glfw: make monitor/joystick events a proper enum

Helps hexops/mach#37

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

glfw/src/Joystick.zig

@@ -288,10 +288,19 @@ pub inline fn getUserPointer(self: Joystick, Type: anytype) ?Type {
     return null;
 }
 
-var _callback: ?fn (joystick: Joystick, event: isize) void = null;
+/// Describes an event relating to a joystick.
+pub const Event = enum(c_int) {
+    /// The device was connected.
+    connected = c.GLFW_CONNECTED,
+
+    /// The device was disconnected.
+    disconnected = c.GLFW_DISCONNECTED,
+};
+
+var _callback: ?fn (joystick: Joystick, event: Event) void = null;
 
 fn callbackWrapper(jid: c_int, event: c_int) callconv(.C) void {
-    _callback.?(Joystick{ .jid = jid }, @intCast(isize, event));
+    _callback.?(Joystick{ .jid = jid }, @intToEnum(Event, event));
 }
 
 /// Sets the joystick configuration callback.
@@ -307,7 +316,7 @@ fn callbackWrapper(jid: c_int, event: c_int) callconv(.C) void {
 /// @param[in] callback The new callback, or null to remove the currently set callback.
 ///
 /// @callback_param `jid` The joystick that was connected or disconnected.
-/// @callback_param `event` One of `glfw.connected` or `glfw.disconnected`. Future releases may add
+/// @callback_param `event` One of `.connected` or `.disconnected`. Future releases may add
 /// more events.
 ///
 /// Possible errors include glfw.Error.NotInitialized.
@@ -315,7 +324,7 @@ fn callbackWrapper(jid: c_int, event: c_int) callconv(.C) void {
 /// @thread_safety This function must only be called from the main thread.
 ///
 /// see also: joystick_event
-pub inline fn setCallback(callback: ?fn (joystick: Joystick, event: isize) void) void {
+pub inline fn setCallback(callback: ?fn (joystick: Joystick, event: Event) void) void {
     _callback = callback;
     _ = if (_callback != null) c.glfwSetJoystickCallback(callbackWrapper) else c.glfwSetJoystickCallback(null);
 
@@ -527,7 +536,7 @@ test "setCallback" {
     defer glfw.terminate();
 
     glfw.Joystick.setCallback((struct {
-        pub fn callback(joystick: Joystick, event: isize) void {
+        pub fn callback(joystick: Joystick, event: Event) void {
             _ = joystick;
             _ = event;
         }

glfw/src/Monitor.zig

@@ -348,29 +348,37 @@ pub inline fn getPrimary() Error!?Monitor {
 var callback_fn_ptr: ?usize = null;
 var callback_data_ptr: ?usize = undefined;
 
+/// Describes an event relating to a monitor.
+pub const Event = enum(c_int) {
+    /// The device was connected.
+    connected = c.GLFW_CONNECTED,
+
+    /// The device was disconnected.
+    disconnected = c.GLFW_DISCONNECTED,
+};
+
 /// Sets the monitor configuration callback.
 ///
 /// This function sets the monitor configuration callback, or removes the currently set callback.
 /// This is called when a monitor is connected to or disconnected from the system. Example:
 ///
 /// ```
-/// fn monitorCallback(monitor: glfw.Monitor, event: usize, data: *MyData) void {
+/// fn monitorCallback(monitor: glfw.Monitor, event: glfw.Monitor.Event, data: *MyData) void {
 ///     // data is the pointer you passed into setCallback.
-///     // event is one of glfw.connected or glfw.disconnected
+///     // event is one of .connected or .disconnected
 /// }
 /// ...
 /// glfw.Monitor.setCallback(MyData, &myData, monitorCallback)
 /// ```
 ///
-/// `event` may be one of glfw.connected or glfw.disconnected. More events may be added in the
+/// `event` may be one of .connected or .disconnected. More events may be added in the future.
-/// future.
 ///
 /// Possible errors include glfw.Error.NotInitialized.
 ///
 /// @thread_safety This function must only be called from the main thread.
 ///
 /// see also: monitor_event
-pub inline fn setCallback(comptime Data: type, data: *Data, f: ?*const fn (monitor: Monitor, event: usize, data: *Data) void) Error!void {
+pub inline fn setCallback(comptime Data: type, data: *Data, f: ?*const fn (monitor: Monitor, event: Event, data: *Data) void) Error!void {
     if (f) |new_callback| {
         callback_fn_ptr = @ptrToInt(new_callback);
         callback_data_ptr = @ptrToInt(data);
@@ -380,7 +388,7 @@ pub inline fn setCallback(comptime Data: type, data: *Data, f: ?*const fn (monit
                 const callback = @intToPtr(NewCallback, callback_fn_ptr.?);
                 callback.*(
                     Monitor{ .handle = monitor.? },
-                    @intCast(usize, event),
+                    @intToEnum(Event, event),
                     @intToPtr(*Data, callback_data_ptr.?),
                 );
             }
@@ -489,7 +497,7 @@ test "setCallback" {
 
     var custom_data: u32 = 5;
     try setCallback(u32, &custom_data, &(struct {
-        fn callback(monitor: Monitor, event: usize, data: *u32) void {
+        fn callback(monitor: Monitor, event: Event, data: *u32) void {
             _ = monitor;
             _ = event;
             _ = data;

glfw/src/consts.zig

@@ -30,10 +30,6 @@ pub const osmesa_context_api = c.GLFW_OSMESA_CONTEXT_API;
 /// Possible value for various window hints, etc.
 pub const dont_care = c.GLFW_DONT_CARE;
 
-// TODO(enumify)
-pub const connected = c.GLFW_CONNECTED;
-pub const disconnected = c.GLFW_DISCONNECTED;
-
 // TODO(enumify)
 /// Joystick hat buttons init hint.
 pub const joystick_hat_buttons = c.GLFW_JOYSTICK_HAT_BUTTONS;