From e0c351a2d7dd30c52a1067fbc5cdb6517b6eeed0 Mon Sep 17 00:00:00 2001
From: Pietro Gagliardi <pietro10@mac.com>
Date: Thu, 27 Feb 2014 23:07:45 -0500
Subject: Added code to create new Objective-C types at runtime, which will be
 important both for handling custom messages and for handling events.

---
 darwintest/newtypes.go | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)
 create mode 100644 darwintest/newtypes.go

(limited to 'darwintest/newtypes.go')

diff --git a/darwintest/newtypes.go b/darwintest/newtypes.go
new file mode 100644
index 0000000..8fa0147
--- /dev/null
+++ b/darwintest/newtypes.go
@@ -0,0 +1,58 @@
+// 27 february 2014
+package main
+
+import (
+	"fmt"
+	"unsafe"
+)
+
+// #cgo CFLAGS: -Dqqq
+// #cgo LDFLAGS: -lobjc -framework Foundation
+// #include <stdlib.h>
+// #include <objc/message.h>
+// #include <objc/objc.h>
+// #include <objc/runtime.h>
+// extern void ourMethod(id, SEL);
+// /* cgo doesn't like Nil */
+// extern Class NilClass; /* in runtimetest.go because of cgo limitations */
+import "C"
+
+var NSObject = C.object_getClass(objc_getClass("NSObject"))
+
+func newClass(name string) C.Class {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	c := C.objc_allocateClassPair(NSObject, cname, 0)
+	if c == C.NilClass {
+		panic("unable to create Objective-C class " + name)
+	}
+	return c
+}
+
+//export ourMethod
+func ourMethod(self C.id, sel C.SEL) {
+	fmt.Println("hello, world")
+}
+
+func addOurMethod(class C.Class, sel C.SEL) {
+	ty := []C.char{'v', '@', ':', 0}		// according to the example for class_addMethod()
+
+	// clas methods get stored in the metaclass; the objc_allocateClassPair() docs say this will work
+	metaclass := C.object_getClass(C.id(unsafe.Pointer(class)))
+	ok := C.class_addMethod(metaclass,
+		sel,
+		// using &C.ourMethod causes faults for some reason
+		C.IMP(unsafe.Pointer(C.ourMethod)),
+		&ty[0])
+	if ok == C.BOOL(C.NO) {
+		panic("unable to add ourMethod")
+	}
+}
+
+func mk(name string, sel C.SEL) C.id {
+	class := newClass(name)
+	addOurMethod(class, sel)
+	C.objc_registerClassPair(class)
+	return objc_getClass(name)
+}
-- 
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