progressag/sys

1 files changed, 100 insertions, 0 deletions

diff --git a/src/dir.rs b/src/dir.rs
new file mode 100644
index 0000000..667f3a4
--- /dev/null
+++ b/src/dir.rs
@@ -0,0 +1,100 @@
+#[cfg(unix)]
+use std::ffi::CStr;
+use std::io;
+#[cfg(unix)]
+use std::os::unix::io::RawFd;
+
+#[cfg(target_os = "linux")]
+use crate::os::linux;
+#[cfg(unix)]
+use crate::os::unix;
+#[cfg(unix)]
+use crate::os::unix::RawPathBuf;
+
+#[derive(Debug)]
+pub struct Cursor {
+    #[cfg(unix)]
+    dir: unix::Dir,
+    #[cfg(unix)]
+    dent: unix::DirEntry,
+    #[cfg(target_os = "linux")]
+    linux_cursor: linux::DirEntryCursor,
+}
+
+impl Cursor {
+    #[cfg(unix)]
+    pub fn new(parent: RawFd, dir_name: &CStr) -> io::Result<Cursor> {
+        let dir = unix::Dir::openat_c(parent, dir_name)?;
+        Ok(Cursor {
+            dir,
+            #[cfg(unix)]
+            dent: unix::DirEntry::empty(),
+            #[cfg(target_os = "linux")]
+            linux_cursor: linux::DirEntryCursor::new(),
+        })
+    }
+
+    /// Reset this cursor to the beginning of the given directory.
+    ///
+    /// An error is returned if the given directory could not be opened for
+    /// reading. If an error is returned, the behavior of this cursor is
+    /// unspecified until a subsequent and successful `reset` call is made.
+    #[cfg(unix)]
+    pub fn reset(&mut self, parent: RawFd, dir_name: &CStr) -> io::Result<()> {
+        self.dir = unix::Dir::openat_c(parent, dir_name)?;
+        Ok(())
+    }
+
+    #[cfg(all(unix, walkdir_getdents))]
+    pub fn read(&mut self) -> io::Result<Option<CursorEntry>> {
+        use std::os::unix::io::AsRawFd;
+
+        let c = &mut self.linux_cursor;
+        loop {
+            if c.advance() {
+                if is_dots(c.current().file_name_bytes()) {
+                    continue;
+                }
+                return Ok(Some(CursorEntry { linux_dent: c.current() }));
+            }
+            if !linux::getdents(self.dir.as_raw_fd(), c)? {
+                return Ok(None);
+            }
+            // This is guaranteed since getdents returning true means
+            // that the buffer has at least one item in it.
+            assert!(c.advance());
+            if is_dots(c.current().file_name_bytes()) {
+                continue;
+            }
+            return Ok(Some(CursorEntry { linux_dent: c.current() }));
+        }
+    }
+
+    #[cfg(all(unix, not(walkdir_getdents)))]
+    pub fn read(&mut self) -> io::Result<Option<CursorEntry>> {
+        loop {
+            return if self.dir.read_into(&mut self.dent)? {
+                if is_dots(dent.file_name_bytes()) {
+                    continue;
+                }
+                Ok(Some(CursorEntry { cursor: self }))
+            } else {
+                Ok(None)
+            };
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct CursorEntry<'a> {
+    #[cfg(not(all(unix, walkdir_getdents)))]
+    cursor: &'a Cursor,
+    #[cfg(all(unix, walkdir_getdents))]
+    linux_dent: linux::DirEntry<'a>,
+}
+
+impl<'a> CursorEntry<'a> {}
+
+fn is_dots(file_name: &[u8]) -> bool {
+    file_name == b"." || file_name == b".."
+}