1 files changed, 100 insertions, 0 deletions
diff --git a/delegate_darwin.go b/delegate_darwin.go
new file mode 100644
index 0000000..e903a13
--- /dev/null
+++ b/delegate_darwin.go
@@ -0,0 +1,100 @@
+// 27 february 2014
+package ui
+
+import (
+	"fmt"
+	"unsafe"
+)
+
+/*
+This creates a class goAppDelegate that will be used as the delegate for /everything/. Specifically, it:
+	- runs uitask requests (uitask:)
+	- handles window close events (windowShouldClose:)
+	- handles window resize events (xxxx:)
+	- handles button click events (buttonClick:)
+*/
+
+// #cgo LDFLAGS: -lobjc -framework Foundation -framework AppKit
+// #include <stdlib.h>
+// #include "objc_darwin.h"
+// extern void appDelegate_uitask(id, SEL, id);		/* from uitask_darwin.go */
+// extern BOOL appDelegate_windowShouldClose(id, SEL, id);
+// /* because cgo doesn't like Nil */
+// static Class NilClass = Nil;
+import "C"
+
+var (
+	appDelegate C.id
+)
+
+const (
+	_goAppDelegate = "goAppDelegate"
+)
+
+var (
+	_uitask = sel_getUid("uitask:")
+	_windowShouldClose = sel_getUid("windowShouldClose:")
+)
+
+func mkAppDelegate() error {
+	var appdelegateclass C.Class
+
+	appdelegateclass, err = makeDelegateClass(_goAppDelegate)
+	if err != nil {
+		return fmt.Errorf("error creating NSApplication delegate: %v", err)
+	}
+	err = addDelegateMethod(appdelegateclass, _uitask,
+		C.appDelegate_uitask, delegate_void)
+	if err != nil {
+		return fmt.Errorf("error adding NSApplication delegate uitask: method (to do UI tasks): %v", err)
+	}
+	err = addDelegateMethod(appdelegateclass, _windowShouldClose,
+		C.appDelegate_windowShouldClose, delegate_bool)
+	if err != nil {
+		return fmt.Errorf("error adding NSApplication delegate windowShouldClose: method (to handle window close button events): %v", err)
+	}
+	// TODO using objc_new() causes a segfault; find out why
+	// TODO make alloc followed by init (I thought NSObject provided its own init?)
+	appDelegate = objc_alloc(objc_getClass(_goAppDelegate))
+	return nil
+}
+
+//export appDelegate_windowShouldClose
+func appDelegate_windowShouldClose(self C.id, sel C.SEL, win C.id) C.BOOL {
+	sysData := getSysData(win)
+	sysData.signal()
+	return C.BOOL(C.NO)		// don't close
+}
+
+// this actually constructs the delegate class
+
+var (
+	_NSObject_Class = C.object_getClass(_NSObject)
+)
+
+func makeDelegateClass(name string) (C.Class, error) {
+	cname := C.CString(name)
+	defer C.free(unsafe.Pointer(cname))
+
+	c := C.objc_allocateClassPair(_NSObject_Class, cname, 0)
+	if c == C.NilClass {
+		return C.NilClass, fmt.Errorf("unable to create Objective-C class %s; reason unknown", name)
+	}
+	C.objc_registerClassPair(c)
+	return c, nil
+}
+
+var (
+	delegate_void = []C.char{'v', '@', ':', '@', 0}		// void (*)(id, SEL, id)
+	delegate_bool = []C.char{'#', '@', ':', '@', 0}		// BOOL (*)(id, SEL, id)
+)
+
+// according to errors spit out by cgo, C function pointers are unsafe.Pointer
+func addDelegateMethod(class C.Class, sel C.SEL, imp unsafe.Pointer, ty []C.char) error {
+	ok := C.class_addMethod(class, sel, C.IMP(imp), &ty[0])
+	if ok == C.BOOL(C.NO) {
+		// TODO get function name
+		return fmt.Errorf("unable to add selector %v/imp %v (reason unknown)", sel, imp)
+	}
+	return nil
+}