winit-core: new crate + split out as_any

winit-core/Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+authors = ["The winit contributors", "Kirill Chibisov <contact@kchibisov.com>"]
+categories = ["gui"]
+description = "winit core API."
+documentation = "https://docs.rs/winit-core"
+edition.workspace = true
+keywords = ["windowing"]
+license.workspace = true
+name = "winit-core"
+readme = "README.md"
+repository.workspace = true
+rust-version.workspace = true
+version = "0.0.0"
+
+[features]
+serde = ["dep:serde", "cursor-icon/serde", "smol_str/serde", "dpi/serde", "bitflags/serde"]
+
+[dependencies]
+bitflags = "2"
+cursor-icon = "1.1.0"
+dpi = { version = "0.1.1", path = "../dpi" }
+rwh_06 = { package = "raw-window-handle", version = "0.6", features = ["std"] }
+serde = { workspace = true, optional = true }
+smol_str = "0.3"
+
+[target.'cfg(target_family = "wasm")'.dependencies]
+web-time = "1"
+
+[build-dependencies]
+cfg_aliases = "0.2.1"

winit-core/LICENSE

@@ -0,0 +1 @@
+../LICENSE

winit-core/README.md

@@ -0,0 +1 @@
+../README.md

winit-core/build.rs

@@ -0,0 +1,26 @@
+use cfg_aliases::cfg_aliases;
+
+fn main() {
+    // The script doesn't depend on our code.
+    println!("cargo:rerun-if-changed=build.rs");
+
+    // Setup cfg aliases.
+    cfg_aliases! {
+        // Systems.
+        android_platform: { target_os = "android" },
+        web_platform: { all(target_family = "wasm", target_os = "unknown") },
+        macos_platform: { target_os = "macos" },
+        ios_platform: { all(target_vendor = "apple", not(target_os = "macos")) },
+        windows_platform: { target_os = "windows" },
+        free_unix: { all(unix, not(target_vendor = "apple"), not(android_platform), not(target_os = "emscripten")) },
+        redox: { target_os = "redox" },
+
+        // Native displays.
+        x11_platform: { all(feature = "x11", free_unix, not(redox)) },
+        wayland_platform: { all(feature = "wayland", free_unix, not(redox)) },
+        orbital_platform: { redox },
+    }
+
+    // Winit defined cfgs.
+    println!("cargo:rustc-check-cfg=cfg(unreleased_changelogs)");
+}

winit-core/src/as_any.rs

@@ -0,0 +1,71 @@
+use std::any::Any;
+
+// NOTE: This is `pub`, but isn't actually exposed outside the crate.
+// NOTE: Marked as `#[doc(hidden)]` and underscored, because they can be quite difficult to use
+// correctly, see discussion in #4160.
+// FIXME: Remove and replace with a coercion once rust-lang/rust#65991 is in MSRV (1.86).
+#[doc(hidden)]
+pub trait AsAny: Any {
+    #[doc(hidden)]
+    fn __as_any(&self) -> &dyn Any;
+    #[doc(hidden)]
+    fn __as_any_mut(&mut self) -> &mut dyn Any;
+    #[doc(hidden)]
+    fn __into_any(self: Box<Self>) -> Box<dyn Any>;
+}
+
+impl<T: Any> AsAny for T {
+    #[inline(always)]
+    fn __as_any(&self) -> &dyn Any {
+        self
+    }
+
+    #[inline(always)]
+    fn __as_any_mut(&mut self) -> &mut dyn Any {
+        self
+    }
+
+    #[inline(always)]
+    fn __into_any(self: Box<Self>) -> Box<dyn Any> {
+        self
+    }
+}
+
+#[macro_export]
+macro_rules! impl_dyn_casting {
+    ($trait:ident) => {
+        impl dyn $trait + '_ {
+            /// Downcast to the backend concrete type.
+            ///
+            /// Returns `None` if the object was not from that backend.
+            pub fn cast_ref<T: $trait>(&self) -> Option<&T> {
+                let this: &dyn std::any::Any = self.__as_any();
+                this.downcast_ref::<T>()
+            }
+
+            /// Mutable downcast to the backend concrete type.
+            ///
+            /// Returns `None` if the object was not from that backend.
+            pub fn cast_mut<T: $trait>(&mut self) -> Option<&mut T> {
+                let this: &mut dyn std::any::Any = self.__as_any_mut();
+                this.downcast_mut::<T>()
+            }
+
+            /// Owned downcast to the backend concrete type.
+            ///
+            /// Returns `Err` with `self` if the object was not from that backend.
+            pub fn cast<T: $trait>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
+                let reference: &dyn std::any::Any = self.__as_any();
+                if reference.is::<T>() {
+                    let this: Box<dyn std::any::Any> = self.__into_any();
+                    // Unwrap is okay, we just checked the type of `self` is `T`.
+                    Ok(this.downcast::<T>().unwrap())
+                } else {
+                    Err(self)
+                }
+            }
+        }
+    };
+}
+
+pub use impl_dyn_casting;

winit-core/src/lib.rs

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+#[macro_use]
+pub mod as_any;