pkg/objc: properties

pkg/objc/class.zig

@@ -14,6 +14,21 @@ pub const Class = struct {
             .value = c.objc_getClass(name.ptr) orelse return null,
         };
     }
+
+    /// Returns a property with a given name of a given class.
+    pub fn getProperty(self: Class, name: [:0]const u8) ?objc.Property {
+        return objc.Property{
+            .value = c.class_getProperty(self.value, name.ptr) orelse return null,
+        };
+    }
+
+    /// Describes the properties declared by a class. This must be freed.
+    pub fn copyPropertyList(self: Class) []objc.Property {
+        var count: c_uint = undefined;
+        const list = @ptrCast([*c]objc.Property, c.class_copyPropertyList(self.value, &count));
+        if (count == 0) return list[0..0];
+        return list[0..count];
+    }
 };
 
 test "getClass" {
@@ -40,3 +55,20 @@ test "msgSend" {
     try testing.expect(obj.value != null);
     obj.msgSend(void, objc.sel("dealloc"), .{});
 }
+
+test "getProperty" {
+    const testing = std.testing;
+    const NSObject = Class.getClass("NSObject").?;
+
+    try testing.expect(NSObject.getProperty("className") != null);
+    try testing.expect(NSObject.getProperty("nope") == null);
+}
+
+test "copyProperyList" {
+    const testing = std.testing;
+    const NSObject = Class.getClass("NSObject").?;
+
+    const list = NSObject.copyPropertyList();
+    defer objc.free(list);
+    try testing.expect(list.len > 20);
+}

pkg/objc/main.zig

@@ -1,11 +1,17 @@
+const std = @import("std");
+
 pub const c = @import("c.zig");
 pub usingnamespace @import("class.zig");
 pub usingnamespace @import("object.zig");
+pub usingnamespace @import("property.zig");
 pub usingnamespace @import("sel.zig");
 
-test {
-    @import("std").testing.refAllDecls(@This());
-
-    // TODO: remove once we integrate this
-    _ = @import("msg_send.zig");
+/// This just calls the C allocator free. Some things need to be freed
+/// and this is how they can be freed for objc.
+pub inline fn free(ptr: anytype) void {
+    std.heap.c_allocator.free(ptr);
+}
+
+test {
+    std.testing.refAllDecls(@This());
 }

pkg/objc/msg_send.zig

@@ -29,7 +29,10 @@ pub fn MsgSend(comptime T: type) type {
             // This lets msgSend magically work with Object and so on.
             const is_pkg_struct = comptime is_pkg_struct: {
                 for (@typeInfo(objc).Struct.decls) |decl| {
-                    if (decl.is_pub and Return == @field(objc, decl.name)) {
+                    if (decl.is_pub and
+                        @TypeOf(@field(objc, decl.name)) == type and
+                        Return == @field(objc, decl.name))
+                    {
                         break :is_pkg_struct true;
                     }
                 }

pkg/objc/object.zig

@@ -8,3 +8,13 @@ pub const Object = struct {
 
     pub usingnamespace MsgSend(Object);
 };
+
+test {
+    const testing = std.testing;
+    const NSObject = objc.Class.getClass("NSObject").?;
+
+    // Should work with our wrappers
+    const obj = NSObject.msgSend(objc.Object, objc.Sel.registerName("alloc"), .{});
+    try testing.expect(obj.value != null);
+    obj.msgSend(void, objc.sel("dealloc"), .{});
+}

pkg/objc/property.zig

@@ -0,0 +1,27 @@
+const std = @import("std");
+const c = @import("c.zig");
+const objc = @import("main.zig");
+
+pub const Property = extern struct {
+    value: c.objc_property_t,
+
+    /// Returns the name of a property.
+    pub fn getName(self: Property) [:0]const u8 {
+        return std.mem.sliceTo(c.property_getName(self.value), 0);
+    }
+};
+
+test {
+    // Critical properties because we ptrCast C pointers to this.
+    const testing = std.testing;
+    try testing.expect(@sizeOf(Property) == @sizeOf(c.objc_property_t));
+    try testing.expect(@alignOf(Property) == @alignOf(c.objc_property_t));
+}
+
+test {
+    const testing = std.testing;
+    const NSObject = objc.Class.getClass("NSObject").?;
+
+    const prop = NSObject.getProperty("className").?;
+    try testing.expectEqualStrings("className", prop.getName());
+}