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1 #!/usr/bin/perl
2 # Feed aggregation plugin.
3 package IkiWiki::Plugin::aggregate;
4
5 use warnings;
6 use strict;
7 use IkiWiki 3.00;
8 use HTML::Parser;
9 use HTML::Tagset;
10 use HTML::Entities;
11 use open qw{:utf8 :std};
12
13 my %feeds;
14 my %guids;
15
16 sub import {
17         hook(type => "getopt", id => "aggregate", call => \&getopt);
18         hook(type => "getsetup", id => "aggregate", call => \&getsetup);
19         hook(type => "checkconfig", id => "aggregate", call => \&checkconfig);
20         hook(type => "needsbuild", id => "aggregate", call => \&needsbuild);
21         hook(type => "preprocess", id => "aggregate", call => \&preprocess);
22         hook(type => "delete", id => "aggregate", call => \&delete);
23         hook(type => "savestate", id => "aggregate", call => \&savestate);
24         hook(type => "htmlize", id => "_aggregated", call => \&htmlize);
25         if (exists $config{aggregate_webtrigger} && $config{aggregate_webtrigger}) {
26                 hook(type => "cgi", id => "aggregate", call => \&cgi);
27         }
28 }
29
30 sub getopt () {
31         eval q{use Getopt::Long};
32         error($@) if $@;
33         Getopt::Long::Configure('pass_through');
34         GetOptions(
35                 "aggregate" => \$config{aggregate},
36                 "aggregateinternal!" => \$config{aggregateinternal},
37         );
38 }
39
40 sub getsetup () {
41         return
42                 plugin => {
43                         safe => 1,
44                         rebuild => undef,
45                 },
46                 aggregateinternal => {
47                         type => "boolean",
48                         example => 1,
49                         description => "enable aggregation to internal pages?",
50                         safe => 0, # enabling needs manual transition
51                         rebuild => 0,
52                 },
53                 aggregate_webtrigger => {
54                         type => "boolean",
55                         example => 0,
56                         description => "allow aggregation to be triggered via the web?",
57                         safe => 1,
58                         rebuild => 0,
59                 },
60 }
61
62 sub checkconfig () {
63         if (! defined $config{aggregateinternal}) {
64                 $config{aggregateinternal}=1;
65         }
66
67         if ($config{aggregate} && ! ($config{post_commit} && 
68                                      IkiWiki::commit_hook_enabled())) {
69                 launchaggregation();
70         }
71 }
72
73 sub cgi ($) {
74         my $cgi=shift;
75
76         if (defined $cgi->param('do') &&
77             $cgi->param("do") eq "aggregate_webtrigger") {
78                 $|=1;
79                 print "Content-Type: text/plain\n\n";
80                 $config{cgi}=0;
81                 $config{verbose}=1;
82                 $config{syslog}=0;
83                 print gettext("Aggregation triggered via web.")."\n\n";
84                 if (launchaggregation()) {
85                         IkiWiki::lockwiki();
86                         IkiWiki::loadindex();
87                         require IkiWiki::Render;
88                         IkiWiki::refresh();
89                         IkiWiki::saveindex();
90                 }
91                 else {
92                         print gettext("Nothing to do right now, all feeds are up-to-date!")."\n";
93                 }
94                 exit 0;
95         }
96 }
97
98 sub launchaggregation () {
99         # See if any feeds need aggregation.
100         loadstate();
101         my @feeds=needsaggregate();
102         return unless @feeds;
103         if (! lockaggregate()) {
104                 debug("an aggregation process is already running");
105                 return;
106         }
107         # force a later rebuild of source pages
108         $IkiWiki::forcerebuild{$_->{sourcepage}}=1
109                 foreach @feeds;
110
111         # Fork a child process to handle the aggregation.
112         # The parent process will then handle building the
113         # result. This avoids messy code to clear state
114         # accumulated while aggregating.
115         defined(my $pid = fork) or error("Can't fork: $!");
116         if (! $pid) {
117                 IkiWiki::loadindex();
118                 # Aggregation happens without the main wiki lock
119                 # being held. This allows editing pages etc while
120                 # aggregation is running.
121                 aggregate(@feeds);
122
123                 IkiWiki::lockwiki;
124                 # Merge changes, since aggregation state may have
125                 # changed on disk while the aggregation was happening.
126                 mergestate();
127                 expire();
128                 savestate();
129                 IkiWiki::unlockwiki;
130                 exit 0;
131         }
132         waitpid($pid,0);
133         if ($?) {
134                 error "aggregation failed with code $?";
135         }
136
137         clearstate();
138         unlockaggregate();
139
140         return 1;
141 }
142
143 #  Pages with extension _aggregated have plain html markup, pass through.
144 sub htmlize (@) {
145         my %params=@_;
146         return $params{content};
147 }
148
149 # Used by ikiwiki-transition aggregateinternal.
150 sub migrate_to_internal {
151         if (! lockaggregate()) {
152                 error("an aggregation process is currently running");
153         }
154
155         IkiWiki::lockwiki();
156         loadstate();
157         $config{verbose}=1;
158
159         foreach my $data (values %guids) {
160                 next unless $data->{page};
161                 next if $data->{expired};
162                 
163                 $config{aggregateinternal} = 0;
164                 my $oldname = "$config{srcdir}/".htmlfn($data->{page});
165                 my $oldoutput = $config{destdir}."/".IkiWiki::htmlpage($data->{page});
166                 
167                 $config{aggregateinternal} = 1;
168                 my $newname = "$config{srcdir}/".htmlfn($data->{page});
169                 
170                 debug "moving $oldname -> $newname";
171                 if (-e $newname) {
172                         if (-e $oldname) {
173                                 error("$newname already exists");
174                         }
175                         else {
176                                 debug("already renamed to $newname?");
177                         }
178                 }
179                 elsif (-e $oldname) {
180                         rename($oldname, $newname) || error("$!");
181                 }
182                 else {
183                         debug("$oldname not found");
184                 }
185                 if (-e $oldoutput) {
186                         require IkiWiki::Render;
187                         debug("removing output file $oldoutput");
188                         IkiWiki::prune($oldoutput);
189                 }
190         }
191         
192         savestate();
193         IkiWiki::unlockwiki;
194         
195         unlockaggregate();
196 }
197
198 sub needsbuild (@) {
199         my $needsbuild=shift;
200         
201         loadstate();
202
203         foreach my $feed (values %feeds) {
204                 if (exists $pagesources{$feed->{sourcepage}} && 
205                     grep { $_ eq $pagesources{$feed->{sourcepage}} } @$needsbuild) {
206                         # Mark all feeds originating on this page as 
207                         # not yet seen; preprocess will unmark those that
208                         # still exist.
209                         markunseen($feed->{sourcepage});
210                 }
211         }
212
213         return $needsbuild;
214 }
215
216 sub preprocess (@) {
217         my %params=@_;
218
219         foreach my $required (qw{name url}) {
220                 if (! exists $params{$required}) {
221                         error sprintf(gettext("missing %s parameter"), $required)
222                 }
223         }
224
225         my $feed={};
226         my $name=$params{name};
227         if (exists $feeds{$name}) {
228                 $feed=$feeds{$name};
229         }
230         else {
231                 $feeds{$name}=$feed;
232         }
233         $feed->{name}=$name;
234         $feed->{sourcepage}=$params{page};
235         $feed->{url}=$params{url};
236         my $dir=exists $params{dir} ? $params{dir} : $params{page}."/".titlepage($params{name});
237         $dir=~s/^\/+//;
238         ($dir)=$dir=~/$config{wiki_file_regexp}/;
239         $feed->{dir}=$dir;
240         $feed->{feedurl}=defined $params{feedurl} ? $params{feedurl} : "";
241         $feed->{updateinterval}=defined $params{updateinterval} ? $params{updateinterval} * 60 : 15 * 60;
242         $feed->{expireage}=defined $params{expireage} ? $params{expireage} : 0;
243         $feed->{expirecount}=defined $params{expirecount} ? $params{expirecount} : 0;
244         if (exists $params{template}) {
245                 $params{template}=~s/[^-_a-zA-Z0-9]+//g;
246         }
247         else {
248                 $params{template} = "aggregatepost"
249         }
250         $feed->{template}=$params{template} . ".tmpl";
251         delete $feed->{unseen};
252         $feed->{lastupdate}=0 unless defined $feed->{lastupdate};
253         $feed->{lasttry}=$feed->{lastupdate} unless defined $feed->{lasttry};
254         $feed->{numposts}=0 unless defined $feed->{numposts};
255         $feed->{newposts}=0 unless defined $feed->{newposts};
256         $feed->{message}=gettext("new feed") unless defined $feed->{message};
257         $feed->{error}=0 unless defined $feed->{error};
258         $feed->{tags}=[];
259         while (@_) {
260                 my $key=shift;
261                 my $value=shift;
262                 if ($key eq 'tag') {
263                         push @{$feed->{tags}}, $value;
264                 }
265         }
266
267         return "<a href=\"".$feed->{url}."\">".$feed->{name}."</a>: ".
268                ($feed->{error} ? "<em>" : "").$feed->{message}.
269                ($feed->{error} ? "</em>" : "").
270                " (".$feed->{numposts}." ".gettext("posts").
271                ($feed->{newposts} ? "; ".$feed->{newposts}.
272                                     " ".gettext("new") : "").
273                ")";
274 }
275
276 sub delete (@) {
277         my @files=@_;
278
279         # Remove feed data for removed pages.
280         foreach my $file (@files) {
281                 my $page=pagename($file);
282                 markunseen($page);
283         }
284 }
285
286 sub markunseen ($) {
287         my $page=shift;
288
289         foreach my $id (keys %feeds) {
290                 if ($feeds{$id}->{sourcepage} eq $page) {
291                         $feeds{$id}->{unseen}=1;
292                 }
293         }
294 }
295
296 my $state_loaded=0;
297
298 sub loadstate () {
299         return if $state_loaded;
300         $state_loaded=1;
301         if (-e "$config{wikistatedir}/aggregate") {
302                 open(IN, "<", "$config{wikistatedir}/aggregate") ||
303                         die "$config{wikistatedir}/aggregate: $!";
304                 while (<IN>) {
305                         $_=IkiWiki::possibly_foolish_untaint($_);
306                         chomp;
307                         my $data={};
308                         foreach my $i (split(/ /, $_)) {
309                                 my ($field, $val)=split(/=/, $i, 2);
310                                 if ($field eq "name" || $field eq "feed" ||
311                                     $field eq "guid" || $field eq "message") {
312                                         $data->{$field}=decode_entities($val, " \t\n");
313                                 }
314                                 elsif ($field eq "tag") {
315                                         push @{$data->{tags}}, $val;
316                                 }
317                                 else {
318                                         $data->{$field}=$val;
319                                 }
320                         }
321                         
322                         if (exists $data->{name}) {
323                                 $feeds{$data->{name}}=$data;
324                         }
325                         elsif (exists $data->{guid}) {
326                                 $guids{$data->{guid}}=$data;
327                         }
328                 }
329
330                 close IN;
331         }
332 }
333
334 sub savestate () {
335         return unless $state_loaded;
336         garbage_collect();
337         my $newfile="$config{wikistatedir}/aggregate.new";
338         my $cleanup = sub { unlink($newfile) };
339         open (OUT, ">", $newfile) || error("open $newfile: $!", $cleanup);
340         foreach my $data (values %feeds, values %guids) {
341                 my @line;
342                 foreach my $field (keys %$data) {
343                         if ($field eq "name" || $field eq "feed" ||
344                             $field eq "guid" || $field eq "message") {
345                                 push @line, "$field=".encode_entities($data->{$field}, " \t\n");
346                         }
347                         elsif ($field eq "tags") {
348                                 push @line, "tag=$_" foreach @{$data->{tags}};
349                         }
350                         else {
351                                 push @line, "$field=".$data->{$field}
352                                         if defined $data->{$field};
353                         }
354                 }
355                 print OUT join(" ", @line)."\n" || error("write $newfile: $!", $cleanup);
356         }
357         close OUT || error("save $newfile: $!", $cleanup);
358         rename($newfile, "$config{wikistatedir}/aggregate") ||
359                 error("rename $newfile: $!", $cleanup);
360
361         my $timestamp=undef;
362         foreach my $feed (keys %feeds) {
363                 my $t=$feeds{$feed}->{lastupdate}+$feeds{$feed}->{updateinterval};
364                 if (! defined $timestamp || $timestamp > $t) {
365                         $timestamp=$t;
366                 }
367         }
368         $newfile=~s/\.new$/time/;
369         open (OUT, ">", $newfile) || error("open $newfile: $!", $cleanup);
370         if (defined $timestamp) {
371                 print OUT $timestamp."\n";
372         }
373         close OUT || error("save $newfile: $!", $cleanup);
374 }
375
376 sub garbage_collect () {
377         foreach my $name (keys %feeds) {
378                 # remove any feeds that were not seen while building the pages
379                 # that used to contain them
380                 if ($feeds{$name}->{unseen}) {
381                         delete $feeds{$name};
382                 }
383         }
384
385         foreach my $guid (values %guids) {
386                 # any guid whose feed is gone should be removed
387                 if (! exists $feeds{$guid->{feed}}) {
388                         unlink "$config{srcdir}/".htmlfn($guid->{page})
389                                 if exists $guid->{page};
390                         delete $guids{$guid->{guid}};
391                 }
392                 # handle expired guids
393                 elsif ($guid->{expired} && exists $guid->{page}) {
394                         unlink "$config{srcdir}/".htmlfn($guid->{page});
395                         delete $guid->{page};
396                         delete $guid->{md5};
397                 }
398         }
399 }
400
401 sub mergestate () {
402         # Load the current state in from disk, and merge into it
403         # values from the state in memory that might have changed
404         # during aggregation.
405         my %myfeeds=%feeds;
406         my %myguids=%guids;
407         clearstate();
408         loadstate();
409
410         # All that can change in feed state during aggregation is a few
411         # fields.
412         foreach my $name (keys %myfeeds) {
413                 if (exists $feeds{$name}) {
414                         foreach my $field (qw{message lastupdate lasttry
415                                               numposts newposts error}) {
416                                 $feeds{$name}->{$field}=$myfeeds{$name}->{$field};
417                         }
418                 }
419         }
420
421         # New guids can be created during aggregation.
422         # Guids have a few fields that may be updated during aggregation.
423         # It's also possible that guids were removed from the on-disk state
424         # while the aggregation was in process. That would only happen if
425         # their feed was also removed, so any removed guids added back here
426         # will be garbage collected later.
427         foreach my $guid (keys %myguids) {
428                 if (! exists $guids{$guid}) {
429                         $guids{$guid}=$myguids{$guid};
430                 }
431                 else {
432                         foreach my $field (qw{md5}) {
433                                 $guids{$guid}->{$field}=$myguids{$guid}->{$field};
434                         }
435                 }
436         }
437 }
438
439 sub clearstate () {
440         %feeds=();
441         %guids=();
442         $state_loaded=0;
443 }
444
445 sub expire () {
446         foreach my $feed (values %feeds) {
447                 next unless $feed->{expireage} || $feed->{expirecount};
448                 my $count=0;
449                 my %seen;
450                 foreach my $item (sort { ($IkiWiki::pagectime{$b->{page}} || 0) <=> ($IkiWiki::pagectime{$a->{page}} || 0) }
451                                   grep { exists $_->{page} && $_->{feed} eq $feed->{name} }
452                                   values %guids) {
453                         if ($feed->{expireage}) {
454                                 my $days_old = (time - ($IkiWiki::pagectime{$item->{page}} || 0)) / 60 / 60 / 24;
455                                 if ($days_old > $feed->{expireage}) {
456                                         debug(sprintf(gettext("expiring %s (%s days old)"),
457                                                 $item->{page}, int($days_old)));
458                                         $item->{expired}=1;
459                                 }
460                         }
461                         elsif ($feed->{expirecount} &&
462                                $count >= $feed->{expirecount}) {
463                                 debug(sprintf(gettext("expiring %s"), $item->{page}));
464                                 $item->{expired}=1;
465                         }
466                         else {
467                                 if (! $seen{$item->{page}}) {
468                                         $seen{$item->{page}}=1;
469                                         $count++;
470                                 }
471                         }
472                 }
473         }
474 }
475
476 sub needsaggregate () {
477         return values %feeds if $config{rebuild};
478         return grep { time - $_->{lastupdate} >= $_->{updateinterval} } values %feeds;
479 }
480
481 sub aggregate (@) {
482         eval q{use XML::Feed};
483         error($@) if $@;
484         eval q{use URI::Fetch};
485         error($@) if $@;
486
487         foreach my $feed (@_) {
488                 $feed->{lasttry}=time;
489                 $feed->{newposts}=0;
490                 $feed->{message}=sprintf(gettext("last checked %s"),
491                         displaytime($feed->{lasttry}));
492                 $feed->{error}=0;
493
494                 debug(sprintf(gettext("checking feed %s ..."), $feed->{name}));
495
496                 if (! length $feed->{feedurl}) {
497                         my @urls=XML::Feed->find_feeds($feed->{url});
498                         if (! @urls) {
499                                 $feed->{message}=sprintf(gettext("could not find feed at %s"), $feed->{url});
500                                 $feed->{error}=1;
501                                 debug($feed->{message});
502                                 next;
503                         }
504                         $feed->{feedurl}=pop @urls;
505                 }
506                 my $res=URI::Fetch->fetch($feed->{feedurl});
507                 if (! $res) {
508                         $feed->{message}=URI::Fetch->errstr;
509                         $feed->{error}=1;
510                         debug($feed->{message});
511                         next;
512                 }
513
514                 # lastupdate is only set if we were able to contact the server
515                 $feed->{lastupdate}=$feed->{lasttry};
516
517                 if ($res->status == URI::Fetch::URI_GONE()) {
518                         $feed->{message}=gettext("feed not found");
519                         $feed->{error}=1;
520                         debug($feed->{message});
521                         next;
522                 }
523                 my $content=$res->content;
524                 my $f=eval{XML::Feed->parse(\$content)};
525                 if ($@) {
526                         # One common cause of XML::Feed crashing is a feed
527                         # that contains invalid UTF-8 sequences. Convert
528                         # feed to ascii to try to work around.
529                         $feed->{message}.=" ".sprintf(gettext("(invalid UTF-8 stripped from feed)"));
530                         $f=eval {
531                                 $content=Encode::decode_utf8($content, 0);
532                                 XML::Feed->parse(\$content)
533                         };
534                 }
535                 if ($@) {
536                         # Another possibility is badly escaped entities.
537                         $feed->{message}.=" ".sprintf(gettext("(feed entities escaped)"));
538                         $content=~s/\&(?!amp)(\w+);/&amp;$1;/g;
539                         $f=eval {
540                                 $content=Encode::decode_utf8($content, 0);
541                                 XML::Feed->parse(\$content)
542                         };
543                 }
544                 if ($@) {
545                         $feed->{message}=gettext("feed crashed XML::Feed!")." ($@)";
546                         $feed->{error}=1;
547                         debug($feed->{message});
548                         next;
549                 }
550                 if (! $f) {
551                         $feed->{message}=XML::Feed->errstr;
552                         $feed->{error}=1;
553                         debug($feed->{message});
554                         next;
555                 }
556
557                 foreach my $entry ($f->entries) {
558                         # XML::Feed doesn't work around XML::Atom's bizarre
559                         # API, so we will. Real unicode strings? Yes please.
560                         # See [[bugs/Aggregated_Atom_feeds_are_double-encoded]]
561                         local $XML::Atom::ForceUnicode = 1;
562
563                         my $c=$entry->content;
564                         # atom feeds may have no content, only a summary
565                         if (! defined $c && ref $entry->summary) {
566                                 $c=$entry->summary;
567                         }
568
569                         add_page(
570                                 feed => $feed,
571                                 copyright => $f->copyright,
572                                 title => defined $entry->title ? decode_entities($entry->title) : "untitled",
573                                 link => $entry->link,
574                                 content => (defined $c && defined $c->body) ? $c->body : "",
575                                 guid => defined $entry->id ? $entry->id : time."_".$feed->{name},
576                                 ctime => $entry->issued ? ($entry->issued->epoch || time) : time,
577                                 base => (defined $c && $c->can("base")) ? $c->base : undef,
578                         );
579                 }
580         }
581 }
582
583 sub add_page (@) {
584         my %params=@_;
585         
586         my $feed=$params{feed};
587         my $guid={};
588         my $mtime;
589         if (exists $guids{$params{guid}}) {
590                 # updating an existing post
591                 $guid=$guids{$params{guid}};
592                 return if $guid->{expired};
593         }
594         else {
595                 # new post
596                 $guid->{guid}=$params{guid};
597                 $guids{$params{guid}}=$guid;
598                 $mtime=$params{ctime};
599                 $feed->{numposts}++;
600                 $feed->{newposts}++;
601
602                 # assign it an unused page
603                 my $page=titlepage($params{title});
604                 # escape slashes and periods in title so it doesn't specify
605                 # directory name or trigger ".." disallowing code.
606                 $page=~s!([/.])!"__".ord($1)."__"!eg;
607                 $page=$feed->{dir}."/".$page;
608                 ($page)=$page=~/$config{wiki_file_regexp}/;
609                 if (! defined $page || ! length $page) {
610                         $page=$feed->{dir}."/item";
611                 }
612                 my $c="";
613                 while (exists $IkiWiki::pagecase{lc $page.$c} ||
614                        -e "$config{srcdir}/".htmlfn($page.$c)) {
615                         $c++
616                 }
617
618                 # Make sure that the file name isn't too long. 
619                 # NB: This doesn't check for path length limits.
620                 my $max=POSIX::pathconf($config{srcdir}, &POSIX::_PC_NAME_MAX);
621                 if (defined $max && length(htmlfn($page)) >= $max) {
622                         $c="";
623                         $page=$feed->{dir}."/item";
624                         while (exists $IkiWiki::pagecase{lc $page.$c} ||
625                                -e "$config{srcdir}/".htmlfn($page.$c)) {
626                                 $c++
627                         }
628                 }
629
630                 $guid->{page}=$page;
631                 debug(sprintf(gettext("creating new page %s"), $page));
632         }
633         $guid->{feed}=$feed->{name};
634         
635         # To write or not to write? Need to avoid writing unchanged pages
636         # to avoid unneccessary rebuilding. The mtime from rss cannot be
637         # trusted; let's use a digest.
638         eval q{use Digest::MD5 'md5_hex'};
639         error($@) if $@;
640         require Encode;
641         my $digest=md5_hex(Encode::encode_utf8($params{content}));
642         return unless ! exists $guid->{md5} || $guid->{md5} ne $digest || $config{rebuild};
643         $guid->{md5}=$digest;
644
645         # Create the page.
646         my $template;
647         eval {
648                 $template=template($feed->{template}, blind_cache => 1);
649         };
650         if ($@) {
651                 print STDERR gettext("failed to process template:")." $@";
652                 return;
653         }
654         $template->param(title => $params{title})
655                 if defined $params{title} && length($params{title});
656         $template->param(content => wikiescape(htmlabs($params{content},
657                 defined $params{base} ? $params{base} : $feed->{feedurl})));
658         $template->param(name => $feed->{name});
659         $template->param(url => $feed->{url});
660         $template->param(copyright => $params{copyright})
661                 if defined $params{copyright} && length $params{copyright};
662         $template->param(permalink => IkiWiki::urlabs($params{link}, $feed->{feedurl}))
663                 if defined $params{link};
664         if (ref $feed->{tags}) {
665                 $template->param(tags => [map { tag => $_ }, @{$feed->{tags}}]);
666         }
667         writefile(htmlfn($guid->{page}), $config{srcdir},
668                 $template->output);
669
670         if (defined $mtime && $mtime <= time) {
671                 # Set the mtime, this lets the build process get the right
672                 # creation time on record for the new page.
673                 utime $mtime, $mtime, "$config{srcdir}/".htmlfn($guid->{page});
674                 # Store it in pagectime for expiry code to use also.
675                 $IkiWiki::pagectime{$guid->{page}}=$mtime
676                         unless exists $IkiWiki::pagectime{$guid->{page}};
677         }
678         else {
679                 # Dummy value for expiry code.
680                 $IkiWiki::pagectime{$guid->{page}}=time
681                         unless exists $IkiWiki::pagectime{$guid->{page}};
682         }
683 }
684
685 sub wikiescape ($) {
686         # escape accidental wikilinks and preprocessor stuff
687         return encode_entities(shift, '\[\]');
688 }
689
690 sub htmlabs ($$) {
691         # Convert links in html from relative to absolute.
692         # Note that this is a heuristic, which is not specified by the rss
693         # spec and may not be right for all feeds. Also, see Debian
694         # bug #381359.
695         my $html=shift;
696         my $urlbase=shift;
697
698         my $ret="";
699         my $p = HTML::Parser->new(api_version => 3);
700         $p->handler(default => sub { $ret.=join("", @_) }, "text");
701         $p->handler(start => sub {
702                 my ($tagname, $pos, $text) = @_;
703                 if (ref $HTML::Tagset::linkElements{$tagname}) {
704                         while (4 <= @$pos) {
705                                 # use attribute sets from right to left
706                                 # to avoid invalidating the offsets
707                                 # when replacing the values
708                                 my($k_offset, $k_len, $v_offset, $v_len) =
709                                         splice(@$pos, -4);
710                                 my $attrname = lc(substr($text, $k_offset, $k_len));
711                                 next unless grep { $_ eq $attrname } @{$HTML::Tagset::linkElements{$tagname}};
712                                 next unless $v_offset; # 0 v_offset means no value
713                                 my $v = substr($text, $v_offset, $v_len);
714                                 $v =~ s/^([\'\"])(.*)\1$/$2/;
715                                 my $new_v=IkiWiki::urlabs($v, $urlbase);
716                                 $new_v =~ s/\"/&quot;/g; # since we quote with ""
717                                 substr($text, $v_offset, $v_len) = qq("$new_v");
718                         }
719                 }
720                 $ret.=$text;
721         }, "tagname, tokenpos, text");
722         $p->parse($html);
723         $p->eof;
724
725         return $ret;
726 }
727
728 sub htmlfn ($) {
729         return shift().".".($config{aggregateinternal} ? "_aggregated" : $config{htmlext});
730 }
731
732 my $aggregatelock;
733
734 sub lockaggregate () {
735         # Take an exclusive lock to prevent multiple concurrent aggregators.
736         # Returns true if the lock was aquired.
737         if (! -d $config{wikistatedir}) {
738                 mkdir($config{wikistatedir});
739         }
740         open($aggregatelock, '>', "$config{wikistatedir}/aggregatelock") ||
741                 error ("cannot open to $config{wikistatedir}/aggregatelock: $!");
742         if (! flock($aggregatelock, 2 | 4)) { # LOCK_EX | LOCK_NB
743                 close($aggregatelock) || error("failed closing aggregatelock: $!");
744                 return 0;
745         }
746         return 1;
747 }
748
749 sub unlockaggregate () {
750         return close($aggregatelock) if $aggregatelock;
751         return;
752 }
753
754 1