db/message: do not delay loading the email file

This simplifies the following refactorings. It will be made asynchronous
later.

1 files changed, 20 insertions, 16 deletions

diff --git a/alot/db/message.py b/alot/db/message.py
index d9866384..f20e3af6 100644
--- a/alot/db/message.py
+++ b/alot/db/message.py
@@ -78,14 +78,15 @@ class Message:
             raise ValueError('No filenames for a message returned')
         self.filenames = filenames
 
-        self._email = None  # will be read upon first use
-        self._attachments = None  # will be read upon first use
-        self._tags = set(msg.get_tags())
-
-        self._session_keys = []
+        session_keys = []
         for name, value in msg.get_properties("session-key", exact=True):
             if name == "session-key":
-                self._session_keys.append(value)
+                session_keys.append(value)
+
+        self._email = self._load_email(session_keys)
+
+        self._attachments = None  # will be read upon first use
+        self._tags = set(msg.get_tags())
 
         try:
             sender = decode_header(msg.get_header('From'))
@@ -121,18 +122,21 @@ class Message:
     def filename(self):
         return self.filenames[0]
 
-    def get_email(self):
-        """returns :class:`email.email.EmailMessage` for this message"""
+    def _load_email(self, session_keys):
         warning = "Subject: Caution!\n"\
                   "Message file is no longer accessible:\n%s" % self.filename
-        if not self._email:
-            try:
-                with open(self.filename, 'rb') as f:
-                    self._email = utils.decrypted_message_from_bytes(
-                            f.read(), self._session_keys)
-            except IOError:
-                self._email = email.message_from_string(
-                    warning, policy=email.policy.SMTP)
+        try:
+            with open(self.filename, 'rb') as f:
+                email = utils.decrypted_message_from_bytes(
+                        f.read(), session_keys)
+        except IOError:
+            email = email.message_from_string(
+                warning, policy=email.policy.SMTP)
+
+        return email
+
+    def get_email(self):
+        """returns :class:`email.email.EmailMessage` for this message"""
         return self._email
 
     def get_message_parts(self):