permalinks&filetime_from_git:Py3 compat.Fixes #1011

The interface for hashlib.update changed to require input
supporting
[the buffer API](https://docs.python.org/3/c-api/buffer.html).

Also `.next` no longer exists in python 3.

filetime_from_git/actions.py

@@ -79,6 +79,14 @@ def git_sha_metadata(content, git_content):
     content.metadata['gitsha_oldest'] = str(git_content.get_oldest_commit())
 
 
+def update_hash_from_str(hsh, str_input):
+    """
+    Convert a str to object supporting buffer API and update a hash with it.
+    """
+    byte_input = str(str_input).encode("UTF-8")
+    hsh.update(byte_input)
+
+
 @content_git_object_init.connect
 def git_permalink(content, git_content):
     '''
@@ -95,9 +103,10 @@ def git_permalink(content, git_content):
         return
 
     permalink_hash = hashlib.sha1()
-    permalink_hash.update(str(git_content.get_oldest_commit()))
-    permalink_hash.update(str(git_content.get_oldest_filename()))
-    git_permalink_id = base64.urlsafe_b64encode(permalink_hash.digest())
+    update_hash_from_str(permalink_hash, git_content.get_oldest_commit())
+    update_hash_from_str(permalink_hash, git_content.get_oldest_filename())
+    git_permalink_id_raw = base64.urlsafe_b64encode(permalink_hash.digest())
+    git_permalink_id = git_permalink_id_raw.decode("UTF-8")
     permalink_id_metadata_key = content.settings['PERMALINK_ID_METADATA_KEY']
 
     if permalink_id_metadata_key in content.metadata:

filetime_from_git/content_adapter.py

@@ -75,7 +75,7 @@ class GitContentAdapter(object):
         '''
         commit_and_name_iter = self.git.get_commits_and_names_iter(
             self.content.source_path)
-        _commit, name = commit_and_name_iter.next()
+        _commit, name = next(commit_and_name_iter)
         return name
 
     @memoized

permalinks/permalinks.py

@@ -82,9 +82,9 @@ def get_permalink_ids_iter(self):
     Method to get permalink ids from content. To be bound to the class last thing
     '''
     permalink_id_key = self.settings['PERMALINK_ID_METADATA_KEY']
-    permalink_ids_raw = self.metadata.get(permalink_id_key, '')
+    permalink_ids = self.metadata.get(permalink_id_key, '')
 
-    for permalink_id in permalink_ids_raw.split(','):
+    for permalink_id in permalink_ids.split(','):
         if permalink_id:
             yield permalink_id.strip()
 
@@ -98,7 +98,7 @@ def get_permalink_ids(self):
 def get_permalink_path(self):
     """Get just path component of permalink."""
     try:
-        first_permalink_id = self.get_permalink_ids_iter().next()
+        first_permalink_id = next(self.get_permalink_ids_iter())
     except StopIteration:
         return None