Python 3 preparation: update next() usage for iterators.

Tool-assisted patch.  Note that various classes in TAL code with
next() methods are not actually Python iterators and so are not
changed in this patch, but roundup/cgi/ZTUtils/Iterator.py includes
the IterIter class which converts between the two styles of iterator.

Author: jsm28

roundup/cgi/ZTUtils/Iterator.py

@@ -169,7 +169,7 @@ def _supports(self, ob):
 
     def prep_next(self, it):
         try:
-            it._next = it.seq.next()
+            it._next = next(it.seq)
         except StopIteration:
             it._prep_next = self.no_next
             it.end = 1
@@ -181,14 +181,16 @@ class IterIter:
     def __init__(self, it):
         self.it = it
         self.skip = it.nextIndex > 0 and not it.end
-    def next(self):
+    def __next__(self):
         it = self.it
         if self.skip:
             self.skip = 0
             return it.item
         if it.next():
             return it.item
         raise StopIteration
+    # Python 2 compatibility:
+    next = __next__
 
 seqInner = SeqInner()
 iterInner = IterInner()

roundup/mailgw.py

@@ -1351,11 +1351,11 @@ def do_mailbox(self, filename):
             from mailbox import UnixMailbox
             mailbox = UnixMailbox(f, factory=Message)
             # grab one message
-            message = mailbox.next()
+            message = next(mailbox)
             while message:
                 # handle this message
                 self.handle_Message(message)
-                message = mailbox.next()
+                message = next(mailbox)
             # nuke the file contents
             os.ftruncate(f.fileno(), 0)
         except:

roundup/support.py

@@ -76,19 +76,21 @@ def __init__(self, info, sequence):
 
     def __iter__(self): return self
 
-    def next(self):
+    def __next__(self):
         self.num += 1
 
         if self.num > self.total:
             print(self.info, 'done', ' '*(75-len(self.info)-6))
             sys.stdout.flush()
-            return self.sequence.next()
+            return next(self.sequence)
 
         if self.num % self.stepsize:
-            return self.sequence.next()
+            return next(self.sequence)
 
         self.display()
-        return self.sequence.next()
+        return next(self.sequence)
+    # Python 2 compatibility:
+    next = __next__
 
     def display(self):
         # figure how long we've spent - guess how long to go