mac: avoid unnecessary unsafe conversions; fixes crash in debug builds

Previously, running a debug build of mpv would crash with this output
when preinit() at vo_libmpv.c:732 calls control(vo, VOCTRL_PREINIT, NULL):

Swift/Optional.swift:247: Fatal error: unsafelyUnwrapped of nil optional

This comes from this line of code:

var data = UnsafeMutableRawPointer.init(bitPattern: 0).unsafelyUnwrapped

Unsafely unwrapping a UnsafeMutableRawPointer.init has always been UB,
but the Swift runtime began asserting on it in debug builds a couple macOS
versions ago.

1 files changed, 2 insertions, 10 deletions

diff --git a/video/out/cocoa_cb_common.swift b/video/out/cocoa_cb_common.swift
index dd0738f7e3..5c312cbff0 100644
--- a/video/out/cocoa_cb_common.swift
+++ b/video/out/cocoa_cb_common.swift
@@ -167,17 +167,9 @@ class CocoaCB: Common {
         layer?.update(force: true)
     }
 
-    var controlCallback: mp_render_cb_control_fn = { ( v, ctx, e, request, d ) -> Int32 in
+    var controlCallback: mp_render_cb_control_fn = { ( v, ctx, e, request, data ) -> Int32 in
         let ccb = unsafeBitCast(ctx, to: CocoaCB.self)
 
-        // the data pointer can be a null pointer, the libmpv control callback
-        // provides nil instead of the 0 address like the usual control call of
-        // an internal vo, workaround to create a null pointer instead of nil
-        var data = UnsafeMutableRawPointer.init(bitPattern: 0).unsafelyUnwrapped
-        if let dunwrapped = d {
-            data = dunwrapped
-        }
-
         guard let vo = v, let events = e else {
             ccb.log.sendWarning("Unexpected nil value in Control Callback")
             return VO_FALSE
@@ -189,7 +181,7 @@ class CocoaCB: Common {
     override func control(_ vo: UnsafeMutablePointer<vo>,
                     events: UnsafeMutablePointer<Int32>,
                     request: UInt32,
-                    data: UnsafeMutableRawPointer) -> Int32
+                    data: UnsafeMutableRawPointer?) -> Int32
     {
         switch mp_voctrl(request) {
         case VOCTRL_PREINIT: