move towards message creation API, refactor constructors for messages

python/src/deltachat/account.py

@@ -104,12 +104,13 @@ class Account(object):
         return Contact(self._dc_context, const.DC_CONTACT_ID_SELF)
 
     def create_message(self, view_type):
-        """ create a new message (not yet persistent in database).
+        """ create a new non persistent message.
 
         :param view_type: a string specifying "text", "video",
                           "image", "audio" or "file".
         :returns: :class:`deltachat.chatting.Message` instance.
         """
+        return Message.new(self._dc_context, view_type)
 
     def create_contact(self, email, name=None):
         """ create a (new) Contact. If there already is a Contact
@@ -205,8 +206,7 @@ class Account(object):
 
     def get_message_by_id(self, msg_id):
         """ return Message instance. """
-        assert msg_id > 0
-        return Message(self._dc_context, msg_id)
+        return Message.from_id(self._dc_context, msg_id)
 
     def mark_seen_messages(self, messages):
         """ mark the given set of messages as seen.

python/src/deltachat/chatting.py

@@ -118,7 +118,7 @@ class Chat(object):
         msg_id = lib.dc_send_text_msg(self._dc_context, self.id, msg)
         if msg_id == 0:
             raise ValueError("message could not be send, does chat exist?")
-        return Message(self._dc_context, msg_id)
+        return Message.from_id(self._dc_context, msg_id)
 
     def send_file(self, path, mime_type="application/octet-stream"):
         """ send a file and return the resulting Message instance.
@@ -133,7 +133,7 @@ class Chat(object):
         msg_id = lib.dc_send_file_msg(self._dc_context, self.id, path, mtype)
         if msg_id == 0:
             raise ValueError("message could not be send, does chat exist?")
-        return Message(self._dc_context, msg_id)
+        return Message.from_id(self._dc_context, msg_id)
 
     def send_image(self, path):
         """ send an image message and return the resulting Message instance.
@@ -148,7 +148,7 @@ class Chat(object):
         msg_id = lib.dc_send_image_msg(self._dc_context, self.id, path, ffi.NULL, 0, 0)
         if msg_id == 0:
             raise ValueError("chat does not exist")
-        return Message(self._dc_context, msg_id)
+        return Message.from_id(self._dc_context, msg_id)
 
     def get_messages(self):
         """ return list of messages in this chat.
@@ -159,7 +159,7 @@ class Chat(object):
             lib.dc_get_chat_msgs(self._dc_context, self.id, 0, 0),
             lib.dc_array_unref
         )
-        return list(iter_array(dc_array, lambda x: Message(self._dc_context, x)))
+        return list(iter_array(dc_array, lambda x: Message.from_id(self._dc_context, x)))
 
     def count_fresh_messages(self):
         """ return number of fresh messages in this chat.

python/src/deltachat/message.py

@@ -1,6 +1,6 @@
 """ chatting related objects: Contact, Chat, Message. """
 
-from .cutil import from_dc_charpointer
+from .cutil import from_dc_charpointer, as_dc_charpointer
 from .capi import lib, ffi
 from .types import property_with_doc
 from . import const
@@ -21,10 +21,32 @@ class Message(object):
 
     @property
     def _dc_msg(self):
-        return ffi.gc(
-            lib.dc_get_msg(self._dc_context, self.id),
+        if self.id > 0:
+            return ffi.gc(
+                lib.dc_get_msg(self._dc_context, self.id),
+                lib.dc_msg_unref
+            )
+        return self._dc_msg_volatile
+
+    @classmethod
+    def from_id(cls, _dc_context, id):
+        assert id > 0
+        return cls(_dc_context, id)
+
+    @classmethod
+    def new(cls, dc_context, view_type):
+        """ create a non-persistent method. """
+        msg = cls(dc_context, 0)
+        msg._dc_msg_volatile = ffi.gc(
+            lib.dc_msg_new(dc_context),
             lib.dc_msg_unref
         )
+        lib.dc_msg_set_type(msg._dc_msg, MessageType.get_typecode(view_type))
+        return msg
+
+    def is_persistent(self):
+        """ return True if the message is persistent in the database. """
+        return self.id > 0
 
     def get_state(self):
         """ get the message in/out state.
@@ -38,11 +60,18 @@ class Message(object):
         """unicode text of this messages (might be empty if not a text message). """
         return from_dc_charpointer(lib.dc_msg_get_text(self._dc_msg))
 
+    def set_text(self, text):
+        """set text of this message. """
+        return lib.dc_msg_set_text(self._dc_msg, as_dc_charpointer(text))
+
     @property_with_doc
     def filename(self):
         """filename if there was an attachment, otherwise empty string. """
         return from_dc_charpointer(lib.dc_msg_get_file(self._dc_msg))
 
+    def set_file(self, path, mime_type=None):
+        """set file for this message. """
+
     @property_with_doc
     def basename(self):
         """basename of the attachment if it exists, otherwise empty string. """
@@ -103,6 +132,13 @@ class MessageType(object):
             const.DC_MSG_FILE: 'file'
     }
 
+    @classmethod
+    def get_typecode(cls, view_type):
+        for code, value in cls._mapping.items():
+            if value == view_type:
+                return code
+        raise ValueError("message typecode not found for {!r}".format(view_type))
+
     @property_with_doc
     def name(self):
         """ human readable type name. """

python/tests/test_account.py

@@ -92,6 +92,15 @@ class TestOfflineAccount:
         with pytest.raises(ValueError):
             chat.send_text("msg1")
 
+    def test_create_message(self, acfactory):
+        ac1 = acfactory.get_configured_offline_account()
+        message = ac1.create_message("text")
+        assert message.id == 0
+        assert message._dc_msg is message._dc_msg
+        message.set_text("hello")
+        assert message.text == "hello"
+        assert not message.is_persistent()
+
     def test_message(self, acfactory):
         ac1 = acfactory.get_configured_offline_account()
         contact1 = ac1.create_contact("some1@hello.com", name="some1")