1 files changed, 340 insertions, 0 deletions
diff --git a/xwayland/selection/dnd.c b/xwayland/selection/dnd.c
new file mode 100644
index 00000000..ed265c28
--- /dev/null
+++ b/xwayland/selection/dnd.c
@@ -0,0 +1,340 @@
+#define _XOPEN_SOURCE 700
+#include <assert.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <wlr/types/wlr_data_device.h>
+#include <wlr/types/wlr_primary_selection.h>
+#include <wlr/util/log.h>
+#include <xcb/xfixes.h>
+#include "xwayland/xwm.h"
+#include "xwayland/selection.h"
+
+static xcb_atom_t data_device_manager_dnd_action_to_atom(
+		struct wlr_xwm *xwm, enum wl_data_device_manager_dnd_action action) {
+	if (action & WL_DATA_DEVICE_MANAGER_DND_ACTION_COPY) {
+		return xwm->atoms[DND_ACTION_COPY];
+	} else if (action & WL_DATA_DEVICE_MANAGER_DND_ACTION_MOVE) {
+		return xwm->atoms[DND_ACTION_MOVE];
+	} else if (action & WL_DATA_DEVICE_MANAGER_DND_ACTION_ASK) {
+		return xwm->atoms[DND_ACTION_ASK];
+	}
+	return XCB_ATOM_NONE;
+}
+
+static enum wl_data_device_manager_dnd_action
+		data_device_manager_dnd_action_from_atom(struct wlr_xwm *xwm,
+		enum atom_name atom) {
+	if (atom == xwm->atoms[DND_ACTION_COPY] ||
+			atom == xwm->atoms[DND_ACTION_PRIVATE]) {
+		return WL_DATA_DEVICE_MANAGER_DND_ACTION_COPY;
+	} else if (atom == xwm->atoms[DND_ACTION_MOVE]) {
+		return WL_DATA_DEVICE_MANAGER_DND_ACTION_MOVE;
+	} else if (atom == xwm->atoms[DND_ACTION_ASK]) {
+		return WL_DATA_DEVICE_MANAGER_DND_ACTION_ASK;
+	}
+	return WL_DATA_DEVICE_MANAGER_DND_ACTION_NONE;
+}
+
+static void xwm_dnd_send_event(struct wlr_xwm *xwm, xcb_atom_t type,
+		xcb_client_message_data_t *data) {
+	struct wlr_xwayland_surface *dest = xwm->drag_focus;
+	assert(dest != NULL);
+
+	xcb_client_message_event_t event = {
+		.response_type = XCB_CLIENT_MESSAGE,
+		.format = 32,
+		.sequence = 0,
+		.window = dest->window_id,
+		.type = type,
+		.data = *data,
+	};
+
+	xcb_send_event(xwm->xcb_conn,
+		0, // propagate
+		dest->window_id,
+		XCB_EVENT_MASK_NO_EVENT,
+		(const char *)&event);
+	xcb_flush(xwm->xcb_conn);
+}
+
+static void xwm_dnd_send_enter(struct wlr_xwm *xwm) {
+	struct wlr_drag *drag = xwm->drag;
+	assert(drag != NULL);
+	struct wl_array *mime_types = &drag->source->mime_types;
+
+	xcb_client_message_data_t data = { 0 };
+	data.data32[0] = xwm->dnd_window;
+	data.data32[1] = XDND_VERSION << 24;
+
+	// If we have 3 MIME types or less, we can send them directly in the
+	// DND_ENTER message
+	size_t n = mime_types->size / sizeof(char *);
+	if (n <= 3) {
+		size_t i = 0;
+		char **mime_type_ptr;
+		wl_array_for_each(mime_type_ptr, mime_types) {
+			char *mime_type = *mime_type_ptr;
+			data.data32[2+i] = xwm_mime_type_to_atom(xwm, mime_type);
+			++i;
+		}
+	} else {
+		// Let the client know that targets are not contained in the message
+		// data and must be retrieved with the DND_TYPE_LIST property
+		data.data32[1] |= 1;
+
+		xcb_atom_t targets[n];
+		size_t i = 0;
+		char **mime_type_ptr;
+		wl_array_for_each(mime_type_ptr, mime_types) {
+			char *mime_type = *mime_type_ptr;
+			targets[i] = xwm_mime_type_to_atom(xwm, mime_type);
+			++i;
+		}
+
+		xcb_change_property(xwm->xcb_conn,
+			XCB_PROP_MODE_REPLACE,
+			xwm->dnd_window,
+			xwm->atoms[DND_TYPE_LIST],
+			XCB_ATOM_ATOM,
+			32, // format
+			n, targets);
+	}
+
+	xwm_dnd_send_event(xwm, xwm->atoms[DND_ENTER], &data);
+}
+
+static void xwm_dnd_send_position(struct wlr_xwm *xwm, uint32_t time, int16_t x,
+		int16_t y) {
+	struct wlr_drag *drag = xwm->drag;
+	assert(drag != NULL);
+
+	xcb_client_message_data_t data = { 0 };
+	data.data32[0] = xwm->dnd_window;
+	data.data32[2] = (x << 16) | y;
+	data.data32[3] = time;
+	data.data32[4] =
+		data_device_manager_dnd_action_to_atom(xwm, drag->source->actions);
+
+	xwm_dnd_send_event(xwm, xwm->atoms[DND_POSITION], &data);
+}
+
+static void xwm_dnd_send_drop(struct wlr_xwm *xwm, uint32_t time) {
+	struct wlr_drag *drag = xwm->drag;
+	assert(drag != NULL);
+	struct wlr_xwayland_surface *dest = xwm->drag_focus;
+	assert(dest != NULL);
+
+	xcb_client_message_data_t data = { 0 };
+	data.data32[0] = xwm->dnd_window;
+	data.data32[2] = time;
+
+	xwm_dnd_send_event(xwm, xwm->atoms[DND_DROP], &data);
+}
+
+static void xwm_dnd_send_leave(struct wlr_xwm *xwm) {
+	struct wlr_drag *drag = xwm->drag;
+	assert(drag != NULL);
+	struct wlr_xwayland_surface *dest = xwm->drag_focus;
+	assert(dest != NULL);
+
+	xcb_client_message_data_t data = { 0 };
+	data.data32[0] = xwm->dnd_window;
+
+	xwm_dnd_send_event(xwm, xwm->atoms[DND_LEAVE], &data);
+}
+
+/*static void xwm_dnd_send_finished(struct wlr_xwm *xwm) {
+	struct wlr_drag *drag = xwm->drag;
+	assert(drag != NULL);
+	struct wlr_xwayland_surface *dest = xwm->drag_focus;
+	assert(dest != NULL);
+
+	xcb_client_message_data_t data = { 0 };
+	data.data32[0] = xwm->dnd_window;
+	data.data32[1] = drag->source->accepted;
+
+	if (drag->source->accepted) {
+		data.data32[2] = data_device_manager_dnd_action_to_atom(xwm,
+			drag->source->current_dnd_action);
+	}
+
+	xwm_dnd_send_event(xwm, xwm->atoms[DND_FINISHED], &data);
+}*/
+
+int xwm_handle_selection_client_message(struct wlr_xwm *xwm,
+		xcb_client_message_event_t *ev) {
+	if (ev->type == xwm->atoms[DND_STATUS]) {
+		if (xwm->drag == NULL) {
+			wlr_log(L_DEBUG, "ignoring XdndStatus client message because "
+				"there's no drag");
+			return 1;
+		}
+
+		xcb_client_message_data_t *data = &ev->data;
+		xcb_window_t target_window = data->data32[0];
+		bool accepted = data->data32[1] & 1;
+		xcb_atom_t action_atom = data->data32[4];
+
+		if (xwm->drag_focus == NULL ||
+				target_window != xwm->drag_focus->window_id) {
+			wlr_log(L_DEBUG, "ignoring XdndStatus client message because "
+				"it doesn't match the current drag focus window ID");
+			return 1;
+		}
+
+		enum wl_data_device_manager_dnd_action action =
+			data_device_manager_dnd_action_from_atom(xwm, action_atom);
+
+		struct wlr_drag *drag = xwm->drag;
+		assert(drag != NULL);
+
+		drag->source->accepted = accepted;
+		wlr_data_source_dnd_action(drag->source, action);
+
+		wlr_log(L_DEBUG, "DND_STATUS window=%d accepted=%d action=%d",
+			target_window, accepted, action);
+		return 1;
+	} else if (ev->type == xwm->atoms[DND_FINISHED]) {
+		// This should only happen after the drag has ended, but before the drag
+		// source is destroyed
+		if (xwm->seat == NULL || xwm->seat->drag_source == NULL ||
+				xwm->drag != NULL) {
+			wlr_log(L_DEBUG, "ignoring XdndFinished client message because "
+				"there's no finished drag");
+			return 1;
+		}
+
+		struct wlr_data_source *source = xwm->seat->drag_source;
+
+		xcb_client_message_data_t *data = &ev->data;
+		xcb_window_t target_window = data->data32[0];
+		bool performed = data->data32[1] & 1;
+		xcb_atom_t action_atom = data->data32[2];
+
+		if (xwm->drag_focus == NULL ||
+				target_window != xwm->drag_focus->window_id) {
+			wlr_log(L_DEBUG, "ignoring XdndFinished client message because "
+				"it doesn't match the finished drag focus window ID");
+			return 1;
+		}
+
+		enum wl_data_device_manager_dnd_action action =
+			data_device_manager_dnd_action_from_atom(xwm, action_atom);
+
+		if (performed) {
+			wlr_data_source_dnd_finish(source);
+		}
+
+		wlr_log(L_DEBUG, "DND_FINISH window=%d performed=%d action=%d",
+			target_window, performed, action);
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
+static void seat_handle_drag_focus(struct wl_listener *listener, void *data) {
+	struct wlr_drag *drag = data;
+	struct wlr_xwm *xwm = wl_container_of(listener, xwm, seat_drag_focus);
+
+	struct wlr_xwayland_surface *focus = NULL;
+	if (drag->focus != NULL) {
+		// TODO: check for subsurfaces?
+		struct wlr_xwayland_surface *surface;
+		wl_list_for_each(surface, &xwm->surfaces, link) {
+			if (surface->surface == drag->focus) {
+				focus = surface;
+				break;
+			}
+		}
+	}
+
+	if (focus == xwm->drag_focus) {
+		return;
+	}
+
+	if (xwm->drag_focus != NULL) {
+		wlr_data_source_dnd_action(drag->source,
+			WL_DATA_DEVICE_MANAGER_DND_ACTION_NONE);
+		xwm_dnd_send_leave(xwm);
+	}
+
+	xwm->drag_focus = focus;
+
+	if (xwm->drag_focus != NULL) {
+		xwm_dnd_send_enter(xwm);
+	}
+}
+
+static void seat_handle_drag_motion(struct wl_listener *listener, void *data) {
+	struct wlr_xwm *xwm = wl_container_of(listener, xwm, seat_drag_motion);
+	struct wlr_drag_motion_event *event = data;
+	struct wlr_xwayland_surface *surface = xwm->drag_focus;
+
+	if (surface == NULL) {
+		return; // No xwayland surface focused
+	}
+
+	xwm_dnd_send_position(xwm, event->time, surface->x + (int16_t)event->sx,
+		surface->y + (int16_t)event->sy);
+}
+
+static void seat_handle_drag_drop(struct wl_listener *listener, void *data) {
+	struct wlr_xwm *xwm = wl_container_of(listener, xwm, seat_drag_drop);
+	struct wlr_drag_drop_event *event = data;
+
+	if (xwm->drag_focus == NULL) {
+		return; // No xwayland surface focused
+	}
+
+	wlr_log(L_DEBUG, "Wayland drag dropped over an Xwayland window");
+	xwm_dnd_send_drop(xwm, event->time);
+}
+
+static void seat_handle_drag_destroy(struct wl_listener *listener, void *data) {
+	struct wlr_xwm *xwm = wl_container_of(listener, xwm, seat_drag_destroy);
+
+	// Don't reset drag focus yet because the target will read the drag source
+	// right after
+	if (xwm->drag_focus != NULL && !xwm->drag->source->accepted) {
+		wlr_log(L_DEBUG, "Wayland drag cancelled over an Xwayland window");
+		xwm_dnd_send_leave(xwm);
+	}
+
+	wl_list_remove(&xwm->seat_drag_focus.link);
+	wl_list_remove(&xwm->seat_drag_motion.link);
+	wl_list_remove(&xwm->seat_drag_drop.link);
+	wl_list_remove(&xwm->seat_drag_destroy.link);
+	xwm->drag = NULL;
+}
+
+static void seat_handle_drag_source_destroy(struct wl_listener *listener,
+		void *data) {
+	struct wlr_xwm *xwm =
+		wl_container_of(listener, xwm, seat_drag_source_destroy);
+
+	wl_list_remove(&xwm->seat_drag_source_destroy.link);
+	xwm->drag_focus = NULL;
+}
+
+void xwm_seat_handle_start_drag(struct wlr_xwm *xwm, struct wlr_drag *drag) {
+	xwm->drag = drag;
+	xwm->drag_focus = NULL;
+
+	if (drag != NULL) {
+		wl_signal_add(&drag->events.focus, &xwm->seat_drag_focus);
+		xwm->seat_drag_focus.notify = seat_handle_drag_focus;
+		wl_signal_add(&drag->events.motion, &xwm->seat_drag_motion);
+		xwm->seat_drag_motion.notify = seat_handle_drag_motion;
+		wl_signal_add(&drag->events.drop, &xwm->seat_drag_drop);
+		xwm->seat_drag_drop.notify = seat_handle_drag_drop;
+		wl_signal_add(&drag->events.destroy, &xwm->seat_drag_destroy);
+		xwm->seat_drag_destroy.notify = seat_handle_drag_destroy;
+
+		wl_signal_add(&drag->source->events.destroy,
+			&xwm->seat_drag_source_destroy);
+		xwm->seat_drag_source_destroy.notify = seat_handle_drag_source_destroy;
+	}
+}