#![no_std]
#![cfg_attr(docsrs, feature(doc_cfg))]

//! Interoperability library for Rust Windowing applications.
//!
//! This library provides standard types for accessing a window's platform-specific raw window
//! handle. This does not provide any utilities for creating and managing windows; instead, it
//! provides a common interface that window creation libraries (e.g. Winit, SDL) can use to easily
//! talk with graphics libraries (e.g. gfx-hal).
//!
//! ## Safety guarantees
//!
//! Please see the docs of [`HasRawWindowHandle`].
//!
//! ## Platform handle initialization
//!
//! Each platform handle struct is purposefully non-exhaustive, so that additional fields may be
//! added without breaking backwards compatibility. Each struct provides an `empty` method that may
//! be used along with the struct update syntax to construct it. See each specific struct for
//! examples.

#[cfg(feature = "alloc")]
extern crate alloc;

mod android;
mod appkit;
mod haiku;
mod redox;
mod uikit;
mod unix;
mod web;
mod windows;

pub use android::AndroidNdkHandle;
pub use appkit::AppKitHandle;
pub use haiku::HaikuHandle;
pub use redox::OrbitalHandle;
pub use uikit::UiKitHandle;
pub use unix::{WaylandHandle, XcbHandle, XlibHandle};
pub use web::WebHandle;
pub use windows::{Win32Handle, WinRtHandle};

/// Window that wraps around a raw window handle.
///
/// # Safety guarantees
///
/// Users can safely assume that non-`null`/`0` fields are valid handles, and it is up to the
/// implementer of this trait to ensure that condition is upheld.
///
/// Despite that qualification, implementers should still make a best-effort attempt to fill in all
/// available fields. If an implementation doesn't, and a downstream user needs the field, it should
/// try to derive the field from other fields the implementer *does* provide via whatever methods the
/// platform provides.
///
/// The exact handles returned by `raw_window_handle` must remain consistent between multiple calls
/// to `raw_window_handle` as long as not indicated otherwise by platform specific events.
pub unsafe trait HasRawWindowHandle {
    fn raw_window_handle(&self) -> RawWindowHandle;
}

unsafe impl<'a, T: HasRawWindowHandle + ?Sized> HasRawWindowHandle for &'a T {
    fn raw_window_handle(&self) -> RawWindowHandle {
        (*self).raw_window_handle()
    }
}
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
unsafe impl<T: HasRawWindowHandle + ?Sized> HasRawWindowHandle for alloc::rc::Rc<T> {
    fn raw_window_handle(&self) -> RawWindowHandle {
        (**self).raw_window_handle()
    }
}
#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
unsafe impl<T: HasRawWindowHandle + ?Sized> HasRawWindowHandle for alloc::sync::Arc<T> {
    fn raw_window_handle(&self) -> RawWindowHandle {
        (**self).raw_window_handle()
    }
}

/// An enum to simply combine the different possible raw window handle variants.
///
/// # Variant Availability
///
/// Note that all variants are present on all targets (none are disabled behind
/// `#[cfg]`s), but see the "Availability Hints" section on each variant for
/// some hints on where this variant might be expected.
///
/// Note that these "Availability Hints" are not normative. That is to say, a
/// [`HasRawWindowHandle`] implementor is completely allowed to return something
/// unexpected. (For example, it's legal for someone to return a
/// [`RawWindowHandle::Xlib`] on macOS, it would just be weird, and probably
/// requires something like XQuartz be used).
#[non_exhaustive]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum RawWindowHandle {
    /// A raw window handle for UIKit (Apple's non-macOS windowing library).
    ///
    /// ## Availability Hints
    /// This variant is likely to be used on iOS, tvOS, (in theory) watchOS, and
    /// Mac Catalyst (`$arch-apple-ios-macabi` targets, which can notably use
    /// UIKit *or* AppKit), as these are the targets that (currently) support
    /// UIKit.
    UiKit(UiKitHandle),
    /// A raw window handle for AppKit.
    ///
    /// ## Availability Hints
    /// This variant is likely to be used on macOS, although Mac Catalyst
    /// (`$arch-apple-ios-macabi` targets, which can notably use UIKit *or*
    /// AppKit) can also use it despite being `target_os = "ios"`.
    AppKit(AppKitHandle),
    /// A raw window handle for the Redox operating system.
    ///
    /// ## Availability Hints
    /// This variant is used by the Orbital Windowing System in the Redox
    /// operating system.
    Orbital(OrbitalHandle),
    /// A raw window handle for Xlib.
    ///
    /// ## Availability Hints
    /// This variant is likely to show up anywhere someone manages to get X11
    /// working that Xlib can be built for, which is to say, most (but not all)
    /// Unix systems.
    Xlib(XlibHandle),
    /// A raw window handle for Xcb.
    ///
    /// ## Availability Hints
    /// This variant is likely to show up anywhere someone manages to get X11
    /// working that XCB can be built for, which is to say, most (but not all)
    /// Unix systems.
    Xcb(XcbHandle),
    /// A raw window handle for Wayland.
    ///
    /// ## Availability Hints
    /// This variant should be expected anywhere Wayland works, which is
    /// currently some subset of unix systems.
    Wayland(WaylandHandle),
    /// A raw window handle for Win32.
    ///
    /// ## Availability Hints
    /// This variant is used on Windows systems.
    Win32(Win32Handle),
    /// A raw window handle for WinRT.
    ///
    /// ## Availability Hints
    /// This variant is used on Windows systems.
    WinRt(WinRtHandle),
    /// A raw window handle for the Web.
    ///
    /// ## Availability Hints
    /// This variant is used on Wasm or asm.js targets when targeting the Web/HTML5.
    Web(WebHandle),
    /// A raw window handle for Android NDK.
    ///
    /// ## Availability Hints
    /// This variant is used on Android targets.
    AndroidNdk(AndroidNdkHandle),
    /// A raw window handle for Haiku.
    ///
    /// ## Availability Hints
    /// This variant is used on HaikuOS.
    Haiku(HaikuHandle),
}