1 files changed, 109 insertions, 0 deletions
diff --git a/src/command_buffer/validity/descriptor_sets.rs b/src/command_buffer/validity/descriptor_sets.rs
new file mode 100644
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--- /dev/null
+++ b/src/command_buffer/validity/descriptor_sets.rs
@@ -0,0 +1,109 @@
+// Copyright (c) 2017 The vulkano developers
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT
+// license <LICENSE-MIT or https://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::fmt;
+
+use crate::descriptor_set::layout::DescriptorDescSupersetError;
+use crate::descriptor_set::DescriptorSetWithOffsets;
+use crate::pipeline::layout::PipelineLayout;
+
+/// Checks whether descriptor sets are compatible with the pipeline.
+pub fn check_descriptor_sets_validity(
+    pipeline_layout: &PipelineLayout,
+    descriptor_sets: &[DescriptorSetWithOffsets],
+) -> Result<(), CheckDescriptorSetsValidityError> {
+    // What's important is not that the pipeline layout and the descriptor sets *match*. Instead
+    // what's important is that the descriptor sets are a superset of the pipeline layout. It's not
+    // a problem if the descriptor sets provide more elements than expected.
+
+    for (set_num, set) in pipeline_layout.descriptor_set_layouts().iter().enumerate() {
+        for (binding_num, pipeline_desc) in
+            (0..set.num_bindings()).filter_map(|i| set.descriptor(i).map(|d| (i, d)))
+        {
+            let set_desc = descriptor_sets
+                .get(set_num)
+                .and_then(|so| so.as_ref().0.layout().descriptor(binding_num));
+
+            let set_desc = match set_desc {
+                Some(s) => s,
+                None => {
+                    return Err(CheckDescriptorSetsValidityError::MissingDescriptor {
+                        set_num: set_num,
+                        binding_num: binding_num,
+                    })
+                }
+            };
+
+            if let Err(err) = set_desc.ensure_superset_of(&pipeline_desc) {
+                return Err(CheckDescriptorSetsValidityError::IncompatibleDescriptor {
+                    error: err,
+                    set_num: set_num,
+                    binding_num: binding_num,
+                });
+            }
+        }
+    }
+
+    Ok(())
+}
+
+/// Error that can happen when checking descriptor sets validity.
+#[derive(Debug, Clone)]
+pub enum CheckDescriptorSetsValidityError {
+    /// A descriptor is missing in the descriptor sets that were provided.
+    MissingDescriptor {
+        /// The index of the set of the descriptor.
+        set_num: usize,
+        /// The binding number of the descriptor.
+        binding_num: usize,
+    },
+
+    /// A descriptor in the provided sets is not compatible with what is expected.
+    IncompatibleDescriptor {
+        /// The reason why the two descriptors aren't compatible.
+        error: DescriptorDescSupersetError,
+        /// The index of the set of the descriptor.
+        set_num: usize,
+        /// The binding number of the descriptor.
+        binding_num: usize,
+    },
+}
+
+impl error::Error for CheckDescriptorSetsValidityError {
+    #[inline]
+    fn source(&self) -> Option<&(dyn error::Error + 'static)> {
+        match *self {
+            CheckDescriptorSetsValidityError::IncompatibleDescriptor { ref error, .. } => {
+                Some(error)
+            }
+            _ => None,
+        }
+    }
+}
+
+impl fmt::Display for CheckDescriptorSetsValidityError {
+    #[inline]
+    fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(
+            fmt,
+            "{}",
+            match *self {
+                CheckDescriptorSetsValidityError::MissingDescriptor { .. } => {
+                    "a descriptor is missing in the descriptor sets that were provided"
+                }
+                CheckDescriptorSetsValidityError::IncompatibleDescriptor { .. } => {
+                    "a descriptor in the provided sets is not compatible with what is expected"
+                }
+            }
+        )
+    }
+}
+
+// TODO: tests