1 files changed, 108 insertions, 0 deletions
diff --git a/ignore/src/pathutil.rs b/ignore/src/pathutil.rs
new file mode 100644
index 00000000..bfd43de3
--- /dev/null
+++ b/ignore/src/pathutil.rs
@@ -0,0 +1,108 @@
+use std::ffi::OsStr;
+use std::path::Path;
+
+/// Returns true if and only if this file path is considered to be hidden.
+#[cfg(unix)]
+pub fn is_hidden<P: AsRef<Path>>(path: P) -> bool {
+    use std::os::unix::ffi::OsStrExt;
+
+    if let Some(name) = file_name(path.as_ref()) {
+        name.as_bytes().get(0) == Some(&b'.')
+    } else {
+        false
+    }
+}
+
+/// Returns true if and only if this file path is considered to be hidden.
+#[cfg(not(unix))]
+pub fn is_hidden<P: AsRef<Path>>(path: P) -> bool {
+    if let Some(name) = file_name(path.as_ref()) {
+        name.to_str().map(|s| s.starts_with(".")).unwrap_or(false)
+    } else {
+        false
+    }
+}
+
+/// Strip `prefix` from the `path` and return the remainder.
+///
+/// If `path` doesn't have a prefix `prefix`, then return `None`.
+#[cfg(unix)]
+pub fn strip_prefix<'a, P: AsRef<Path> + ?Sized>(
+    prefix: &'a P,
+    path: &'a Path,
+) -> Option<&'a Path> {
+    use std::os::unix::ffi::OsStrExt;
+
+    let prefix = prefix.as_ref().as_os_str().as_bytes();
+    let path = path.as_os_str().as_bytes();
+    if prefix.len() > path.len() || prefix != &path[0..prefix.len()] {
+        None
+    } else {
+        Some(&Path::new(OsStr::from_bytes(&path[prefix.len()..])))
+    }
+}
+
+/// Strip `prefix` from the `path` and return the remainder.
+///
+/// If `path` doesn't have a prefix `prefix`, then return `None`.
+#[cfg(not(unix))]
+pub fn strip_prefix<'a, P: AsRef<Path> + ?Sized>(
+    prefix: &'a P,
+    path: &'a Path,
+) -> Option<&'a Path> {
+    path.strip_prefix(prefix).ok()
+}
+
+/// Returns true if this file path is just a file name. i.e., Its parent is
+/// the empty string.
+#[cfg(unix)]
+pub fn is_file_name<P: AsRef<Path>>(path: P) -> bool {
+    use std::os::unix::ffi::OsStrExt;
+    use memchr::memchr;
+
+    let path = path.as_ref().as_os_str().as_bytes();
+    memchr(b'/', path).is_none()
+}
+
+/// Returns true if this file path is just a file name. i.e., Its parent is
+/// the empty string.
+#[cfg(not(unix))]
+pub fn is_file_name<P: AsRef<Path>>(path: P) -> bool {
+    path.as_ref().parent().map(|p| p.as_os_str().is_empty()).unwrap_or(false)
+}
+
+/// The final component of the path, if it is a normal file.
+///
+/// If the path terminates in ., .., or consists solely of a root of prefix,
+/// file_name will return None.
+#[cfg(unix)]
+pub fn file_name<'a, P: AsRef<Path> + ?Sized>(
+    path: &'a P,
+) -> Option<&'a OsStr> {
+    use std::os::unix::ffi::OsStrExt;
+    use memchr::memrchr;
+
+    let path = path.as_ref().as_os_str().as_bytes();
+    if path.is_empty() {
+        return None;
+    } else if path.len() == 1 && path[0] == b'.' {
+        return None;
+    } else if path.last() == Some(&b'.') {
+        return None;
+    } else if path.len() >= 2 && &path[path.len() - 2..] == &b".."[..] {
+        return None;
+    }
+    let last_slash = memrchr(b'/', path).map(|i| i + 1).unwrap_or(0);
+    Some(OsStr::from_bytes(&path[last_slash..]))
+}
+
+/// The final component of the path, if it is a normal file.
+///
+/// If the path terminates in ., .., or consists solely of a root of prefix,
+/// file_name will return None.
+#[cfg(not(unix))]
+pub fn file_name<'a, P: AsRef<Path> + ?Sized>(
+    path: &'a P,
+) -> Option<&'a OsStr> {
+    path.as_ref().file_name()
+}