all: more efficient type asserting (#341)

Closes #340

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

5 files · +45 -5

M func.go +2 -1


@@ -15,6 +15,7 @@ import (
15	15		"unsafe"
16	16
17	17		"github.com/ebitengine/purego/internal/strings"
	18	+	"github.com/ebitengine/purego/internal/xreflect"
18	19		)
19	20
20	21		var thePool = sync.Pool{New: func() any {

@@ -271,7 +272,7 @@ func RegisterFunc(fptr any, cfn uintptr) {
271	272		}
272	273		}
273	274		for i, v := range args {
274		-	if variadic, ok := args[i].Interface().([]any); ok {
	275	+	if variadic, ok := xreflect.TypeAssert[[]any](args[i]); ok {
275	276		if i != len(args)-1 {
276	277		panic("purego: can only expand last parameter")
277	278		}

 	"unsafe"
 	"github.com/ebitengine/purego/internal/strings"
+	"github.com/ebitengine/purego/internal/xreflect"
 )
 var thePool = sync.Pool{New: func() any {
 			}
 		}
 		for i, v := range args {
-			if variadic, ok := args[i].Interface().([]any); ok {
+			if variadic, ok := xreflect.TypeAssert[[]any](args[i]); ok {
 				if i != len(args)-1 {
 					panic("purego: can only expand last parameter")
 				}

A internal/xreflect/reflect_go124.go +15 -0

@@ -0,0 +1,15 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	//go:build !go1.25
	5	+
	6	+	package xreflect
	7	+
	8	+	import "reflect"
	9	+
	10	+	// TODO: remove this and use Go 1.25's reflect.TypeAssert when minimum go.mod version is 1.25
	11	+
	12	+	func TypeAssert[T any](v reflect.Value) (T, bool) {
	13	+	v2, ok := v.Interface().(T)
	14	+	return v2, ok
	15	+	}

@@ -0,0 +1,15 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	//go:build !go1.25
	5	+
	6	+	package xreflect
	7	+
	8	+	import "reflect"
	9	+
	10	+	// TODO: remove this and use Go 1.25's reflect.TypeAssert when minimum go.mod version is 1.25
	11	+
	12	+	func TypeAssert[T any](v reflect.Value) (T, bool) {
	13	+	v2, ok := v.Interface().(T)
	14	+	return v2, ok
	15	+	}

A internal/xreflect/reflect_go125.go +12 -0

@@ -0,0 +1,12 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	//go:build go1.25
	5	+
	6	+	package xreflect
	7	+
	8	+	import "reflect"
	9	+
	10	+	func TypeAssert[T any](v reflect.Value) (T, bool) {
	11	+	return reflect.TypeAssert[T](v)
	12	+	}

@@ -0,0 +1,12 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	//go:build go1.25
	5	+
	6	+	package xreflect
	7	+
	8	+	import "reflect"
	9	+
	10	+	func TypeAssert[T any](v reflect.Value) (T, bool) {
	11	+	return reflect.TypeAssert[T](v)
	12	+	}

M objc/objc_block_darwin.go +7 -2


@@ -10,6 +10,7 @@ import (
10	10		"unsafe"
11	11
12	12		"github.com/ebitengine/purego"
	13	+	"github.com/ebitengine/purego/internal/xreflect"
13	14		)
14	15
15	16		const (

@@ -167,7 +168,11 @@ func (b *blockCache) getLayout(typ reflect.Type) blockLayout {
167	168		reflect.MakeFunc(
168	169		typ,
169	170		func(args []reflect.Value) (results []reflect.Value) {
170		-	return b.Functions.Load(args[0].Interface().(Block)).Call(args)
	171	+	block, ok := xreflect.TypeAssert[Block](args[0])
	172	+	if !ok {
	173	+	panic(fmt.Sprintf("objc: block argument is not a block but %s", args[0].Type().String()))
	174	+	}
	175	+	return b.Functions.Load(block).Call(args)
171	176		},
172	177		).Interface(),
173	178		)

@@ -258,7 +263,7 @@ func InvokeBlock[T any](block Block, args ...any) (result T, err error) {
258	263		callResult := fn.Call(reflectedArgs)
259	264
260	265		var ok bool
261		-	result, ok = callResult[0].Interface().(T)
	266	+	result, ok = xreflect.TypeAssert[T](callResult[0])
262	267		if !ok {
263	268		return result, fmt.Errorf("objc: the returned value type %s was not %T", callResult[0].Type().String(), result)
264	269		}

 	"unsafe"
 	"github.com/ebitengine/purego"
+	"github.com/ebitengine/purego/internal/xreflect"
 )
 const (
 		reflect.MakeFunc(
 			typ,
 			func(args []reflect.Value) (results []reflect.Value) {
-				return b.Functions.Load(args[0].Interface().(Block)).Call(args)
+				block, ok := xreflect.TypeAssert[Block](args[0])
+				if !ok {
+					panic(fmt.Sprintf("objc: block argument is not a block but %s", args[0].Type().String()))
+				}
+				return b.Functions.Load(block).Call(args)
 			},
 		).Interface(),
 	)
 	callResult := fn.Call(reflectedArgs)
 	var ok bool
-	result, ok = callResult[0].Interface().(T)
+	result, ok = xreflect.TypeAssert[T](callResult[0])
 	if !ok {
 		return result, fmt.Errorf("objc: the returned value type %s was not %T", callResult[0].Type().String(), result)
 	}

M objc/objc_runtime_darwin.go +9 -2


@@ -17,6 +17,7 @@ import (
17	17
18	18		"github.com/ebitengine/purego"
19	19		"github.com/ebitengine/purego/internal/strings"
	20	+	"github.com/ebitengine/purego/internal/xreflect"
20	21		)
21	22
22	23		// TODO: support try/catch?

@@ -341,7 +342,10 @@ func RegisterClass(name string, superClass Class, protocols []*Protocol, ivars [
341	342		// })(unsafe.Pointer(args[0].Interface().(ID)))).v = 123
342	343		//
343	344		// However, since the type of the variable is unknown reflection is used to actually assign the value
344		-	id := args[0].Interface().(ID)
	345	+	id, ok := xreflect.TypeAssert[ID](args[0])
	346	+	if !ok {
	347	+	panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
	348	+	}
345	349		ptr := (unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
346	350		reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem().Set(args[2])
347	351		return nil

@@ -366,7 +370,10 @@ func RegisterClass(name string, superClass Class, protocols []*Protocol, ivars [
366	370		if len(args) != 2 {
367	371		panic(fmt.Sprintf("objc: incorrect number of args. expected 2 got %d", len(args)))
368	372		}
369		-	id := args[0].Interface().(ID)
	373	+	id, ok := xreflect.TypeAssert[ID](args[0])
	374	+	if !ok {
	375	+	panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
	376	+	}
370	377		ptr := (unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
371	378		// the variable is located at an offset from the id
372	379		return []reflect.Value{reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem()}

 	"github.com/ebitengine/purego"
 	"github.com/ebitengine/purego/internal/strings"
+	"github.com/ebitengine/purego/internal/xreflect"
 )
 // TODO: support try/catch?
 				//	})(unsafe.Pointer(args[0].Interface().(ID)))).v = 123
 				//
 				// However, since the type of the variable is unknown reflection is used to actually assign the value
-				id := args[0].Interface().(ID)
+				id, ok := xreflect.TypeAssert[ID](args[0])
+				if !ok {
+					panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
+				}
 				ptr := *(*unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
 				reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem().Set(args[2])
 				return nil
 				if len(args) != 2 {
 					panic(fmt.Sprintf("objc: incorrect number of args. expected 2 got %d", len(args)))
 				}
-				id := args[0].Interface().(ID)
+				id, ok := xreflect.TypeAssert[ID](args[0])
+				if !ok {
+					panic(fmt.Sprintf("objc: id argument is not a ID but %s", args[0].Type().String()))
+				}
 				ptr := *(*unsafe.Pointer)(unsafe.Pointer(&id)) // circumvent go vet
 				// the variable is located at an offset from the id
 				return []reflect.Value{reflect.NewAt(ivar.Type, unsafe.Add(ptr, offset)).Elem()}