rust-dirstate-status: add `walk_explicit` implementation, use `Matcher` trait

This is the first time we actually use the `Matcher` trait, still for a small
subset of all matchers defined in Python.

While I haven't yet actually measured the performance of this, I have tried
to avoid any unnecessary allocations. This forces the use of heavy lifetimes
annotations which I am not sure we can simplify, although I would be happy
to be proven wrong.

Differential Revision: https://phab.mercurial-scm.org/D7529

rust/hg-core/src/dirstate/status.rs

@@ -1,228 +1,306 b''
 // status.rs
 //
 // Copyright 2019 Raphaël Gomès <[e-mail]>
 //
 // This software may be used and distributed according to the terms of the
 // GNU General Public License version 2 or any later version.
 
 //! Rust implementation of dirstate.status (dirstate.py).
 //! It is currently missing a lot of functionality compared to the Python one
 //! and will only be triggered in narrow cases.
 
 use crate::{
     dirstate::SIZE_FROM_OTHER_PARENT,
+    matchers::Matcher,
     utils::{
         files::HgMetadata,
         hg_path::{hg_path_to_path_buf, HgPath},
     },
     CopyMap, DirstateEntry, DirstateMap, EntryState,
 };
 use rayon::prelude::*;
+use std::collections::HashSet;
 use std::path::Path;
 
 /// Marker enum used to dispatch new status entries into the right collections.
 /// Is similar to `crate::EntryState`, but represents the transient state of
 /// entries during the lifetime of a command.
 enum Dispatch {
     Unsure,
     Modified,
     Added,
     Removed,
     Deleted,
     Clean,
     Unknown,
 }
 
+type IoResult<T> = std::io::Result<T>;
+
 /// Dates and times that are outside the 31-bit signed range are compared
 /// modulo 2^31. This should prevent hg from behaving badly with very large
 /// files or corrupt dates while still having a high probability of detecting
 /// changes. (issue2608)
 /// TODO I haven't found a way of having `b` be `Into<i32>`, since `From<u64>`
 /// is not defined for `i32`, and there is no `As` trait. This forces the
 /// caller to cast `b` as `i32`.
 fn mod_compare(a: i32, b: i32) -> bool {
     a & i32::max_value() != b & i32::max_value()
 }
 
 /// The file corresponding to the dirstate entry was found on the filesystem.
 fn dispatch_found(
     filename: impl AsRef<HgPath>,
     entry: DirstateEntry,
     metadata: HgMetadata,
     copy_map: &CopyMap,
     check_exec: bool,
     list_clean: bool,
     last_normal_time: i64,
 ) -> Dispatch {
     let DirstateEntry {
         state,
         mode,
         mtime,
         size,
     } = entry;
 
     let HgMetadata {
         st_mode,
         st_size,
         st_mtime,
         ..
     } = metadata;
 
     match state {
         EntryState::Normal => {
             let size_changed = mod_compare(size, st_size as i32);
             let mode_changed =
                 (mode ^ st_mode as i32) & 0o100 != 0o000 && check_exec;
             let metadata_changed = size >= 0 && (size_changed || mode_changed);
             let other_parent = size == SIZE_FROM_OTHER_PARENT;
             if metadata_changed
                 || other_parent
                 || copy_map.contains_key(filename.as_ref())
             {
                 Dispatch::Modified
             } else if mod_compare(mtime, st_mtime as i32) {
                 Dispatch::Unsure
             } else if st_mtime == last_normal_time {
                 // the file may have just been marked as normal and
                 // it may have changed in the same second without
                 // changing its size. This can happen if we quickly
                 // do multiple commits. Force lookup, so we don't
                 // miss such a racy file change.
                 Dispatch::Unsure
             } else if list_clean {
                 Dispatch::Clean
             } else {
                 Dispatch::Unknown
             }
         }
         EntryState::Merged => Dispatch::Modified,
         EntryState::Added => Dispatch::Added,
         EntryState::Removed => Dispatch::Removed,
         EntryState::Unknown => Dispatch::Unknown,
     }
 }
 
 /// The file corresponding to this Dirstate entry is missing.
 fn dispatch_missing(state: EntryState) -> Dispatch {
     match state {
         // File was removed from the filesystem during commands
         EntryState::Normal | EntryState::Merged | EntryState::Added => {
             Dispatch::Deleted
         }
         // File was removed, everything is normal
         EntryState::Removed => Dispatch::Removed,
         // File is unknown to Mercurial, everything is normal
         EntryState::Unknown => Dispatch::Unknown,
     }
 }
 
+/// Get stat data about the files explicitly specified by match.
+/// TODO subrepos
+fn walk_explicit<'a>(
+    files: &'a HashSet<&HgPath>,
+    dmap: &'a DirstateMap,
+    root_dir: impl AsRef<Path> + Sync + Send,
+    check_exec: bool,
+    list_clean: bool,
+    last_normal_time: i64,
+) -> impl ParallelIterator<Item = IoResult<(&'a HgPath, Dispatch)>> {
+    files.par_iter().filter_map(move |filename| {
+        // TODO normalization
+        let normalized = filename.as_ref();
+
+        let buf = match hg_path_to_path_buf(normalized) {
+            Ok(x) => x,
+            Err(e) => return Some(Err(e.into())),
+        };
+        let target = root_dir.as_ref().join(buf);
+        let st = target.symlink_metadata();
+        match st {
+            Ok(meta) => {
+                let file_type = meta.file_type();
+                if file_type.is_file() || file_type.is_symlink() {
+                    if let Some(entry) = dmap.get(normalized) {
+                        return Some(Ok((
+                            normalized,
+                            dispatch_found(
+                                &normalized,
+                                *entry,
+                                HgMetadata::from_metadata(meta),
+                                &dmap.copy_map,
+                                check_exec,
+                                list_clean,
+                                last_normal_time,
+                            ),
+                        )));
+                    }
+                } else {
+                    if dmap.contains_key(normalized) {
+                        return Some(Ok((normalized, Dispatch::Removed)));
+                    }
+                }
+            }
+            Err(_) => {
+                if let Some(entry) = dmap.get(normalized) {
+                    return Some(Ok((
+                        normalized,
+                        dispatch_missing(entry.state),
+                    )));
+                }
+            }
+        };
+        None
+    })
+}
+
 /// Stat all entries in the `DirstateMap` and mark them for dispatch into
 /// the relevant collections.
 fn stat_dmap_entries(
     dmap: &DirstateMap,
     root_dir: impl AsRef<Path> + Sync + Send,
     check_exec: bool,
     list_clean: bool,
     last_normal_time: i64,
-) -> impl ParallelIterator<Item = std::io::Result<(&HgPath, Dispatch)>> {
+) -> impl ParallelIterator<Item = IoResult<(&HgPath, Dispatch)>> {
     dmap.par_iter().map(move |(filename, entry)| {
         let filename: &HgPath = filename;
         let filename_as_path = hg_path_to_path_buf(filename)?;
         let meta = root_dir.as_ref().join(filename_as_path).symlink_metadata();
 
         match meta {
             Ok(ref m)
                 if !(m.file_type().is_file()
                     || m.file_type().is_symlink()) =>
             {
                 Ok((filename, dispatch_missing(entry.state)))
             }
             Ok(m) => Ok((
                 filename,
                 dispatch_found(
                     filename,
                     *entry,
                     HgMetadata::from_metadata(m),
                     &dmap.copy_map,
                     check_exec,
                     list_clean,
                     last_normal_time,
                 ),
             )),
             Err(ref e)
                 if e.kind() == std::io::ErrorKind::NotFound
                     || e.raw_os_error() == Some(20) =>
             {
                 // Rust does not yet have an `ErrorKind` for
                 // `NotADirectory` (errno 20)
                 // It happens if the dirstate contains `foo/bar` and
                 // foo is not a directory
                 Ok((filename, dispatch_missing(entry.state)))
             }
             Err(e) => Err(e),
         }
     })
 }
 
 pub struct StatusResult<'a> {
     pub modified: Vec<&'a HgPath>,
     pub added: Vec<&'a HgPath>,
     pub removed: Vec<&'a HgPath>,
     pub deleted: Vec<&'a HgPath>,
     pub clean: Vec<&'a HgPath>,
     /* TODO ignored
      * TODO unknown */
 }
 
-fn build_response(
-    results: Vec<(&HgPath, Dispatch)>,
-) -> (Vec<&HgPath>, StatusResult) {
+fn build_response<'a>(
+    results: impl IntoIterator<Item = IoResult<(&'a HgPath, Dispatch)>>,
+) -> IoResult<(Vec<&'a HgPath>, StatusResult<'a>)> {
     let mut lookup = vec![];
     let mut modified = vec![];
     let mut added = vec![];
     let mut removed = vec![];
     let mut deleted = vec![];
     let mut clean = vec![];
 
-    for (filename, dispatch) in results.into_iter() {
+    for res in results.into_iter() {
+        let (filename, dispatch) = res?;
         match dispatch {
             Dispatch::Unknown => {}
             Dispatch::Unsure => lookup.push(filename),
             Dispatch::Modified => modified.push(filename),
             Dispatch::Added => added.push(filename),
             Dispatch::Removed => removed.push(filename),
             Dispatch::Deleted => deleted.push(filename),
             Dispatch::Clean => clean.push(filename),
         }
     }
 
-    (
+    Ok((
         lookup,
         StatusResult {
             modified,
             added,
             removed,
             deleted,
             clean,
         },
-    )
+    ))
 }
 
-pub fn status(
-    dmap: &DirstateMap,
+pub fn status<'a: 'c, 'b: 'c, 'c>(
+    dmap: &'a DirstateMap,
+    matcher: &'b (impl Matcher),
     root_dir: impl AsRef<Path> + Sync + Send + Copy,
     list_clean: bool,
     last_normal_time: i64,
     check_exec: bool,
-) -> std::io::Result<(Vec<&HgPath>, StatusResult)> {
-    let results: std::io::Result<_> = stat_dmap_entries(
+) -> IoResult<(Vec<&'c HgPath>, StatusResult<'c>)> {
+    let files = matcher.file_set();
+    let mut results = vec![];
+    if let Some(files) = files {
+        results.par_extend(walk_explicit(
+            &files,
         &dmap,
         root_dir,
         check_exec,
         list_clean,
         last_normal_time,
-    )
-    .collect();
+        ));
+    }
 
-    Ok(build_response(results?))
+    if !matcher.is_exact() {
+        let stat_results = stat_dmap_entries(
+            &dmap,
+            root_dir,
+            check_exec,
+            list_clean,
+            last_normal_time,
+        );
+        results.par_extend(stat_results);
 }
+
+    build_response(results)
+}

rust/hg-cpython/src/dirstate/status.rs

@@ -1,69 +1,80 b''
 // status.rs
 //
 // Copyright 2019, Raphaël Gomès <[e-mail]>
 //
 // 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::status` module provided by the
 //! `hg-core` crate. From Python, this will be seen as
 //! `rustext.dirstate.status`.
 
 use crate::dirstate::DirstateMap;
 use cpython::exc::ValueError;
 use cpython::{
     PyBytes, PyErr, PyList, PyObject, PyResult, Python, PythonObject,
     ToPyObject,
 };
 use hg::utils::files::get_path_from_bytes;
 
+use hg::matchers::AlwaysMatcher;
 use hg::status;
 use hg::utils::hg_path::HgPath;
 
 /// This will be useless once trait impls for collection are added to `PyBytes`
 /// upstream.
 fn collect_pybytes_list<P: AsRef<HgPath>>(
     py: Python,
     collection: &[P],
 ) -> PyList {
     let list = PyList::new(py, &[]);
 
     for (i, path) in collection.iter().enumerate() {
         list.insert_item(
             py,
             i,
             PyBytes::new(py, path.as_ref().as_bytes()).into_object(),
         )
     }
 
     list
 }
 
 pub fn status_wrapper(
     py: Python,
     dmap: DirstateMap,
     root_dir: PyObject,
     list_clean: bool,
     last_normal_time: i64,
     check_exec: bool,
 ) -> PyResult<(PyList, PyList, PyList, PyList, PyList, PyList, PyList)> {
     let bytes = root_dir.extract::<PyBytes>(py)?;
     let root_dir = get_path_from_bytes(bytes.data(py));
 
     let dmap: DirstateMap = dmap.to_py_object(py);
     let dmap = dmap.get_inner(py);
 
-    let (lookup, status_res) =
-        status(&dmap, &root_dir, list_clean, last_normal_time, check_exec)
+    // TODO removed in the next patch to get the code to compile. This patch
+    // is part of a series and does not make real sense on its own.
+    let matcher = AlwaysMatcher;
+
+    let (lookup, status_res) = status(
+        &dmap,
+        &matcher,
+        &root_dir,
+        list_clean,
+        last_normal_time,
+        check_exec,
+    )
             .map_err(|e| PyErr::new::<ValueError, _>(py, e.to_string()))?;
 
     let modified = collect_pybytes_list(py, status_res.modified.as_ref());
     let added = collect_pybytes_list(py, status_res.added.as_ref());
     let removed = collect_pybytes_list(py, status_res.removed.as_ref());
     let deleted = collect_pybytes_list(py, status_res.deleted.as_ref());
     let clean = collect_pybytes_list(py, status_res.clean.as_ref());
     let lookup = collect_pybytes_list(py, lookup.as_ref());
     let unknown = PyList::new(py, &[]);
 
     Ok((lookup, modified, added, removed, deleted, unknown, clean))
 }