[telepathy-spec/master] Add an ImmutableStreams property to StreamedMedia.FUTURE

[Will Thompson]

---
 spec/Channel_Type_Streamed_Media_Future.xml |   36 +++++++++++++++++++++++++++
 1 files changed, 36 insertions(+), 0 deletions(-)

diff --git a/spec/Channel_Type_Streamed_Media_Future.xml b/spec/Channel_Type_Streamed_Media_Future.xml
index 07a181e..b534283 100644
--- a/spec/Channel_Type_Streamed_Media_Future.xml
+++ b/spec/Channel_Type_Streamed_Media_Future.xml
@@ -147,5 +147,41 @@
       </tp:docstring>
     </property>
 
+    <property name="ImmutableStreams" tp:name-for-bindings="Immutable_Streams"
+      type="b" access="read">
+      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
+        <p>If <tt>True</tt>, once streams have been requested for this channel
+          (either by setting <tp:member-ref>InitialAudio</tp:member-ref> or
+          <tp:member-ref>InitialVideo</tp:member-ref> when the channel is
+          requested, or by calling <tp:dbus-ref
+            namespace='org.freedesktop.Telepathy.Channel.Type.StreamedMedia'>RequestStreams</tp:dbus-ref>
+          on a channel with no streams), the channel's streams cannot be changed;
+          subsequent calls to <tp:dbus-ref
+            namespace='org.freedesktop.Telepathy.Channel.Type.StreamedMedia'>RequestStreams</tp:dbus-ref>
+          or <tp:dbus-ref
+            namespace='org.freedesktop.Telepathy.Channel.Type.StreamedMedia'>RemoveStreams</tp:dbus-ref>
+          will fail.</p>
+
+        <p>If this property is missing, clients SHOULD assume that it is false,
+          and thus that the channel's streams can be changed once the call has
+          started.</p>
+
+        <p>If this property is present in all of the <tp:dbus-ref
+            namespace='org.freedesktop.Telepathy.Channel.Type'>StreamedMedia</tp:dbus-ref>
+          entries in a contact's capabilities, then user interfaces MAY choose
+          to show a separate "call" option for each class of call.</p>
+
+        <tp:rationale>
+          <p>On protocols like XMPP Jingle, it is possible to start an
+            audio-only call and then add a video stream, so the user interface
+            could be a single "call" button, which places an audio call, and an
+            "enable video" button in the call interface. However, on protocols
+            like Google Talk it is not possible to upgrade a call once it has
+            started; the user interface will thus need to adapt in order to
+            allow the user to place video calls.</p>
+        </tp:rationale>
+      </tp:docstring>
+    </property>
+
   </interface>
 </node>
-- 
1.5.6.5