--- a/degal/utils.py	Fri Jun 05 19:30:28 2009 +0300
+++ b/degal/utils.py	Fri Jun 05 19:30:53 2009 +0300
@@ -1,73 +1,53 @@
-import os, os.path
-
-import settings
-
 """
     Miscellaneous utilities
 """
 
-def isImage (fname) :
-    """
-        Is the given filename likely to be an image file?
-    """
-
-    fname = fname.lower()
-    base, ext = os.path.splitext(fname)
-    ext = ext.lstrip('.')
-
-    return ext in settings.IMAGE_EXTS
+import functools
 
-def readFile (path) :
-    fo = open(path, 'r')
-    data = fo.read()
-    fo.close()
-
-    return data
-
-def fuzzyDecode (bytes) :
-    try :
-        return bytes.decode('utf8')
-    except UnicodeDecodeError :
-        return bytes.decode('latin1', 'replace')
-
-def readTitleDescr (path) :
+class LazyProperty (property) :
     """
-        Read a title.txt or <imgname>.txt file
+        Lazy-loaded properties
     """
 
-    if os.path.exists(path) :
-        content = readFile(path)
-
-        if '---' in content :
-            title, descr = content.split('---', 1)
-        else :
-            title, descr = content, ''
-        
-        title, descr = fuzzyDecode(title), fuzzyDecode(descr)
-
-        return title.strip(), descr.strip()
-
-    return u"", u""
+    def __init__ (self, func) :
+        """
+            Initialize with no value
+        """
 
-def url (*parts, **kwargs) :
-    abs = kwargs.pop('abs', False)
-    up = kwargs.pop('up', 0)
-    trailing = kwargs.pop('trailing', False)
-    
-    return '/'.join(([""]*int(abs)) + ([".."]*up) + list(parts) + ([""]*int(trailing)))
-
-url_join = url
+        super(LazyProperty, self).__init__(func)
 
-def path_join (*parts) :
-    return os.path.join(*[part for part in parts if part is not None])
-
-def strip_path (path) :
-    return path.lstrip('.').lstrip('/')
+        self.value = None
 
-def mtime (path) :
-    try :
-        return os.stat(path).st_mtime
-    except OSError :
-        # no such file or directory
-        return None
+    def run (self) :
+        """
+            Run the background func and return the to-be-cached value
+        """
 
+        return super(LazyProperty, self).__call__()
+
+    def __call__ (self) :
+        """
+            Return the cached value if it exists, otherwise, call the func
+        """
+
+        if not self.value :
+            # generate it
+            self.value = self.run()
+
+        return self.value
+
+class LazyIteratorProperty (LazyProperty) :
+    """
+        A lazy-loaded property that automatically converts an iterator/genexp into a list.
+    """
+
+    def run (self) :
+        """
+            Wrap LazyProperty.run to return a list
+        """
+
+        return list(super(LazyIteratorProperty, self).run())
+
+lazy_load = LazyProperty
+lazy_load_iter = LazyIteratorProperty
+