W3C home > Mailing lists > Public > public-webrtc@w3.org > June 2012

some comments on the IDL in the WebRTC spec

From: Cameron McCormack <cam@mcc.id.au>
Date: Thu, 21 Jun 2012 15:22:11 +1000
Message-ID: <4FE2AF83.9030607@mcc.id.au>
To: public-webrtc@w3.org
Hi,

Below are some comments on the IDL currently in the spec after a brief 
look.  I haven't reviewed any prose.


4.1.1 SdpType
4.1.3 SessionDescriptionCallback
4.1.4 PeerConnectionErrorCallback
4.1.5 PeerState Enum
4.1.6 IceState Enum
4.1.7 IceCandidate Type
4.1.8 IceCandidateCallback

The definitions in these sections are all missing semicolons at the end.


4.1.2 SessionDescription Class

If you want, you can just write "stringifier;" rather than "stringifier 
DOMString ();", since they are equivalent.

Why do you want these to be stringifiable, by the way?


4.1.9 IceServers Type - Option 1

The attribute needs to be written as:

   attribute DOMString[][] servers;

Similarly for 4.1.10 (square brackets as part of the type).


4.1.11 PeerConnection interface

s/Boolean/boolean/g in the IDL block.

If you specify default values for optional arguments, then all preceding 
optional arguments must also have default values.  So I would either 
rewrite createAnswer to:

   void createAnswer
     (SessionDescription offer,
      SessionDescriptionCallback successCallback,
      optional PeerConnectionErrorCallback? failureCallback = null,
      optional MediaConstraints? constraints = null,
      optional boolean createProvisionalAnswer = false);

or

   void createAnswer
     (SessionDescription offer,
      SessionDescriptionCallback successCallback,
      optional PeerConnectionErrorCallback failureCallback,
      optional MediaConstraints constraints,
      optional boolean createProvisionalAnswer);

and just describe the behaviour when createProvisionalAnswer is not 
specified in prose.  Similarly for updateIce.

You can't use [TreatNullAs=EmptyString] on a type that already accepts 
null, like createDataChannel's label argument does.  Either remove the 
"?" from the type or drop the [TreatNullAs=EmptyString] and describe in 
prose what happens when you pass null.

Please put [TreatNonCallableAsNull] on all of the event listener 
attributes, like you do for DataChannel.  We want the behaviour of all 
event listener attributes across the platform to be consistent.  (There 
should hopefully be a simpler definition to reference at some point in 
the future that won't look as awkward as "[TreatNonCallableAsNull] 
attribute Function?".)


8.1 DataChannel

I recommend using enums instead of integer constants.  I see there is a 
PeerState enum defined earlier in the document -- can you use this instead?

It might be good to support all the same kinds of types being passed to 
send() that XHR allows.


10.3 MediaStreamTrackEvent

The "readonly" should be removed from the dictionary member.

It seems like the attribute on MediaStreamTrackEvent should be of type 
"MediaStreamTrack?" rather than "MediaStreamTrack", if you can use null 
in the event initialisation dictionary.  (Similarly for MediaStreamEvent 
in the following section.)
Received on Thursday, 21 June 2012 05:22:43 UTC

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