rust/hg-core/src/matchers.rs

rust: Parse "subinclude"d files along the way, not later

When parsing a `.hgignore` file and encountering an `include:` line,
the included file is parsed recursively right then in a depth-first fashion.

With `subinclude:` however included files were parsed (recursively) much later.
This changes it to be expanded during parsing, like `.hgignore`.

The motivation for this is an upcoming changeset that needs to detect changes
in which files are ignored or not. The plan is to hash all ignore files while
they are being read, and store that hash in the dirstate (in v2 format).
In order to allow a potential alternative implementations to read that format,
the algorithm to compute that hash must be documented. Having a well-defined
depth-first ordering for the tree of (sub-)included files makes that easier.

Differential Revision: https://phab.mercurial-scm.org/D10834

// matchers.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.

//! Structs and types for matching files and directories.

use crate::{
    dirstate::dirs_multiset::DirsChildrenMultiset,
    filepatterns::{
        build_single_regex, filter_subincludes, get_patterns_from_file,
        PatternFileWarning, PatternResult,
    },
    utils::{
        files::find_dirs,
        hg_path::{HgPath, HgPathBuf},
        Escaped,
    },
    DirsMultiset, DirstateMapError, FastHashMap, IgnorePattern, PatternError,
    PatternSyntax,
};

use crate::filepatterns::normalize_path_bytes;
use std::borrow::ToOwned;
use std::collections::HashSet;
use std::fmt::{Display, Error, Formatter};
use std::iter::FromIterator;
use std::ops::Deref;
use std::path::{Path, PathBuf};

use micro_timer::timed;

#[derive(Debug, PartialEq)]
pub enum VisitChildrenSet<'a> {
    /// Don't visit anything
    Empty,
    /// Only visit this directory
    This,
    /// Visit this directory and these subdirectories
    /// TODO Should we implement a `NonEmptyHashSet`?
    Set(HashSet<&'a HgPath>),
    /// Visit this directory and all subdirectories
    Recursive,
}

pub trait Matcher {
    /// Explicitly listed files
    fn file_set(&self) -> Option<&HashSet<&HgPath>>;
    /// Returns whether `filename` is in `file_set`
    fn exact_match(&self, filename: &HgPath) -> bool;
    /// Returns whether `filename` is matched by this matcher
    fn matches(&self, filename: &HgPath) -> bool;
    /// Decides whether a directory should be visited based on whether it
    /// has potential matches in it or one of its subdirectories, and
    /// potentially lists which subdirectories of that directory should be
    /// visited. This is based on the match's primary, included, and excluded
    /// patterns.
    ///
    /// # Example
    ///
    /// Assume matchers `['path:foo/bar', 'rootfilesin:qux']`, we would
    /// return the following values (assuming the implementation of
    /// visit_children_set is capable of recognizing this; some implementations
    /// are not).
    ///
    /// ```text
    /// ```ignore
    /// '' -> {'foo', 'qux'}
    /// 'baz' -> set()
    /// 'foo' -> {'bar'}
    /// // Ideally this would be `Recursive`, but since the prefix nature of
    /// // matchers is applied to the entire matcher, we have to downgrade this
    /// // to `This` due to the (yet to be implemented in Rust) non-prefix
    /// // `RootFilesIn'-kind matcher being mixed in.
    /// 'foo/bar' -> 'this'
    /// 'qux' -> 'this'
    /// ```
    /// # Important
    ///
    /// Most matchers do not know if they're representing files or
    /// directories. They see `['path:dir/f']` and don't know whether `f` is a
    /// file or a directory, so `visit_children_set('dir')` for most matchers
    /// will return `HashSet{ HgPath { "f" } }`, but if the matcher knows it's
    /// a file (like the yet to be implemented in Rust `ExactMatcher` does),
    /// it may return `VisitChildrenSet::This`.
    /// Do not rely on the return being a `HashSet` indicating that there are
    /// no files in this dir to investigate (or equivalently that if there are
    /// files to investigate in 'dir' that it will always return
    /// `VisitChildrenSet::This`).
    fn visit_children_set(&self, directory: &HgPath) -> VisitChildrenSet;
    /// Matcher will match everything and `files_set()` will be empty:
    /// optimization might be possible.
    fn matches_everything(&self) -> bool;
    /// Matcher will match exactly the files in `files_set()`: optimization
    /// might be possible.
    fn is_exact(&self) -> bool;
}

/// Matches everything.
///```
/// use hg::{ matchers::{Matcher, AlwaysMatcher}, utils::hg_path::HgPath };
///
/// let matcher = AlwaysMatcher;
///
/// assert_eq!(matcher.matches(HgPath::new(b"whatever")), true);
/// assert_eq!(matcher.matches(HgPath::new(b"b.txt")), true);
/// assert_eq!(matcher.matches(HgPath::new(b"main.c")), true);
/// assert_eq!(matcher.matches(HgPath::new(br"re:.*\.c$")), true);
/// ```
#[derive(Debug)]
pub struct AlwaysMatcher;

impl Matcher for AlwaysMatcher {
    fn file_set(&self) -> Option<&HashSet<&HgPath>> {
        None
    }
    fn exact_match(&self, _filename: &HgPath) -> bool {
        false
    }
    fn matches(&self, _filename: &HgPath) -> bool {
        true
    }
    fn visit_children_set(&self, _directory: &HgPath) -> VisitChildrenSet {
        VisitChildrenSet::Recursive
    }
    fn matches_everything(&self) -> bool {
        true
    }
    fn is_exact(&self) -> bool {
        false
    }
}

/// Matches the input files exactly. They are interpreted as paths, not
/// patterns.
///
///```
/// use hg::{ matchers::{Matcher, FileMatcher}, utils::hg_path::{HgPath, HgPathBuf} };
///
/// let files = [HgPathBuf::from_bytes(b"a.txt"), HgPathBuf::from_bytes(br"re:.*\.c$")];
/// let matcher = FileMatcher::new(&files).unwrap();
///
/// assert_eq!(matcher.matches(HgPath::new(b"a.txt")), true);
/// assert_eq!(matcher.matches(HgPath::new(b"b.txt")), false);
/// assert_eq!(matcher.matches(HgPath::new(b"main.c")), false);
/// assert_eq!(matcher.matches(HgPath::new(br"re:.*\.c$")), true);
/// ```
#[derive(Debug)]
pub struct FileMatcher<'a> {
    files: HashSet<&'a HgPath>,
    dirs: DirsMultiset,
}

impl<'a> FileMatcher<'a> {
    pub fn new(files: &'a [HgPathBuf]) -> Result<Self, DirstateMapError> {
        Ok(Self {
            files: HashSet::from_iter(files.iter().map(AsRef::as_ref)),
            dirs: DirsMultiset::from_manifest(files)?,
        })
    }
    fn inner_matches(&self, filename: &HgPath) -> bool {
        self.files.contains(filename.as_ref())
    }
}

impl<'a> Matcher for FileMatcher<'a> {
    fn file_set(&self) -> Option<&HashSet<&HgPath>> {
        Some(&self.files)
    }
    fn exact_match(&self, filename: &HgPath) -> bool {
        self.inner_matches(filename)
    }
    fn matches(&self, filename: &HgPath) -> bool {
        self.inner_matches(filename)
    }
    fn visit_children_set(&self, directory: &HgPath) -> VisitChildrenSet {
        if self.files.is_empty() || !self.dirs.contains(&directory) {
            return VisitChildrenSet::Empty;
        }
        let dirs_as_set = self.dirs.iter().map(Deref::deref).collect();

        let mut candidates: HashSet<&HgPath> =
            self.files.union(&dirs_as_set).cloned().collect();
        candidates.remove(HgPath::new(b""));

        if !directory.as_ref().is_empty() {
            let directory = [directory.as_ref().as_bytes(), b"/"].concat();
            candidates = candidates
                .iter()
                .filter_map(|c| {
                    if c.as_bytes().starts_with(&directory) {
                        Some(HgPath::new(&c.as_bytes()[directory.len()..]))
                    } else {
                        None
                    }
                })
                .collect();
        }

        // `self.dirs` includes all of the directories, recursively, so if
        // we're attempting to match 'foo/bar/baz.txt', it'll have '', 'foo',
        // 'foo/bar' in it. Thus we can safely ignore a candidate that has a
        // '/' in it, indicating it's for a subdir-of-a-subdir; the immediate
        // subdir will be in there without a slash.
        VisitChildrenSet::Set(
            candidates
                .iter()
                .filter_map(|c| {
                    if c.bytes().all(|b| *b != b'/') {
                        Some(*c)
                    } else {
                        None
                    }
                })
                .collect(),
        )
    }
    fn matches_everything(&self) -> bool {
        false
    }
    fn is_exact(&self) -> bool {
        true
    }
}

/// Matches files that are included in the ignore rules.
/// ```
/// use hg::{
///     matchers::{IncludeMatcher, Matcher},
///     IgnorePattern,
///     PatternSyntax,
///     utils::hg_path::HgPath
/// };
/// use std::path::Path;
/// ///
/// let ignore_patterns =
/// vec![IgnorePattern::new(PatternSyntax::RootGlob, b"this*", Path::new(""))];
/// let matcher = IncludeMatcher::new(ignore_patterns).unwrap();
/// ///
/// assert_eq!(matcher.matches(HgPath::new(b"testing")), false);
/// assert_eq!(matcher.matches(HgPath::new(b"this should work")), true);
/// assert_eq!(matcher.matches(HgPath::new(b"this also")), true);
/// assert_eq!(matcher.matches(HgPath::new(b"but not this")), false);
/// ```
pub struct IncludeMatcher<'a> {
    patterns: Vec<u8>,
    match_fn: Box<dyn for<'r> Fn(&'r HgPath) -> bool + 'a + Sync>,
    /// Whether all the patterns match a prefix (i.e. recursively)
    prefix: bool,
    roots: HashSet<HgPathBuf>,
    dirs: HashSet<HgPathBuf>,
    parents: HashSet<HgPathBuf>,
}

impl<'a> Matcher for IncludeMatcher<'a> {
    fn file_set(&self) -> Option<&HashSet<&HgPath>> {
        None
    }

    fn exact_match(&self, _filename: &HgPath) -> bool {
        false
    }

    fn matches(&self, filename: &HgPath) -> bool {
        (self.match_fn)(filename.as_ref())
    }

    fn visit_children_set(&self, directory: &HgPath) -> VisitChildrenSet {
        let dir = directory.as_ref();
        if self.prefix && self.roots.contains(dir) {
            return VisitChildrenSet::Recursive;
        }
        if self.roots.contains(HgPath::new(b""))
            || self.roots.contains(dir)
            || self.dirs.contains(dir)
            || find_dirs(dir).any(|parent_dir| self.roots.contains(parent_dir))
        {
            return VisitChildrenSet::This;
        }

        if self.parents.contains(directory.as_ref()) {
            let multiset = self.get_all_parents_children();
            if let Some(children) = multiset.get(dir) {
                return VisitChildrenSet::Set(children.to_owned());
            }
        }
        VisitChildrenSet::Empty
    }

    fn matches_everything(&self) -> bool {
        false
    }

    fn is_exact(&self) -> bool {
        false
    }
}

/// Returns a function that matches an `HgPath` against the given regex
/// pattern.
///
/// This can fail when the pattern is invalid or not supported by the
/// underlying engine (the `regex` crate), for instance anything with
/// back-references.
#[timed]
fn re_matcher(
    pattern: &[u8],
) -> PatternResult<impl Fn(&HgPath) -> bool + Sync> {
    use std::io::Write;

    // The `regex` crate adds `.*` to the start and end of expressions if there
    // are no anchors, so add the start anchor.
    let mut escaped_bytes = vec![b'^', b'(', b'?', b':'];
    for byte in pattern {
        if *byte > 127 {
            write!(escaped_bytes, "\\x{:x}", *byte).unwrap();
        } else {
            escaped_bytes.push(*byte);
        }
    }
    escaped_bytes.push(b')');

    // Avoid the cost of UTF8 checking
    //
    // # Safety
    // This is safe because we escaped all non-ASCII bytes.
    let pattern_string = unsafe { String::from_utf8_unchecked(escaped_bytes) };
    let re = regex::bytes::RegexBuilder::new(&pattern_string)
        .unicode(false)
        // Big repos with big `.hgignore` will hit the default limit and
        // incur a significant performance hit. One repo's `hg status` hit
        // multiple *minutes*.
        .dfa_size_limit(50 * (1 << 20))
        .build()
        .map_err(|e| PatternError::UnsupportedSyntax(e.to_string()))?;

    Ok(move |path: &HgPath| re.is_match(path.as_bytes()))
}

/// Returns the regex pattern and a function that matches an `HgPath` against
/// said regex formed by the given ignore patterns.
fn build_regex_match(
    ignore_patterns: &[IgnorePattern],
) -> PatternResult<(Vec<u8>, Box<dyn Fn(&HgPath) -> bool + Sync>)> {
    let mut regexps = vec![];
    let mut exact_set = HashSet::new();

    for pattern in ignore_patterns {
        if let Some(re) = build_single_regex(pattern)? {
            regexps.push(re);
        } else {
            let exact = normalize_path_bytes(&pattern.pattern);
            exact_set.insert(HgPathBuf::from_bytes(&exact));
        }
    }

    let full_regex = regexps.join(&b'|');

    // An empty pattern would cause the regex engine to incorrectly match the
    // (empty) root directory
    let func = if !(regexps.is_empty()) {
        let matcher = re_matcher(&full_regex)?;
        let func = move |filename: &HgPath| {
            exact_set.contains(filename) || matcher(filename)
        };
        Box::new(func) as Box<dyn Fn(&HgPath) -> bool + Sync>
    } else {
        let func = move |filename: &HgPath| exact_set.contains(filename);
        Box::new(func) as Box<dyn Fn(&HgPath) -> bool + Sync>
    };

    Ok((full_regex, func))
}

/// Returns roots and directories corresponding to each pattern.
///
/// This calculates the roots and directories exactly matching the patterns and
/// returns a tuple of (roots, dirs). It does not return other directories
/// which may also need to be considered, like the parent directories.
fn roots_and_dirs(
    ignore_patterns: &[IgnorePattern],
) -> (Vec<HgPathBuf>, Vec<HgPathBuf>) {
    let mut roots = Vec::new();
    let mut dirs = Vec::new();

    for ignore_pattern in ignore_patterns {
        let IgnorePattern {
            syntax, pattern, ..
        } = ignore_pattern;
        match syntax {
            PatternSyntax::RootGlob | PatternSyntax::Glob => {
                let mut root = vec![];

                for p in pattern.split(|c| *c == b'/') {
                    if p.iter().any(|c| match *c {
                        b'[' | b'{' | b'*' | b'?' => true,
                        _ => false,
                    }) {
                        break;
                    }
                    root.push(HgPathBuf::from_bytes(p));
                }
                let buf =
                    root.iter().fold(HgPathBuf::new(), |acc, r| acc.join(r));
                roots.push(buf);
            }
            PatternSyntax::Path | PatternSyntax::RelPath => {
                let pat = HgPath::new(if pattern == b"." {
                    &[] as &[u8]
                } else {
                    pattern
                });
                roots.push(pat.to_owned());
            }
            PatternSyntax::RootFiles => {
                let pat = if pattern == b"." {
                    &[] as &[u8]
                } else {
                    pattern
                };
                dirs.push(HgPathBuf::from_bytes(pat));
            }
            _ => {
                roots.push(HgPathBuf::new());
            }
        }
    }
    (roots, dirs)
}

/// Paths extracted from patterns
#[derive(Debug, PartialEq)]
struct RootsDirsAndParents {
    /// Directories to match recursively
    pub roots: HashSet<HgPathBuf>,
    /// Directories to match non-recursively
    pub dirs: HashSet<HgPathBuf>,
    /// Implicitly required directories to go to items in either roots or dirs
    pub parents: HashSet<HgPathBuf>,
}

/// Extract roots, dirs and parents from patterns.
fn roots_dirs_and_parents(
    ignore_patterns: &[IgnorePattern],
) -> PatternResult<RootsDirsAndParents> {
    let (roots, dirs) = roots_and_dirs(ignore_patterns);

    let mut parents = HashSet::new();

    parents.extend(
        DirsMultiset::from_manifest(&dirs)
            .map_err(|e| match e {
                DirstateMapError::InvalidPath(e) => e,
                _ => unreachable!(),
            })?
            .iter()
            .map(ToOwned::to_owned),
    );
    parents.extend(
        DirsMultiset::from_manifest(&roots)
            .map_err(|e| match e {
                DirstateMapError::InvalidPath(e) => e,
                _ => unreachable!(),
            })?
            .iter()
            .map(ToOwned::to_owned),
    );

    Ok(RootsDirsAndParents {
        roots: HashSet::from_iter(roots),
        dirs: HashSet::from_iter(dirs),
        parents,
    })
}

/// Returns a function that checks whether a given file (in the general sense)
/// should be matched.
fn build_match<'a, 'b>(
    ignore_patterns: Vec<IgnorePattern>,
) -> PatternResult<(Vec<u8>, Box<dyn Fn(&HgPath) -> bool + 'b + Sync>)> {
    let mut match_funcs: Vec<Box<dyn Fn(&HgPath) -> bool + Sync>> = vec![];
    // For debugging and printing
    let mut patterns = vec![];

    let (subincludes, ignore_patterns) = filter_subincludes(ignore_patterns)?;

    if !subincludes.is_empty() {
        // Build prefix-based matcher functions for subincludes
        let mut submatchers = FastHashMap::default();
        let mut prefixes = vec![];

        for sub_include in subincludes {
            let matcher = IncludeMatcher::new(sub_include.included_patterns)?;
            let match_fn =
                Box::new(move |path: &HgPath| matcher.matches(path));
            prefixes.push(sub_include.prefix.clone());
            submatchers.insert(sub_include.prefix.clone(), match_fn);
        }

        let match_subinclude = move |filename: &HgPath| {
            for prefix in prefixes.iter() {
                if let Some(rel) = filename.relative_to(prefix) {
                    if (submatchers[prefix])(rel) {
                        return true;
                    }
                }
            }
            false
        };

        match_funcs.push(Box::new(match_subinclude));
    }

    if !ignore_patterns.is_empty() {
        // Either do dumb matching if all patterns are rootfiles, or match
        // with a regex.
        if ignore_patterns
            .iter()
            .all(|k| k.syntax == PatternSyntax::RootFiles)
        {
            let dirs: HashSet<_> = ignore_patterns
                .iter()
                .map(|k| k.pattern.to_owned())
                .collect();
            let mut dirs_vec: Vec<_> = dirs.iter().cloned().collect();

            let match_func = move |path: &HgPath| -> bool {
                let path = path.as_bytes();
                let i = path.iter().rfind(|a| **a == b'/');
                let dir = if let Some(i) = i {
                    &path[..*i as usize]
                } else {
                    b"."
                };
                dirs.contains(dir.deref())
            };
            match_funcs.push(Box::new(match_func));

            patterns.extend(b"rootfilesin: ");
            dirs_vec.sort();
            patterns.extend(dirs_vec.escaped_bytes());
        } else {
            let (new_re, match_func) = build_regex_match(&ignore_patterns)?;
            patterns = new_re;
            match_funcs.push(match_func)
        }
    }

    Ok(if match_funcs.len() == 1 {
        (patterns, match_funcs.remove(0))
    } else {
        (
            patterns,
            Box::new(move |f: &HgPath| -> bool {
                match_funcs.iter().any(|match_func| match_func(f))
            }),
        )
    })
}

/// Parses all "ignore" files with their recursive includes and returns a
/// function that checks whether a given file (in the general sense) should be
/// ignored.
pub fn get_ignore_function<'a>(
    all_pattern_files: Vec<PathBuf>,
    root_dir: &Path,
) -> PatternResult<(
    Box<dyn for<'r> Fn(&'r HgPath) -> bool + Sync + 'a>,
    Vec<PatternFileWarning>,
)> {
    let mut all_patterns = vec![];
    let mut all_warnings = vec![];

    for pattern_file in &all_pattern_files {
        let (patterns, warnings) =
            get_patterns_from_file(pattern_file, root_dir)?;

        all_patterns.extend(patterns.to_owned());
        all_warnings.extend(warnings);
    }
    let matcher = IncludeMatcher::new(all_patterns)?;
    Ok((
        Box::new(move |path: &HgPath| matcher.matches(path)),
        all_warnings,
    ))
}

impl<'a> IncludeMatcher<'a> {
    pub fn new(ignore_patterns: Vec<IgnorePattern>) -> PatternResult<Self> {
        let RootsDirsAndParents {
            roots,
            dirs,
            parents,
        } = roots_dirs_and_parents(&ignore_patterns)?;
        let prefix = ignore_patterns.iter().any(|k| match k.syntax {
            PatternSyntax::Path | PatternSyntax::RelPath => true,
            _ => false,
        });
        let (patterns, match_fn) = build_match(ignore_patterns)?;

        Ok(Self {
            patterns,
            match_fn,
            prefix,
            roots,
            dirs,
            parents,
        })
    }

    fn get_all_parents_children(&self) -> DirsChildrenMultiset {
        // TODO cache
        let thing = self
            .dirs
            .iter()
            .chain(self.roots.iter())
            .chain(self.parents.iter());
        DirsChildrenMultiset::new(thing, Some(&self.parents))
    }
}

impl<'a> Display for IncludeMatcher<'a> {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> {
        // XXX What about exact matches?
        // I'm not sure it's worth it to clone the HashSet and keep it
        // around just in case someone wants to display the matcher, plus
        // it's going to be unreadable after a few entries, but we need to
        // inform in this display that exact matches are being used and are
        // (on purpose) missing from the `includes`.
        write!(
            f,
            "IncludeMatcher(includes='{}')",
            String::from_utf8_lossy(&self.patterns.escaped_bytes())
        )
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use pretty_assertions::assert_eq;
    use std::path::Path;

    #[test]
    fn test_roots_and_dirs() {
        let pats = vec![
            IgnorePattern::new(PatternSyntax::Glob, b"g/h/*", Path::new("")),
            IgnorePattern::new(PatternSyntax::Glob, b"g/h", Path::new("")),
            IgnorePattern::new(PatternSyntax::Glob, b"g*", Path::new("")),
        ];
        let (roots, dirs) = roots_and_dirs(&pats);

        assert_eq!(
            roots,
            vec!(
                HgPathBuf::from_bytes(b"g/h"),
                HgPathBuf::from_bytes(b"g/h"),
                HgPathBuf::new()
            ),
        );
        assert_eq!(dirs, vec!());
    }

    #[test]
    fn test_roots_dirs_and_parents() {
        let pats = vec![
            IgnorePattern::new(PatternSyntax::Glob, b"g/h/*", Path::new("")),
            IgnorePattern::new(PatternSyntax::Glob, b"g/h", Path::new("")),
            IgnorePattern::new(PatternSyntax::Glob, b"g*", Path::new("")),
        ];

        let mut roots = HashSet::new();
        roots.insert(HgPathBuf::from_bytes(b"g/h"));
        roots.insert(HgPathBuf::new());

        let dirs = HashSet::new();

        let mut parents = HashSet::new();
        parents.insert(HgPathBuf::new());
        parents.insert(HgPathBuf::from_bytes(b"g"));

        assert_eq!(
            roots_dirs_and_parents(&pats).unwrap(),
            RootsDirsAndParents {
                roots,
                dirs,
                parents
            }
        );
    }

    #[test]
    fn test_filematcher_visit_children_set() {
        // Visitchildrenset
        let files = vec![HgPathBuf::from_bytes(b"dir/subdir/foo.txt")];
        let matcher = FileMatcher::new(&files).unwrap();

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"dir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"subdir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"foo.txt"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir")),
            VisitChildrenSet::Set(set)
        );

        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir/x")),
            VisitChildrenSet::Empty
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir/foo.txt")),
            VisitChildrenSet::Empty
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"folder")),
            VisitChildrenSet::Empty
        );
    }

    #[test]
    fn test_filematcher_visit_children_set_files_and_dirs() {
        let files = vec![
            HgPathBuf::from_bytes(b"rootfile.txt"),
            HgPathBuf::from_bytes(b"a/file1.txt"),
            HgPathBuf::from_bytes(b"a/b/file2.txt"),
            // No file in a/b/c
            HgPathBuf::from_bytes(b"a/b/c/d/file4.txt"),
        ];
        let matcher = FileMatcher::new(&files).unwrap();

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"a"));
        set.insert(HgPath::new(b"rootfile.txt"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"b"));
        set.insert(HgPath::new(b"file1.txt"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"a")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"c"));
        set.insert(HgPath::new(b"file2.txt"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"a/b")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"d"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"a/b/c")),
            VisitChildrenSet::Set(set)
        );
        let mut set = HashSet::new();
        set.insert(HgPath::new(b"file4.txt"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"a/b/c/d")),
            VisitChildrenSet::Set(set)
        );

        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"a/b/c/d/e")),
            VisitChildrenSet::Empty
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"folder")),
            VisitChildrenSet::Empty
        );
    }

    #[test]
    fn test_includematcher() {
        // VisitchildrensetPrefix
        let matcher = IncludeMatcher::new(vec![IgnorePattern::new(
            PatternSyntax::RelPath,
            b"dir/subdir",
            Path::new(""),
        )])
        .unwrap();

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"dir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"subdir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir")),
            VisitChildrenSet::Set(set)
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir")),
            VisitChildrenSet::Recursive
        );
        // OPT: This should probably be 'all' if its parent is?
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir/x")),
            VisitChildrenSet::This
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"folder")),
            VisitChildrenSet::Empty
        );

        // VisitchildrensetRootfilesin
        let matcher = IncludeMatcher::new(vec![IgnorePattern::new(
            PatternSyntax::RootFiles,
            b"dir/subdir",
            Path::new(""),
        )])
        .unwrap();

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"dir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"")),
            VisitChildrenSet::Set(set)
        );

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"subdir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir")),
            VisitChildrenSet::Set(set)
        );

        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir")),
            VisitChildrenSet::This
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir/x")),
            VisitChildrenSet::Empty
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"folder")),
            VisitChildrenSet::Empty
        );

        // VisitchildrensetGlob
        let matcher = IncludeMatcher::new(vec![IgnorePattern::new(
            PatternSyntax::Glob,
            b"dir/z*",
            Path::new(""),
        )])
        .unwrap();

        let mut set = HashSet::new();
        set.insert(HgPath::new(b"dir"));
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"")),
            VisitChildrenSet::Set(set)
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"folder")),
            VisitChildrenSet::Empty
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir")),
            VisitChildrenSet::This
        );
        // OPT: these should probably be set().
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir")),
            VisitChildrenSet::This
        );
        assert_eq!(
            matcher.visit_children_set(HgPath::new(b"dir/subdir/x")),
            VisitChildrenSet::This
        );
    }
}