3 files changed, 31 insertions, 8 deletions
diff --git a/django/utils/functional.py b/django/utils/functional.py
index 0c31c1f375..a57546ad2d 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -3,6 +3,21 @@ def curry(_curried_func, *args, **kwargs):
         return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs))
     return _curried
 
+def memoize(func, cache):
+    """
+    Wrap a function so that results for any argument tuple are stored in
+    'cache'. Note that the args to the function must be usable as dictionary
+    keys.
+    """
+    def wrapper(*args):
+        if args in cache:
+            return cache[args]
+
+        result = func(*args)
+        cache[args] = result
+        return result
+    return wrapper
+
 class Promise:
     """
     This is just a base class for the proxy class created in
diff --git a/django/utils/html.py b/django/utils/html.py
index 607362817b..e1860627ce 100644
--- a/django/utils/html.py
+++ b/django/utils/html.py
@@ -53,16 +53,18 @@ def fix_ampersands(value):
 
 def urlize(text, trim_url_limit=None, nofollow=False):
     """
-    Converts any URLs in text into clickable links. Works on http://, https:// and
-    www. links. Links can have trailing punctuation (periods, commas, close-parens)
-    and leading punctuation (opening parens) and it'll still do the right thing.
+    Converts any URLs in text into clickable links. Works on http://, https://
+    and www. links. Links can have trailing punctuation (periods, commas,
+    close-parens) and leading punctuation (opening parens) and it'll still do
+    the right thing.
 
-    If trim_url_limit is not None, the URLs in link text will be limited to
-    trim_url_limit characters.
+    If trim_url_limit is not None, the URLs in link text longer than this limit
+    will truncated to trim_url_limit-3 characters and appended with an elipsis.
 
-    If nofollow is True, the URLs in link text will get a rel="nofollow" attribute.
+    If nofollow is True, the URLs in link text will get a rel="nofollow"
+    attribute.
     """
-    trim_url = lambda x, limit=trim_url_limit: limit is not None and (x[:limit] + (len(x) >=limit and '...' or ''))  or x
+    trim_url = lambda x, limit=trim_url_limit: limit is not None and (len(x) > limit and ('%s...' % x[:max(0, limit - 3)])) or x
     words = word_split_re.split(text)
     nofollow_attr = nofollow and ' rel="nofollow"' or ''
     for i, word in enumerate(words):
diff --git a/django/utils/itercompat.py b/django/utils/itercompat.py
index 48a2d99d3a..0de1b6cbe2 100644
--- a/django/utils/itercompat.py
+++ b/django/utils/itercompat.py
@@ -34,7 +34,7 @@ def groupby(iterable, keyfunc=None):
         keyfunc = lambda x:x
     iterable = iter(iterable)
     l = [iterable.next()]
-    lastkey = keyfunc(l)
+    lastkey = keyfunc(l[0])
     for item in iterable:
         key = keyfunc(item)
         if key != lastkey:
@@ -45,6 +45,12 @@ def groupby(iterable, keyfunc=None):
             l.append(item)
     yield lastkey, l
 
+# Not really in itertools, since it's a builtin in Python 2.4 and later, but it
+# does operate as an iterator.
+def reversed(data):
+    for index in xrange(len(data)-1, -1, -1):
+        yield data[index]
+
 if hasattr(itertools, 'tee'):
     tee = itertools.tee
 else: