move delta Node into resolve.rs

The `Node` type is only used in `resolve.rs`, and using it safely
depends on using the child items correctly, so let's define it there.

Author: martinvonz

gix-pack/src/cache/delta/traverse/resolve.rs

@@ -7,16 +7,55 @@ use gix_features::{progress::Progress, threading, zlib};
 
 use crate::{
     cache::delta::{
-        traverse::{
-            util::{ItemSliceSend, Node},
-            Context, Error,
-        },
+        traverse::{util::ItemSliceSend, Context, Error},
         Item,
     },
     data,
     data::EntryRange,
 };
 
+/// An item returned by `iter_root_chunks`, allowing access to the `data` stored alongside nodes in a [`Tree`].
+pub(crate) struct Node<'a, T: Send> {
+    pub item: &'a mut Item<T>,
+    pub child_items: ItemSliceSend<'a, Item<T>>,
+}
+
+impl<'a, T: Send> Node<'a, T> {
+    /// Returns the offset into the pack at which the `Node`s data is located.
+    pub fn offset(&self) -> u64 {
+        self.item.offset
+    }
+
+    /// Returns the slice into the data pack at which the pack entry is located.
+    pub fn entry_slice(&self) -> crate::data::EntryRange {
+        self.item.offset..self.item.next_offset
+    }
+
+    /// Returns the node data associated with this node.
+    pub fn data(&mut self) -> &mut T {
+        &mut self.item.data
+    }
+
+    /// Returns true if this node has children, e.g. is not a leaf in the tree.
+    pub fn has_children(&self) -> bool {
+        !self.item.children.is_empty()
+    }
+
+    /// Transform this `Node` into an iterator over its children.
+    ///
+    /// Children are `Node`s referring to pack entries whose base object is this pack entry.
+    pub fn into_child_iter(self) -> impl Iterator<Item = Node<'a, T>> + 'a {
+        let children = self.child_items;
+        // SAFETY: The index is a valid index into the children array.
+        // SAFETY: The resulting mutable pointer cannot be yielded by any other node.
+        #[allow(unsafe_code)]
+        self.item.children.iter().map(move |&index| Node {
+            item: unsafe { children.get_mut(index as usize) },
+            child_items: children.clone(),
+        })
+    }
+}
+
 pub(crate) struct State<'items, F, MBFN, T: Send> {
     pub delta_bytes: Vec<u8>,
     pub fully_resolved_delta_bytes: Vec<u8>,

gix-pack/src/cache/delta/traverse/util.rs

@@ -1,7 +1,5 @@
 use std::marker::PhantomData;
 
-use crate::cache::delta::Item;
-
 pub(crate) struct ItemSliceSend<'a, T>
 where
     T: Send,
@@ -46,45 +44,3 @@ where
 // SAFETY: T is `Send`, and we only ever access one T at a time. And, ptrs need that assurance, I wonder if it's always right.
 #[allow(unsafe_code)]
 unsafe impl<T> Send for ItemSliceSend<'_, T> where T: Send {}
-
-/// An item returned by `iter_root_chunks`, allowing access to the `data` stored alongside nodes in a [`Tree`].
-pub(crate) struct Node<'a, T: Send> {
-    pub item: &'a mut Item<T>,
-    pub child_items: ItemSliceSend<'a, Item<T>>,
-}
-
-impl<'a, T: Send> Node<'a, T> {
-    /// Returns the offset into the pack at which the `Node`s data is located.
-    pub fn offset(&self) -> u64 {
-        self.item.offset
-    }
-
-    /// Returns the slice into the data pack at which the pack entry is located.
-    pub fn entry_slice(&self) -> crate::data::EntryRange {
-        self.item.offset..self.item.next_offset
-    }
-
-    /// Returns the node data associated with this node.
-    pub fn data(&mut self) -> &mut T {
-        &mut self.item.data
-    }
-
-    /// Returns true if this node has children, e.g. is not a leaf in the tree.
-    pub fn has_children(&self) -> bool {
-        !self.item.children.is_empty()
-    }
-
-    /// Transform this `Node` into an iterator over its children.
-    ///
-    /// Children are `Node`s referring to pack entries whose base object is this pack entry.
-    pub fn into_child_iter(self) -> impl Iterator<Item = Node<'a, T>> + 'a {
-        let children = self.child_items;
-        // SAFETY: The index is a valid index into the children array.
-        // SAFETY: The resulting mutable pointer cannot be yielded by any other node.
-        #[allow(unsafe_code)]
-        self.item.children.iter().map(move |&index| Node {
-            item: unsafe { children.get_mut(index as usize) },
-            child_items: children.clone(),
-        })
-    }
-}