1 files changed, 69 insertions, 0 deletions
diff --git a/IkiWiki/Plugin/editdiff.pm b/IkiWiki/Plugin/editdiff.pm
new file mode 100644
index 000000000..46eb1168e
--- /dev/null
+++ b/IkiWiki/Plugin/editdiff.pm
@@ -0,0 +1,69 @@
+#!/usr/bin/perl
+# This plugin adds a "Diff" button to the page edit form.
+package IkiWiki::Plugin::editdiff;
+
+use warnings;
+use strict;
+use IkiWiki 2.00;
+use HTML::Entities;
+use IPC::Open2;
+
+sub import { #{{{
+	hook(type => "formbuilder_setup", id => "editdiff",
+		call => \&formbuilder_setup);
+} #}}}
+
+sub diff ($$) { #{{{
+	my $orig=shift;
+	my $content=shift;
+
+	my $sigpipe=0;
+	$SIG{PIPE} = sub { $sigpipe=1; };
+
+	my $pid = open2(*DIFFOUT, *DIFFIN, 'diff', '-u', $orig, '-');
+	binmode($_, ':utf8') foreach (*DIFFIN, *DIFFOUT);
+
+	print DIFFIN $content;
+	close DIFFIN;
+	my $ret;
+	while (<DIFFOUT>) {
+		if (defined $ret) {
+			$ret.=$_;
+		}
+		elsif (/^\@\@/) {
+			$ret=$_;
+		}
+	}
+	close DIFFOUT;
+	waitpid $pid, 0;
+
+	$SIG{PIPE}="default";
+	return "couldn't run diff\n" if $sigpipe;
+
+	return "<pre>".encode_entities($ret)."</pre>";
+} #}}}
+
+sub formbuilder_setup { #{{{
+	my %params=@_;
+	my $form=$params{form};
+	my $page=$form->field("page");
+
+	return if $form->title ne "editpage"
+	          || $form->field("do") ne "edit";
+
+	$page = IkiWiki::titlepage(IkiWiki::possibly_foolish_untaint($page));
+	return unless exists $pagesources{$page};
+
+	push @{$params{buttons}}, "Diff";
+
+	if ($form->submitted eq "Diff") {
+		my $content=$form->field('editcontent');
+		$content=~s/\r\n/\n/g;
+		$content=~s/\r/\n/g;
+
+		my $diff = diff(srcfile($pagesources{$page}), $content);
+		$form->tmpl_param("page_preview", $diff);
+	}
+} #}}}
+
+1