If the title of a trail or trail-member changes, rebuild affected pages
[ikiwiki.git] / IkiWiki / Plugin / trail.pm
index e9b4d9cd4fc589ff2b35f2256f6d7d76bd697770..b1bb6d5b532fb25120f6da1d4a371e43e04cfb72 100644 (file)
@@ -1,6 +1,6 @@
 #!/usr/bin/perl
 # Copyright © 2008-2011 Joey Hess
-# Copyright © 2009-2011 Simon McVittie <http://smcv.pseudorandom.co.uk/>
+# Copyright © 2009-2012 Simon McVittie <http://smcv.pseudorandom.co.uk/>
 # Licensed under the GNU GPL, version 2, or any later version published by the
 # Free Software Foundation
 package IkiWiki::Plugin::trail;
@@ -12,54 +12,47 @@ use IkiWiki 3.00;
 sub import {
        hook(type => "getsetup", id => "trail", call => \&getsetup);
        hook(type => "needsbuild", id => "trail", call => \&needsbuild);
-       hook(type => "preprocess", id => "trail", call => \&preprocess_trail, scan => 1);
-       hook(type => "preprocess", id => "trailinline", call => \&preprocess_trailinline, scan => 1);
+       hook(type => "preprocess", id => "trailoptions", call => \&preprocess_trailoptions, scan => 1);
        hook(type => "preprocess", id => "trailitem", call => \&preprocess_trailitem, scan => 1);
+       hook(type => "preprocess", id => "trailitems", call => \&preprocess_trailitems, scan => 1);
        hook(type => "preprocess", id => "traillink", call => \&preprocess_traillink, scan => 1);
        hook(type => "pagetemplate", id => "trail", call => \&pagetemplate);
+       hook(type => "build_affected", id => "trail", call => \&build_affected);
 }
 
-=head1 Page state
-
-If a page C<$T> is a trail, then it can have
-
-=over
-
-=item * C<$pagestate{$T}{trail}{contents}>
-
-Reference to an array of pagespecs or links in the trail.
-
-=item * C<$pagestate{$T}{trail}{sort}>
-
-A [[ikiwiki/pagespec/sorting]] order; if absent or undef, the trail is in
-the order given by the links that form it
-
-=item * C<$pagestate{$T}{trail}{circular}>
-
-True if this trail is circular (i.e. going "next" from the last item is
-allowed, and takes you back to the first)
-
-=item * C<$pagestate{$T}{trail}{reverse}>
-
-True if C<sort> is to be reversed.
-
-=back
-
-If a page C<$M> is a member of a trail C<$T>, then it has
-
-=over
-
-=item * C<$pagestate{$M}{trail}{item}{$T}[0]>
-
-The page before this one in C<$T> at the last rebuild, or undef.
-
-=item * C<$pagestate{$M}{trail}{item}{$T}[1]>
-
-The page after this one in C<$T> at the last refresh, or undef.
-
-=back
-
-=cut
+# Page state
+# 
+# If a page $T is a trail, then it can have
+# 
+# * $pagestate{$T}{trail}{contents} 
+#   Reference to an array of lists each containing either:
+#     - [pagenames => "page1", "page2"]
+#       Those literal pages
+#     - [link => "link"]
+#       A link specification, pointing to the same page that [[link]]
+#       would select
+#     - [pagespec => "posts/*", "age", 0]
+#       A match by pagespec; the third array element is the sort order
+#       and the fourth is whether to reverse sorting
+# 
+# * $pagestate{$T}{trail}{sort}
+#   A sorting order; if absent or undef, the trail is in the order given
+#   by the links that form it
+#
+# * $pagestate{$T}{trail}{circular}
+#   True if this trail is circular (i.e. going "next" from the last item is
+#   allowed, and takes you back to the first)
+#
+# * $pagestate{$T}{trail}{reverse}
+#   True if C<sort> is to be reversed.
+# 
+# If a page $M is a member of a trail $T, then it has
+#
+# * $pagestate{$M}{trail}{item}{$T}[0]
+#   The page before this one in C<$T> at the last rebuild, or undef.
+#
+# * $pagestate{$M}{trail}{item}{$T}[1]
+#   The page after this one in C<$T> at the last refresh, or undef.
 
 sub getsetup () {
        return
@@ -69,12 +62,20 @@ sub getsetup () {
                },
 }
 
+# Cache of pages' old titles, so we can tell whether they changed
+my %old_trail_titles;
+
 sub needsbuild (@) {
        my $needsbuild=shift;
+
        foreach my $page (keys %pagestate) {
                if (exists $pagestate{$page}{trail}) {
                        if (exists $pagesources{$page} &&
                            grep { $_ eq $pagesources{$page} } @$needsbuild) {
+                               # Remember its title, so we can know whether
+                               # it changed.
+                               $old_trail_titles{$page} = title_of($page);
+
                                # Remove state, it will be re-added
                                # if the preprocessor directive is still
                                # there during the rebuild. {item} is the
@@ -85,31 +86,13 @@ sub needsbuild (@) {
                        }
                }
        }
+
        return $needsbuild;
 }
 
-=for wiki
-
-The `trail` directive is supplied by the [[plugins/contrib/trail]]
-plugin. It sets options for the trail represented by this page. Example usage:
-
-    \[[!trail sort="meta(date)" circular="no" pages="blog/posts/*"]]
-
-The available options are:
+my $scanned = 0;
 
-* `sort`: sets a [[ikiwiki/pagespec/sorting]] order; if not specified, the
-  items of the trail are ordered according to the first link to each item
-  found on the trail page
-
-* `circular`: if set to `yes` or `1`, the trail is made into a loop by
-  making the last page's "next" link point to the first page, and the first
-  page's "previous" link point to the last page
-
-* `pages`: add the given pages to the trail
-
-=cut
-
-sub preprocess_trail (@) {
+sub preprocess_trailoptions (@) {
        my %params = @_;
 
        if (exists $params{circular}) {
@@ -125,73 +108,21 @@ sub preprocess_trail (@) {
                $pagestate{$params{page}}{trail}{reverse} = $params{reverse};
        }
 
-       if (exists $params{pages}) {
-               push @{$pagestate{$params{page}}{trail}{contents}}, "pagespec $params{pages}";
-       }
-
-       if (exists $params{pagenames}) {
-               my @list = map { "link $_" } split ' ', $params{pagenames};
-               push @{$pagestate{$params{page}}{trail}{contents}}, @list;
-       }
-
        return "";
 }
 
-=for wiki
-
-The `trailinline` directive is supplied by the [[plugins/contrib/trail]]
-plugin. It behaves like the [[trail]] and [[inline]] directives combined.
-Like [[inline]], it includes the selected pages into the page with the
-directive and/or an RSS or Atom feed; like [[trail]], it turns the
-included pages into a "trail" in which each page has a link to the
-previous and next pages.
-
-    \[[!inline sort="meta(date)" circular="no" pages="blog/posts/*"]]
-
-All the options for the [[inline]] and [[trail]] directives are valid.
-
-The `show`, `skip` and `feedshow` options from [[inline]] do not apply
-to the trail.
-
-* `sort`: sets a [[ikiwiki/pagespec/sorting]] order; if not specified, the
-  items of the trail are ordered according to the first link to each item
-  found on the trail page
-
-* `circular`: if set to `yes` or `1`, the trail is made into a loop by
-  making the last page's "next" link point to the first page, and the first
-  page's "previous" link point to the last page
-
-* `pages`: add the given pages to the trail
-
-=cut
-
-sub preprocess_trailinline (@) {
-       preprocess_trail(@_);
-       return unless defined wantarray;
+sub preprocess_trailitem (@) {
+       my $link = shift;
+       shift;
 
-       if (IkiWiki->can("preprocess_inline")) {
-               return IkiWiki::preprocess_inline(@_);
+       # avoid collecting everything in the preprocess stage if we already
+       # did in the scan stage
+       if (defined wantarray) {
+               return "" if $scanned;
        }
        else {
-               error("trailinline directive requires the inline plugin");
+               $scanned = 1;
        }
-}
-
-=for wiki
-
-The `trailitem` directive is supplied by the [[plugins/contrib/trail]] plugin.
-It is used like this:
-
-    \[[!trailitem some_other_page]]
-
-to add `some_other_page` to the trail represented by this page, without
-generating a visible hyperlink.
-
-=cut
-
-sub preprocess_trailitem (@) {
-       my $link = shift;
-       shift;
 
        my %params = @_;
        my $trail = $params{page};
@@ -199,28 +130,41 @@ sub preprocess_trailitem (@) {
        $link = linkpage($link);
 
        add_link($params{page}, $link, 'trail');
-       push @{$pagestate{$params{page}}{trail}{contents}}, "link $link";
+       push @{$pagestate{$params{page}}{trail}{contents}}, [link => $link];
 
        return "";
 }
 
-=for wiki
-
-The `traillink` directive is supplied by the [[plugins/contrib/trail]] plugin.
-It generates a visible [[ikiwiki/WikiLink]], and also adds the linked page to
-the trail represented by the page containing the directive.
+sub preprocess_trailitems (@) {
+       my %params = @_;
 
-In its simplest form, the first parameter is like the content of a WikiLink:
+       # avoid collecting everything in the preprocess stage if we already
+       # did in the scan stage
+       if (defined wantarray) {
+               return "" if $scanned;
+       }
+       else {
+               $scanned = 1;
+       }
 
-    \[[!traillink some_other_page]]
+       # trail members from a pagespec ought to be in some sort of order,
+       # and path is a nice obvious default
+       $params{sort} = 'path' unless exists $params{sort};
+       $params{reverse} = 'no' unless exists $params{reverse};
 
-The displayed text can also be overridden, either with a `|` symbol or with
-a `text` parameter:
+       if (exists $params{pages}) {
+               push @{$pagestate{$params{page}}{trail}{contents}},
+                       ["pagespec" => $params{pages}, $params{sort},
+                               IkiWiki::yesno($params{reverse})];
+       }
 
-    \[[!traillink Click_here_to_start_the_trail|some_other_page]]
-    \[[!traillink some_other_page text="Click here to start the trail"]]
+       if (exists $params{pagenames}) {
+               push @{$pagestate{$params{page}}{trail}{contents}},
+                       [pagenames => (split ' ', $params{pagenames})];
+       }
 
-=cut
+       return "";
+}
 
 sub preprocess_traillink (@) {
        my $link = shift;
@@ -242,7 +186,18 @@ sub preprocess_traillink (@) {
        $link = linkpage($2);
 
        add_link($params{page}, $link, 'trail');
-       push @{$pagestate{$params{page}}{trail}{contents}}, "link $link";
+
+       # avoid collecting everything in the preprocess stage if we already
+       # did in the scan stage
+       my $already;
+       if (defined wantarray) {
+               $already = $scanned;
+       }
+       else {
+               $scanned = 1;
+       }
+
+       push @{$pagestate{$params{page}}{trail}{contents}}, [link => $link] unless $already;
 
        if (defined $linktext) {
                $linktext = pagetitle($linktext);
@@ -284,6 +239,12 @@ sub trails_differ {
                if (! exists $new->{$trail}) {
                        return 1;
                }
+
+               if (exists $old_trail_titles{$trail} &&
+                       title_of($trail) ne $old_trail_titles{$trail}) {
+                       return 1;
+               }
+
                my ($old_p, $old_n) = @{$old->{$trail}};
                my ($new_p, $new_n) = @{$new->{$trail}};
                $old_p = "" unless defined $old_p;
@@ -293,9 +254,20 @@ sub trails_differ {
                if ($old_p ne $new_p) {
                        return 1;
                }
+
+               if (exists $old_trail_titles{$old_p} &&
+                       title_of($old_p) ne $old_trail_titles{$old_p}) {
+                       return 1;
+               }
+
                if ($old_n ne $new_n) {
                        return 1;
                }
+
+               if (exists $old_trail_titles{$old_n} &&
+                       title_of($old_n) ne $old_trail_titles{$old_n}) {
+                       return 1;
+               }
        }
 
        foreach my $trail (keys %$new) {
@@ -309,14 +281,9 @@ sub trails_differ {
 
 my $done_prerender = 0;
 
-my %origsubs;
-
 sub prerender {
        return if $done_prerender;
 
-       $origsubs{render_backlinks} = \&IkiWiki::render_backlinks;
-       inject(name => "IkiWiki::render_backlinks", call => \&render_backlinks);
-
        %trail_to_members = ();
        %member_to_trails = ();
 
@@ -326,13 +293,27 @@ sub prerender {
                my $members = [];
                my @contents = @{$pagestate{$trail}{trail}{contents}};
 
-
                foreach my $c (@contents) {
-                       if ($c =~ m/^pagespec (.*)$/) {
-                               push @$members, pagespec_match_list($trail, $1);
+                       if ($c->[0] eq 'pagespec') {
+                               push @$members, pagespec_match_list($trail,
+                                       $c->[1], sort => $c->[2],
+                                       reverse => $c->[3]);
+                       }
+                       elsif ($c->[0] eq 'pagenames') {
+                               my @pagenames = @$c;
+                               shift @pagenames;
+                               foreach my $page (@pagenames) {
+                                       if (exists $pagesources{$page}) {
+                                               push @$members, $page;
+                                       }
+                                       else {
+                                               # rebuild trail if it turns up
+                                               add_depends($trail, $page, deptype("presence"));
+                                       }
+                               }
                        }
-                       elsif ($c =~ m/^link (.*)$/) {
-                               my $best = bestlink($trail, $1);
+                       elsif ($c->[0] eq 'link') {
+                               my $best = bestlink($trail, $c->[1]);
                                push @$members, $best if length $best;
                        }
                }
@@ -363,7 +344,7 @@ sub prerender {
                        $prev = $members->[$i - 1] if $i > 0;
                        my $next = $members->[$i + 1];
 
-                       add_depends($member, $trail);
+                       add_depends($member, $trail, deptype("presence"));
 
                        $member_to_trails{$member}{$trail} = [$prev, $next];
                }
@@ -380,7 +361,7 @@ sub prerender {
                if (exists $pagestate{$member}{trail}{item} &&
                        ! exists $member_to_trails{$member}) {
                        $rebuild_trail_members{$member} = 1;
-                       delete $pagestate{$member}{trailitem};
+                       delete $pagestate{$member}{trail}{item};
                }
        }
 
@@ -401,18 +382,20 @@ sub prerender {
        $done_prerender = 1;
 }
 
-# This is called at about the right time that we can hijack it to render
-# extra pages.
-sub render_backlinks ($) {
-       my $blc = shift;
+sub build_affected {
+       my %affected;
 
-       foreach my $member (keys %rebuild_trail_members) {
-               next unless exists $pagesources{$member};
+       # In principle we might not have done this yet, although in practice
+       # at least the trail itself has probably changed, and its template
+       # almost certainly contains TRAILS or TRAILLOOP, triggering our
+       # prerender as a side-effect.
+       prerender();
 
-               IkiWiki::render($pagesources{$member}, sprintf(gettext("building %s, its previous or next page has changed"), $member));
+       foreach my $member (keys %rebuild_trail_members) {
+               $affected{$member} = sprintf(gettext("building %s, its previous or next page has changed"), $member);
        }
 
-       $origsubs{render_backlinks}($blc);
+       return %affected;
 }
 
 sub title_of ($) {
@@ -455,13 +438,13 @@ sub pagetemplate (@) {
                        my ($prevurl, $nexturl, $prevtitle, $nexttitle);
 
                        if (defined $prev) {
-                               add_depends($params{destpage}, $prev);
+                               add_depends($params{destpage}, $prev, deptype("presence"));
                                $prevurl = urlto($prev, $page);
                                $prevtitle = title_of($prev);
                        }
 
                        if (defined $next) {
-                               add_depends($params{destpage}, $next);
+                               add_depends($params{destpage}, $next, deptype("presence"));
                                $nexturl = urlto($next, $page);
                                $nexttitle = title_of($next);
                        }