Color support for "git-add -i"

This is mostly lifted from earlier series by Dan Zwell, but updated to
use "git config --get-color" and "git config --get-colorbool" to make it
simpler and more consistent with commands written in C.

A new configuration color.interactive variable is like color.diff and
color.status, and controls if "git-add -i" uses color.

A set of configuration variables, color.interactive.<slot>, are used to
define what color is used for the prompt, header, and help text.

For perl scripts, Git.pm provides $repo->get_color() method, which takes
the slot name and the default color, and returns the terminal escape
sequence to color the output text.  $repo->get_colorbool() method can be
used to check if color is set to be used for a given operation.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/perl/Git.pm b/perl/Git.pm
index 7468460f9a..a2812ea612 100644
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -581,6 +581,41 @@ sub config_int {
 	};
 }
 
+=item get_colorbool ( NAME )
+
+Finds if color should be used for NAMEd operation from the configuration,
+and returns boolean (true for "use color", false for "do not use color").
+
+=cut
+
+sub get_colorbool {
+	my ($self, $var) = @_;
+	my $stdout_to_tty = (-t STDOUT) ? "true" : "false";
+	my $use_color = $self->command_oneline('config', '--get-colorbool',
+					       $var, $stdout_to_tty);
+	return ($use_color eq 'true');
+}
+
+=item get_color ( SLOT, COLOR )
+
+Finds color for SLOT from the configuration, while defaulting to COLOR,
+and returns the ANSI color escape sequence:
+
+	print $repo->get_color("color.interactive.prompt", "underline blue white");
+	print "some text";
+	print $repo->get_color("", "normal");
+
+=cut
+
+sub get_color {
+	my ($self, $slot, $default) = @_;
+	my $color = $self->command_oneline('config', '--get-color', $slot, $default);
+	if (!defined $color) {
+		$color = "";
+	}
+	return $color;
+}
+
 =item ident ( TYPE | IDENTSTR )
 
 =item ident_person ( TYPE | IDENTSTR | IDENTARRAY )