1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
//! Borrowable window handles based on the ones in this crate.
//!
//! These should be 100% safe to pass around and use, no possibility of dangling or invalidity.

use core::borrow::Borrow;
use core::fmt;
use core::marker::PhantomData;

use crate::{HandleError, RawDisplayHandle, RawWindowHandle};

/// A display that acts as a wrapper around a display handle.
///
/// Objects that implement this trait should be able to return a [`DisplayHandle`] for the display
/// that they are associated with. This handle should last for the lifetime of the object, and should
/// return an error if the application is inactive.
///
/// Implementors of this trait will be windowing systems, like [`winit`] and [`sdl2`]. These windowing
/// systems should implement this trait on types that represent the top-level display server. It
/// should be implemented by tying the lifetime of the [`DisplayHandle`] to the lifetime of the
/// display object.
///
/// Users of this trait will include graphics libraries, like [`wgpu`] and [`glutin`]. These APIs
/// should be generic over a type that implements `HasDisplayHandle`, and should use the
/// [`DisplayHandle`] type to access the display handle.
///
/// Note that these requirements are not enforced on `HasDisplayHandle`, rather, they are enforced on the
/// constructors of [`DisplayHandle`]. This is because the `HasDisplayHandle` trait is safe to implement.
///
/// [`winit`]: https://crates.io/crates/winit
/// [`sdl2`]: https://crates.io/crates/sdl2
/// [`wgpu`]: https://crates.io/crates/wgpu
/// [`glutin`]: https://crates.io/crates/glutin
pub trait HasDisplayHandle {
    /// Get a handle to the display controller of the windowing system.
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError>;
}

impl<H: HasDisplayHandle + ?Sized> HasDisplayHandle for &H {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        (**self).display_handle()
    }
}

impl<H: HasDisplayHandle + ?Sized> HasDisplayHandle for &mut H {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        (**self).display_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasDisplayHandle + ?Sized> HasDisplayHandle for alloc::boxed::Box<H> {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        (**self).display_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasDisplayHandle + ?Sized> HasDisplayHandle for alloc::rc::Rc<H> {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        (**self).display_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasDisplayHandle + ?Sized> HasDisplayHandle for alloc::sync::Arc<H> {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        (**self).display_handle()
    }
}

/// The handle to the display controller of the windowing system.
///
/// This is the primary return type of the [`HasDisplayHandle`] trait. It is guaranteed to contain
/// a valid platform-specific display handle for its lifetime.
#[repr(transparent)]
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
pub struct DisplayHandle<'a> {
    raw: RawDisplayHandle,
    _marker: PhantomData<&'a *const ()>,
}

impl fmt::Debug for DisplayHandle<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("DisplayHandle").field(&self.raw).finish()
    }
}

impl<'a> DisplayHandle<'a> {
    /// Create a `DisplayHandle` from a [`RawDisplayHandle`].
    ///
    /// # Safety
    ///
    /// 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, implementors 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.
    ///
    /// It is not possible to invalidate a [`DisplayHandle`] on any platform without additional unsafe code.
    pub unsafe fn borrow_raw(raw: RawDisplayHandle) -> Self {
        Self {
            raw,
            _marker: PhantomData,
        }
    }

    /// Get the underlying raw display handle.
    pub fn as_raw(&self) -> RawDisplayHandle {
        self.raw
    }
}

impl AsRef<RawDisplayHandle> for DisplayHandle<'_> {
    fn as_ref(&self) -> &RawDisplayHandle {
        &self.raw
    }
}

impl Borrow<RawDisplayHandle> for DisplayHandle<'_> {
    fn borrow(&self) -> &RawDisplayHandle {
        &self.raw
    }
}

impl From<DisplayHandle<'_>> for RawDisplayHandle {
    fn from(handle: DisplayHandle<'_>) -> Self {
        handle.raw
    }
}

impl<'a> HasDisplayHandle for DisplayHandle<'a> {
    fn display_handle(&self) -> Result<DisplayHandle<'_>, HandleError> {
        Ok(*self)
    }
}

/// A handle to a window.
///
/// Objects that implement this trait should be able to return a [`WindowHandle`] for the window
/// that they are associated with. This handle should last for the lifetime of the object, and should
/// return an error if the application is inactive.
///
/// Implementors of this trait will be windowing systems, like [`winit`] and [`sdl2`]. These windowing
/// systems should implement this trait on types that represent windows.
///
/// Users of this trait will include graphics libraries, like [`wgpu`] and [`glutin`]. These APIs
/// should be generic over a type that implements `HasWindowHandle`, and should use the
/// [`WindowHandle`] type to access the window handle. The window handle should be acquired and held
/// while the window is being used, in order to ensure that the window is not deleted while it is in
/// use.
///
/// [`winit`]: https://crates.io/crates/winit
/// [`sdl2`]: https://crates.io/crates/sdl2
/// [`wgpu`]: https://crates.io/crates/wgpu
/// [`glutin`]: https://crates.io/crates/glutin
pub trait HasWindowHandle {
    /// Get a handle to the window.
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError>;
}

impl<H: HasWindowHandle + ?Sized> HasWindowHandle for &H {
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError> {
        (**self).window_handle()
    }
}

impl<H: HasWindowHandle + ?Sized> HasWindowHandle for &mut H {
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError> {
        (**self).window_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasWindowHandle + ?Sized> HasWindowHandle for alloc::boxed::Box<H> {
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError> {
        (**self).window_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasWindowHandle + ?Sized> HasWindowHandle for alloc::rc::Rc<H> {
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError> {
        (**self).window_handle()
    }
}

#[cfg(feature = "alloc")]
#[cfg_attr(docsrs, doc(cfg(feature = "alloc")))]
impl<H: HasWindowHandle + ?Sized> HasWindowHandle for alloc::sync::Arc<H> {
    fn window_handle(&self) -> Result<WindowHandle<'_>, HandleError> {
        (**self).window_handle()
    }
}

/// The handle to a window.
///
/// This is the primary return type of the [`HasWindowHandle`] trait. All *pointers* within this type
/// are guaranteed to be valid and not dangling for the lifetime of the handle. This excludes window IDs
/// like XIDs and the window ID for web platforms. See the documentation on the [`HasWindowHandle`]
/// trait for more information about these safety requirements.
///
/// This handle is guaranteed to be safe and valid.
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
pub struct WindowHandle<'a> {
    raw: RawWindowHandle,
    _marker: PhantomData<&'a *const ()>,
}

impl fmt::Debug for WindowHandle<'_> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("WindowHandle").field(&self.raw).finish()
    }
}

impl<'a> WindowHandle<'a> {
    /// Borrow a `WindowHandle` from a [`RawWindowHandle`].
    ///
    /// # Safety
    ///
    /// 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.
    ///
    /// Note that this guarantee only applies to *pointers*, and not any window ID types in the handle.
    /// This includes Window IDs (XIDs) from X11 and the window ID for web platforms. There is no way for
    /// Rust to enforce any kind of invariant on these types, since:
    ///
    /// - For all three listed platforms, it is possible for safe code in the same process to delete
    ///   the window.
    /// - For X11, it is possible for code in a different process to delete the window. In fact, it is
    ///   possible for code on a different *machine* to delete the window.
    ///
    /// It is *also* possible for the window to be replaced with another, valid-but-different window. User
    /// code should be aware of this possibility, and should be ready to soundly handle the possible error
    /// conditions that can arise from this.
    pub unsafe fn borrow_raw(raw: RawWindowHandle) -> Self {
        Self {
            raw,
            _marker: PhantomData,
        }
    }

    /// Get the underlying raw window handle.
    pub fn as_raw(&self) -> RawWindowHandle {
        self.raw.clone()
    }
}

impl AsRef<RawWindowHandle> for WindowHandle<'_> {
    fn as_ref(&self) -> &RawWindowHandle {
        &self.raw
    }
}

impl Borrow<RawWindowHandle> for WindowHandle<'_> {
    fn borrow(&self) -> &RawWindowHandle {
        &self.raw
    }
}

impl From<WindowHandle<'_>> for RawWindowHandle {
    fn from(handle: WindowHandle<'_>) -> Self {
        handle.raw
    }
}

impl HasWindowHandle for WindowHandle<'_> {
    fn window_handle(&self) -> Result<Self, HandleError> {
        Ok(*self)
    }
}

/// ```compile_fail
/// use raw_window_handle::{DisplayHandle, WindowHandle};
/// fn _assert<T: Send + Sync>() {}
/// _assert::<DisplayHandle<'static>>();
/// _assert::<WindowHandle<'static>>();
/// ```
fn _not_send_or_sync() {}