[pack #167] Use custom uluru version to avoid a lot of allocations…

…even though that doesn't really translate into much performance, despite technically saving millions of allocations. Maybe allocators are already pretty good at this.
GitoxideLabs · Aug 22, 2021 · 8d49976 · 8d49976
1 parent 65e29de
commit 8d49976
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Showing 3 changed files with 17 additions and 7 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/git-pack/Cargo.toml b/git-pack/Cargo.toml
@@ -48,7 +48,7 @@ itoa = "0.4.6"
 bytesize = "1.0.1"
 parking_lot = { version = "0.11.0", default-features = false }
 thiserror = "1.0.26"
-uluru = { version = "2.2.0", optional = true }
+uluru = { version = "2.2.0", optional = true, git = "https://github.com/Byron/uluru", features = ["std"], branch = "master"}
 memory-lru = { version = "0.1.0", optional = true }
 dashmap = "4.0.2"
 

diff --git a/git-pack/src/cache.rs b/git-pack/src/cache.rs
@@ -106,17 +106,28 @@ pub mod lru {
         /// The cache must be small as the search is 'naive' and the underlying data structure is a linked list.
         /// Values of 64 seem to improve performance.
         #[derive(Default)]
-        pub struct StaticLinkedList<const SIZE: usize>(uluru::LRUCache<Entry, SIZE>);
+        pub struct StaticLinkedList<const SIZE: usize>(uluru::LRUCache<Entry, SIZE>, Vec<Vec<u8>>);
 
         impl<const SIZE: usize> DecodeEntry for StaticLinkedList<SIZE> {
             fn put(&mut self, pack_id: u32, offset: u64, data: &[u8], kind: git_object::Kind, compressed_size: usize) {
-                self.0.insert(Entry {
+                if let Some(previous) = self.0.insert(Entry {
                     offset,
                     pack_id,
-                    data: Vec::from(data),
+                    data: self
+                        .1
+                        .pop()
+                        .map(|mut v| {
+                            v.clear();
+                            v.resize(data.len(), 0);
+                            v.copy_from_slice(data);
+                            v
+                        })
+                        .unwrap_or_else(|| Vec::from(data)),
                     kind,
                     compressed_size,
-                })
+                }) {
+                    self.1.push(previous.data)
+                }
             }
 
             fn get(&mut self, pack_id: u32, offset: u64, out: &mut Vec<u8>) -> Option<(git_object::Kind, usize)> {