add profile image API to python, tests, Rust fixes/cleanups

python/src/deltachat/chatting.py

@@ -1,6 +1,7 @@
 """ chatting related objects: Contact, Chat, Message. """
 
 import mimetypes
+import os
 from . import props
 from .cutil import as_dc_charpointer, from_dc_charpointer, iter_array
 from .capi import lib, ffi
@@ -315,3 +316,46 @@ class Chat(object):
         return list(iter_array(
             dc_array, lambda id: Contact(self._dc_context, id))
         )
+
+    def set_profile_image(self, img_path):
+        """Set group profile image.
+
+        If the group is already promoted (any message was sent to the group),
+        all group members are informed by a special status message that is sent
+        automatically by this function.
+        :params img_path: path to image object
+        :raises ValueError: if profile image could not be set
+        :returns: None
+        """
+        assert os.path.exists(img_path), img_path
+        p = as_dc_charpointer(img_path)
+        res = lib.dc_set_chat_profile_image(self._dc_context, self.id, p)
+        if res != 1:
+            raise ValueError("Setting Profile Image {!r} failed".format(p))
+
+    def remove_profile_image(self):
+        """remove group profile image.
+
+        If the group is already promoted (any message was sent to the group),
+        all group members are informed by a special status message that is sent
+        automatically by this function.
+        :raises ValueError: if profile image could not be reset
+        :returns: None
+        """
+        res = lib.dc_set_chat_profile_image(self._dc_context, self.id, ffi.NULL)
+        if res != 1:
+            raise ValueError("Removing Profile Image failed")
+
+    def get_profile_image(self):
+        """Get group profile image.
+
+        For groups, this is the image set by any group member using
+        dc_set_chat_profile_image(). For normal chats, this is the image
+        set by each remote user on their own using dc_set_config(context,
+        "selfavatar", image).
+        :returns: path to profile image, None if no profile image exists.
+        """
+        dc_res = lib.dc_chat_get_profile_image(self._dc_chat)
+        if dc_res == ffi.NULL:
+            return None
+        return from_dc_charpointer(dc_res)