gpu,app: [Metal] don't store CFTypeRef values in pointer types

CFTypeRefs may not always contain valid pointers, so they must not be
stored in pointer types lest the Go runtime treats them as such.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/metal_darwin.go

@@ -7,7 +7,6 @@ package app
 
 import (
 	"errors"
-	"unsafe"
 
 	"gioui.org/gpu"
 )
@@ -123,14 +122,14 @@ func (c *mtlContext) RenderTarget() (gpu.RenderTarget, error) {
 		return nil, errors.New("metal: CADrawable.texture is nil")
 	}
 	return gpu.MetalRenderTarget{
-		Texture: unsafe.Pointer(c.texture),
+		Texture: uintptr(c.texture),
 	}, nil
 }
 
 func (c *mtlContext) API() gpu.API {
 	return gpu.Metal{
-		Device:      unsafe.Pointer(c.dev),
-		Queue:       unsafe.Pointer(c.queue),
+		Device:      uintptr(c.dev),
+		Queue:       uintptr(c.queue),
 		PixelFormat: int(C.MTLPixelFormatBGRA8Unorm_sRGB),
 	}
 }

gpu/headless/headless_darwin.go

@@ -4,7 +4,6 @@ package headless
 
 import (
 	"errors"
-	"unsafe"
 
 	"gioui.org/gpu"
 	_ "gioui.org/internal/cocoainit"
@@ -54,8 +53,8 @@ func init() {
 
 func (c *mtlContext) API() gpu.API {
 	return gpu.Metal{
-		Device:      unsafe.Pointer(c.dev),
-		Queue:       unsafe.Pointer(c.queue),
+		Device:      uintptr(c.dev),
+		Queue:       uintptr(c.queue),
 		PixelFormat: int(C.MTLPixelFormatRGBA8Unorm_sRGB),
 	}
 }

gpu/internal/driver/api.go

@@ -28,7 +28,7 @@ type Direct3D11RenderTarget struct {
 
 type MetalRenderTarget struct {
 	// Texture is a MTLTexture.
-	Texture unsafe.Pointer
+	Texture uintptr
 }
 
 type VulkanRenderTarget struct {
@@ -59,9 +59,9 @@ type Direct3D11 struct {
 
 type Metal struct {
 	// Device is an MTLDevice.
-	Device unsafe.Pointer
+	Device uintptr
 	// Queue is a MTLCommandQueue.
-	Queue unsafe.Pointer
+	Queue uintptr
 	// PixelFormat is the MTLPixelFormat of the default framebuffer.
 	PixelFormat int
 }