From d7f7f59419c69580f22d7b74eb5d399412ad5483 Mon Sep 17 00:00:00 2001
From: Simon Ruderich <simon@ruderich.org>
Date: Sat, 16 Mar 2013 17:20:31 +0100
Subject: [PATCH] tig.pl: Spawn a pager.

---
 gitconfig.m4 |  2 +-
 tig.pl       | 21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/gitconfig.m4 b/gitconfig.m4
index 5b16dad..1977f2e 100644
--- a/gitconfig.m4
+++ b/gitconfig.m4
@@ -120,7 +120,7 @@ include(../lib.m4)
 	# precise enough control over formats and colors.
 	#
 	# tig = log --pretty=oneline --graph --all --decorate --abbrev-commit
-	tig = ! TIG | less
+	tig = ! TIG
 
 	# Create backup of uncommitted and untracked changes.
 	ssb = "! git stash save --include-untracked \
diff --git a/tig.pl b/tig.pl
index 3939deb..0d80e1f 100755
--- a/tig.pl
+++ b/tig.pl
@@ -43,6 +43,21 @@ my $format = '%x00'         # separator from --graph
 my @cmd = ('git', 'log', '--all', '--graph', "--format=$format");
 open my $fh, '-|', @cmd or die $!;
 
+my $pager = $ENV{PAGER};
+# Try to find an usable pager without searching $PATH.
+if (not defined $pager) {
+    foreach my $path (qw(/usr/bin/less /bin/less /usr/bin/more /bin/more)) {
+        next if not -x $path;
+
+        $pager = $path;
+        last;
+    }
+}
+# Use a pager if STDOUT is a terminal.
+if (-t STDOUT and defined $pager) {
+    open STDOUT, '|-', $pager or die $!;
+}
+
 while (my $line = <$fh>) {
     # History graph line.
     if ($line =~ m{^([|/\\_ ]+)$}) {
@@ -94,3 +109,9 @@ while (my $line = <$fh>) {
 }
 
 close $fh or die $!;
+
+# Necessary for the redirection to a pager or the pager terminates after our
+# script finishes without displaying all data.
+if (defined $pager) {
+    close STDOUT or die $!;
+}
-- 
2.44.1