Mercurial > hg
diff rust/hg-core/src/dirstate_tree/on_disk.rs @ 47680:a8b0f29dc0d7
dirstate-v2: Reuse existing paths when appending to a data file
When writing a dirstate in v2 format by appending to an existing data file,
filenames / paths that are borrowed from the previous on-disk representation
can be reused.
Differential Revision: https://phab.mercurial-scm.org/D11096
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Thu, 15 Jul 2021 10:31:43 +0200 |
parents | 731286dc5321 |
children | d94118365ec5 |
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--- a/rust/hg-core/src/dirstate_tree/on_disk.rs Thu Jul 15 08:53:03 2021 +0200 +++ b/rust/hg-core/src/dirstate_tree/on_disk.rs Thu Jul 15 10:31:43 2021 +0200 @@ -593,7 +593,9 @@ // Reuse already-written nodes if possible if self.append { if let dirstate_map::ChildNodesRef::OnDisk(nodes_slice) = nodes { - let start = self.offset_of(nodes_slice); + let start = self.on_disk_offset_of(nodes_slice).expect( + "dirstate-v2 OnDisk nodes not found within on_disk", + ); let len = child_nodes_len_from_usize(nodes_slice.len()); return Ok(ChildNodes { start, len }); } @@ -679,11 +681,9 @@ Ok(ChildNodes { start, len }) } - /// Takes a slice of items within `on_disk` and returns its offset for the - /// start of `on_disk`. - /// - /// Panics if the given slice is not within `on_disk`. - fn offset_of<T>(&self, slice: &[T]) -> Offset + /// If the given slice of items is within `on_disk`, returns its offset + /// from the start of `on_disk`. + fn on_disk_offset_of<T>(&self, slice: &[T]) -> Option<Offset> where T: BytesCast, { @@ -694,10 +694,14 @@ } let slice_addresses = address_range(slice.as_bytes()); let on_disk_addresses = address_range(self.dirstate_map.on_disk); - assert!(on_disk_addresses.contains(slice_addresses.start())); - assert!(on_disk_addresses.contains(slice_addresses.end())); - let offset = slice_addresses.start() - on_disk_addresses.start(); - offset_from_usize(offset) + if on_disk_addresses.contains(slice_addresses.start()) + && on_disk_addresses.contains(slice_addresses.end()) + { + let offset = slice_addresses.start() - on_disk_addresses.start(); + Some(offset_from_usize(offset)) + } else { + None + } } fn current_offset(&mut self) -> Offset { @@ -709,8 +713,14 @@ } fn write_path(&mut self, slice: &[u8]) -> PathSlice { + let len = path_len_from_usize(slice.len()); + // Reuse an already-written path if possible + if self.append { + if let Some(start) = self.on_disk_offset_of(slice) { + return PathSlice { start, len }; + } + } let start = self.current_offset(); - let len = path_len_from_usize(slice.len()); self.out.extend(slice.as_bytes()); PathSlice { start, len } }