1 files changed, 127 insertions, 0 deletions
diff --git a/third_party/rust/wasmparser/src/readers/component/aliases.rs b/third_party/rust/wasmparser/src/readers/component/aliases.rs
new file mode 100644
index 0000000000..2ef6e78338
--- /dev/null
+++ b/third_party/rust/wasmparser/src/readers/component/aliases.rs
@@ -0,0 +1,127 @@
+use crate::{
+    BinaryReader, ComponentExternalKind, ExternalKind, Result, SectionIteratorLimited,
+    SectionReader, SectionWithLimitedItems,
+};
+use std::ops::Range;
+
+/// Represents the kind of an outer alias in a WebAssembly component.
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum ComponentOuterAliasKind {
+    /// The alias is to a core module.
+    CoreModule,
+    /// The alias is to a core type.
+    CoreType,
+    /// The alias is to a component type.
+    Type,
+    /// The alias is to a component.
+    Component,
+}
+
+/// Represents an alias in a WebAssembly component.
+#[derive(Debug, Clone)]
+pub enum ComponentAlias<'a> {
+    /// The alias is to an export of a component instance.
+    InstanceExport {
+        /// The alias kind.
+        kind: ComponentExternalKind,
+        /// The instance index.
+        instance_index: u32,
+        /// The export name.
+        name: &'a str,
+    },
+    /// The alias is to an export of a module instance.
+    CoreInstanceExport {
+        /// The alias kind.
+        kind: ExternalKind,
+        /// The instance index.
+        instance_index: u32,
+        /// The export name.
+        name: &'a str,
+    },
+    /// The alias is to an outer item.
+    Outer {
+        /// The alias kind.
+        kind: ComponentOuterAliasKind,
+        /// The outward count, starting at zero for the current component.
+        count: u32,
+        /// The index of the item within the outer component.
+        index: u32,
+    },
+}
+
+/// A reader for the alias section of a WebAssembly component.
+#[derive(Clone)]
+pub struct ComponentAliasSectionReader<'a> {
+    reader: BinaryReader<'a>,
+    count: u32,
+}
+
+impl<'a> ComponentAliasSectionReader<'a> {
+    /// Constructs a new `ComponentAliasSectionReader` for the given data and offset.
+    pub fn new(data: &'a [u8], offset: usize) -> Result<Self> {
+        let mut reader = BinaryReader::new_with_offset(data, offset);
+        let count = reader.read_var_u32()?;
+        Ok(Self { reader, count })
+    }
+
+    /// Gets the original position of the section reader.
+    pub fn original_position(&self) -> usize {
+        self.reader.original_position()
+    }
+
+    /// Gets the count of items in the section.
+    pub fn get_count(&self) -> u32 {
+        self.count
+    }
+
+    /// Reads content of the alias section.
+    ///
+    /// # Examples
+    /// ```
+    /// use wasmparser::ComponentAliasSectionReader;
+    /// let data: &[u8] = &[0x01, 0x01, 0x00, 0x00, 0x03, b'f', b'o', b'o'];
+    /// let mut reader = ComponentAliasSectionReader::new(data, 0).unwrap();
+    /// for _ in 0..reader.get_count() {
+    ///     let alias = reader.read().expect("alias");
+    ///     println!("Alias: {:?}", alias);
+    /// }
+    /// ```
+    pub fn read(&mut self) -> Result<ComponentAlias<'a>> {
+        self.reader.read_component_alias()
+    }
+}
+
+impl<'a> SectionReader for ComponentAliasSectionReader<'a> {
+    type Item = ComponentAlias<'a>;
+
+    fn read(&mut self) -> Result<Self::Item> {
+        Self::read(self)
+    }
+
+    fn eof(&self) -> bool {
+        self.reader.eof()
+    }
+
+    fn original_position(&self) -> usize {
+        Self::original_position(self)
+    }
+
+    fn range(&self) -> Range<usize> {
+        self.reader.range()
+    }
+}
+
+impl<'a> SectionWithLimitedItems for ComponentAliasSectionReader<'a> {
+    fn get_count(&self) -> u32 {
+        Self::get_count(self)
+    }
+}
+
+impl<'a> IntoIterator for ComponentAliasSectionReader<'a> {
+    type Item = Result<ComponentAlias<'a>>;
+    type IntoIter = SectionIteratorLimited<Self>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        SectionIteratorLimited::new(self)
+    }
+}