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
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
//! This library safely implements WebGPU on native platforms.
//! It is designed for integration into browsers, as well as wrapping
//! into other language-specific user-friendly libraries.
//!
//! ## Feature flags
#![doc = document_features::document_features!()]
//!

// When we have no backends, we end up with a lot of dead or otherwise unreachable code.
#![cfg_attr(
    all(
        not(all(feature = "vulkan", not(target_arch = "wasm32"))),
        not(all(feature = "metal", any(target_os = "macos", target_os = "ios"))),
        not(all(feature = "dx12", windows)),
        not(feature = "gles"),
    ),
    allow(unused, clippy::let_and_return)
)]
#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]
#![allow(
    // It is much clearer to assert negative conditions with eq! false
    clippy::bool_assert_comparison,
    // We use loops for getting early-out of scope without closures.
    clippy::never_loop,
    // We don't use syntax sugar where it's not necessary.
    clippy::match_like_matches_macro,
    // Redundant matching is more explicit.
    clippy::redundant_pattern_matching,
    // Explicit lifetimes are often easier to reason about.
    clippy::needless_lifetimes,
    // No need for defaults in the internal types.
    clippy::new_without_default,
    // Needless updates are more scalable, easier to play with features.
    clippy::needless_update,
    // Need many arguments for some core functions to be able to re-use code in many situations.
    clippy::too_many_arguments,
    // For some reason `rustc` can warn about these in const generics even
    // though they are required.
    unused_braces,
    // It gets in the way a lot and does not prevent bugs in practice.
    clippy::pattern_type_mismatch,
    // `wgpu-core` isn't entirely user-facing, so it's useful to document internal items.
    rustdoc::private_intra_doc_links
)]
#![warn(
    trivial_casts,
    trivial_numeric_casts,
    unsafe_op_in_unsafe_fn,
    unused_extern_crates,
    unused_qualifications
)]

pub mod binding_model;
pub mod command;
mod conv;
pub mod device;
pub mod error;
pub mod global;
pub mod hal_api;
mod hash_utils;
pub mod hub;
pub mod id;
pub mod identity;
mod init_tracker;
pub mod instance;
mod lock;
pub mod pipeline;
mod pool;
pub mod present;
pub mod registry;
pub mod resource;
mod snatch;
pub mod storage;
mod track;
// This is public for users who pre-compile shaders while still wanting to
// preserve all run-time checks that `wgpu-core` does.
// See <https://github.com/gfx-rs/wgpu/issues/3103>, after which this can be
// made private again.
pub mod validation;

pub use hal::{api, MAX_BIND_GROUPS, MAX_COLOR_ATTACHMENTS, MAX_VERTEX_BUFFERS};
pub use naga;

use std::{borrow::Cow, os::raw::c_char};

pub(crate) use hash_utils::*;

/// The index of a queue submission.
///
/// These are the values stored in `Device::fence`.
type SubmissionIndex = hal::FenceValue;

type Index = u32;
type Epoch = u32;

pub type RawString = *const c_char;
pub type Label<'a> = Option<Cow<'a, str>>;

trait LabelHelpers<'a> {
    fn borrow_option(&'a self) -> Option<&'a str>;
    fn to_hal(&'a self, flags: wgt::InstanceFlags) -> Option<&'a str>;
    fn borrow_or_default(&'a self) -> &'a str;
}
impl<'a> LabelHelpers<'a> for Label<'a> {
    fn borrow_option(&'a self) -> Option<&'a str> {
        self.as_ref().map(|cow| cow.as_ref())
    }
    fn to_hal(&'a self, flags: wgt::InstanceFlags) -> Option<&'a str> {
        if flags.contains(wgt::InstanceFlags::DISCARD_HAL_LABELS) {
            return None;
        }

        self.as_ref().map(|cow| cow.as_ref())
    }
    fn borrow_or_default(&'a self) -> &'a str {
        self.borrow_option().unwrap_or_default()
    }
}

pub fn hal_label(opt: Option<&str>, flags: wgt::InstanceFlags) -> Option<&str> {
    if flags.contains(wgt::InstanceFlags::DISCARD_HAL_LABELS) {
        return None;
    }

    opt
}

const DOWNLEVEL_WARNING_MESSAGE: &str = "The underlying API or device in use does not \
support enough features to be a fully compliant implementation of WebGPU. A subset of the features can still be used. \
If you are running this program on native and not in a browser and wish to limit the features you use to the supported subset, \
call Adapter::downlevel_properties or Device::downlevel_properties to get a listing of the features the current \
platform supports.";
const DOWNLEVEL_ERROR_MESSAGE: &str = "This is not an invalid use of WebGPU: the underlying API or device does not \
support enough features to be a fully compliant implementation. A subset of the features can still be used. \
If you are running this program on native and not in a browser and wish to work around this issue, call \
Adapter::downlevel_properties or Device::downlevel_properties to get a listing of the features the current \
platform supports.";

// #[cfg] attributes in exported macros are interesting!
//
// The #[cfg] conditions in a macro's expansion are evaluated using the
// configuration options (features, target architecture and os, etc.) in force
// where the macro is *used*, not where it is *defined*. That is, if crate A
// defines a macro like this:
//
//     #[macro_export]
//     macro_rules! if_bleep {
//         { } => {
//             #[cfg(feature = "bleep")]
//             bleep();
//         }
//     }
//
// and then crate B uses it like this:
//
//     fn f() {
//         if_bleep! { }
//     }
//
// then it is crate B's `"bleep"` feature, not crate A's, that determines
// whether the macro expands to a function call or an empty statement. The
// entire configuration predicate is evaluated in the use's context, not the
// definition's.
//
// Since `wgpu-core` selects back ends using features, we need to make sure the
// arms of the `gfx_select!` macro are pruned according to `wgpu-core`'s
// features, not those of whatever crate happens to be using `gfx_select!`. This
// means we can't use `#[cfg]` attributes in `gfx_select!`s definition itself.
// Instead, for each backend, `gfx_select!` must use a macro whose definition is
// selected by `#[cfg]` in `wgpu-core`. The configuration predicate is still
// evaluated when the macro is used; we've just moved the `#[cfg]` into a macro
// used by `wgpu-core` itself.

/// Define an exported macro named `$public` that expands to an expression if
/// the feature `$feature` is enabled, or to a panic otherwise.
///
/// This is used in the definition of `gfx_select!`, to dispatch the
/// call to the appropriate backend, but panic if that backend was not
/// compiled in.
///
/// For a call like this:
///
/// ```ignore
/// define_backend_caller! { name, private, "feature" if cfg_condition }
/// ```
///
/// define a macro `name`, used like this:
///
/// ```ignore
/// name!(expr)
/// ```
///
/// that expands to `expr` if `#[cfg(cfg_condition)]` is enabled, or a
/// panic otherwise. The panic message complains that `"feature"` is
/// not enabled.
///
/// Because of odd technical limitations on exporting macros expanded
/// by other macros, you must supply both a public-facing name for the
/// macro and a private name, `$private`, which is never used
/// outside this macro. For details:
/// <https://github.com/rust-lang/rust/pull/52234#issuecomment-976702997>
macro_rules! define_backend_caller {
    { $public:ident, $private:ident, $feature:literal if $cfg:meta } => {
        #[cfg($cfg)]
        #[macro_export]
        macro_rules! $private {
            ( $call:expr ) => ( $call )
        }

        #[cfg(not($cfg))]
        #[macro_export]
        macro_rules! $private {
            ( $call:expr ) => (
                panic!("Identifier refers to disabled backend feature {:?}", $feature)
            )
        }

        // See note about rust-lang#52234 above.
        #[doc(hidden)] pub use $private as $public;
    }
}

// Define a macro for each `gfx_select!` match arm. For example,
//
//     gfx_if_vulkan!(expr)
//
// expands to `expr` if the `"vulkan"` feature is enabled, or to a panic
// otherwise.
define_backend_caller! { gfx_if_vulkan, gfx_if_vulkan_hidden, "vulkan" if all(feature = "vulkan", not(target_arch = "wasm32")) }
define_backend_caller! { gfx_if_metal, gfx_if_metal_hidden, "metal" if all(feature = "metal", any(target_os = "macos", target_os = "ios")) }
define_backend_caller! { gfx_if_dx12, gfx_if_dx12_hidden, "dx12" if all(feature = "dx12", windows) }
define_backend_caller! { gfx_if_gles, gfx_if_gles_hidden, "gles" if feature = "gles" }
define_backend_caller! { gfx_if_empty, gfx_if_empty_hidden, "empty" if all(
    not(any(feature = "metal", feature = "vulkan", feature = "gles")),
    any(target_os = "macos", target_os = "ios"),
) }

/// Dispatch on an [`Id`]'s backend to a backend-generic method.
///
/// Uses of this macro have the form:
///
/// ```ignore
///
///     gfx_select!(id => value.method(args...))
///
/// ```
///
/// This expands to an expression that calls `value.method::<A>(args...)` for
/// the backend `A` selected by `id`. The expansion matches on `id.backend()`,
/// with an arm for each backend type in [`wgpu_types::Backend`] which calls the
/// specialization of `method` for the given backend. This allows resource
/// identifiers to select backends dynamically, even though many `wgpu_core`
/// methods are compiled and optimized for a specific back end.
///
/// This macro is typically used to call methods on [`wgpu_core::global::Global`],
/// many of which take a single `hal::Api` type parameter. For example, to
/// create a new buffer on the device indicated by `device_id`, one would say:
///
/// ```ignore
/// gfx_select!(device_id => global.device_create_buffer(device_id, ...))
/// ```
///
/// where the `device_create_buffer` method is defined like this:
///
/// ```ignore
/// impl Global {
///    pub fn device_create_buffer<A: HalApi>(&self, ...) -> ...
///    { ... }
/// }
/// ```
///
/// That `gfx_select!` call uses `device_id`'s backend to select the right
/// backend type `A` for a call to `Global::device_create_buffer<A>`.
///
/// However, there's nothing about this macro that is specific to `hub::Global`.
/// For example, Firefox's embedding of `wgpu_core` defines its own types with
/// methods that take `hal::Api` type parameters. Firefox uses `gfx_select!` to
/// dynamically dispatch to the right specialization based on the resource's id.
///
/// [`wgpu_types::Backend`]: wgt::Backend
/// [`wgpu_core::global::Global`]: crate::global::Global
/// [`Id`]: id::Id
#[macro_export]
macro_rules! gfx_select {
    // Simple two-component expression, like `self.0.method(..)`.
    ($id:expr => $c0:ident.$c1:tt.$method:ident $params:tt) => {
        $crate::gfx_select!($id => {$c0.$c1}, $method $params)
    };

    // Simple identifier-only expression, like `global.method(..)`.
    ($id:expr => $c0:ident.$method:ident $params:tt) => {
        $crate::gfx_select!($id => {$c0}, $method $params)
    };

    ($id:expr => {$($c:tt)*}, $method:ident $params:tt) => {
        match $id.backend() {
            wgt::Backend::Vulkan => $crate::gfx_if_vulkan!($($c)*.$method::<$crate::api::Vulkan> $params),
            wgt::Backend::Metal => $crate::gfx_if_metal!($($c)*.$method::<$crate::api::Metal> $params),
            wgt::Backend::Dx12 => $crate::gfx_if_dx12!($($c)*.$method::<$crate::api::Dx12> $params),
            wgt::Backend::Gl => $crate::gfx_if_gles!($($c)*.$method::<$crate::api::Gles> $params),
            wgt::Backend::Empty => $crate::gfx_if_empty!($($c)*.$method::<$crate::api::Empty> $params),
            other => panic!("Unexpected backend {:?}", other),
        }
    };
}

#[cfg(feature = "api_log_info")]
macro_rules! api_log {
    ($($arg:tt)+) => (log::info!($($arg)+))
}
#[cfg(not(feature = "api_log_info"))]
macro_rules! api_log {
    ($($arg:tt)+) => (log::trace!($($arg)+))
}
pub(crate) use api_log;

#[cfg(feature = "resource_log_info")]
macro_rules! resource_log {
    ($($arg:tt)+) => (log::info!($($arg)+))
}
#[cfg(not(feature = "resource_log_info"))]
macro_rules! resource_log {
    ($($arg:tt)+) => (log::trace!($($arg)+))
}
pub(crate) use resource_log;

#[inline]
pub(crate) fn get_lowest_common_denom(a: u32, b: u32) -> u32 {
    let gcd = if a >= b {
        get_greatest_common_divisor(a, b)
    } else {
        get_greatest_common_divisor(b, a)
    };
    a * b / gcd
}

#[inline]
pub(crate) fn get_greatest_common_divisor(mut a: u32, mut b: u32) -> u32 {
    assert!(a >= b);
    loop {
        let c = a % b;
        if c == 0 {
            return b;
        } else {
            a = b;
            b = c;
        }
    }
}

#[test]
fn test_lcd() {
    assert_eq!(get_lowest_common_denom(2, 2), 2);
    assert_eq!(get_lowest_common_denom(2, 3), 6);
    assert_eq!(get_lowest_common_denom(6, 4), 12);
}

#[test]
fn test_gcd() {
    assert_eq!(get_greatest_common_divisor(5, 1), 1);
    assert_eq!(get_greatest_common_divisor(4, 2), 2);
    assert_eq!(get_greatest_common_divisor(6, 4), 2);
    assert_eq!(get_greatest_common_divisor(7, 7), 7);
}