1 files changed, 107 insertions, 0 deletions
diff --git a/src/client/fs/dcache.rs b/src/client/fs/dcache.rs
new file mode 100644
index 0000000..b171abc
--- /dev/null
+++ b/src/client/fs/dcache.rs
@@ -0,0 +1,107 @@
+use super::ino::Ino;
+use std::{
+    collections::{
+        btree_map::{self, OccupiedError},
+        BTreeMap, HashMap,
+    },
+    ffi::{OsStr, OsString},
+};
+
+#[derive(Debug)]
+pub(super) struct Dcache {
+    inner: HashMap<Ino, Dentry>,
+}
+
+impl Dcache {
+    pub fn new() -> Self {
+        Self {
+            inner: HashMap::new(),
+        }
+    }
+
+    pub fn get_ino(&self, parent: Ino, name: &OsStr) -> Option<&Ino> {
+        self.get(parent).and_then(|dentry| dentry.get(name))
+    }
+
+    pub fn try_insert_name(
+        &mut self,
+        parent: Ino,
+        name: OsString,
+        ino: Ino,
+    ) -> Option<Result<(), ()>> {
+        match self
+            .get_mut(parent)
+            .map(|dentry| dentry.try_insert(name, ino))
+        {
+            Some(Ok(_)) => Some(Ok(())),
+            Some(Err(_)) => Some(Err(())),
+            None => None,
+        }
+    }
+
+    pub fn add_dentry(&mut self, ino: Ino, parent: Ino) -> Option<Dentry> {
+        self.insert(ino, Dentry::new(ino, parent))
+    }
+
+    // Map-like API
+
+    pub fn insert(&mut self, ino: Ino, dentry: Dentry) -> Option<Dentry> {
+        self.inner.insert(ino, dentry)
+    }
+
+    pub fn get(&self, ino: Ino) -> Option<&Dentry> {
+        self.inner.get(&ino)
+    }
+
+    pub fn get_mut(&mut self, ino: Ino) -> Option<&mut Dentry> {
+        self.inner.get_mut(&ino)
+    }
+
+    pub fn remove(&mut self, ino: Ino) -> Option<Dentry> {
+        self.inner.remove(&ino)
+    }
+}
+
+#[derive(Debug)]
+pub(super) struct Dentry {
+    inner: BTreeMap<OsString, Ino>,
+    pub loaded: bool,
+}
+
+impl Dentry {
+    pub fn new(ino: Ino, parent: Ino) -> Self {
+        let mut dentry = Self {
+            inner: BTreeMap::new(),
+            loaded: false,
+        };
+
+        dentry.insert(".".into(), ino);
+        dentry.insert("..".into(), parent);
+
+        dentry
+    }
+
+    pub fn insert(&mut self, k: OsString, v: Ino) -> Option<Ino> {
+        self.inner.insert(k, v)
+    }
+
+    pub fn try_insert(
+        &mut self,
+        k: OsString,
+        v: Ino,
+    ) -> Result<&mut Ino, btree_map::OccupiedError<'_, OsString, Ino>> {
+        self.inner.try_insert(k, v)
+    }
+
+    pub fn get(&self, k: &OsStr) -> Option<&Ino> {
+        self.inner.get(k)
+    }
+
+    pub fn remove(&mut self, k: &OsStr) -> Option<Ino> {
+        self.inner.remove(k)
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&OsString, &Ino)> {
+        self.inner.iter()
+    }
+}