Moved the Objective-C wrappers and helpers out of darwintest.

bleh_darwin.m

@@ -0,0 +1,46 @@
+/* 28 february 2014 */
+
+/*
+I wanted to avoid invoking Objective-C directly, preferring to do everything directly with the API. However, there are some things that simply cannot be done too well; for those situations, there's this. It does use the Objective-C runtime, eschewing the actual Objective-C part of this being an Objective-C file.
+
+The main culprits are:
+- data types listed as being defined in nonexistent headers
+- 32-bit/64-bit type differences that are more than just a different typedef
+
+Go wrapper functions (bleh_darwin.go) call these directly and take care of stdint.h -> Go type conversions.
+*/
+
+#include <objc/message.h>
+#include <objc/objc.h>
+#include <objc/runtime.h>
+
+#include <stdint.h>
+
+#include <Foundation/NSGeometry.h>
+
+/*
+NSUInteger is listed as being in <objc/NSObjCRuntime.h>... which doesn't exist. Rather than relying on undocumented header file locations or explicitly typedef-ing NSUInteger to the (documented) unsigned long, I'll just place things here for maximum safety. I use uintptr_t as that should encompass every possible unsigned long.
+*/
+
+id _objc_msgSend_uint(id obj, SEL sel, uintptr_t a)
+{
+	return objc_msgSend(obj, sel, (NSUInteger) a);
+}
+
+/*
+These are the objc_msgSend() wrappers around NSRect. The problem is that while on 32-bit systems, NSRect is a concrete structure, on 64-bit systems it's just a typedef to CGRect. While in practice just using CGRect everywhere seems to work, better to be safe than sorry.
+
+I use int64_t for maximum safety, as my coordinates are stored as Go ints and Go int -> C int (which is what is documented as happening) isn't reliable.
+*/
+
+#define OurRect() (NSMakeRect((CGFloat) x, (CGFloat) y, (CGFloat) w, (CGFloat) h))
+
+id _objc_msgSend_rect(id obj, SEL sel, int64_t x, int64_t y, int64_t w, int64_t h)
+{
+	return objc_msgSend(obj, sel, OurRect());
+}
+
+id _objc_msgSend_rect_uint_uint_bool(id obj, SEL sel, int64_t x, int64_t y, int64_t w, int64_t h, uintptr_t b, uintptr_t c, BOOL d)
+{
+	return objc_msgSend(obj, sel, OurRect(), (NSUInteger) b, (NSUInteger) c, d);
+}

objc_darwin.go

@@ -0,0 +1,84 @@
+// 28 february 2014
+package main
+
+import (
+	"unsafe"
+)
+
+// #cgo LDFLAGS: -lobjc -framework Foundation
+// #include <stdlib.h>
+// #include "objc_darwin.h"
+import "C"
+
+func objc_getClass(class string) C.id {
+	cclass := C.CString(class)
+	defer C.free(unsafe.Pointer(cclass))
+
+	return C.objc_getClass(cclass)
+}
+
+func sel_getUid(sel string) C.SEL {
+	csel := C.CString(sel)
+	defer C.free(unsafe.Pointer(csel))
+
+	return C.sel_getUid(csel)
+}
+
+// Common Objective-C types and selectors.
+var (
+	_NSObject = objc_getClass("NSObject")
+	_NSString = objc_getClass("NSString")
+
+	_alloc = sel_getUid("alloc")
+	_new = sel_getUid("new")
+	_release = sel_getUid("release")
+	_stringWithUTF8String = sel_getUid("stringWithUTF8String:")
+	_UTF8String = sel_getUid("UTF8String")
+)
+
+// some helper functions
+
+func objc_alloc(class C.id) C.id {
+	return C.objc_msgSend_noargs(class, _alloc)
+}
+
+func objc_new(class C.id) C.id {
+	return C.objc_msgSend_noargs(class, _new)
+}
+
+func objc_release(obj C.id) {
+	C.objc_msgSend_noargs(obj, _release)
+}
+
+func toNSString(str string) C.id {
+	cstr := C.CString(str)
+	defer C.free(unsafe.Pointer(cstr))
+
+	return C.objc_msgSend_str(_NSString,
+		_stringWithUTF8String,
+		cstr)
+}
+
+func fromNSString(str C.id) string {
+	cstr := C.objc_msgSend_noargs(str, _UTF8String)
+	return C.GoString((*C.char)(unsafe.Pointer(cstr)))
+}
+
+/*
+These are wrapper functions for the functions in bleh_darwin.m to wrap around stdint.h type casting.
+*/
+
+func objc_msgSend_rect(obj C.id, sel C.SEL, x int, y int, w int, h int) C.id {
+	return C._objc_msgSend_rect(obj, sel,
+		C.int64_t(x), C.int64_t(y), C.int64_t(w), C.int64_t(h))
+}
+
+func objc_msgSend_uint(obj C.id, sel C.SEL, a uintptr) C.id {
+	return C._objc_msgSend_uint(obj, sel, C.uintptr_t(a))
+}
+
+func objc_msgSend_rect_uint_uint_bool(obj C.id, sel C.SEL, x int, y int, w int, h int, b uintptr, c uintptr, d C.BOOL) C.id {
+	return C._objc_msgSend_rect_uint_uint_bool(obj, sel,
+		C.int64_t(x), C.int64_t(y), C.int64_t(w), C.int64_t(h),
+		C.uintptr_t(b), C.uintptr_t(c), d)
+}

objc_darwin.h

@@ -0,0 +1,60 @@
+/* 28 february 2014 */
+
+/*
+This includes all Objective-C runtime headers for convenience. It also creates wrappers around objc_msgSend() out of necessity.
+
+cgo doesn't support calling variable argument list C functions, so objc_msgSend() cannot be called directly.
+
+Furthermore, Objective-C selectors work by basically sending the arguments to objc_msgSend() verbatim across the wire. This basically means we're stuck making wrapper functions for every possible argument list. What fun!
+
+The format should be self-explanatory.
+*/
+
+#include <objc/message.h>
+#include <objc/objc.h>
+#include <objc/runtime.h>
+
+#include <stdint.h>
+
+inline id objc_msgSend_noargs(id obj, SEL sel)
+{
+	return objc_msgSend(obj, sel);
+}
+
+#define m1(name, type1) \
+	inline id objc_msgSend_ ## name (id obj, SEL sel, type1 a) \
+	{ \
+		return objc_msgSend(obj, sel, a); \
+	}
+
+#define m2(name, type1, type2) \
+	inline id objc_msgSend_ ## name (id obj, SEL sel, type1 a, type2 b) \
+	{ \
+		return objc_msgSend(obj, sel, a, b); \
+	}
+
+#define m3(name, type1, type2, type3) \
+	inline id objc_msgSend_ ## name (id obj, SEL sel, type1 a, type2 b, type3 c) \
+	{ \
+		return objc_msgSend(obj, sel, a, b, c); \
+	}
+
+#define m4(name, type1, type2, type3, type4) \
+	inline id objc_msgSend_ ## name (id obj, SEL sel, type1 a, type2 b, type3 c, type4 d) \
+	{ \
+		return objc_msgSend(obj, sel, a, b, c, d); \
+	}
+
+m1(str, char *)		/* TODO Go string? */
+m1(id, id)
+extern id _objc_msgSend_rect(id obj, SEL sel, int64_t x, int64_t y, int64_t w, int64_t h);
+m1(sel, SEL)
+extern id _objc_msgSend_uint(id obj, SEL sel, uintptr_t a);
+
+m2(id_id, id, id)
+
+m3(id_id_id, id, id, id)
+m3(sel_id_bool, SEL, id, BOOL)
+
+extern id _objc_msgSend_rect_uint_uint_bool(id obj, SEL sel, int64_t x, int64_t y, int64_t w, int64_t h, uintptr_t b, uintptr_t c, BOOL d);
+m4(id_sel_id_id, id, SEL, id, id)