Implement primary selection

 river/Seat.zig   | 10 ++++++++++
 river/Server.zig |  4 ++++
 river/c.zig      |  3 +++
 3 files changed, 17 insertions(+)

diff --git a/river/Seat.zig b/river/Seat.zig
index bb6e557..e80368c 100644
--- a/river/Seat.zig
+++ b/river/Seat.zig
@@ -69,6 +69,7 @@ status_trackers: std.SinglyLinkedList(SeatStatus) = .{},
 listen_request_set_selection: c.wl_listener = undefined,
 listen_request_start_drag: c.wl_listener = undefined,
 listen_start_drag: c.wl_listener = undefined,
+listen_request_set_primary_selection: c.wl_listener = undefined,
 
 pub fn init(self: *Self, input_manager: *InputManager, name: [*:0]const u8) !void {
     self.* = .{
@@ -89,6 +90,9 @@ pub fn init(self: *Self, input_manager: *InputManager, name: [*:0]const u8) !voi
 
     self.listen_start_drag.notify = handleStartDrag;
     c.wl_signal_add(&self.wlr_seat.events.start_drag, &self.listen_start_drag);
+
+    self.listen_request_set_primary_selection.notify = handleRequestPrimarySelection;
+    c.wl_signal_add(&self.wlr_seat.events.request_set_primary_selection, &self.listen_request_set_primary_selection);
 }
 
 pub fn deinit(self: *Self) void {
@@ -366,3 +370,9 @@ fn handleStartDrag(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void
     }
     self.cursor.mode = .passthrough;
 }
+
+fn handleRequestPrimarySelection(listener: ?*c.wl_listener, data: ?*c_void) callconv(.C) void {
+    const self = @fieldParentPtr(Self, "listen_request_set_primary_selection", listener.?);
+    const event = util.voidCast(c.wlr_seat_request_set_primary_selection_event, data.?);
+    c.wlr_seat_set_primary_selection(self.wlr_seat, event.source, event.serial);
+}
diff --git a/river/Server.zig b/river/Server.zig
index fd8aeff..c2eb0c8 100644
--- a/river/Server.zig
+++ b/river/Server.zig
@@ -118,6 +118,10 @@ pub fn init(self: *Self) !void {
         c.wl_signal_add(&self.wlr_xwayland.events.new_surface, &self.listen_new_xwayland_surface);
     }
 
+    // Set up primary selection
+    _ = c.wlr_primary_selection_v1_device_manager_create(self.wl_display);
+    _ = c.wlr_gtk_primary_selection_device_manager_create(self.wl_display);
+
     self.config = try Config.init();
     try self.decoration_manager.init(self);
     try self.root.init(self);
diff --git a/river/c.zig b/river/c.zig
index ead36a3..f9814e6 100644
--- a/river/c.zig
+++ b/river/c.zig
@@ -35,6 +35,7 @@ pub usingnamespace @cImport({
     @cInclude("wlr/types/wlr_data_control_v1.h");
     @cInclude("wlr/types/wlr_data_device.h");
     @cInclude("wlr/types/wlr_gamma_control_v1.h");
+    @cInclude("wlr/types/wlr_gtk_primary_selection.h");
     @cInclude("wlr/types/wlr_idle.h");
     @cInclude("wlr/types/wlr_input_device.h");
     @cInclude("wlr/types/wlr_input_inhibitor.h");
@@ -44,6 +45,8 @@ pub usingnamespace @cImport({
     @cInclude("wlr/types/wlr_output.h");
     @cInclude("wlr/types/wlr_output_layout.h");
     @cInclude("wlr/types/wlr_pointer.h");
+    @cInclude("wlr/types/wlr_primary_selection.h");
+    @cInclude("wlr/types/wlr_primary_selection_v1.h");
     @cInclude("wlr/types/wlr_screencopy_v1.h");
     @cInclude("wlr/types/wlr_seat.h");
     @cInclude("wlr/types/wlr_xcursor_manager.h");