thread: implement tree decorations

They were temporarily removed in the previous commit.
Still not working:
- theming for the decorations
- drawing the connector line properly for expanded messages
- configurable indentation

1 files changed, 16 insertions, 0 deletions

diff --git a/alot/db/message.py b/alot/db/message.py
index 62b85788..4adb0816 100644
--- a/alot/db/message.py
+++ b/alot/db/message.py
@@ -41,6 +41,12 @@ class Message:
     """A list of replies to this message"""
     replies = None
 
+    """
+    This message parent in the list (i.e. the message this message is a reply
+    to). None when this message is top-level.
+    """
+    parent = None
+
     def __init__(self, dbman, thread, msg, depth):
         """
         :param dbman: db manager that is used for further lookups
@@ -248,3 +254,13 @@ class Message:
         """tests if this messages is in the resultset for `querystring`"""
         searchfor = '( {} ) AND id:{}'.format(querystring, self.id)
         return self._dbman.count_messages(searchfor) > 0
+
+    def parents(self):
+        """
+        A generator iterating over this message's parents up to the topmost
+        level.
+        """
+        m = self.parent
+        while m:
+            yield m
+            m = m.parent