Attempt to get clipboard "set_with_data()" to work using ctypes

test_ctypes_clipboard.py

import ctypes

import gi

gi.require_version('Gtk', '3.0')
gi.require_version('GIRepository', '2.0')

from gi.repository import GIRepository
from gi.repository import Gtk


# Load the libraries we need via GIRepository
def _get_shared_library(n):
	repo = GIRepository.Repository.get_default()
	return repo.get_shared_library(n).split(',')[0]

libgtk = ctypes.CDLL(_get_shared_library('Gtk'))
libgdk = ctypes.CDLL(_get_shared_library('Gdk'))


def c_func(dll, name, args, res=None):
	fn = getattr(dll, name)
	fn.restype = res
	fn.argtypes = args
	return fn

def atom_p(name):
	return libgdk.gdk_atom_intern_static_string(name, False)

print("---- clipboard ----")

clipboard = libgtk.gtk_clipboard_get(atom_p(b'CLIPBOARD'))
assert clipboard != 0

# Test passing clipboard pointer works
gtk_clipboard_set_text = c_func(libgtk, 'gtk_clipboard_set_text',
							(ctypes.c_void_p, ctypes.c_void_p, ctypes.c_uint))

gtk_clipboard_wait_for_text = c_func(libgtk, 'gtk_clipboard_wait_for_text',
								(), res=ctypes.c_char_p)

gtk_clipboard_set_text(clipboard, b'Test 123', len(b'Test 123'))
print("Set text")

text = gtk_clipboard_wait_for_text(clipboard)
print("TEXT>", text)
assert text == b'Test 123'

print("----- target entry list ----")

targetentrylist = libgtk.gtk_target_list_new(None, 0)
libgtk.gtk_target_list_add(
	targetentrylist,
	atom_p(b'text/plain'),
	0,
	9,
)

gtk_target_list_find = c_func(libgtk, 'gtk_target_list_find',
						(ctypes.c_void_p, ctypes.c_void_p), res=ctypes.c_bool)

ok = gtk_target_list_find(targetentrylist, atom_p(b'text/plain'), None)
print("FOUND TARGET:", ok)
assert ok

print("---- functions and set_with_data ----")

GetFuncType = ctypes.CFUNCTYPE(None, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p)
def get_func(clipboard, selection, info, data):
	print("GET %r" % ((clipboard, selection, info, data),))
	libgtk.gtk_selection_data_set_text(selection, b'Test 456', len(b'Test 456'))

ClearFuncType = ctypes.CFUNCTYPE(None, ctypes.c_void_p, ctypes.c_void_p)
def clear_func(clipboard, data):
	print("CLEAR %r" % ((clipboard, data),))

c_get_func = GetFuncType(get_func)
c_clear_func = ClearFuncType(clear_func)

gtk_clipboard_set_with_data = c_func(libgtk, 'gtk_clipboard_set_with_data',
								(
									ctypes.c_void_p,
									ctypes.c_void_p,
									ctypes.c_uint,
									ctypes.c_void_p, #ctypes.POINTER(GetFuncType),
									ctypes.c_void_p, #ctypes.POINTER(ClearFuncType),
									ctypes.c_void_p
								),
								res=ctypes.c_bool)


user_data = "userdata 123"
ok = gtk_clipboard_set_with_data(
	clipboard,
	targetentrylist,
	1,
	c_get_func,
	c_clear_func,
	user_data
)
print(">>>", ok)
assert ok


gtk_clipboard_wait_for_contents = c_func(libgtk, 'gtk_clipboard_wait_for_contents',
									(ctypes.c_void_p, ctypes.c_void_p), res=ctypes.c_void_p)

data = gtk_clipboard_wait_for_contents(clipboard, atom_p(b'text/plain'))
print(">>>>", data)

text = gtk_clipboard_wait_for_text(clipboard)
print("TEXT>", text)
assert text == b'Test 456'


# PS need global cache for data so it will not get garbage collected before "clear"

Hey, did you end up having any luck with this?

Afraid I did not have sufficient free time to further pursue it. But still interested in the fix Op vr 24 apr. 2020 22:42 schreef Mladen Mijatov <notifications@github.com>:

…

***@***.**** commented on this gist. ------------------------------ Hey, did you end up having any luck with this? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/4f7d3dba7d5bc725dacf28a382893d69#gistcomment-3268570>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAJQYHRRAC4HOWRFUARWEP3ROH2SVANCNFSM4MQMXKYQ> .

Well, it's an important fix but GTK+ developers decided to give up on every language other than those with direct access to C library. Reason they stated doesn't help either, they just said "The GtkClipboard api is gone." Whatever that meant.

Anyway, I tried many different approaches with your code. From single atom target, to all kinds of variations. I tried getting clipboard for current display but that failed as well. What I found really odd is that even simple set_text makes copied data unavailable to other programs, which led me to believe that getting clipboard does something wrong, even though atom value is correct.

Do you have some insights of your own which might aid me in pursuing this issue?

Yes I understand gtk4 will have an new clipboard API. But that doesn't solve the issue now. One way forward would be to write a small function in C that sets the clipboard and has the soon hardcoded. Then use a ctypes wrapper to get the data from the python code into this wrapper. Op za 25 apr. 2020 14:41 schreef Mladen Mijatov <notifications@github.com>:

…

***@***.**** commented on this gist. ------------------------------ Well, it's an important fix but GTK+ developers decided to give up on every language other than those with direct access to C library. Reason they stated doesn't help either, they just said "The GtkClipboard api is gone." Whatever that meant. Anyway, I tried many different approaches with your code. From single atom target, to all kinds of variations. I tried getting clipboard for current display but that failed as well. What I found really odd is that even simple set_text makes copied data unavailable to other programs, which led me to believe that getting clipboard does something wrong, even though atom value is correct. Do you have some insights of your own which might aid me in pursuing this issue? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <https://gist.github.com/4f7d3dba7d5bc725dacf28a382893d69#gistcomment-3269285>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAJQYHUQKTLKA55U2WTUSCDROLLAZANCNFSM4MQMXKYQ> .

That's what I wanted to avoid. My application is entirely written in Python, which means it's architecture agnostic. I was really hoping I could upgrade your code to functional.

That said, I know Polari is doing the C function approach, since application is written in GJS and they are suffering from same stupid decision made by GTK developers. We should check what they are doing and perhaps take their solution.