[gst-devel] gst_element_class_set_details() gone?

Felipe Contreras felipe.contreras at gmail.com
Sat Apr 24 16:04:48 CEST 2010

2010/4/24 Sebastian Dröge <sebastian.droege at collabora.co.uk>:
> On Sat, 2010-04-24 at 13:36 +0300, Felipe Contreras wrote:
>> About this commit:
>> http://cgit.freedesktop.org/gstreamer/gstreamer/commit/?id=3b4aa3f76a0252560151186bbdfb6be4e28880af
>> The commit message is very bad; it's missing key information: why?
>> According to Stefan; gst_element_class_set_details is causing a extra
>> reloc and pointer copying. While that's probably true, the overhead is
>> almost nothing, and only happens once, when the class is being
>> initialized, right? It's ABI breakage for no reason.
>> If a new API is in the works, that's cool, but since there's no better
>> API right now, IMO the commit is doing more damage than good.
>> FWIW, I'll be removing GST_DISABLE_DEPRECATED instead.
> The replacement for gst_element_class_set_details() is
> gst_element_class_set_details_simple(), which does exactly the same
> thing but more efficient.

How more efficient? I'm looking at the resulting assembly, and this
code actually looks more efficient:

	gst_element_class_set_details(element_class, &(const GstElementDetails) {
				      .longname = "basic video decoder",
				      .klass = "Codec/Decoder/Video",
				      .description = "Decodes video",
				      .author = "John Doe",

If that looks too confusing, this is exactly the same:

	const GstElementDetails details = {
		.longname = "basic video decoder",
		.klass = "Codec/Decoder/Video",
		.description = "Decodes video",
		.author = "John Doe",

	gst_element_class_set_details(element_class, &details);

Personally, I find both versions to be more readable than the
gst_element_class_set_details_simple() alternative.

> gst_element_class_set_details() is still there unless you define
> GST_REMOVE_DEPRECATED but will be hidden from the headers if you define

I'm aware of that.

> That's the same as was done to many other functions in the past too,
> e.g. gst_element_get_pad() or gst_atomic_int_set().

Indeed, but there was a good reason for those. I don't see any for this.


Felipe Contreras

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