Add the skeleton of the message type framework

.gitignore

@@ -82,3 +82,4 @@ Makefile.in
 /src/matrix-event-call-hangup.c
 /src/matrix-event-call-base.c
 /src/matrix-glib-0.0.pc
+/src/matrix-message-base.c

src/Makefile.am

@@ -50,6 +50,7 @@ libmatrix_glib_0_0_la_VALA_SOURCES = \
 	matrix-event-call-candidates.vala \
 	matrix-event-call-answer.vala \
 	matrix-event-call-hangup.vala \
+	matrix-message-base.vala \
 	$(NULL)
 
 AM_CPPFLAGS += \

src/matrix-event-room-message.vala

@@ -16,38 +16,75 @@
  * <http://www.gnu.org/licenses/>.
  */
 
+/**
+ * Class to hold an m.room.message event
+ *
+ * This event is used when sending messages in a room. Messages are
+ * not limited to be text. The `msgtype` key outlines the type of
+ * message, e.g. text, audio, image, video, etc. The `body` key is
+ * text and MUST be used with every kind of `msgtype` as a fallback
+ * mechanism for when a client cannot render a message. This allows
+ * clients to display *something* even if it is just plain text.
+ */
 public class Matrix.Event.RoomMessage : Matrix.Event.Room {
-    public string msg_type { get; set; }
-    public string body { get; set; }
+    /**
+     * The message as a Matrix.Message object.
+     */
+    public Matrix.Message.Base? message { get; set; default = null; }
+
+    /**
+     * The message as a JSON object. This gets set by
+     * Matrix.Message.Base.new_from_json if no handler is installed
+     * for the given message type.
+     */
+    public Json.Node? fallback_content {
+        get {
+            return _fallback_content;
+        }
+    }
+
+    private Json.Node? _fallback_content;
 
     protected override void
     from_json(Json.Node json_data)
         throws Matrix.Error
     {
-        var root = json_data.get_object();
+        var content_node = json_data.get_object().get_member("content");
 
-        if (root.get_member("content") == null) {
-            throw new Matrix.Error.INCOMPLETE(
-                    "Message event without a content!");
+        try {
+            _message = Matrix.Message.Base.new_from_json(content_node);
+
+            // We don't want to fail on unknown message types, so
+            // let's save the JSON content instead. Silent
+            // (ie. without exception) null is only returned if there
+            // is no handler class installed
+            if (_message == null) {
+                _fallback_content = content_node;
+            } else {
+                _fallback_content = null;
+            }
+        } catch (GLib.Error e) {
+            throw new Matrix.Error.INVALID_TYPE(
+                    "Error during message initialization:%s",
+                    e.message);
         }
 
-        var content_root = root.get_member("content").get_object();
-        Json.Node? node;
-
-        if ((node = content_root.get_member("msgtype")) == null) {
-            throw new Matrix.Error.INCOMPLETE(
-                    "Message event without a message type!");
-        }
-
-        _msg_type = node.get_string();
-
-        if ((node = content_root.get_member("body")) == null) {
-            throw new Matrix.Error.INCOMPLETE(
-                    "Message event without a body!");
-        }
-
-        _body = node.get_string();
-
         base.from_json(json_data);
     }
+
+    protected override void
+    to_json(Json.Node json_data)
+        throws Matrix.Error
+    {
+        if (_message == null) {
+            throw new Matrix.Error.INCOMPLETE(
+                    "Won't generate a m.room.message event without content");
+        }
+
+        var root = json_data.get_object();
+
+        root.set_member("content", _message.json);
+
+        base.to_json(json_data);
+    }
 }

src/matrix-message-base.vala

@@ -0,0 +1,220 @@
+/*
+ * This file is part of matrix-glib-sdk
+ *
+ * matrix-glib-sdk is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation, either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * matrix-glib-sdk is distributed in the hope that it will be
+ * useful, but WITHOUT ANY WARRANTY; without even the implied
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with matrix-glib-sdk. If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+/**
+ * Base class for message handlers.
+ *
+ * Message handler base class.
+ */
+public abstract class Matrix.Message.Base : Object, Initable {
+    /**
+     * The message type.
+     */
+    public string? message_type { get; set; default = null; }
+
+    /**
+     * The body of the message.
+     */
+    public string? body { get; set; default = null; }
+
+    public Json.Node? json {
+        get {
+            _json = new Json.Node(Json.NodeType.OBJECT);
+            _json.set_object(new Json.Object());
+
+            try {
+                to_json(_json);
+            } catch (Matrix.Error e) {
+                return null;
+            }
+
+            return _json;
+        }
+
+        construct {
+            if (value != null) {
+                try {
+                    initialize_from_json(value);
+                } catch (Matrix.Error e) {}
+            }
+        }
+    }
+
+    private bool _inited = false;
+    private Error? _construct_error = null;
+    private Json.Node? _json = null;
+
+    public bool
+    init(Cancellable? cancellable = null)
+        throws GLib.Error
+    {
+        if (cancellable != null) {
+            throw new Matrix.Error.UNSUPPORTED(
+                    "Cancellable initialization not supported");
+        }
+
+        if (_construct_error != null) {
+            throw _construct_error;
+        }
+
+        _inited = true;
+
+        return true;
+    }
+
+    private void
+    initialize_from_json(Json.Node json_data)
+        throws Matrix.Error
+    {
+        if (json_data.get_node_type() != Json.NodeType.OBJECT) {
+            throw new Matrix.Error.INVALID_FORMAT(
+                    "The message is not valid");
+        }
+
+        from_json(json_data);
+    }
+
+    public static Matrix.Message.Base?
+    new_from_json(Json.Node json_data)
+        throws Matrix.Error, GLib.Error
+    {
+        var root = json_data.get_object();
+        Json.Node? node;
+
+        if ((node = root.get_member("msgtype")) == null) {
+            throw new Matrix.Error.INCOMPLETE(
+                    "Can not process a message without msgtype");
+        }
+
+        Type? msg_gtype;
+
+        if ((msg_gtype = get_handler(node.get_string())) == null) {
+            return null;
+        }
+
+        var ret = (Base)Object.new(msg_gtype,
+                                   json : json_data);
+
+        ret.init();
+
+        return ret;
+    }
+
+    /**
+     * Subclasses should override this method to initialize themselves
+     * from JSON data while chaining up to allow parent classes to do
+     * the same.
+     */
+    public virtual void
+    from_json(Json.Node json_data)
+        throws Matrix.Error
+    {
+        var root = json_data.get_object();
+        Json.Node? node;
+
+        if ((node = root.get_member("msgtype")) != null) {
+            _message_type = node.get_string();
+        } else if (Config.DEBUG) {
+            warning("msgtype is not present in a message");
+        }
+    }
+
+    /**
+     * Subclasses should override this method to export their data to
+     * JSON, while chaining up to allow parent classes to do the same.
+     */
+    public virtual void
+    to_json(Json.Node json_data)
+        throws Matrix.Error
+    {
+        var root = json_data.get_object();
+
+        if (_message_type == null) {
+            throw new Matrix.Error.INCOMPLETE(
+                    "Won't generate a message with an empty msgtype");
+        }
+
+        root.set_string_member("msgtype", _message_type);
+    }
+}
+
+namespace Matrix.Message {
+
+private HashTable<string, TypeClass>? type_handlers = null;
+
+/**
+ * Get the {@link GLib.Type} of the class that is registered to handle
+ * messages with type @param message_type.
+ *
+ * @param message_type the message type to look up
+ * @return a {@link GLib.Type} or `null` if no handler is registered
+ */
+public static GLib.Type?
+get_handler(string message_type)
+{
+    unowned GLib.TypeClass? klass = null;
+
+    if ((type_handlers != null)
+        && ((klass = type_handlers.get(message_type)) != null)) {
+        return klass.get_type();
+    }
+
+    if (Config.DEBUG) {
+        warning("No registered type for message %s", message_type);
+    }
+
+    return null;
+}
+
+/**
+ * Register @param message_type to be handled by the
+ * type @param message_gtype.
+ *
+ * @param message_type the type of the message
+ * @param message_gtype the {@link GLib.Type} of the event's handler
+ */
+public static void
+register_type(string message_type, GLib.Type message_gtype)
+    throws Matrix.Error
+{
+    if (!message_gtype.is_a(typeof(Matrix.Message.Base))) {
+        throw new Matrix.Error.INVALID_TYPE(
+                "Invalid message handler type");
+    }
+
+    if (type_handlers == null) {
+        type_handlers = new HashTable<string, GLib.TypeClass>(
+                str_hash, str_equal);
+    }
+
+    type_handlers.replace(message_type, message_gtype.class_ref());
+}
+
+/**
+ * Unregister @param message_type.
+ *
+ * @param message_type the message type to remove
+ */
+public void
+unregister_type(string message_type)
+{
+    if (type_handlers != null) {
+        type_handlers.remove(message_type);
+    }
+}
+}

src/namespace-info.vala.in

@@ -20,4 +20,7 @@
 namespace Matrix {
     [CCode (gir_namespace = "Event", gir_version = "@MATRIX_GLIB_API_VERSION@")]
     namespace Event {}
+
+    [CCode (gir_namespace = "Message", gir_version = "@MATRIX_GLIB_API_VERSION@")]
+    namespace Message {}
 }

src/test-client.c

@@ -75,10 +75,19 @@ cb_room_message_event(MatrixClient *client,
                       MatrixEventBase *event,
                       gpointer user_data)
 {
-    g_printf("Message from %s: %s\n",
-             matrix_event_room_get_sender(MATRIX_EVENT_ROOM(event)),
-             matrix_event_room_message_get_body(
-                     MATRIX_EVENT_ROOM_MESSAGE(event)));
+    MatrixMessageBase *message;
+
+    if ((message = matrix_event_room_message_get_message(
+                 MATRIX_EVENT_ROOM_MESSAGE(event))) != NULL) {
+        g_printf("Message from %s in %s: %s\n",
+                 matrix_event_room_get_sender(MATRIX_EVENT_ROOM(event)),
+                 matrix_event_room_get_room_id(MATRIX_EVENT_ROOM(event)),
+                 matrix_message_base_get_body(message));
+    } else {
+        g_printf("Unknown message received from %s in %s\n",
+                 matrix_event_room_get_sender(MATRIX_EVENT_ROOM(event)),
+                 matrix_event_room_get_room_id(MATRIX_EVENT_ROOM(event)));
+    }
 }
 
 int