* Change the aggregate plugin's locking strategy. Now it defers loading state

  until the wiki is building and already locked, unless it's aggregating.
  When aggregating, it does not wait for the lock if it cannot get it, and
  instead exits, to prevent aggregating processes from piling up.

1 files changed, 13 insertions, 5 deletions

diff --git a/IkiWiki/Plugin/aggregate.pm b/IkiWiki/Plugin/aggregate.pm
index 78f8b409c..082290114 100644
--- a/IkiWiki/Plugin/aggregate.pm
+++ b/IkiWiki/Plugin/aggregate.pm
@@ -31,22 +31,26 @@ sub getopt () { #{{{
 } #}}}
 
 sub checkconfig () { #{{{
-	my $nolock=($config{post_commit} && ! IkiWiki::commit_hook_enabled());
-	IkiWiki::lockwiki() unless $nolock;
-	loadstate();
-	if ($config{aggregate} && ! $nolock) {
+	if ($config{aggregate} && ! ($config{post_commit} && 
+	                             IkiWiki::commit_hook_enabled())) {
+		# don't wait for the lock
+		IkiWiki::lockwiki(0) || exit 1;
+	
+		loadstate();
 		IkiWiki::loadindex();
 		aggregate();
 		expire();
 		savestate();
+
+		IkiWiki::unlockwiki();
 	}
-	IkiWiki::unlockwiki() unless $nolock;
 } #}}}
 
 sub filter (@) { #{{{
 	my %params=@_;
 	my $page=$params{page};
 
+	loadstate(); # if not already loaded
 	# Mark all feeds originating on this page as removable;
 	# preprocess will unmark those that still exist.
 	remove_feeds($page);
@@ -117,7 +121,9 @@ sub delete (@) { #{{{
 	}
 } #}}}
 
+my $state_loaded=0;
 sub loadstate () { #{{{
+	return if $state_loaded;
 	if (-e "$config{wikistatedir}/aggregate") {
 		open (IN, "$config{wikistatedir}/aggregate" ||
 			die "$config{wikistatedir}/aggregate: $!");
@@ -148,6 +154,8 @@ sub loadstate () { #{{{
 		}
 
 		close IN;
+		
+		$state_loaded=1;
 	}
 } #}}}