1 files changed, 46 insertions, 0 deletions
diff --git a/src/bindgen/dependencies.rs b/src/bindgen/dependencies.rs
new file mode 100644
index 0000000..6a98738
--- /dev/null
+++ b/src/bindgen/dependencies.rs
@@ -0,0 +1,46 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use std::cmp::Ordering;
+use std::collections::HashSet;
+
+use crate::bindgen::ir::{ItemContainer, Path};
+
+/// A dependency list is used for gathering what order to output the types.
+#[derive(Default)]
+pub struct Dependencies {
+    pub order: Vec<ItemContainer>,
+    pub items: HashSet<Path>,
+}
+
+impl Dependencies {
+    pub fn new() -> Dependencies {
+        Dependencies {
+            order: Vec::new(),
+            items: HashSet::new(),
+        }
+    }
+
+    pub fn sort(&mut self) {
+        // Sort untagged enums and opaque structs into their own layers because they don't
+        // depend on each other or anything else.
+        let ordering = |a: &ItemContainer, b: &ItemContainer| match (a, b) {
+            (ItemContainer::Enum(x), ItemContainer::Enum(y))
+                if x.tag.is_none() && y.tag.is_none() =>
+            {
+                x.path.cmp(&y.path)
+            }
+            (ItemContainer::Enum(x), _) if x.tag.is_none() => Ordering::Less,
+            (_, ItemContainer::Enum(x)) if x.tag.is_none() => Ordering::Greater,
+
+            (ItemContainer::OpaqueItem(x), ItemContainer::OpaqueItem(y)) => x.path.cmp(&y.path),
+            (&ItemContainer::OpaqueItem(_), _) => Ordering::Less,
+            (_, &ItemContainer::OpaqueItem(_)) => Ordering::Greater,
+
+            _ => Ordering::Equal,
+        };
+
+        self.order.sort_by(ordering);
+    }
+}