006-04-16)
2.- caef71a535 (Do not fork PAGER=cat, 2006-04-16)
Signed-off-by: Rubén Justo <rjusto@xxxxxxxxx>
---
pager.c | 46 ++++++++++++++++++++++++++++++++++++++++------
pager.h | 1 +
2 files changed, 41 insertions(+), 6 deletions(-)
diff --git a/pager.c b/pager.c
index 251adfc2ad..896f40fcd2 100644
--- a/pager.c
+++ b/pager.c
@@ -14,7 +14,7 @@ int pager_use_color = 1;
static struct child_process pager_process;
static char *pager_program;
-static int close_fd2;
+static int old_fd1 = -1, old_fd2 = -1;
/* Is the value coming back from term_columns() just a guess? */
static int term_columns_guessed;
@@ -24,11 +24,11 @@ static void close_pager_fds(void)
{
/* signal EOF to pager */
close(1);
- if (close_fd2)
+ if (old_fd2 != -1)
close(2);
}
-static void wait_for_pager_atexit(void)
+static void finish_pager(void)
{
fflush(stdout);
fflush(stderr);
@@ -36,8 +36,37 @@ static void wait_for_pager_atexit(void)
finish_command(&pager_process);
}
+static void wait_for_pager_atexit(void)
+{
+ if (old_fd1 == -1)
+ return;
+
+ finish_pager();
+}
+
+void wait_for_pager(void)
+{
+ if (old_fd1 == -1)
+ return;
+
+ finish_pager();
+ sigchain_pop_common();
+ unsetenv("GIT_PAGER_IN_USE");
+ dup2(old_fd1, 1);
+ close(old_fd1);
+ old_fd1 = -1;
+ if (old_fd2 != -1) {
+ dup2(old_fd2, 2);
+ close(old_fd2);
+ old_fd2 = -1;
+ }
+}
+
static void wait_for_pager_signal(int signo)
{
+ if (old_fd1 == -1)
+ return;
+
close_pager_fds();
finish_command_in_signal(&pager_process);
sigchain_pop(signo);
@@ -113,6 +142,7 @@ void prepare_pager_args(struct child_process *pager_process, const char *pager)
void setup_pager(void)
{
+ static int once = 0;
const char *pager = git_pager(isatty(1));
if (!pager)
@@ -142,16 +172,20 @@ void setup_pager(void)
die("unable to execute pager '%s'", pager);
/* original process continues, but writes to the pipe */
+ old_fd1 = dup(1);
dup2(pager_process.in, 1);
if (isatty(2)) {
- close_fd2 = 1;
+ old_fd2 = dup(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);
+
+ if (!once) {
+ once++;
+ atexit(wait_for_pager_atexit);
+ }
}
int pager_in_use(void)
diff --git a/pager.h b/pager.h
index b77433026d..103ecac476 100644
--- a/pager.h
+++ b/pager.h
@@ -5,6 +5,7 @@ struct child_process;
const char *git_pager(int stdout_is_tty);
void setup_pager(void);
+void wait_for_pager(void);
int pager_in_use(void);
int term_columns(void);
void term_clear_line(void);
--
2.46.0.rc0.4.g6f4990c0d4
