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.

2 files changed, 14 insertions, 22 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:
diff --git a/video/out/mac/common.swift b/video/out/mac/common.swift
index 5a48ccef7b..66faf816d0 100644
--- a/video/out/mac/common.swift
+++ b/video/out/mac/common.swift
@@ -523,7 +523,7 @@ class Common: NSObject {
     @objc func control(_ vo: UnsafeMutablePointer<vo>,
                          events: UnsafeMutablePointer<Int32>,
                          request: UInt32,
-                         data: UnsafeMutableRawPointer) -> Int32
+                         data: UnsafeMutableRawPointer?) -> Int32
     {
         guard let mpv = mpv else {
             log.sendWarning("Unexpected nil value in Control Callback")
@@ -573,11 +573,11 @@ class Common: NSObject {
             }
             return VO_TRUE
         case VOCTRL_GET_DISPLAY_FPS:
-            let fps = data.assumingMemoryBound(to: CDouble.self)
+            let fps = data!.assumingMemoryBound(to: CDouble.self)
             fps.pointee = currentFps()
             return VO_TRUE
         case VOCTRL_GET_HIDPI_SCALE:
-            let scaleFactor = data.assumingMemoryBound(to: CDouble.self)
+            let scaleFactor = data!.assumingMemoryBound(to: CDouble.self)
             let screen = getCurrentScreen()
             let factor = window?.backingScaleFactor ??
                          screen?.backingScaleFactor ?? 1.0
@@ -590,7 +590,7 @@ class Common: NSObject {
             disableDisplaySleep()
             return VO_TRUE
         case VOCTRL_SET_CURSOR_VISIBILITY:
-            let cursorVisibility = data.assumingMemoryBound(to: CBool.self)
+            let cursorVisibility = data!.assumingMemoryBound(to: CBool.self)
             cursorVisibilityWanted = cursorVisibility.pointee
             DispatchQueue.main.async {
                 self.setCursorVisibility(self.cursorVisibilityWanted)
@@ -603,7 +603,7 @@ class Common: NSObject {
                 return VO_TRUE
             }
 
-            let icc = data.assumingMemoryBound(to: bstr.self)
+            let icc = data!.assumingMemoryBound(to: bstr.self)
             iccData.withUnsafeMutableBytes { (ptr: UnsafeMutableRawBufferPointer) in
                 guard let baseAddress = ptr.baseAddress, ptr.count > 0 else { return }
                 let u8Ptr = baseAddress.assumingMemoryBound(to: UInt8.self)
@@ -612,13 +612,13 @@ class Common: NSObject {
             return VO_TRUE
         case VOCTRL_GET_AMBIENT_LUX:
             if lightSensor != 0 {
-                let lux = data.assumingMemoryBound(to: Int32.self)
+                let lux = data!.assumingMemoryBound(to: Int32.self)
                 lux.pointee = Int32(lmuToLux(lastLmu))
                 return VO_TRUE;
             }
             return VO_NOTIMPL
         case VOCTRL_GET_UNFS_WINDOW_SIZE:
-            let sizeData = data.assumingMemoryBound(to: Int32.self)
+            let sizeData = data!.assumingMemoryBound(to: Int32.self)
             let size = UnsafeMutableBufferPointer(start: sizeData, count: 2)
             var rect = window?.unfsContentFrame ?? NSRect(x: 0, y: 0, width: 1280, height: 720)
             if let screen = window?.currentScreen, !Bool(mpv.opts.hidpi_window_scale) {
@@ -629,7 +629,7 @@ class Common: NSObject {
             size[1] = Int32(rect.size.height)
             return VO_TRUE
         case VOCTRL_SET_UNFS_WINDOW_SIZE:
-            let sizeData = data.assumingMemoryBound(to: Int32.self)
+            let sizeData = data!.assumingMemoryBound(to: Int32.self)
             let size = UnsafeBufferPointer(start: sizeData, count: 2)
             var rect = NSMakeRect(0, 0, CGFloat(size[0]), CGFloat(size[1]))
             DispatchQueue.main.async {
@@ -640,7 +640,7 @@ class Common: NSObject {
             }
             return VO_TRUE
         case VOCTRL_GET_DISPLAY_NAMES:
-            let dnames = data.assumingMemoryBound(to: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>?.self)
+            let dnames = data!.assumingMemoryBound(to: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>?.self)
             var array: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>? = nil
             var count: Int32 = 0
             let displayName = getCurrentScreen()?.displayName ?? "Unknown"
@@ -654,18 +654,18 @@ class Common: NSObject {
                 log.sendWarning("No Screen available to retrieve frame")
                 return VO_NOTAVAIL
             }
-            let sizeData = data.assumingMemoryBound(to: Int32.self)
+            let sizeData = data!.assumingMemoryBound(to: Int32.self)
             let size = UnsafeMutableBufferPointer(start: sizeData, count: 2)
             let frame = screen.convertRectToBacking(screen.frame)
             size[0] = Int32(frame.size.width)
             size[1] = Int32(frame.size.height)
             return VO_TRUE
         case VOCTRL_GET_FOCUSED:
-            let focus = data.assumingMemoryBound(to: CBool.self)
+            let focus = data!.assumingMemoryBound(to: CBool.self)
             focus.pointee = NSApp.isActive
             return VO_TRUE
         case VOCTRL_UPDATE_WINDOW_TITLE:
-            let titleData = data.assumingMemoryBound(to: Int8.self)
+            let titleData = data!.assumingMemoryBound(to: Int8.self)
             DispatchQueue.main.async {
                 let title = NSString(utf8String: titleData) as String?
                 self.title = title ?? "Unknown Title"