Original commit message from CVS:
2005-07-01  Andy Wingo  <wingo@pobox.com>

* tests/network-clock.scm: Commentary update.

* gst/elements/gstidentity.c (PROP_DUPLICATE): Gone daddy gone.
Didn't really make sense, not implementable with basetransform,
etc.
(gst_identity_transform): Unref inbuf via make_writable. Feeble
attempt at implementing the sync property, needs an unlock method.

* gst/base/gstbasetransform.c (gst_base_transform_transform_caps):
New func, by default returns the same caps (the identity
transformation).
(gst_base_transform_getcaps): Uses transform_caps to return
something sensible.
(gst_base_transform_setcaps): Complicated logic to get caps on
both pads, even if they are different, and to call set_caps once
for every time both pads get their caps set.
(gst_base_transform_handle_buffer): Give the ref to the transform
function. Allows in-place modification of the buffer.

* gst/base/gstbasetransform.h (transform_caps): New class method.
Given caps on one side, what can I do on the other.
(set_caps): Take two caps, one for each side of the element.

* gst/gstpad.h:
* gst/gstpad.c (gst_pad_fixate_caps): Change prototype to modify
caps in place. This is safe because we can check the mutability of
the caps, and a good idea because fixate functions are just called
as a matter of last resort. (Not actually implemented.)
(gst_pad_set_caps): If the caps we're setting is actually the same
as the existing pad caps, just update the pointer without calling
setcaps. Assert that caps is either NULL or fixed, as per the
docs.

* gst/gstghostpad.c: Update for fixate changes.