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
// Copyright (c) 2016 The vulkano developers
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>,
// at your option. All files in the project carrying such
// notice may not be copied, modified, or distributed except
// according to those terms.

use std::error;
use std::ffi::CStr;
use std::fmt;
use std::ptr;
use std::vec::IntoIter;

use Error;
use OomError;
use check_errors;
use instance::loader;
use instance::loader::LoadingError;
use version::Version;
use vk;

/// Queries the list of layers that are available when creating an instance.
///
/// On success, this function returns an iterator that produces
/// [`LayerProperties`](struct.LayerProperties.html) objects. In order to enable a layer, you need
/// to pass its name (returned by `LayerProperties::name()`) when creating the
/// [`Instance`](struct.Instance.html).
///
/// This function returns an error if it failed to load the Vulkan library.
///
/// > **Note**: It is possible that one of the layers enumerated here is no longer available when
/// > you create the `Instance`. This will lead to an error when calling `Instance::new`. The
/// > author isn't aware of any situation where this would happen, but it is theoretically possible
/// > according to the specifications.
///
/// # Example
///
/// ```no_run
/// use vulkano::instance;
///
/// for layer in instance::layers_list().unwrap() {
///     println!("Available layer: {}", layer.name());
/// }
/// ```
pub fn layers_list() -> Result<LayersIterator, LayersListError> {
    layers_list_from_loader(loader::auto_loader()?)
}

/// Same as `layers_list()`, but allows specifying a loader.
pub fn layers_list_from_loader<L>(ptrs: &loader::FunctionPointers<L>)
                                  -> Result<LayersIterator, LayersListError>
    where L: loader::Loader
{
    unsafe {
        let entry_points = ptrs.entry_points();

        let mut num = 0;
        check_errors({
                         entry_points.EnumerateInstanceLayerProperties(&mut num, ptr::null_mut())
                     })?;

        let mut layers: Vec<vk::LayerProperties> = Vec::with_capacity(num as usize);
        check_errors({
                         entry_points
                             .EnumerateInstanceLayerProperties(&mut num, layers.as_mut_ptr())
                     })?;
        layers.set_len(num as usize);

        Ok(LayersIterator { iter: layers.into_iter() })
    }
}

/// Properties of a layer.
pub struct LayerProperties {
    props: vk::LayerProperties,
}

impl LayerProperties {
    /// Returns the name of the layer.
    ///
    /// If you want to enable this layer on an instance, you need to pass this value to
    /// `Instance::new`.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use vulkano::instance;
    ///
    /// for layer in instance::layers_list().unwrap() {
    ///     println!("Layer name: {}", layer.name());
    /// }
    /// ```
    #[inline]
    pub fn name(&self) -> &str {
        unsafe {
            CStr::from_ptr(self.props.layerName.as_ptr())
                .to_str()
                .unwrap()
        }
    }

    /// Returns a description of the layer.
    ///
    /// This description is chosen by the layer itself.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use vulkano::instance;
    ///
    /// for layer in instance::layers_list().unwrap() {
    ///     println!("Layer description: {}", layer.description());
    /// }
    /// ```
    #[inline]
    pub fn description(&self) -> &str {
        unsafe {
            CStr::from_ptr(self.props.description.as_ptr())
                .to_str()
                .unwrap()
        }
    }

    /// Returns the version of Vulkan supported by this layer.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use vulkano::instance;
    /// use vulkano::instance::Version;
    ///
    /// for layer in instance::layers_list().unwrap() {
    ///     if layer.vulkan_version() >= (Version { major: 2, minor: 0, patch: 0 }) {
    ///         println!("Layer {} requires Vulkan 2.0", layer.name());
    ///     }
    /// }
    /// ```
    #[inline]
    pub fn vulkan_version(&self) -> Version {
        Version::from_vulkan_version(self.props.specVersion)
    }

    /// Returns an implementation-specific version number for this layer.
    ///
    /// The number is chosen by the layer itself. It can be used for bug reports for example.
    ///
    /// # Example
    ///
    /// ```no_run
    /// use vulkano::instance;
    ///
    /// for layer in instance::layers_list().unwrap() {
    ///     println!("Layer {} - Version: {}", layer.name(), layer.implementation_version());
    /// }
    /// ```
    #[inline]
    pub fn implementation_version(&self) -> u32 {
        self.props.implementationVersion
    }
}

/// Error that can happen when loading the list of layers.
#[derive(Clone, Debug)]
pub enum LayersListError {
    /// Failed to load the Vulkan shared library.
    LoadingError(LoadingError),
    /// Not enough memory.
    OomError(OomError),
}

impl error::Error for LayersListError {
    #[inline]
    fn description(&self) -> &str {
        match *self {
            LayersListError::LoadingError(_) => "failed to load the Vulkan shared library",
            LayersListError::OomError(_) => "not enough memory available",
        }
    }

    #[inline]
    fn cause(&self) -> Option<&dyn error::Error> {
        match *self {
            LayersListError::LoadingError(ref err) => Some(err),
            LayersListError::OomError(ref err) => Some(err),
        }
    }
}

impl fmt::Display for LayersListError {
    #[inline]
    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
        write!(fmt, "{}", error::Error::description(self))
    }
}

impl From<OomError> for LayersListError {
    #[inline]
    fn from(err: OomError) -> LayersListError {
        LayersListError::OomError(err)
    }
}

impl From<LoadingError> for LayersListError {
    #[inline]
    fn from(err: LoadingError) -> LayersListError {
        LayersListError::LoadingError(err)
    }
}

impl From<Error> for LayersListError {
    #[inline]
    fn from(err: Error) -> LayersListError {
        match err {
            err @ Error::OutOfHostMemory => LayersListError::OomError(OomError::from(err)),
            err @ Error::OutOfDeviceMemory => LayersListError::OomError(OomError::from(err)),
            _ => panic!("unexpected error: {:?}", err),
        }
    }
}

/// Iterator that produces the list of layers that are available.
// TODO: #[derive(Debug, Clone)]
pub struct LayersIterator {
    iter: IntoIter<vk::LayerProperties>,
}

impl Iterator for LayersIterator {
    type Item = LayerProperties;

    #[inline]
    fn next(&mut self) -> Option<LayerProperties> {
        self.iter.next().map(|p| LayerProperties { props: p })
    }

    #[inline]
    fn size_hint(&self) -> (usize, Option<usize>) {
        self.iter.size_hint()
    }
}

impl ExactSizeIterator for LayersIterator {
}

#[cfg(test)]
mod tests {
    use instance;

    #[test]
    fn layers_list() {
        let mut list = match instance::layers_list() {
            Ok(l) => l,
            Err(_) => return,
        };

        while let Some(_) = list.next() {}
    }
}