1 files changed, 45 insertions, 0 deletions
diff --git a/vendor/gix-index/src/extension/tree/write.rs b/vendor/gix-index/src/extension/tree/write.rs
new file mode 100644
index 000000000..2b1e3d949
--- /dev/null
+++ b/vendor/gix-index/src/extension/tree/write.rs
@@ -0,0 +1,45 @@
+use std::convert::TryFrom;
+
+use crate::extension::{tree, Tree};
+
+impl Tree {
+    /// Serialize this instance to `out`.
+    pub fn write_to(&self, mut out: impl std::io::Write) -> Result<(), std::io::Error> {
+        fn tree_entry(out: &mut impl std::io::Write, tree: &Tree) -> Result<(), std::io::Error> {
+            let mut buf = itoa::Buffer::new();
+            let num_entries = match tree.num_entries {
+                Some(num_entries) => buf.format(num_entries),
+                None => buf.format(-1),
+            };
+
+            out.write_all(tree.name.as_slice())?;
+            out.write_all(b"\0")?;
+            out.write_all(num_entries.as_bytes())?;
+            out.write_all(b" ")?;
+            let num_children = buf.format(tree.children.len());
+            out.write_all(num_children.as_bytes())?;
+            out.write_all(b"\n")?;
+            if tree.num_entries.is_some() {
+                out.write_all(tree.id.as_bytes())?;
+            }
+
+            for child in &tree.children {
+                tree_entry(out, child)?;
+            }
+
+            Ok(())
+        }
+
+        let signature = tree::SIGNATURE;
+
+        let estimated_size = self.num_entries.unwrap_or(0) * (300 + 3 + 1 + 3 + 1 + 20);
+        let mut entries: Vec<u8> = Vec::with_capacity(estimated_size as usize);
+        tree_entry(&mut entries, self)?;
+
+        out.write_all(&signature)?;
+        out.write_all(&(u32::try_from(entries.len()).expect("less than 4GB tree extension")).to_be_bytes())?;
+        out.write_all(&entries)?;
+
+        Ok(())
+    }
+}