From 598285f72ae22bca87d53a29651e7110a253b25b Mon Sep 17 00:00:00 2001
From: Mischa POSLAWSKY <perl@shiar.org>
Date: Thu, 25 Nov 2021 00:48:49 +0100
Subject: [PATCH] source: cache syntax highlighted html

Massive speedup on repeated requests since Text::VimColor is so slow
(but the only readily available option for plp syntax).
---
 .gitignore |  5 ++++-
 source.plp | 11 +++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/.gitignore b/.gitignore
index 142f46a..8815520 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,12 +2,15 @@
 /data
 /word/put.js
 
-# derived contents
+# derived or compiled contents
 /sitemap.xml
 /light.css
 /UPDATE
 /plan.plp
 /word/*.min.js
 
+# optional cache files
+/source/*.html
+
 # site owner tag for google webmaster tools
 /google????????????????.html
diff --git a/source.plp b/source.plp
index e645cd2..43fddb6 100644
--- a/source.plp
+++ b/source.plp
@@ -74,6 +74,16 @@ else {
 	-r $source or Abort("Requested file not found", '404 source not found');
 	my $size = (stat $source)->[7];
 
+	my $cachefile = "source/$source.html";
+	if (-e $cachefile and (stat $cachefile)->[9] >= (stat $source)->[9]) {
+		say '<pre>';
+		print ReadFile($cachefile);
+		say '</pre>';
+		exit;
+	}
+	open my $cache, '>', $cachefile
+		or Alert("Could not save cache", "Opening $cachefile failed: $!");;
+
 	if (my $hl = eval {
 		$size < 32_768 or die 'large files take too long to parse';
 		require Text::VimColor;
@@ -110,6 +120,7 @@ else {
 
 			$line = qq(<$tag class="sy-\l$type">$line</$tag>) if $tag;
 			print $line;
+			print {$cache} $line if $cache;
 		}
 		say '</pre>';
 	}
-- 
2.30.0