upstream/mercurial-mirror Files · rust/hg-cpython/src/conversion.rs

dirstate-tree: Avoid BTreeMap double-lookup when inserting a dirstate entry...

dirstate-tree: Avoid BTreeMap double-lookup when inserting a dirstate entry The child nodes of a given node in the tree-shaped dirstate are kept in a `BTreeMap` where keys are file names as strings. Finding or inserting a value in the map takes `O(log(n))` string comparisons, which adds up when constructing the tree. The `entry` API allows finding a "spot" in the map that may or may not be occupied and then access that value or insert a new one without doing map lookup again. However the current API is limited in that calling `entry` requires an owned key (and so a memory allocation), even if it ends up not being used in the case where the map already has a value with an equal key. This is still a win, with 4% better end-to-end time for `hg status` measured here with hyperfine: ``` Benchmark : ../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1 Time (mean ± σ): 1.337 s ± 0.018 s [User: 892.9 ms, System: 437.5 ms] Range (min … max): 1.316 s … 1.373 s 10 runs Benchmark : ./hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1 Time (mean ± σ): 1.291 s ± 0.008 s [User: 853.4 ms, System: 431.1 ms] Range (min … max): 1.283 s … 1.309 s 10 runs Summary './hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1' ran 1.04 ± 0.02 times faster than '../hg2/hg status -R $REPO --config=experimental.dirstate-tree.in-memory=1' ``` * ./hg is this revision * ../hg2/hg is its parent * $REPO is an old snapshot of mozilla-central Differential Revision: https://phab.mercurial-scm.org/D10550

Georges Racinet - - Load All Authors

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             conversion.rs
        
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      // conversion.rs

      //

      // Copyright 2019 Georges Racinet <georges.racinet@octobus.net>

      //

      // This software may be used and distributed according to the terms of the

      // GNU General Public License version 2 or any later version.

      //! Bindings for the hg::ancestors module provided by the

      //! `hg-core` crate. From Python, this will be seen as `rustext.ancestor`

      use cpython::{ObjectProtocol, PyObject, PyResult, Python};

      use hg::Revision;

      use std::iter::FromIterator;

      /// Utility function to convert a Python iterable into various collections

      ///

      /// We need this in particular to feed to various methods of inner objects

      /// with `impl IntoIterator<Item=Revision>` arguments, because

      /// a `PyErr` can arise at each step of iteration, whereas these methods

      /// expect iterables over `Revision`, not over some `Result<Revision, PyErr>`

      pub fn rev_pyiter_collect<C>(py: Python, revs: &PyObject) -> PyResult<C>

      where

          C: FromIterator<Revision>,

      {

          revs.iter(py)?

              .map(|r| r.and_then(|o| o.extract::<Revision>(py)))

              .collect()

      }

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				// conversion.rs
				//
				// Copyright 2019 Georges Racinet <georges.racinet@octobus.net>
				//
				// This software may be used and distributed according to the terms of the
				// GNU General Public License version 2 or any later version.

				//! Bindings for the hg::ancestors module provided by the
				//! `hg-core` crate. From Python, this will be seen as `rustext.ancestor`

				use cpython::{ObjectProtocol, PyObject, PyResult, Python};
				use hg::Revision;
				use std::iter::FromIterator;

				/// Utility function to convert a Python iterable into various collections
				///
				/// We need this in particular to feed to various methods of inner objects
				/// with `impl IntoIterator<Item=Revision>` arguments, because
				/// a `PyErr` can arise at each step of iteration, whereas these methods
				/// expect iterables over `Revision`, not over some `Result<Revision, PyErr>`
				pub fn rev_pyiter_collect<C>(py: Python, revs: &PyObject) -> PyResult<C>
				where
				C: FromIterator<Revision>,
				{
				revs.iter(py)?
				.map(\|r\| r.and_then(\|o\| o.extract::<Revision>(py)))
				.collect()
				}