add a function to register a function to be called to detect if the

filesystem object has a better class to handle it than the default
mimetype one...   This means we can handle items in a zip archive
or an iso image..

[git-p4: depot-paths = "//depot/": change = 802]

FSStorage.py

@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 import errno
+import itertools
 import os
 import sets
 import stat
@@ -8,8 +9,18 @@ from DIDLLite import StorageFolder, Item, VideoItem, AudioItem, TextItem, ImageI
 from twisted.web import static
 from twisted.python import log
 
+__all__ = [ 'registerklassfun', 'FSObject', 'FSItem', 'FSVideoItem',
+		'FSAudioItem', 'FSTextItem', 'FSImageItem', 'mimetoklass',
+		'FSDirectory',
+	]
+
 mimedict = static.loadMimeTypes()
 
+klassfuns = []
+
+def registerklassfun(fun):
+	klassfuns.append(fun)
+
 def statcmp(a, b, cmpattrs = [ 'st_ino', 'st_dev', 'st_size', 'st_mtime', ]):
 	if a is None or b is None:
 		return False
@@ -84,14 +95,14 @@ mimetoklass = {
 	'image':		FSImageItem,
 }
 
-def dofileadd(cd, parent, path, name):
-	fn, ext = os.path.splitext(name)
+def defFS(path):
+	fn, ext = os.path.splitext(path)
 	ext = ext.lower()
 	try:
 		mt = mimedict[ext]
 	except KeyError:
-		log.msg('no mime-type for: %s' % name)
-		return
+		log.msg('no mime-type for: %s' % path)
+		return None, None
 
 	ty = mt.split('/')[0]
 	if mimetoklass.has_key(mt):
@@ -100,10 +111,26 @@ def dofileadd(cd, parent, path, name):
 		klass = mimetoklass[ty]
 	else:
 		log.msg('no item for mt: %s' % mt)
+		return None, None
+
+	return klass, { 'path': path, 'mimetype': mt }
+
+def dofileadd(cd, parent, path, name):
+	klass = None
+	for i in itertools.chain(klassfuns, ( defFS, )):
+		try:
+			klass, kwargs = i(os.path.join(path, name))
+			if klass is not None:
+				break
+		except:
+			import traceback
+			traceback.print_exc()
+
+	if klass is None:
 		return
 
-	return cd.addItem(parent, klass, name,
-	    path = os.path.join(path, name), mimetype = mt)
+	log.msg('matched:', os.path.join(path, name), `i`)
+	return cd.addItem(parent, klass, name, **kwargs)
 
 class FSDirectory(FSObject, StorageFolder):
 	def __init__(self, *args, **kwargs):