Remove a few unnecessary usages of Lazy (#3531)

* Convert usage of Lazy to OnceLock on macOS and iOS

* Remove a few uses of Lazy that wrapped Mutex or RwLock

The `new` functions on these were made `const` in Rust 1.63.0

* Use AtomicBool instead of RwLock

src/platform_impl/android/mod.rs

@@ -7,12 +7,11 @@ use std::{
     marker::PhantomData,
     sync::{
         atomic::{AtomicBool, Ordering},
-        mpsc, Arc, Mutex, RwLock,
+        mpsc, Arc, Mutex,
     },
     time::{Duration, Instant},
 };
 
-use crate::utils::Lazy;
 use android_activity::input::{InputEvent, KeyAction, Keycode, MotionAction};
 use android_activity::{
     AndroidApp, AndroidAppWaker, ConfigurationRef, InputStatus, MainEvent, Rect,
@@ -39,7 +38,7 @@ pub(crate) use crate::cursor::NoCustomCursor as PlatformCustomCursor;
 pub(crate) use crate::cursor::NoCustomCursor as PlatformCustomCursorSource;
 pub(crate) use crate::icon::NoIcon as PlatformIcon;
 
-static HAS_FOCUS: Lazy<RwLock<bool>> = Lazy::new(|| RwLock::new(true));
+static HAS_FOCUS: AtomicBool = AtomicBool::new(true);
 
 /// Returns the minimum `Option<Duration>`, taking into account that `None`
 /// equates to an infinite timeout, not a zero timeout (so can't just use
@@ -236,7 +235,7 @@ impl<T: 'static> EventLoop<T> {
                     warn!("TODO: find a way to notify application of content rect change");
                 }
                 MainEvent::GainedFocus => {
-                    *HAS_FOCUS.write().unwrap() = true;
+                    HAS_FOCUS.store(true, Ordering::Relaxed);
                     callback(
                         event::Event::WindowEvent {
                             window_id: window::WindowId(WindowId),
@@ -246,7 +245,7 @@ impl<T: 'static> EventLoop<T> {
                     );
                 }
                 MainEvent::LostFocus => {
-                    *HAS_FOCUS.write().unwrap() = false;
+                    HAS_FOCUS.store(false, Ordering::Relaxed);
                     callback(
                         event::Event::WindowEvent {
                             window_id: window::WindowId(WindowId),
@@ -1046,7 +1045,7 @@ impl Window {
     pub fn set_content_protected(&self, _protected: bool) {}
 
     pub fn has_focus(&self) -> bool {
-        *HAS_FOCUS.read().unwrap()
+        HAS_FOCUS.load(Ordering::Relaxed)
     }
 
     pub fn title(&self) -> String {

src/platform_impl/ios/app_state.rs

@@ -6,11 +6,10 @@ use std::{
     fmt, mem,
     os::raw::c_void,
     ptr,
-    sync::{Arc, Mutex},
+    sync::{Arc, Mutex, OnceLock},
     time::Instant,
 };
 
-use crate::utils::Lazy;
 use core_foundation::base::CFRelease;
 use core_foundation::date::CFAbsoluteTimeGetCurrent;
 use core_foundation::runloop::{
@@ -902,10 +901,10 @@ macro_rules! os_capabilities {
             os_version: NSOperatingSystemVersion,
         }
 
-        impl From<NSOperatingSystemVersion> for OSCapabilities {
-            fn from(os_version: NSOperatingSystemVersion) -> OSCapabilities {
+        impl OSCapabilities {
+            fn from_os_version(os_version: NSOperatingSystemVersion) -> Self {
                 $(let $name = meets_requirements(os_version, $major, $minor);)*
-                OSCapabilities { $($name,)* os_version, }
+                Self { $($name,)* os_version, }
             }
         }
 
@@ -950,25 +949,29 @@ fn meets_requirements(
     (version.majorVersion, version.minorVersion) >= (required_major, required_minor)
 }
 
-pub fn os_capabilities() -> OSCapabilities {
-    static OS_CAPABILITIES: Lazy<OSCapabilities> = Lazy::new(|| {
-        let version: NSOperatingSystemVersion = unsafe {
-            let process_info = NSProcessInfo::processInfo();
-            let atleast_ios_8: bool = msg_send![
-                &process_info,
-                respondsToSelector: sel!(operatingSystemVersion)
-            ];
-            // winit requires atleast iOS 8 because no one has put the time into supporting earlier os versions.
-            // Older iOS versions are increasingly difficult to test. For example, Xcode 11 does not support
-            // debugging on devices with an iOS version of less than 8. Another example, in order to use an iOS
-            // simulator older than iOS 8, you must download an older version of Xcode (<9), and at least Xcode 7
-            // has been tested to not even run on macOS 10.15 - Xcode 8 might?
-            //
-            // The minimum required iOS version is likely to grow in the future.
-            assert!(atleast_ios_8, "`winit` requires iOS version 8 or greater");
-            process_info.operatingSystemVersion()
-        };
-        version.into()
-    });
-    OS_CAPABILITIES.clone()
+fn get_version() -> NSOperatingSystemVersion {
+    unsafe {
+        let process_info = NSProcessInfo::processInfo();
+        let atleast_ios_8: bool = msg_send![
+            &process_info,
+            respondsToSelector: sel!(operatingSystemVersion)
+        ];
+        // winit requires atleast iOS 8 because no one has put the time into supporting earlier os versions.
+        // Older iOS versions are increasingly difficult to test. For example, Xcode 11 does not support
+        // debugging on devices with an iOS version of less than 8. Another example, in order to use an iOS
+        // simulator older than iOS 8, you must download an older version of Xcode (<9), and at least Xcode 7
+        // has been tested to not even run on macOS 10.15 - Xcode 8 might?
+        //
+        // The minimum required iOS version is likely to grow in the future.
+        assert!(atleast_ios_8, "`winit` requires iOS version 8 or greater");
+        process_info.operatingSystemVersion()
+    }
+}
+
+pub fn os_capabilities() -> OSCapabilities {
+    // Cache the version lookup for efficiency
+    static OS_CAPABILITIES: OnceLock<OSCapabilities> = OnceLock::new();
+    OS_CAPABILITIES
+        .get_or_init(|| OSCapabilities::from_os_version(get_version()))
+        .clone()
 }

src/platform_impl/linux/mod.rs

@@ -647,8 +647,7 @@ pub(crate) enum PlatformCustomCursor {
 
 /// Hooks for X11 errors.
 #[cfg(x11_platform)]
-pub(crate) static mut XLIB_ERROR_HOOKS: Lazy<Mutex<Vec<XlibErrorHook>>> =
-    Lazy::new(|| Mutex::new(Vec::new()));
+pub(crate) static mut XLIB_ERROR_HOOKS: Mutex<Vec<XlibErrorHook>> = Mutex::new(Vec::new());
 
 #[cfg(x11_platform)]
 unsafe extern "C" fn x_error_callback(

src/platform_impl/linux/x11/ime/input_method.rs

@@ -8,10 +8,9 @@ use std::{
 };
 
 use super::{super::atoms::*, ffi, util, XConnection, XError};
-use crate::utils::Lazy;
 use x11rb::protocol::xproto;
 
-static GLOBAL_LOCK: Lazy<Mutex<()>> = Lazy::new(Default::default);
+static GLOBAL_LOCK: Mutex<()> = Mutex::new(());
 
 unsafe fn open_im(xconn: &Arc<XConnection>, locale_modifiers: &CStr) -> Option<ffi::XIM> {
     let _lock = GLOBAL_LOCK.lock();

src/platform_impl/linux/x11/util/wm.rs

@@ -1,7 +1,5 @@
 use std::sync::Mutex;
 
-use crate::utils::Lazy;
-
 use super::*;
 
 // https://specifications.freedesktop.org/wm-spec/latest/ar01s04.html#idm46075117309248
@@ -16,9 +14,8 @@ pub const MOVERESIZE_LEFT: isize = 7;
 pub const MOVERESIZE_MOVE: isize = 8;
 
 // This info is global to the window manager.
-static SUPPORTED_HINTS: Lazy<Mutex<Vec<xproto::Atom>>> =
-    Lazy::new(|| Mutex::new(Vec::with_capacity(0)));
-static WM_NAME: Lazy<Mutex<Option<String>>> = Lazy::new(|| Mutex::new(None));
+static SUPPORTED_HINTS: Mutex<Vec<xproto::Atom>> = Mutex::new(Vec::new());
+static WM_NAME: Mutex<Option<String>> = Mutex::new(None);
 
 pub fn hint_is_supported(hint: xproto::Atom) -> bool {
     (*SUPPORTED_HINTS.lock().unwrap()).contains(&hint)

src/platform_impl/macos/cursor.rs

@@ -1,4 +1,7 @@
-use crate::utils::Lazy;
+use std::ffi::c_uchar;
+use std::slice;
+use std::sync::OnceLock;
+
 use icrate::AppKit::{NSBitmapImageRep, NSCursor, NSDeviceRGBColorSpace, NSImage};
 use icrate::Foundation::{
     ns_string, NSData, NSDictionary, NSNumber, NSObject, NSObjectProtocol, NSPoint, NSSize,
@@ -7,8 +10,6 @@ use icrate::Foundation::{
 use objc2::rc::Id;
 use objc2::runtime::Sel;
 use objc2::{msg_send_id, sel, ClassType};
-use std::ffi::c_uchar;
-use std::slice;
 
 use crate::cursor::CursorImage;
 use crate::cursor::OnlyCursorImageSource;
@@ -171,19 +172,20 @@ pub(crate) fn invisible_cursor() -> Id<NSCursor> {
         0xA3, 0x9C, 0xB4, 0xDA, 0x8B, 0xB3, 0x3E, 0x05, 0x00, 0x3B,
     ];
 
-    static CURSOR: Lazy<CustomCursor> = Lazy::new(|| {
+    fn new_invisible() -> Id<NSCursor> {
         // TODO: Consider using `dataWithBytesNoCopy:`
         let data = NSData::with_bytes(CURSOR_BYTES);
         let image = NSImage::initWithData(NSImage::alloc(), &data).unwrap();
         let hotspot = NSPoint::new(0.0, 0.0);
-        CustomCursor(NSCursor::initWithImage_hotSpot(
-            NSCursor::alloc(),
-            &image,
-            hotspot,
-        ))
-    });
+        NSCursor::initWithImage_hotSpot(NSCursor::alloc(), &image, hotspot)
+    }
 
-    CURSOR.0.clone()
+    // Cache this for efficiency
+    static CURSOR: OnceLock<CustomCursor> = OnceLock::new();
+    CURSOR
+        .get_or_init(|| CustomCursor(new_invisible()))
+        .0
+        .clone()
 }
 
 pub(crate) fn cursor_from_icon(icon: CursorIcon) -> Id<NSCursor> {