This is in preparation of using input streams to show that these
coordinates aren't needed most of the time and can otherwise be saved
during GtkWidget::drag-drop.
This is a GSList of GFile and we want it so we can operate with lists of
files and text/uri-list.
I chose GSList over GList because that's what the GtkFileChooser API
uses, too.
Instead of having just one function that has the gtype and mime type as
out arguments, have 3 functions: 1 that finds any match, 1 that finds a
GType match and one for a mime type match.
This makes the API way more convenient to use.
This requires implementing a "pipe" so we can have 2 streams running:
contentprovider => serializer => outputstream
inputstream => deserializer => reader
And the pipe shoves the data from the outputstream into the inputstream.
GdkContentProvider is the object that represents local data in the
clipboard.
This patch only introduces the object and adds the clipboard properties,
it does not yet provide a way for the actual implementations to access
it.
The only access that is implemented is the local shortcut GValue access.
This allows us not just to pass any mime type to the read function, but
it also makes it possible to pass multiple mime types and the clipboard
can then try them in order until it finds a supported one.
This is so far not implemented though.
It's unused. Plain text is not using that framework, neither is
in-process same-display transmission.
So it was only useful for sharing text with custom tags across
applications, and nobody is doing that.
This is not used by anything yet, but add it now, so people looking at
this new code can make sense of it.
Plus, the documentation mentions it, so better have the docs make sense.
It will be used once we add support for conversions to GDK and allow
doing cipboard/dnd by GValue.
Make sure the API reflects the idea that GdkContentFormats is a set
containing mime types. In particular, treat the object itself as a
plural - it's named content format`S' after all - and therefor use
the correct verb form.
Also make GdkContentFormats keep an array instead of a list, now that
it's immutable.
Instead of allowing people to pass a uint user-data, insist on them
comparing mime types.
The user data was a uint instead of a pointer anyway, so uniqueness
could not be guaranteed and it caused more issues than it was worth.
And that's ignoring the fact that it basically wasn't used.
Instead, add a function gtk_image_set_icon_size() for the cases where
overriding the icon size is necessary.
Treat icon sizes the same way as pixel sizes, too. So gtk_image_clear()
no longer unsets the icon size.
