patch-range.pl: extract peculiarities

We pipe the output of the patch program to stderr (to have it show
up in *debug*) and print to stdout the remaining diff (the part of
the diff that was not passed to patch).

The next patch wants to use this script in a different way, so move
these decisions up.

2 files changed, 28 insertions, 16 deletions

diff --git a/rc/tools/patch-range.pl b/rc/tools/patch-range.pl
index 978f45c3..2d54ab26 100755
--- a/rc/tools/patch-range.pl
+++ b/rc/tools/patch-range.pl
@@ -3,6 +3,12 @@
 use strict;
 use warnings;
 
+my $print_remaining = 0;
+if ($ARGV[0] eq "-print-remaining-diff") {
+    $print_remaining = 1;
+    shift @ARGV;
+}
+
 my $min_line = $ARGV[0];
 shift @ARGV;
 my $max_line = $ARGV[0];
@@ -20,13 +26,13 @@ my $lineno = 0;
 my $original = "";
 my $diff_header = "";
 my $wheat = "";
-my $chaff = "";
+my $chaff = "" if $print_remaining;
 my $state = undef;
 my $hunk_wheat = undef;
-my $hunk_chaff = undef;
+my $hunk_chaff = undef if $print_remaining;
 my $hunk_header = undef;
 my $hunk_remaining_lines = undef;
-my $signature = "";
+my $signature = "" if $print_remaining;
 
 sub compute_hunk_header {
     my $original_header = shift;
@@ -50,7 +56,9 @@ sub finish_hunk {
         }
         $wheat .= (compute_hunk_header $hunk_header, $hunk_wheat). $hunk_wheat;
     }
-    $chaff .= (compute_hunk_header $hunk_header, $hunk_chaff) . $hunk_chaff . $signature;
+    if ($print_remaining) {
+        $chaff .= (compute_hunk_header $hunk_header, $hunk_chaff) . $hunk_chaff . $signature;
+    }
     $hunk_header = undef;
 }
 
@@ -63,7 +71,7 @@ while (<STDIN>) {
         $diff_header = "";
     }
     if ($state eq "signature") {
-        $signature .= $_;
+        $signature .= $_ if $print_remaining;
         next;
     }
     if (m{^@@ -\d+(?:,(\d)+)? \+\d+(?:,\d+)? @@}) {
@@ -72,42 +80,46 @@ while (<STDIN>) {
         $state = "diff hunk";
         $hunk_header = $_;
         $hunk_wheat = "";
-        $hunk_chaff = "";
-        $signature = "";
+        if ($print_remaining) {
+            $hunk_chaff = "";
+            $signature = "";
+        }
         next;
     }
     if ($state eq "diff header") {
         $diff_header .= $_;
-        $chaff .= $_;
+        $chaff .= $_ if $print_remaining;
         next;
     }
     if ($hunk_remaining_lines == 0 and m{^-- $}) {
         $state = "signature";
-        $signature .= $_;
+        $signature .= $_ if $print_remaining;
         next;
     }
     --$hunk_remaining_lines if m{^[ -]};
     my $include = m{^ } || ($lineno >= $min_line && $lineno <= $max_line);
     if ($include) {
         $hunk_wheat .= $_;
-        $hunk_chaff .= $_ if m{^ };
-        if ($reverse ? m{^[-]} : m{^\+}) {
-            $hunk_chaff .= " " . substr $_, 1;
+        if ($print_remaining) {
+            $hunk_chaff .= $_ if m{^ };
+            if ($reverse ? m{^[-]} : m{^\+}) {
+                $hunk_chaff .= " " . substr $_, 1;
+            }
         }
     } else {
         if ($reverse ? m{^\+} : m{^-}) {
             $hunk_wheat .= " " . substr $_, 1;
         }
-        $hunk_chaff .= $_;
+        $hunk_chaff .= $_ if $print_remaining;
     }
 }
 finish_hunk();
 
-open PATCH_COMMAND, "|-", "$patch_cmd 1>&2" or die "patch-range.pl: error running '$patch_cmd': $!";
+open PATCH_COMMAND, "|-", "$patch_cmd" or die "patch-range.pl: error running '$patch_cmd': $!";
 print PATCH_COMMAND $wheat;
 if (not close PATCH_COMMAND) {
     print $original;
     print STDERR "patch-range.pl: error running:\n" . "\$ $patch_cmd << EOF\n$wheat" . "EOF\n";
     exit 1;
 }
-print $chaff;
+print $chaff if $print_remaining;
diff --git a/rc/tools/patch.kak b/rc/tools/patch.kak
index a481ff41..4ac50f24 100644
--- a/rc/tools/patch.kak
+++ b/rc/tools/patch.kak
@@ -52,7 +52,7 @@ define-command patch -params .. -docstring %{
             # a shell where it expands to nothing.
             eval set -- "$kak_quoted_reg_a"
 
-            perl "${kak_runtime}"/rc/tools/patch-range.pl $min_line $max_line "$@" ||
+            perl "${kak_runtime}"/rc/tools/patch-range.pl -print-remaining-diff $min_line $max_line "$@" ">&2" ||
                 echo >$kak_command_fifo "set-register e fail 'patch: failed to apply selections, see *debug* buffer'"
         }
         execute-keys |<ret>