objc: implement ability to create Protocols at runtime (#320)

Closes #321

commit: 1a51bed53afae7417fa8f512a1e96b4cc43e938e
author: TotallyGamerJet · 16mo ago · 2025-06-08 18:18 UTC
committer: GitHub · 16mo ago · 2025-06-08 18:18 UTC
parent: 660f0c6
signature: GPG UnverifiedB5690EEEBB952194 The key is unknown
refs: tag: v0.9.0-alpha.7

3 files · +363 -25

A examples/protocol-dumper/main_darwin.go +176 -0

@@ -0,0 +1,176 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	package main
	5	+
	6	+	// #cgo CFLAGS: -x objective-c
	7	+	// #cgo LDFLAGS: -framework AppKit
	8	+	//
	9	+	// #import <AppKit/AppKit.h>
	10	+	//
	11	+	// __attribute__((used))
	12	+	// static void __force_protocol_load() {
	13	+	// id o = NULL;
	14	+	// o = @protocol(NSAccessibility);
	15	+	// o = @protocol(NSApplicationDelegate);
	16	+	// }
	17	+	import "C"
	18	+
	19	+	import (
	20	+	"fmt"
	21	+	"io"
	22	+	"os"
	23	+	"strconv"
	24	+	"strings"
	25	+	"text/template"
	26	+
	27	+	"github.com/ebitengine/purego/objc"
	28	+	)
	29	+
	30	+	var protocols = []string{
	31	+	"NSAccessibility",
	32	+	"NSApplicationDelegate",
	33	+	}
	34	+
	35	+	type ProtocolImpl struct {
	36	+	Name string
	37	+
	38	+	RequiredInstanceMethods []objc.MethodDescription
	39	+	RequiredClassMethods []objc.MethodDescription
	40	+	OptionalInstanceMethods []objc.MethodDescription
	41	+	OptionalClassMethods []objc.MethodDescription
	42	+
	43	+	AdoptedProtocols []*objc.Protocol
	44	+
	45	+	RequiredInstanceProperties []objc.Property
	46	+	RequiredClassProperties []objc.Property
	47	+	OptionalInstanceProperties []objc.Property
	48	+	OptionalClassProperties []objc.Property
	49	+	}
	50	+
	51	+	func readProtocols(names []string) (imps []ProtocolImpl, err error) {
	52	+	for _, name := range names {
	53	+	p := objc.GetProtocol(name)
	54	+	if p == nil {
	55	+	return nil, fmt.Errorf("protocol '%s' does not exist", name)
	56	+	}
	57	+	imp := ProtocolImpl{}
	58	+	imp.Name = name
	59	+	imp.RequiredInstanceMethods = p.CopyMethodDescriptionList(true, true)
	60	+	imp.RequiredClassMethods = p.CopyMethodDescriptionList(true, false)
	61	+	imp.OptionalInstanceMethods = p.CopyMethodDescriptionList(false, true)
	62	+	imp.OptionalClassMethods = p.CopyMethodDescriptionList(false, false)
	63	+
	64	+	imp.AdoptedProtocols = p.CopyProtocolList()
	65	+
	66	+	imp.RequiredInstanceProperties = p.CopyPropertyList(true, true)
	67	+	imp.RequiredClassProperties = p.CopyPropertyList(true, false)
	68	+	imp.OptionalInstanceProperties = p.CopyPropertyList(false, true)
	69	+	imp.OptionalClassProperties = p.CopyPropertyList(false, false)
	70	+	imps = append(imps, imp)
	71	+	}
	72	+	return imps, nil
	73	+	}
	74	+
	75	+	const templ = `// Code generated by protocol-dumper; DO NOT EDIT.
	76	+
	77	+	package main
	78	+
	79	+	import (
	80	+	"log"
	81	+
	82	+	"github.com/ebitengine/purego/objc"
	83	+	)
	84	+
	85	+	func init() {
	86	+	var p *objc.Protocol
	87	+	{{- range . }}
	88	+	{{- $protocolName := .Name }}
	89	+	if p = objc.AllocateProtocol("{{$protocolName}}"); p != nil {
	90	+	{{- range .RequiredInstanceMethods }}
	91	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", true, true)
	92	+	{{- end }}
	93	+
	94	+	{{- range .RequiredClassMethods }}
	95	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", true, false)
	96	+	{{- end }}
	97	+
	98	+	{{- range .OptionalInstanceMethods }}
	99	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", false, true)
	100	+	{{- end }}
	101	+
	102	+	{{- range .OptionalClassMethods }}
	103	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", false, false)
	104	+	{{- end }}
	105	+	var adoptedProtocol *objc.Protocol
	106	+	{{- range .AdoptedProtocols }}
	107	+	adoptedProtocol = objc.GetProtocol("{{ .Name }}")
	108	+	if adoptedProtocol == nil {
	109	+	log.Fatalln("protocol '{{ .Name }}' does not exist")
	110	+	}
	111	+	p.AddProtocol(adoptedProtocol)
	112	+	{{- end }}
	113	+
	114	+	{{- range .RequiredInstanceProperties }}
	115	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, true, true)
	116	+	{{- end }}
	117	+
	118	+
	119	+	{{- range .RequiredClassProperties }}
	120	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, true, false)
	121	+	{{- end }}
	122	+
	123	+	{{- range .OptionalInstanceProperties }}
	124	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, false, true)
	125	+	{{- end }}
	126	+
	127	+	{{- range .OptionalClassProperties }}
	128	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, false, false)
	129	+	{{- end }}
	130	+	p.Register()
	131	+	} // Finished protocol: {{$protocolName}}
	132	+	{{- end }}
	133	+	}
	134	+	`
	135	+
	136	+	func printProtocols(impls []ProtocolImpl, w io.Writer) error {
	137	+	tmpl, err := template.New("protocol.tmpl").Funcs(template.FuncMap{
	138	+	"attributeToStructString": attributeToStructString,
	139	+	}).Parse(templ)
	140	+	if err != nil {
	141	+	return err
	142	+	}
	143	+	err = tmpl.Execute(w, impls)
	144	+	if err != nil {
	145	+	return err
	146	+	}
	147	+	return nil
	148	+	}
	149	+
	150	+	func attributeToStructString(p objc.Property) string {
	151	+	attribs := strings.Split(p.Attributes(), ",")
	152	+	var b strings.Builder
	153	+	b.WriteString("[]objc.PropertyAttribute{")
	154	+	for i, attrib := range attribs {
	155	+	b.WriteString(fmt.Sprintf(`{Name: &[]byte("%s\x00")[0], Value: &[]byte(%s)[0]}`, string(attrib[0]), strconv.Quote(attrib[1:]+"\x00")))
	156	+	if i != len(attribs)-1 {
	157	+	b.WriteString(", ")
	158	+	}
	159	+	}
	160	+	b.WriteString("}")
	161	+	return b.String()
	162	+	}
	163	+
	164	+	// This program prints out the Go code to generate the OBJC protocols list.
	165	+	// To use it add the @protocol(name) to the C import section and then add it to the protocols list.
	166	+	// You'll want to run it as amd64 and arm64 since the types are slightly different for each architecture.
	167	+	func main() {
	168	+	var imps []ProtocolImpl
	169	+	var err error
	170	+	if imps, err = readProtocols(protocols); err != nil {
	171	+	panic(err)
	172	+	}
	173	+	if err = printProtocols(imps, os.Stdout); err != nil {
	174	+	panic(err)
	175	+	}
	176	+	}

@@ -0,0 +1,176 @@
	1	+	// SPDX-License-Identifier: Apache-2.0
	2	+	// SPDX-FileCopyrightText: 2025 The Ebitengine Authors
	3	+
	4	+	package main
	5	+
	6	+	// #cgo CFLAGS: -x objective-c
	7	+	// #cgo LDFLAGS: -framework AppKit
	8	+	//
	9	+	// #import <AppKit/AppKit.h>
	10	+	//
	11	+	// __attribute__((used))
	12	+	// static void __force_protocol_load() {
	13	+	// id o = NULL;
	14	+	// o = @protocol(NSAccessibility);
	15	+	// o = @protocol(NSApplicationDelegate);
	16	+	// }
	17	+	import "C"
	18	+
	19	+	import (
	20	+	"fmt"
	21	+	"io"
	22	+	"os"
	23	+	"strconv"
	24	+	"strings"
	25	+	"text/template"
	26	+
	27	+	"github.com/ebitengine/purego/objc"
	28	+	)
	29	+
	30	+	var protocols = []string{
	31	+	"NSAccessibility",
	32	+	"NSApplicationDelegate",
	33	+	}
	34	+
	35	+	type ProtocolImpl struct {
	36	+	Name string
	37	+
	38	+	RequiredInstanceMethods []objc.MethodDescription
	39	+	RequiredClassMethods []objc.MethodDescription
	40	+	OptionalInstanceMethods []objc.MethodDescription
	41	+	OptionalClassMethods []objc.MethodDescription
	42	+
	43	+	AdoptedProtocols []*objc.Protocol
	44	+
	45	+	RequiredInstanceProperties []objc.Property
	46	+	RequiredClassProperties []objc.Property
	47	+	OptionalInstanceProperties []objc.Property
	48	+	OptionalClassProperties []objc.Property
	49	+	}
	50	+
	51	+	func readProtocols(names []string) (imps []ProtocolImpl, err error) {
	52	+	for _, name := range names {
	53	+	p := objc.GetProtocol(name)
	54	+	if p == nil {
	55	+	return nil, fmt.Errorf("protocol '%s' does not exist", name)
	56	+	}
	57	+	imp := ProtocolImpl{}
	58	+	imp.Name = name
	59	+	imp.RequiredInstanceMethods = p.CopyMethodDescriptionList(true, true)
	60	+	imp.RequiredClassMethods = p.CopyMethodDescriptionList(true, false)
	61	+	imp.OptionalInstanceMethods = p.CopyMethodDescriptionList(false, true)
	62	+	imp.OptionalClassMethods = p.CopyMethodDescriptionList(false, false)
	63	+
	64	+	imp.AdoptedProtocols = p.CopyProtocolList()
	65	+
	66	+	imp.RequiredInstanceProperties = p.CopyPropertyList(true, true)
	67	+	imp.RequiredClassProperties = p.CopyPropertyList(true, false)
	68	+	imp.OptionalInstanceProperties = p.CopyPropertyList(false, true)
	69	+	imp.OptionalClassProperties = p.CopyPropertyList(false, false)
	70	+	imps = append(imps, imp)
	71	+	}
	72	+	return imps, nil
	73	+	}
	74	+
	75	+	const templ = `// Code generated by protocol-dumper; DO NOT EDIT.
	76	+
	77	+	package main
	78	+
	79	+	import (
	80	+	"log"
	81	+
	82	+	"github.com/ebitengine/purego/objc"
	83	+	)
	84	+
	85	+	func init() {
	86	+	var p *objc.Protocol
	87	+	{{- range . }}
	88	+	{{- $protocolName := .Name }}
	89	+	if p = objc.AllocateProtocol("{{$protocolName}}"); p != nil {
	90	+	{{- range .RequiredInstanceMethods }}
	91	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", true, true)
	92	+	{{- end }}
	93	+
	94	+	{{- range .RequiredClassMethods }}
	95	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", true, false)
	96	+	{{- end }}
	97	+
	98	+	{{- range .OptionalInstanceMethods }}
	99	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", false, true)
	100	+	{{- end }}
	101	+
	102	+	{{- range .OptionalClassMethods }}
	103	+	p.AddMethodDescription(objc.RegisterName("{{ .Name }}"), "{{ .Types }}", false, false)
	104	+	{{- end }}
	105	+	var adoptedProtocol *objc.Protocol
	106	+	{{- range .AdoptedProtocols }}
	107	+	adoptedProtocol = objc.GetProtocol("{{ .Name }}")
	108	+	if adoptedProtocol == nil {
	109	+	log.Fatalln("protocol '{{ .Name }}' does not exist")
	110	+	}
	111	+	p.AddProtocol(adoptedProtocol)
	112	+	{{- end }}
	113	+
	114	+	{{- range .RequiredInstanceProperties }}
	115	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, true, true)
	116	+	{{- end }}
	117	+
	118	+
	119	+	{{- range .RequiredClassProperties }}
	120	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, true, false)
	121	+	{{- end }}
	122	+
	123	+	{{- range .OptionalInstanceProperties }}
	124	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, false, true)
	125	+	{{- end }}
	126	+
	127	+	{{- range .OptionalClassProperties }}
	128	+	p.AddProperty("{{ .Name }}", {{ attributeToStructString . }}, false, false)
	129	+	{{- end }}
	130	+	p.Register()
	131	+	} // Finished protocol: {{$protocolName}}
	132	+	{{- end }}
	133	+	}
	134	+	`
	135	+
	136	+	func printProtocols(impls []ProtocolImpl, w io.Writer) error {
	137	+	tmpl, err := template.New("protocol.tmpl").Funcs(template.FuncMap{
	138	+	"attributeToStructString": attributeToStructString,
	139	+	}).Parse(templ)
	140	+	if err != nil {
	141	+	return err
	142	+	}
	143	+	err = tmpl.Execute(w, impls)
	144	+	if err != nil {
	145	+	return err
	146	+	}
	147	+	return nil
	148	+	}
	149	+
	150	+	func attributeToStructString(p objc.Property) string {
	151	+	attribs := strings.Split(p.Attributes(), ",")
	152	+	var b strings.Builder
	153	+	b.WriteString("[]objc.PropertyAttribute{")
	154	+	for i, attrib := range attribs {
	155	+	b.WriteString(fmt.Sprintf(`{Name: &[]byte("%s\x00")[0], Value: &[]byte(%s)[0]}`, string(attrib[0]), strconv.Quote(attrib[1:]+"\x00")))
	156	+	if i != len(attribs)-1 {
	157	+	b.WriteString(", ")
	158	+	}
	159	+	}
	160	+	b.WriteString("}")
	161	+	return b.String()
	162	+	}
	163	+
	164	+	// This program prints out the Go code to generate the OBJC protocols list.
	165	+	// To use it add the @protocol(name) to the C import section and then add it to the protocols list.
	166	+	// You'll want to run it as amd64 and arm64 since the types are slightly different for each architecture.
	167	+	func main() {
	168	+	var imps []ProtocolImpl
	169	+	var err error
	170	+	if imps, err = readProtocols(protocols); err != nil {
	171	+	panic(err)
	172	+	}
	173	+	if err = printProtocols(imps, os.Stdout); err != nil {
	174	+	panic(err)
	175	+	}
	176	+	}

M objc/objc_runtime_darwin.go +151 -25


@@ -16,39 +16,52 @@ import (
16	16		"unsafe"
17	17
18	18		"github.com/ebitengine/purego"
	19	+	"github.com/ebitengine/purego/internal/strings"
19	20		)
20	21
21	22		// TODO: support try/catch?
22	23		// https://stackoverflow.com/questions/7062599/example-of-how-objective-cs-try-catch-implementation-is-executed-at-runtime
23	24		var (
24		-	objc_msgSend_fn uintptr
25		-	objc_msgSend_stret_fn uintptr
26		-	objc_msgSend func(obj ID, cmd SEL, args ...any) ID
27		-	objc_msgSendSuper2_fn uintptr
28		-	objc_msgSendSuper2_stret_fn uintptr
29		-	objc_msgSendSuper2 func(super *objc_super, cmd SEL, args ...any) ID
30		-	objc_getClass func(name string) Class
31		-	objc_getProtocol func(name string) *Protocol
32		-	objc_allocateClassPair func(super Class, name string, extraBytes uintptr) Class
33		-	objc_registerClassPair func(class Class)
34		-	sel_registerName func(name string) SEL
35		-	class_getSuperclass func(class Class) Class
36		-	class_getInstanceVariable func(class Class, name string) Ivar
37		-	class_getInstanceSize func(class Class) uintptr
38		-	class_addMethod func(class Class, name SEL, imp IMP, types string) bool
39		-	class_addIvar func(class Class, name string, size uintptr, alignment uint8, types string) bool
40		-	class_addProtocol func(class Class, protocol *Protocol) bool
41		-	ivar_getOffset func(ivar Ivar) uintptr
42		-	ivar_getName func(ivar Ivar) string
43		-	object_getClass func(obj ID) Class
44		-	object_getIvar func(obj ID, ivar Ivar) ID
45		-	object_setIvar func(obj ID, ivar Ivar, value ID)
46		-	protocol_getName func(protocol *Protocol) string
47		-	protocol_isEqual func(p Protocol, p2 Protocol) bool
	25	+	objc_msgSend_fn uintptr
	26	+	objc_msgSend_stret_fn uintptr
	27	+	objc_msgSend func(obj ID, cmd SEL, args ...any) ID
	28	+	objc_msgSendSuper2_fn uintptr
	29	+	objc_msgSendSuper2_stret_fn uintptr
	30	+	objc_msgSendSuper2 func(super *objc_super, cmd SEL, args ...any) ID
	31	+	objc_getClass func(name string) Class
	32	+	objc_getProtocol func(name string) *Protocol
	33	+	objc_allocateProtocol func(name string) *Protocol
	34	+	objc_registerProtocol func(protocol *Protocol)
	35	+	objc_allocateClassPair func(super Class, name string, extraBytes uintptr) Class
	36	+	objc_registerClassPair func(class Class)
	37	+	sel_registerName func(name string) SEL
	38	+	class_getSuperclass func(class Class) Class
	39	+	class_getInstanceVariable func(class Class, name string) Ivar
	40	+	class_getInstanceSize func(class Class) uintptr
	41	+	class_addMethod func(class Class, name SEL, imp IMP, types string) bool
	42	+	class_addIvar func(class Class, name string, size uintptr, alignment uint8, types string) bool
	43	+	class_addProtocol func(class Class, protocol *Protocol) bool
	44	+	ivar_getOffset func(ivar Ivar) uintptr
	45	+	ivar_getName func(ivar Ivar) string
	46	+	object_getClass func(obj ID) Class
	47	+	object_getIvar func(obj ID, ivar Ivar) ID
	48	+	object_setIvar func(obj ID, ivar Ivar, value ID)
	49	+	protocol_getName func(protocol *Protocol) string
	50	+	protocol_isEqual func(p Protocol, p2 Protocol) bool
	51	+	protocol_addMethodDescription func(p *Protocol, name SEL, types string, isRequiredMethod bool, isInstanceMethod bool)
	52	+	protocol_copyMethodDescriptionList func(p Protocol, isRequiredMethod bool, isInstanceMethod bool, outCount uint32) *MethodDescription
	53	+	protocol_copyProtocolList func(p Protocol, outCount uint32) **Protocol
	54	+	protocol_copyPropertyList2 func(p Protocol, outCount uint32, isRequiredProperty, isInstanceProperty bool) *Property
	55	+	protocol_addProtocol func(p Protocol, p2 Protocol)
	56	+	protocol_addProperty func(p *Protocol, name string, attributes []PropertyAttribute, attributeCount uint32, isRequiredProperty bool, isInstanceProperty bool)
	57	+	property_getName func(p Property) string
	58	+	property_getAttributes func(p Property) string
	59	+
	60	+	free func(ptr unsafe.Pointer)
48	61		)
49	62
50	63		func init() {
51		-	objc, err := purego.Dlopen("/usr/lib/libobjc.A.dylib", purego.RTLD_GLOBAL)
	64	+	objc, err := purego.Dlopen("/usr/lib/libobjc.A.dylib", purego.RTLD_GLOBAL\|purego.RTLD_NOW)
52	65		if err != nil {
53	66		panic(fmt.Errorf("objc: %w", err))
54	67		}

@@ -75,6 +88,8 @@ func init() {
75	88		purego.RegisterLibFunc(&object_getClass, objc, "object_getClass")
76	89		purego.RegisterLibFunc(&objc_getClass, objc, "objc_getClass")
77	90		purego.RegisterLibFunc(&objc_getProtocol, objc, "objc_getProtocol")
	91	+	purego.RegisterLibFunc(&objc_allocateProtocol, objc, "objc_allocateProtocol")
	92	+	purego.RegisterLibFunc(&objc_registerProtocol, objc, "objc_registerProtocol")
78	93		purego.RegisterLibFunc(&objc_allocateClassPair, objc, "objc_allocateClassPair")
79	94		purego.RegisterLibFunc(&objc_registerClassPair, objc, "objc_registerClassPair")
80	95		purego.RegisterLibFunc(&sel_registerName, objc, "sel_registerName")

@@ -88,8 +103,17 @@ func init() {
88	103		purego.RegisterLibFunc(&ivar_getName, objc, "ivar_getName")
89	104		purego.RegisterLibFunc(&protocol_getName, objc, "protocol_getName")
90	105		purego.RegisterLibFunc(&protocol_isEqual, objc, "protocol_isEqual")
	106	+	purego.RegisterLibFunc(&protocol_addMethodDescription, objc, "protocol_addMethodDescription")
	107	+	purego.RegisterLibFunc(&protocol_copyMethodDescriptionList, objc, "protocol_copyMethodDescriptionList")
	108	+	purego.RegisterLibFunc(&protocol_copyProtocolList, objc, "protocol_copyProtocolList")
	109	+	purego.RegisterLibFunc(&protocol_addProtocol, objc, "protocol_addProtocol")
	110	+	purego.RegisterLibFunc(&protocol_addProperty, objc, "protocol_addProperty")
	111	+	purego.RegisterLibFunc(&protocol_copyPropertyList2, objc, "protocol_copyPropertyList2")
	112	+	purego.RegisterLibFunc(&property_getName, objc, "property_getName")
	113	+	purego.RegisterLibFunc(&property_getAttributes, objc, "property_getAttributes")
91	114		purego.RegisterLibFunc(&object_getIvar, objc, "object_getIvar")
92	115		purego.RegisterLibFunc(&object_setIvar, objc, "object_setIvar")
	116	+	purego.RegisterLibFunc(&free, purego.RTLD_DEFAULT, "free")
93	117		}
94	118
95	119		// ID is an opaque pointer to some Objective-C object

@@ -531,6 +555,39 @@ func (i Ivar) Name() string {
531	555		return ivar_getName(i)
532	556		}
533	557
	558	+	// MethodDescription holds the name and type definition of a method.
	559	+	type MethodDescription struct {
	560	+	name, types uintptr
	561	+	}
	562	+
	563	+	// Name returns the name of this method.
	564	+	func (m MethodDescription) Name() string {
	565	+	return strings.GoString(m.name)
	566	+	}
	567	+
	568	+	// Types returns the OBJC runtime encoded type description.
	569	+	func (m MethodDescription) Types() string {
	570	+	return strings.GoString(m.types)
	571	+	}
	572	+
	573	+	// PropertyAttribute contains the null-terminated Name and Value pair of a Properties internal description.
	574	+	type PropertyAttribute struct {
	575	+	Name, Value *byte
	576	+	}
	577	+
	578	+	// Property is an opaque type for Objective-C property metadata.
	579	+	type Property uintptr
	580	+
	581	+	// Name returns the name of this property.
	582	+	func (p Property) Name() string {
	583	+	return property_getName(p)
	584	+	}
	585	+
	586	+	// Attributes returns a comma separated list of PropertyAttribute
	587	+	func (p Property) Attributes() string {
	588	+	return property_getAttributes(p)
	589	+	}
	590	+
534	591		// Protocol is a type that declares methods that can be implemented by any class.
535	592		type Protocol [0]func()
536	593

@@ -539,11 +596,69 @@ func GetProtocol(name string) *Protocol {
539	596		return objc_getProtocol(name)
540	597		}
541	598
	599	+	// AllocateProtocol creates a new protocol in the OBJC runtime or nil if the protocol already exists.
	600	+	func AllocateProtocol(name string) *Protocol {
	601	+	return objc_allocateProtocol(name)
	602	+	}
	603	+
	604	+	// Register registers the protocol created using AllocateProtocol with the runtime. This must be done
	605	+	// before it is used anywhere and can only be called once.
	606	+	func (p *Protocol) Register() {
	607	+	objc_registerProtocol(p)
	608	+	}
	609	+
	610	+	// CopyMethodDescriptionList returns a list of methods that this protocol has given it isRequiredMethod and isInstanceMethod.
	611	+	func (p *Protocol) CopyMethodDescriptionList(isRequiredMethod, isInstanceMethod bool) []MethodDescription {
	612	+	count := uint32(0)
	613	+	desc := protocol_copyMethodDescriptionList(p, isRequiredMethod, isInstanceMethod, &count)
	614	+	methods := clone(unsafe.Slice(desc, count))
	615	+	free(unsafe.Pointer(desc))
	616	+	return methods
	617	+	}
	618	+
	619	+	// CopyProtocolList returns a list of the protocols that this protocol inherits from.
	620	+	func (p Protocol) CopyProtocolList() []Protocol {
	621	+	count := uint32(0)
	622	+	desc := protocol_copyProtocolList(p, &count)
	623	+	protocols := clone(unsafe.Slice(desc, count))
	624	+	free(unsafe.Pointer(desc))
	625	+	return protocols
	626	+	}
	627	+
	628	+	// CopyPropertyList returns a list of properties that this protocol has given it isRequiredProperty and isInstanceProperty.
	629	+	func (p *Protocol) CopyPropertyList(isRequiredProperty, isInstanceProperty bool) []Property {
	630	+	count := uint32(0)
	631	+	desc := protocol_copyPropertyList2(p, &count, isRequiredProperty, isInstanceProperty)
	632	+	protocols := clone(unsafe.Slice(desc, count))
	633	+	free(unsafe.Pointer(desc))
	634	+	return protocols
	635	+	}
	636	+
	637	+	// Name returns the name of this protocol.
	638	+	func (p *Protocol) Name() string {
	639	+	return protocol_getName(p)
	640	+	}
	641	+
542	642		// Equals return true if the two protocols are the same.
543	643		func (p Protocol) Equals(p2 Protocol) bool {
544	644		return protocol_isEqual(p, p2)
545	645		}
546	646
	647	+	// AddMethodDescription adds a method to a protocol. This can only be called between AllocateProtocol and Protocol.Register.
	648	+	func (p *Protocol) AddMethodDescription(name SEL, types string, isRequiredMethod, isInstanceMethod bool) {
	649	+	protocol_addMethodDescription(p, name, types, isRequiredMethod, isInstanceMethod)
	650	+	}
	651	+
	652	+	// AddProtocol marks the protocol as inheriting from another. This can only be called between AllocateProtocol and Protocol.Register.
	653	+	func (p Protocol) AddProtocol(protocol Protocol) {
	654	+	protocol_addProtocol(p, protocol)
	655	+	}
	656	+
	657	+	// AddProperty adds a property to the protocol. This can only be called between AllocateProtocol and Protocol.Register.
	658	+	func (p *Protocol) AddProperty(name string, attributes []PropertyAttribute, isRequiredProperty, isInstanceProperty bool) {
	659	+	protocol_addProperty(p, name, attributes, uint32(len(attributes)), isRequiredProperty, isInstanceProperty)
	660	+	}
	661	+
547	662		// IMP is a function pointer that can be called by Objective-C code.
548	663		type IMP uintptr
549	664

@@ -568,3 +683,14 @@ func NewIMP(fn any) IMP {
568	683		}
569	684		return IMP(purego.NewCallback(fn))
570	685		}
	686	+
	687	+	// TODO: remove and use slices.Clone when minimum version for purego is 1.21
	688	+	func clone[S ~[]E, E any](s S) S {
	689	+	// Preserve nilness in case it matters.
	690	+	if s == nil {
	691	+	return nil
	692	+	}
	693	+	// Avoid s[:0:0] as it leads to unwanted liveness when cloning a
	694	+	// zero-length slice of a large array; see https://go.dev/issue/68488.
	695	+	return append(S{}, s...)
	696	+	}


@@ -16,39 +16,52 @@ import (
16		"unsafe"	16		"unsafe"
17			17
18		"github.com/ebitengine/purego"	18		"github.com/ebitengine/purego"
			19	+	"github.com/ebitengine/purego/internal/strings"
19		)	20		)
20			21
21		// TODO: support try/catch?	22		// TODO: support try/catch?
22		// https://stackoverflow.com/questions/7062599/example-of-how-objective-cs-try-catch-implementation-is-executed-at-runtime	23		// https://stackoverflow.com/questions/7062599/example-of-how-objective-cs-try-catch-implementation-is-executed-at-runtime
23		var (	24		var (
24	-	objc_msgSend_fn uintptr	25	+	objc_msgSend_fn uintptr
25	-	objc_msgSend_stret_fn uintptr	26	+	objc_msgSend_stret_fn uintptr
26	-	objc_msgSend func(obj ID, cmd SEL, args ...any) ID	27	+	objc_msgSend func(obj ID, cmd SEL, args ...any) ID
27	-	objc_msgSendSuper2_fn uintptr	28	+	objc_msgSendSuper2_fn uintptr
28	-	objc_msgSendSuper2_stret_fn uintptr	29	+	objc_msgSendSuper2_stret_fn uintptr
29	-	objc_msgSendSuper2 func(super *objc_super, cmd SEL, args ...any) ID	30	+	objc_msgSendSuper2 func(super *objc_super, cmd SEL, args ...any) ID
30	-	objc_getClass func(name string) Class	31	+	objc_getClass func(name string) Class
31	-	objc_getProtocol func(name string) *Protocol	32	+	objc_getProtocol func(name string) *Protocol
32	-	objc_allocateClassPair func(super Class, name string, extraBytes uintptr) Class	33	+	objc_allocateProtocol func(name string) *Protocol
33	-	objc_registerClassPair func(class Class)	34	+	objc_registerProtocol func(protocol *Protocol)
34	-	sel_registerName func(name string) SEL	35	+	objc_allocateClassPair func(super Class, name string, extraBytes uintptr) Class
35	-	class_getSuperclass func(class Class) Class	36	+	objc_registerClassPair func(class Class)
36	-	class_getInstanceVariable func(class Class, name string) Ivar	37	+	sel_registerName func(name string) SEL
37	-	class_getInstanceSize func(class Class) uintptr	38	+	class_getSuperclass func(class Class) Class
38	-	class_addMethod func(class Class, name SEL, imp IMP, types string) bool	39	+	class_getInstanceVariable func(class Class, name string) Ivar
39	-	class_addIvar func(class Class, name string, size uintptr, alignment uint8, types string) bool	40	+	class_getInstanceSize func(class Class) uintptr
40	-	class_addProtocol func(class Class, protocol *Protocol) bool	41	+	class_addMethod func(class Class, name SEL, imp IMP, types string) bool
41	-	ivar_getOffset func(ivar Ivar) uintptr	42	+	class_addIvar func(class Class, name string, size uintptr, alignment uint8, types string) bool
42	-	ivar_getName func(ivar Ivar) string	43	+	class_addProtocol func(class Class, protocol *Protocol) bool
43	-	object_getClass func(obj ID) Class	44	+	ivar_getOffset func(ivar Ivar) uintptr
44	-	object_getIvar func(obj ID, ivar Ivar) ID	45	+	ivar_getName func(ivar Ivar) string
45	-	object_setIvar func(obj ID, ivar Ivar, value ID)	46	+	object_getClass func(obj ID) Class
46	-	protocol_getName func(protocol *Protocol) string	47	+	object_getIvar func(obj ID, ivar Ivar) ID
47	-	protocol_isEqual func(p Protocol, p2 Protocol) bool	48	+	object_setIvar func(obj ID, ivar Ivar, value ID)
			49	+	protocol_getName func(protocol *Protocol) string
			50	+	protocol_isEqual func(p Protocol, p2 Protocol) bool
			51	+	protocol_addMethodDescription func(p *Protocol, name SEL, types string, isRequiredMethod bool, isInstanceMethod bool)
			52	+	protocol_copyMethodDescriptionList func(p Protocol, isRequiredMethod bool, isInstanceMethod bool, outCount uint32) *MethodDescription
			53	+	protocol_copyProtocolList func(p Protocol, outCount uint32) **Protocol
			54	+	protocol_copyPropertyList2 func(p Protocol, outCount uint32, isRequiredProperty, isInstanceProperty bool) *Property
			55	+	protocol_addProtocol func(p Protocol, p2 Protocol)
			56	+	protocol_addProperty func(p *Protocol, name string, attributes []PropertyAttribute, attributeCount uint32, isRequiredProperty bool, isInstanceProperty bool)
			57	+	property_getName func(p Property) string
			58	+	property_getAttributes func(p Property) string
			59	+
			60	+	free func(ptr unsafe.Pointer)
48		)	61		)
49			62
50		func init() {	63		func init() {
51	-	objc, err := purego.Dlopen("/usr/lib/libobjc.A.dylib", purego.RTLD_GLOBAL)	64	+	objc, err := purego.Dlopen("/usr/lib/libobjc.A.dylib", purego.RTLD_GLOBAL\|purego.RTLD_NOW)
52		if err != nil {	65		if err != nil {
53		panic(fmt.Errorf("objc: %w", err))	66		panic(fmt.Errorf("objc: %w", err))
54		}	67		}

@@ -75,6 +88,8 @@ func init() {
75		purego.RegisterLibFunc(&object_getClass, objc, "object_getClass")	88		purego.RegisterLibFunc(&object_getClass, objc, "object_getClass")
76		purego.RegisterLibFunc(&objc_getClass, objc, "objc_getClass")	89		purego.RegisterLibFunc(&objc_getClass, objc, "objc_getClass")
77		purego.RegisterLibFunc(&objc_getProtocol, objc, "objc_getProtocol")	90		purego.RegisterLibFunc(&objc_getProtocol, objc, "objc_getProtocol")
			91	+	purego.RegisterLibFunc(&objc_allocateProtocol, objc, "objc_allocateProtocol")
			92	+	purego.RegisterLibFunc(&objc_registerProtocol, objc, "objc_registerProtocol")
78		purego.RegisterLibFunc(&objc_allocateClassPair, objc, "objc_allocateClassPair")	93		purego.RegisterLibFunc(&objc_allocateClassPair, objc, "objc_allocateClassPair")
79		purego.RegisterLibFunc(&objc_registerClassPair, objc, "objc_registerClassPair")	94		purego.RegisterLibFunc(&objc_registerClassPair, objc, "objc_registerClassPair")
80		purego.RegisterLibFunc(&sel_registerName, objc, "sel_registerName")	95		purego.RegisterLibFunc(&sel_registerName, objc, "sel_registerName")

@@ -88,8 +103,17 @@ func init() {
88		purego.RegisterLibFunc(&ivar_getName, objc, "ivar_getName")	103		purego.RegisterLibFunc(&ivar_getName, objc, "ivar_getName")
89		purego.RegisterLibFunc(&protocol_getName, objc, "protocol_getName")	104		purego.RegisterLibFunc(&protocol_getName, objc, "protocol_getName")
90		purego.RegisterLibFunc(&protocol_isEqual, objc, "protocol_isEqual")	105		purego.RegisterLibFunc(&protocol_isEqual, objc, "protocol_isEqual")
			106	+	purego.RegisterLibFunc(&protocol_addMethodDescription, objc, "protocol_addMethodDescription")
			107	+	purego.RegisterLibFunc(&protocol_copyMethodDescriptionList, objc, "protocol_copyMethodDescriptionList")
			108	+	purego.RegisterLibFunc(&protocol_copyProtocolList, objc, "protocol_copyProtocolList")
			109	+	purego.RegisterLibFunc(&protocol_addProtocol, objc, "protocol_addProtocol")
			110	+	purego.RegisterLibFunc(&protocol_addProperty, objc, "protocol_addProperty")
			111	+	purego.RegisterLibFunc(&protocol_copyPropertyList2, objc, "protocol_copyPropertyList2")
			112	+	purego.RegisterLibFunc(&property_getName, objc, "property_getName")
			113	+	purego.RegisterLibFunc(&property_getAttributes, objc, "property_getAttributes")
91		purego.RegisterLibFunc(&object_getIvar, objc, "object_getIvar")	114		purego.RegisterLibFunc(&object_getIvar, objc, "object_getIvar")
92		purego.RegisterLibFunc(&object_setIvar, objc, "object_setIvar")	115		purego.RegisterLibFunc(&object_setIvar, objc, "object_setIvar")
			116	+	purego.RegisterLibFunc(&free, purego.RTLD_DEFAULT, "free")
93		}	117		}
94			118
95		// ID is an opaque pointer to some Objective-C object	119		// ID is an opaque pointer to some Objective-C object

@@ -531,6 +555,39 @@ func (i Ivar) Name() string {
531		return ivar_getName(i)	555		return ivar_getName(i)
532		}	556		}
533			557
			558	+	// MethodDescription holds the name and type definition of a method.
			559	+	type MethodDescription struct {
			560	+	name, types uintptr
			561	+	}
			562	+
			563	+	// Name returns the name of this method.
			564	+	func (m MethodDescription) Name() string {
			565	+	return strings.GoString(m.name)
			566	+	}
			567	+
			568	+	// Types returns the OBJC runtime encoded type description.
			569	+	func (m MethodDescription) Types() string {
			570	+	return strings.GoString(m.types)
			571	+	}
			572	+
			573	+	// PropertyAttribute contains the null-terminated Name and Value pair of a Properties internal description.
			574	+	type PropertyAttribute struct {
			575	+	Name, Value *byte
			576	+	}
			577	+
			578	+	// Property is an opaque type for Objective-C property metadata.
			579	+	type Property uintptr
			580	+
			581	+	// Name returns the name of this property.
			582	+	func (p Property) Name() string {
			583	+	return property_getName(p)
			584	+	}
			585	+
			586	+	// Attributes returns a comma separated list of PropertyAttribute
			587	+	func (p Property) Attributes() string {
			588	+	return property_getAttributes(p)
			589	+	}
			590	+
534		// Protocol is a type that declares methods that can be implemented by any class.	591		// Protocol is a type that declares methods that can be implemented by any class.
535		type Protocol [0]func()	592		type Protocol [0]func()
536			593

@@ -539,11 +596,69 @@ func GetProtocol(name string) *Protocol {
539		return objc_getProtocol(name)	596		return objc_getProtocol(name)
540		}	597		}
541			598
			599	+	// AllocateProtocol creates a new protocol in the OBJC runtime or nil if the protocol already exists.
			600	+	func AllocateProtocol(name string) *Protocol {
			601	+	return objc_allocateProtocol(name)
			602	+	}
			603	+
			604	+	// Register registers the protocol created using AllocateProtocol with the runtime. This must be done
			605	+	// before it is used anywhere and can only be called once.
			606	+	func (p *Protocol) Register() {
			607	+	objc_registerProtocol(p)
			608	+	}
			609	+
			610	+	// CopyMethodDescriptionList returns a list of methods that this protocol has given it isRequiredMethod and isInstanceMethod.
			611	+	func (p *Protocol) CopyMethodDescriptionList(isRequiredMethod, isInstanceMethod bool) []MethodDescription {
			612	+	count := uint32(0)
			613	+	desc := protocol_copyMethodDescriptionList(p, isRequiredMethod, isInstanceMethod, &count)
			614	+	methods := clone(unsafe.Slice(desc, count))
			615	+	free(unsafe.Pointer(desc))
			616	+	return methods
			617	+	}
			618	+
			619	+	// CopyProtocolList returns a list of the protocols that this protocol inherits from.
			620	+	func (p Protocol) CopyProtocolList() []Protocol {
			621	+	count := uint32(0)
			622	+	desc := protocol_copyProtocolList(p, &count)
			623	+	protocols := clone(unsafe.Slice(desc, count))
			624	+	free(unsafe.Pointer(desc))
			625	+	return protocols
			626	+	}
			627	+
			628	+	// CopyPropertyList returns a list of properties that this protocol has given it isRequiredProperty and isInstanceProperty.
			629	+	func (p *Protocol) CopyPropertyList(isRequiredProperty, isInstanceProperty bool) []Property {
			630	+	count := uint32(0)
			631	+	desc := protocol_copyPropertyList2(p, &count, isRequiredProperty, isInstanceProperty)
			632	+	protocols := clone(unsafe.Slice(desc, count))
			633	+	free(unsafe.Pointer(desc))
			634	+	return protocols
			635	+	}
			636	+
			637	+	// Name returns the name of this protocol.
			638	+	func (p *Protocol) Name() string {
			639	+	return protocol_getName(p)
			640	+	}
			641	+
542		// Equals return true if the two protocols are the same.	642		// Equals return true if the two protocols are the same.
543		func (p Protocol) Equals(p2 Protocol) bool {	643		func (p Protocol) Equals(p2 Protocol) bool {
544		return protocol_isEqual(p, p2)	644		return protocol_isEqual(p, p2)
545		}	645		}
546			646
			647	+	// AddMethodDescription adds a method to a protocol. This can only be called between AllocateProtocol and Protocol.Register.
			648	+	func (p *Protocol) AddMethodDescription(name SEL, types string, isRequiredMethod, isInstanceMethod bool) {
			649	+	protocol_addMethodDescription(p, name, types, isRequiredMethod, isInstanceMethod)
			650	+	}
			651	+
			652	+	// AddProtocol marks the protocol as inheriting from another. This can only be called between AllocateProtocol and Protocol.Register.
			653	+	func (p Protocol) AddProtocol(protocol Protocol) {
			654	+	protocol_addProtocol(p, protocol)
			655	+	}
			656	+
			657	+	// AddProperty adds a property to the protocol. This can only be called between AllocateProtocol and Protocol.Register.
			658	+	func (p *Protocol) AddProperty(name string, attributes []PropertyAttribute, isRequiredProperty, isInstanceProperty bool) {
			659	+	protocol_addProperty(p, name, attributes, uint32(len(attributes)), isRequiredProperty, isInstanceProperty)
			660	+	}
			661	+
547		// IMP is a function pointer that can be called by Objective-C code.	662		// IMP is a function pointer that can be called by Objective-C code.
548		type IMP uintptr	663		type IMP uintptr
549			664

@@ -568,3 +683,14 @@ func NewIMP(fn any) IMP {
568		}	683		}
569		return IMP(purego.NewCallback(fn))	684		return IMP(purego.NewCallback(fn))
570		}	685		}
			686	+
			687	+	// TODO: remove and use slices.Clone when minimum version for purego is 1.21
			688	+	func clone[S ~[]E, E any](s S) S {
			689	+	// Preserve nilness in case it matters.
			690	+	if s == nil {
			691	+	return nil
			692	+	}
			693	+	// Avoid s[:0:0] as it leads to unwanted liveness when cloning a
			694	+	// zero-length slice of a large array; see https://go.dev/issue/68488.
			695	+	return append(S{}, s...)
			696	+	}

M objc/objc_runtime_darwin_test.go +36 -0


@@ -5,6 +5,7 @@ package objc_test
5	5
6	6		import (
7	7		"fmt"
	8	+	"log"
8	9		"reflect"
9	10		"testing"
10	11

@@ -208,3 +209,38 @@ func ExampleSendSuper() {
208	209		fmt.Println(res)
209	210		// Output: 16
210	211		}
	212	+
	213	+	func ExampleAllocateProtocol() {
	214	+	var p *objc.Protocol
	215	+	if p = objc.AllocateProtocol("MyCustomProtocol"); p != nil {
	216	+	p.AddMethodDescription(objc.RegisterName("isFoo"), "B16@0:8", true, true)
	217	+	var adoptedProtocol *objc.Protocol
	218	+	adoptedProtocol = objc.GetProtocol("NSObject")
	219	+	if adoptedProtocol == nil {
	220	+	log.Fatalln("protocol 'NSObject' does not exist")
	221	+	}
	222	+	p.AddProtocol(adoptedProtocol)
	223	+	p.AddProperty("accessibilityElement", []objc.PropertyAttribute{
	224	+	{Name: &[]byte("T\x00")[0], Value: &[]byte("B\x00")[0]},
	225	+	{Name: &[]byte("G\x00")[0], Value: &[]byte("isBar\x00")[0]},
	226	+	}, true, true)
	227	+	p.Register()
	228	+	}
	229	+
	230	+	p = objc.GetProtocol("MyCustomProtocol")
	231	+
	232	+	for _, protocol := range p.CopyProtocolList() {
	233	+	fmt.Println(protocol.Name())
	234	+	}
	235	+	for _, property := range p.CopyPropertyList(true, true) {
	236	+	fmt.Println(property.Name(), property.Attributes())
	237	+	}
	238	+	for _, method := range p.CopyMethodDescriptionList(true, true) {
	239	+	fmt.Println(method.Name(), method.Types())
	240	+	}
	241	+
	242	+	// Output:
	243	+	// NSObject
	244	+	// accessibilityElement TB,GisBar
	245	+	// isFoo B16@0:8
	246	+	}


@@ -5,6 +5,7 @@ package objc_test
5		5
6	import (	6		import (
7	"fmt"	7		"fmt"
		8	+	"log"
8	"reflect"	9		"reflect"
9	"testing"	10		"testing"
10		11

@@ -208,3 +209,38 @@ func ExampleSendSuper() {
208	fmt.Println(res)	209		fmt.Println(res)
209	// Output: 16	210		// Output: 16
210	}	211		}
		212	+
		213	+	func ExampleAllocateProtocol() {
		214	+	var p *objc.Protocol
		215	+	if p = objc.AllocateProtocol("MyCustomProtocol"); p != nil {
		216	+	p.AddMethodDescription(objc.RegisterName("isFoo"), "B16@0:8", true, true)
		217	+	var adoptedProtocol *objc.Protocol
		218	+	adoptedProtocol = objc.GetProtocol("NSObject")
		219	+	if adoptedProtocol == nil {
		220	+	log.Fatalln("protocol 'NSObject' does not exist")
		221	+	}
		222	+	p.AddProtocol(adoptedProtocol)
		223	+	p.AddProperty("accessibilityElement", []objc.PropertyAttribute{
		224	+	{Name: &[]byte("T\x00")[0], Value: &[]byte("B\x00")[0]},
		225	+	{Name: &[]byte("G\x00")[0], Value: &[]byte("isBar\x00")[0]},
		226	+	}, true, true)
		227	+	p.Register()
		228	+	}
		229	+
		230	+	p = objc.GetProtocol("MyCustomProtocol")
		231	+
		232	+	for _, protocol := range p.CopyProtocolList() {
		233	+	fmt.Println(protocol.Name())
		234	+	}
		235	+	for _, property := range p.CopyPropertyList(true, true) {
		236	+	fmt.Println(property.Name(), property.Attributes())
		237	+	}
		238	+	for _, method := range p.CopyMethodDescriptionList(true, true) {
		239	+	fmt.Println(method.Name(), method.Types())
		240	+	}
		241	+
		242	+	// Output:
		243	+	// NSObject
		244	+	// accessibilityElement TB,GisBar
		245	+	// isFoo B16@0:8
		246	+	}