If CT tries to change an Application Setting providing only one
setting, the size of the PDU will be 3 bytes. Therefore we should check
if the PDU is shorter than or equal 3, not only shorter.
If media attribute is not available for a certain media file, return an
empty string instead of rejecting the request. The spec is not so clear
if only the title should be handled as an empty string when not present,
but this is the only alternative to rejecting the request.
IOP tests showed that some CT devices don't like reject messages: they
never ask for an attribute again if they previously received a REJECTED
message for that attribute. They consider REJECTED as "TG doesn't
implement it these optional attributes" as opposed to what we had
before, "this attribute is currently not available".
AVRCP is an extension of AV/C spec which has a limit of 512 bytes. The
only place where it can exceed this value is in the response to
GetElementAttributes command.
Now we simply don't add the attributes that would overflow the available
buffer space.
The response of GetCurrentPlayerApplicationSettingValue expects the
first operand to be the number of attributes in response. Since we start
with len=0, we were overwriting this number with the value of the first
attribute.
Also use g_memdup instead of g_malloc + memcpy.
