I decided to put this in a custom subclass, because then I could keep
the whole gtk primary protocol self-contained.
The other option would have been reusing GdkWaylandClipboard, but that
didn't seem worth it, especially because that code needs to interact
with the DND machinery, while the primary doesn't.
When the reply to a TARGETS request comes in, the clipboard may already
be reclaimed by the local app. Deal with that case (in an ugly way,
strictly speaking we should use a cancellable here).
This happens for example at startup when the initial TARGETS requests
have not been answered until after the main widow popped up. And if such
a window immediately claims the primary clipboard (like when the initial
focus is inside an entry), this race will happen.
This object tracks the SelectionNotifyEvent that has to be sent in
response to a SelectionRequest.
Currently it just looks like code reshuffling, but it's a prerequisite
for handling MULTIPLE, which requires to only send the notify after
every stream has writtten at least once.
But anyway, code is cleaner now, so it's a win!
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 using GtkClipboard and handling everything ourselves, we now
put GtkTextBuffer into the GdkClipboard and register (de)serializers for
text/plain.
Also make clipboard_claim() a vfunc so backends can override it.
Because the whole operation a vfunc, backends have the option of adding
code before the actual claim is done and potentially even fail or do
something after the successful claim.
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.
(1) Try all passed in formats in order if one of them fails.
(2) Don't blindly accept all formats, make sure they are mime types
(3) Add a bunch of special non-mime types that plug converters to
get to mime types
