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| 1 | +//! Everything related to `EGLDevice`. |
| 2 | +
|
| 3 | +use std::collections::HashSet; |
| 4 | +use std::ffi::{c_void, CStr}; |
| 5 | +use std::ptr; |
| 6 | + |
| 7 | +use glutin_egl_sys::egl; |
| 8 | +use glutin_egl_sys::egl::types::EGLDeviceEXT; |
| 9 | + |
| 10 | +use crate::error::{ErrorKind, Result}; |
| 11 | + |
| 12 | +use super::display::{extensions_from_ptr, get_extensions, NO_DISPLAY_EXTENSIONS}; |
| 13 | +use super::{Egl, EGL}; |
| 14 | + |
| 15 | +/// Wrapper for `EGLDevice`. |
| 16 | +#[derive(Debug, Clone, PartialEq, Eq)] |
| 17 | +pub struct Device { |
| 18 | + inner: EGLDeviceEXT, |
| 19 | + extensions: HashSet<&'static str>, |
| 20 | + name: Option<String>, |
| 21 | + vendor: Option<String>, |
| 22 | +} |
| 23 | + |
| 24 | +impl Device { |
| 25 | + /// Query the available devices. |
| 26 | + /// |
| 27 | + /// This function returns [`Err`] if the `EGL_EXT_device_query` and |
| 28 | + /// `EGL_EXT_device_enumeration` or `EGL_EXT_device_base` extensions are |
| 29 | + /// not available. |
| 30 | + pub fn query_devices() -> Result<impl Iterator<Item = Device>> { |
| 31 | + let egl = match EGL.as_ref() { |
| 32 | + Some(egl) => egl, |
| 33 | + None => return Err(ErrorKind::NotFound.into()), |
| 34 | + }; |
| 35 | + |
| 36 | + let no_display_extensions = |
| 37 | + NO_DISPLAY_EXTENSIONS.get_or_init(|| get_extensions(egl, egl::NO_DISPLAY)); |
| 38 | + |
| 39 | + // Querying devices requires EGL_EXT_device_enumeration and |
| 40 | + // EGL_EXT_device_query. |
| 41 | + // |
| 42 | + // Or we can check for the EGL_EXT_device_base extension since it contains both |
| 43 | + // extensions. |
| 44 | + if (!no_display_extensions.contains("EGL_EXT_device_enumeration") |
| 45 | + && !no_display_extensions.contains("EGL_EXT_device_query")) |
| 46 | + || !no_display_extensions.contains("EGL_EXT_device_base") |
| 47 | + { |
| 48 | + return Err(ErrorKind::NotSupported("EGL does not support EGL_EXT_device_base").into()); |
| 49 | + } |
| 50 | + |
| 51 | + let mut device_count = 0; |
| 52 | + |
| 53 | + if unsafe { |
| 54 | + // The specification states: |
| 55 | + // > An EGL_BAD_PARAMETER error is generated if <max_devices> is |
| 56 | + // > less than or equal to zero unless <devices> is NULL, or if |
| 57 | + // > <num_devices> is NULL. |
| 58 | + // |
| 59 | + // The error will never be generated since num_devices is a pointer |
| 60 | + // to the count being queried. Therefore there is no need to check |
| 61 | + // the error. |
| 62 | + egl.QueryDevicesEXT(0, ptr::null_mut(), &mut device_count) == egl::FALSE |
| 63 | + } { |
| 64 | + super::check_error()?; |
| 65 | + // On failure, EGL_FALSE is returned. |
| 66 | + return Err(ErrorKind::NotSupported("Querying device count failed").into()); |
| 67 | + } |
| 68 | + |
| 69 | + let mut devices = Vec::with_capacity(device_count as usize); |
| 70 | + |
| 71 | + unsafe { |
| 72 | + let mut count = device_count; |
| 73 | + if egl.QueryDevicesEXT(device_count, devices.as_mut_ptr(), &mut count) == egl::FALSE { |
| 74 | + super::check_error()?; |
| 75 | + // On failure, EGL_FALSE is returned. |
| 76 | + return Err(ErrorKind::NotSupported("Querying devices failed").into()); |
| 77 | + } |
| 78 | + |
| 79 | + // SAFETY: EGL has initialized the vector for the number of devices. |
| 80 | + devices.set_len(device_count as usize); |
| 81 | + } |
| 82 | + |
| 83 | + Ok(devices.into_iter().flat_map(|ptr| Device::from_ptr(egl, ptr))) |
| 84 | + } |
| 85 | + |
| 86 | + /// Get the device extensions supported by this device. |
| 87 | + /// |
| 88 | + /// These extensions are distinct from the display extensions and should not |
| 89 | + /// be used interchangeably. |
| 90 | + pub fn extensions(&self) -> &HashSet<&str> { |
| 91 | + &self.extensions |
| 92 | + } |
| 93 | + |
| 94 | + /// Get the name of the device. |
| 95 | + /// |
| 96 | + /// This function will return [`None`] if the `EGL_EXT_device_query_name` |
| 97 | + /// device extension is not available. |
| 98 | + pub fn name(&self) -> Option<&str> { |
| 99 | + self.name.as_deref() |
| 100 | + } |
| 101 | + |
| 102 | + /// Get the vendor of the device. |
| 103 | + /// |
| 104 | + /// This function will return [`None`] if the `EGL_EXT_device_query_name` |
| 105 | + /// device extension is not available. |
| 106 | + pub fn vendor(&self) -> Option<&str> { |
| 107 | + self.vendor.as_deref() |
| 108 | + } |
| 109 | + |
| 110 | + /// Get a raw handle to the `EGLDevice`. |
| 111 | + pub fn raw_device(&self) -> *const c_void { |
| 112 | + self.inner |
| 113 | + } |
| 114 | +} |
| 115 | + |
| 116 | +// SAFETY: An EGLDevice is immutable and valid for the lifetime of the EGL |
| 117 | +// library. |
| 118 | +unsafe impl Send for Device {} |
| 119 | +unsafe impl Sync for Device {} |
| 120 | + |
| 121 | +impl Device { |
| 122 | + unsafe fn query_string(egl_device: *const c_void, name: egl::types::EGLenum) -> Option<String> { |
| 123 | + let egl = super::EGL.as_ref().unwrap(); |
| 124 | + |
| 125 | + // SAFETY: The caller has ensured the name is valid. |
| 126 | + let ptr = unsafe { egl.QueryDeviceStringEXT(egl_device, name as _) }; |
| 127 | + |
| 128 | + if ptr.is_null() { |
| 129 | + return None; |
| 130 | + } |
| 131 | + |
| 132 | + unsafe { CStr::from_ptr(ptr) }.to_str().ok().map(String::from) |
| 133 | + } |
| 134 | + |
| 135 | + pub(crate) fn from_ptr(egl: &Egl, ptr: *const c_void) -> Result<Self> { |
| 136 | + // SAFETY: The EGL specification guarantees the returned string is |
| 137 | + // static and null terminated: |
| 138 | + // |
| 139 | + // > eglQueryDeviceStringEXT returns a pointer to a static, |
| 140 | + // > zero-terminated string describing some aspect of the specified |
| 141 | + // > EGLDeviceEXT. <name> must be EGL_EXTENSIONS. |
| 142 | + let extensions = |
| 143 | + unsafe { extensions_from_ptr(egl.QueryDeviceStringEXT(ptr, egl::EXTENSIONS as _)) }; |
| 144 | + |
| 145 | + let (name, vendor) = if extensions.contains("EGL_EXT_device_query_name") { |
| 146 | + // SAFETY: RENDERER_EXT and VENDOR are valid strings for device string queries |
| 147 | + // if EGL_EXT_device_query_name. |
| 148 | + unsafe { |
| 149 | + (Self::query_string(ptr, egl::RENDERER_EXT), Self::query_string(ptr, egl::VENDOR)) |
| 150 | + } |
| 151 | + } else { |
| 152 | + (None, None) |
| 153 | + }; |
| 154 | + |
| 155 | + Ok(Self { inner: ptr, extensions, name, vendor }) |
| 156 | + } |
| 157 | +} |
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