attachment: Support perl 5.8's buggy version of CGI.pm.

This is truely horribly disgusting. CGI::tmpFileName, in current perls, is
an undocumented function (which should be a clue..) that takes the original
filename of an uploaded attachment, and returns the name of the tempfile
that CGI has stored it in.

In old perls, though, CGI::tmpFileName does not take a filename. It takes
a key from the object's {'.tmpfiles'} hash. This key is something
crazy like '*Fh::fh00001group' -- apparently the stringification of a
filehandle object.

Just to add to the fun, tmpFileName doesn't take the key, it expects a
refernce to the key. Argh?!

But the fun doesn't stop there, because in perl 5.8, CGI.pm is also broken
in two other ways. The upload() method is supposed to return a filehandle
to the temp file. It doesn't. The param() method is supposed to return
a filehandle to the temp file, that stringifies to the original filename.
It returns just the original filename, no filehandle.

Combine all these bugs, and you end up with this disgusting commit. Since
I have no way to get the filehandle, I *need* to get the tempfile name.
If I had the filehandle, I could probably pass it into tmpFileName, and
it might strigify to the right key name. But I don't, so the only way to
determine the key is to grub through the .tmpfiles hash ourselves.

And finally, one the temp file name is discovered, a filehandle can finally
be obtained by (re)opening it.

I recommend that this commit be reverted when perl 5.8 is a mercifully
faded memory.

I'm really, really, really glad I'm actually being paid for working on
this right now!

3 files changed, 16 insertions, 3 deletions

diff --git a/IkiWiki/Plugin/attachment.pm b/IkiWiki/Plugin/attachment.pm
index 84bf64390..ef6d79a9c 100644
--- a/IkiWiki/Plugin/attachment.pm
+++ b/IkiWiki/Plugin/attachment.pm
@@ -89,9 +89,17 @@ sub formbuilder (@) { #{{{
 		# This is an (apparently undocumented) way to get the name
 		# of the temp file that CGI writes the upload to.
 		my $tempfile=$q->tmpFileName($filename);
-		
 		if (! defined $tempfile || ! length $tempfile) {
-			error("failed to determine tempfile name");
+			# perl 5.8 needs an alternative, awful method
+			if ($q =~ /HASH/ && exists $q->{'.tmpfiles'}) {
+				foreach my $key (keys(%{$q->{'.tmpfiles'}})) {
+					$tempfile=$q->tmpFileName(\$key);
+					last if defined $tempfile && length $tempfile;
+				}
+			}
+			if (! defined $tempfile || ! length $tempfile) {
+				error("CGI::tmpFileName failed to return the uploaded file name");
+			}
 		}
 
 		$filename=IkiWiki::titlepage(
@@ -145,7 +153,7 @@ sub formbuilder (@) { #{{{
 					# even that doesn't always work,
 					# fall back to opening the tempfile
 					$fh=undef;
-					open($fh, "<", $tempfile) || error("failed to open $tempfile: $!");
+					open($fh, "<", $tempfile) || error("failed to open \"$tempfile\": $!");
 				}
 			}
 			binmode($fh);
diff --git a/debian/changelog b/debian/changelog
index b933065d9..725b9c1bc 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -7,6 +7,7 @@ ikiwiki (2.53) UNRELEASED; urgency=low
   * Fix a bug with links to pages whose names contained colons.
   * attachment: Support old versions of CGI.pm that lack an upload method.
   * Include ikiwiki.setup in examples in the debian package.
+  * attachment: Support perl 5.8's buggy version of CGI.pm.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 07 Jul 2008 01:52:48 -0400
 
diff --git a/doc/bugs/attachment:_failed_to_get_filehandle.mdwn b/doc/bugs/attachment:_failed_to_get_filehandle.mdwn
index 9053e1abf..09546dcb5 100644
--- a/doc/bugs/attachment:_failed_to_get_filehandle.mdwn
+++ b/doc/bugs/attachment:_failed_to_get_filehandle.mdwn
@@ -96,3 +96,7 @@ Is it Ikiwiki bug or my attachment plugin is misconfigured? --[[Paweł|ptecza]]
 
 > I've reproduced the bug, and it does seem to be a bug with the perl in
 > debian stable/ubuntu hardy. Trying to figure it out --[[Joey]]
+
+> This was amazingly disgusting, see commit message for the full horror of
+> the details. I think it's [[done]] -- at least it works on debian stable
+> now. --[[Joey]]