Whoo boy this is a big one

src/db.rs

@@ -1,368 +0,0 @@
-use std::{
-    mem::size_of,
-    ops::Deref,
-    ptr::NonNull,
-    rc::Rc,
-    sync::Arc,
-    marker::PhantomData,
-    hash::{
-        Hash,
-        Hasher,
-        BuildHasher,
-    },
-    collections::hash_map::RandomState,
-};
-
-use rkyv::{
-    Archive,
-    Archived,
-    archived_root,
-
-    Serialize,
-    Deserialize,
-
-    ser::serializers::AllocScratchError,
-};
-
-use lmdb::{
-    Database,
-    Cursor,
-    RoCursor,
-    Iter,
-};
-
-pub use rkyv::{
-    Fallible,
-};
-pub use lmdb::{
-    Environment,
-
-    DatabaseFlags,
-    WriteFlags,
-
-    Transaction,
-    RoTransaction,
-    RwTransaction,
-};
-
-
-#[derive(Debug, Clone)]
-pub struct RawDB {
-    db: Database,
-}
-
-impl RawDB {
-    pub fn open(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
-        env.open_db(name).map(|db| Self { db })
-    }
-    
-    pub fn create(env: &Environment, name: Option<&str>, flags: DatabaseFlags) -> lmdb::Result<Self> {
-        env.create_db(name, flags).map(|db| Self { db })
-    }
-
-    pub fn get<'txn, T: Transaction, K>(&self, txn: &'txn T, key: &K) -> lmdb::Result<Option<&'txn [u8]>>
-        where K: AsRef<[u8]>
-    {
-        match txn.get(self.db, key) {
-            Ok(buf) => Ok(Some(buf)),
-            Err(lmdb::Error::NotFound) => Ok(None),
-            Err(e) => Err(e),
-        }
-    }
-
-    pub fn put<K, V>(&self, txn: &mut RwTransaction, key: &K, value: &V, flags: WriteFlags)
-        -> lmdb::Result<()>
-        where K: AsRef<[u8]>,
-              V: AsRef<[u8]>,
-    {
-        txn.put(self.db, key, value, flags)
-    }
-
-    pub fn reserve<'txn, K>(&self, txn: &'txn mut RwTransaction, key: &K, size: usize, flags: WriteFlags) 
-        -> lmdb::Result<&'txn mut [u8]>
-        where K: AsRef<[u8]>
-    {
-        txn.reserve(self.db, key, size, flags)
-    }
-
-    pub fn del<K, V>(&self, txn: &mut RwTransaction, key: &K, value: Option<&V>) -> lmdb::Result<()>
-        where K: AsRef<[u8]>,
-              V: AsRef<[u8]>,
-    {
-        txn.del(self.db, key, value.map(AsRef::as_ref))
-    }
-
-    pub fn iter<'txn, C: Cursor<'txn>>(&self, cursor: &'txn mut C) -> Iter<'txn> {
-        cursor.iter_start()
-    }
-
-    pub fn open_ro_cursor<'txn, T: Transaction>(&self, txn: &'txn T) -> lmdb::Result<RoCursor<'txn>> {
-        txn.open_ro_cursor(self.db)
-    }
-}
-
-/// An read-only entry reference
-pub struct EntryPtr<'txn, K, V> {
-    key: &'txn K,
-    val: &'txn V,
-}
-
-#[derive(Archive, Serialize, Deserialize)]
-/// The entry as it is stored inside the database.
-struct Entry<K: Archive, V: Archive> {
-    key: K,
-    val: V,
-}
-
-pub struct HashDB<'txn, K, V, S = RandomState> {
-    db: RawDB,
-    hash_builder: S,
-    phantom: &'txn PhantomData<(K,V)>,
-}
-
-impl<K, V> HashDB<'_, K, V>
-{
-    pub fn create(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
-        Self::create_with_hasher(env, name, RandomState::new())
-    }
-    pub fn open(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
-        Self::open_with_hasher(env, name, RandomState::new())
-    }
-}
-
-impl<K, V, S> HashDB<'_, K, V, S>
-{
-    pub fn create_with_hasher(env: &Environment, name: Option<&str>, hash_builder: S) -> lmdb::Result<Self> {
-        let flags = DatabaseFlags::INTEGER_KEY | DatabaseFlags::DUP_SORT;
-        let db = RawDB::create(env, name, flags)?;
-
-        Ok(Self {
-            db,
-            hash_builder,
-            phantom: &PhantomData,
-        })
-    }
-    pub fn open_with_hasher(env: &Environment, name: Option<&str>, hash_builder: S) -> lmdb::Result<Self> {
-        let db = RawDB::open(env, name)?;
-
-        Ok(Self {
-            db,
-            hash_builder,
-            phantom: &PhantomData,
-        })
-    }
-
-}
-
-impl<'txn, K, V, S> HashDB<'txn, K, V, S>
-    where K: Eq + Hash + Archive,
-          V: Archive,
-          S: BuildHasher,
-          K::Archived: PartialEq<K>,
-{
-    /// Retrieve an entry from the hashdb
-    ///
-    /// The result is a view pinned to the lifetime of the transaction. You can get owned Values
-    /// using [`Deserialize`].
-    pub fn get<T: Transaction>(&self, txn: &'txn T, key: &K) -> lmdb::Result<Option<&'txn Archived<Entry<K, V>>>>
-    {
-        let mut hasher = self.hash_builder.build_hasher();
-        key.hash(&mut hasher);
-        let hash = hasher.finish();
-
-        let mut cursor = self.db.open_ro_cursor(txn)?;
-        for res in cursor.iter_dup_of(&hash.to_ne_bytes()) {
-            let (_keybuf, valbuf) = res?;
-            let entry: &Archived<Entry<K, V>> = unsafe { archived_root::<Entry<K,V>>(valbuf.as_ref()) };
-
-            if &entry.key == key {
-                return Ok(Some(entry)) /*(EntryPtr {
-                    key: &entry.key,
-                    val: &entry.val,
-                }))*/;
-            }
-        }
-
-        Ok(None)
-    }
-
-    pub fn insert(&self, txn: &mut RwTransaction, entry: Archived<Entry<K, V>>) -> lmdb::Result<()> {
-
-    }
-}
-
-/// Memory Fixpoint for a value in the DB
-///
-/// LMDB binds lifetimes of buffers to the transaction that returned the buffer. As long as this
-/// transaction is not `commit()`ed, `abort()`ed or `reset()`ed the pages containing these values
-/// are not returned into circulation.
-/// This struct encodes this by binding a live reference to the Transaction to the returned
-/// and interpreted buffer. The placeholder `T` is the container for the transaction. This may be a
-/// plain `RoTransaction<'env>`, a `Rc<RoTxn>` (meaning Fix is !Send) or an `Arc<RoTxn>`, depending
-/// on your needs.
-pub struct Fix<T, V: Archive> {
-    ptr: NonNull<V::Archived>,
-    txn: T,
-}
-pub type PinnedGet<'env, V> = Fix<RoTransaction<'env>, V>;
-pub type LocalKeep<'env, V> = Fix<Rc<RoTransaction<'env>>, V>;
-pub type GlobalKeep<'env, V> = Fix<Arc<RoTransaction<'env>>, V>;
-
-impl<'env, T, V> Fix<T, V>
-    where T: AsRef<RoTransaction<'env>>,
-          V: Archive,
-{
-    pub fn get(txn: T, db: &DB<V>, key: u64) -> lmdb::Result<Option<Self>> {
-        match db.get(txn.as_ref(), &key.to_ne_bytes()) {
-            Ok(buf) => Ok(Some(
-                Self { 
-                    ptr: unsafe { archived_root::<V>(buf.as_ref()).into() },
-                    txn, 
-                }
-            )),
-            Err(lmdb::Error::NotFound) => Ok(None),
-            Err(e) => Err(e),
-        }
-    }
-}
-impl<'env, T, V> Deref for Fix<T, V>
-    where T: AsRef<RoTransaction<'env>>,
-          V: Archive,
-{
-    type Target = V::Archived;
-
-    fn deref(&self) -> &Self::Target {
-        // As long as the transaction is kept alive (which it is, because it's in self) state is a
-        // valid pointer so this is safe.
-        unsafe { self.ptr.as_ref() }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::result::Result;
-    use std::ops::Deref;
-
-    use lmdb::{
-        EnvironmentFlags as EF,
-        DatabaseFlags as DF,
-        WriteFlags as WF,
-    };
-
-    pub struct TempEnv {
-        dir: tempfile::TempDir,
-        env: Arc<Environment>,
-    }
-
-    impl Deref for TempEnv {
-        type Target = Arc<Environment>;
-        fn deref(&self) -> &Self::Target {
-            &self.env
-        }
-    }
-
-    pub fn open_test_env() -> TempEnv {
-        let dir = tempfile::tempdir().expect("Failed to create tempdir for testdb");
-        let env = Environment::new()
-            .set_flags(EF::NO_SYNC | EF::WRITE_MAP)
-            .open(dir.path()).expect("Failed to open lmdb");
-        let env = Arc::new(env);
-
-        TempEnv { dir, env }
-    }
-
-    struct TestAdapter;
-
-    #[derive(Debug)]
-    enum TestErr {
-        Utf8(std::str::Utf8Error),
-        Binc(Box<bincode::ErrorKind>),
-        LMDB(lmdb::Error),
-    }
-
-    impl From<lmdb::Error> for TestErr {
-        fn from(e: lmdb::Error) -> TestErr {
-            TestErr::LMDB(e)
-        }
-    }
-
-    impl From<std::str::Utf8Error> for TestErr {
-        fn from(e: std::str::Utf8Error) -> TestErr {
-            TestErr::Utf8(e)
-        }
-    }
-
-    impl From<bincode::Error> for TestErr {
-        fn from(e: bincode::Error) -> TestErr {
-            TestErr::Binc(e)
-        }
-    }
-
-    impl DatabaseAdapter for TestAdapter {
-        type Key = str;
-        type Err = TestErr;
-
-        fn serialize_key(key: &Self::Key) -> &[u8] {
-            key.as_bytes()
-        }
-        fn deserialize_key<'de>(input: &'de [u8]) -> Result<&'de Self::Key, Self::Err> {
-            std::str::from_utf8(input).map_err(|e| e.into())
-        }
-    }
-
-    type TestDB<'txn> = Objectstore<'txn, TestAdapter, &'txn str>;
-
-    #[test]
-    fn simple_get() {
-        let e = open_test_env();
-        let ldb = e.create_db(None, DF::empty()).expect("Failed to create lmdb db");
-
-        let db = DB::new(e.env.clone(), ldb);
-
-        let testdb = TestDB::new(db.clone());
-
-        let mut val = "value";
-        let mut txn = db.begin_rw_txn().expect("Failed to being rw txn");
-        testdb.put(&mut txn, "key", &val, WF::empty()).expect("Failed to insert");
-        testdb.put(&mut txn, "key2", &val, WF::empty()).expect("Failed to insert");
-        testdb.put(&mut txn, "key3", &val, WF::empty()).expect("Failed to insert");
-        testdb.put(&mut txn, "key4", &val, WF::empty()).expect("Failed to insert");
-        testdb.put(&mut txn, "key5", &val, WF::empty()).expect("Failed to insert");
-        txn.commit().expect("commit failed");
-
-        {
-            let txn;
-            txn = db.begin_ro_txn().unwrap();
-
-            let val = testdb.get(&txn, "key").expect("Failed to retrieve");
-            assert_eq!(Some("value"), val);
-        }
-
-        {
-            let val2 = "longer_value";
-            let mut txn = db.begin_rw_txn().unwrap();
-            testdb.put(&mut txn, "key", &val2, WF::empty()).expect("Failed to update");
-            txn.commit().unwrap();
-        }
-
-        {
-            let txn = db.begin_ro_txn().unwrap();
-            let found = testdb.get_in_place(&txn, "key", &mut val).expect("Failed to retrieve update");
-            assert!(found);
-            assert_eq!("longer_value", val);
-        }
-
-        {
-            let txn = db.begin_ro_txn().unwrap();
-            let mut it = testdb.iter(&txn).unwrap();
-            assert_eq!("longer_value", it.next().unwrap().unwrap());
-            let mut i = 0;
-            while let Some(e) = it.next() {
-                assert_eq!("value", e.unwrap());
-                i += 1;
-            }
-            assert_eq!(i, 4)
-        }
-    }
-}

src/db/fix.rs

@@ -0,0 +1,41 @@
+use std::{
+    ptr::NonNull,
+    ops::Deref,
+};
+
+use lmdb::Transaction;
+
+/// Memory Fixpoint for a value in the DB
+///
+/// LMDB binds lifetimes of buffers to the transaction that returned the buffer. As long as this
+/// transaction is not `commit()`ed, `abort()`ed or `reset()`ed the pages containing these values
+/// are not returned into circulation.
+/// This struct encodes this by binding a live reference to the Transaction to the returned
+/// and interpreted buffer. The placeholder `T` is the container for the transaction. This may be a
+/// plain `RoTransaction<'env>`, a `Rc<RoTxn>` (meaning Fix is !Send) or an `Arc<RoTxn>`, depending
+/// on your needs.
+pub struct LMDBorrow<T, V> {
+    ptr: NonNull<V>,
+    txn: T,
+}
+
+impl<'env, T, V> LMDBorrow<T, V>
+    where T: Transaction,
+{
+    pub unsafe fn fix(txn: T, ptr: &'_ V) -> Self {
+        Self { ptr: ptr.into(), txn, }
+    }
+}
+
+impl<'env, T, V> Deref for LMDBorrow<T, V>
+{
+    type Target = V;
+
+    fn deref(&self) -> &Self::Target {
+        // As long as the transaction is kept alive (which it is, because it's in self) state is a
+        // valid pointer so this is safe.
+        unsafe { self.ptr.as_ref() }
+    }
+}
+
+

src/db/hash.rs

@@ -0,0 +1,163 @@
+use std::{
+    marker::PhantomData,
+    hash::{
+        Hash,
+        Hasher,
+        BuildHasher,
+    },
+    collections::hash_map::RandomState,
+};
+
+use rkyv::{
+    Archive,
+    Archived,
+    Serialize,
+    Deserialize,
+    Fallible,
+};
+
+use super::{
+    DB,
+    Adapter,
+    OutputBuffer,
+
+    Environment,
+
+    DatabaseFlags,
+    WriteFlags,
+
+    Transaction,
+    RwTransaction,
+};
+
+
+#[derive(Archive, Serialize, Deserialize)]
+/// The entry as it is stored inside the database.
+pub struct Entry<K: Archive, V: Archive> {
+    pub key: K,
+    pub val: V,
+}
+
+pub struct HashAdapter<K, A> {
+    k: PhantomData<K>,
+    a: PhantomData<A>,
+}
+impl<K, A> HashAdapter<K, A> {
+    pub fn new() -> Self {
+        Self { k: PhantomData, a: PhantomData }
+    }
+}
+
+impl<K, A: Fallible> Fallible for HashAdapter<K, A> { type Error = <A as Fallible>::Error; }
+impl<K, A: Adapter> Adapter for HashAdapter<K, A>
+    where K: Archive,
+          Entry<K, A::Value>: Serialize<A::Serializer>,
+{
+    type Value = Entry<K, A::Value>;
+    type Serializer = A::Serializer;
+
+    fn new_serializer() -> Self::Serializer
+        { A::new_serializer() }
+
+    fn from_db_err(e: lmdb::Error) -> <A as Fallible>::Error
+        { A::from_db_err(e) }
+
+    fn from_ser_err(e: <Self::Serializer as Fallible>::Error) -> <A as Fallible>::Error
+        { A::from_ser_err(e) }
+}
+
+
+const DEFAULT_HASH_FLAGS: libc::c_uint = 
+    DatabaseFlags::INTEGER_KEY.bits() + DatabaseFlags::DUP_SORT.bits();
+
+pub struct HashDB<A, K, H = RandomState>
+{
+    db: DB<HashAdapter<K, A>>,
+    hash_builder: H,
+}
+
+impl<A, K> HashDB<A, K>
+{
+    pub unsafe fn create(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
+        Self::create_with_hasher(env, name, RandomState::new())
+    }
+    pub unsafe fn open(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
+        Self::open_with_hasher(env, name, RandomState::new())
+    }
+}
+
+impl<A, K, H: BuildHasher> HashDB<A, K, H>
+{
+    fn new(db: DB<HashAdapter<K, A>>, hash_builder: H) -> Self {
+        Self { db, hash_builder }
+    }
+
+    pub unsafe fn create_with_hasher(env: &Environment, name: Option<&str>, hash_builder: H)
+        -> lmdb::Result<Self>
+    {
+        let flags = DatabaseFlags::from_bits(DEFAULT_HASH_FLAGS).unwrap();
+        DB::create(env, name, flags).map(|db| Self::new(db, hash_builder))
+    }
+    pub unsafe fn open_with_hasher(env: &Environment, name: Option<&str>, hash_builder: H)
+        -> lmdb::Result<Self>
+    {
+        DB::open(env, name).map(|db| Self::new(db, hash_builder))
+    }
+
+}
+
+impl<A, K, H> HashDB<A, K, H>
+    where A: Adapter,
+          HashAdapter<K, A>: Adapter<Value=Entry<K, A::Value>>,
+          H: BuildHasher,
+          K: Hash + Archive,
+          K::Archived: PartialEq<K>,
+{
+    /// Retrieve an entry from the hashdb
+    ///
+    /// The result is a view pinned to the lifetime of the transaction. You can get owned Values
+    /// using [`Deserialize`].
+    pub fn get<'txn, T: Transaction>(&self, txn: &'txn T, key: &K)
+        -> Result<
+            Option<&'txn Archived<<HashAdapter<K, A> as Adapter>::Value>>,
+            <HashAdapter<K, A> as Fallible>::Error
+            >
+    {
+        let mut hasher = self.hash_builder.build_hasher();
+        key.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        let mut cursor = self.db.open_ro_cursor(txn)?;
+        let i = cursor
+            .iter_dup_of(&hash.to_ne_bytes()).filter_map(|r| r.ok())
+            .map(|(_keybuf, entry)| entry);
+        for entry in i {
+            let entry: &Archived<Entry<K, A::Value>> = entry;
+            if entry.key == *key {
+                return Ok(Some(entry));
+            }
+        }
+
+        Ok(None)
+    }
+}
+
+impl<'a, A, K, H> HashDB<A, K, H>
+    where A: Adapter,
+          A::Serializer: OutputBuffer,
+          H: BuildHasher,
+          K: Hash + Serialize<A::Serializer>,
+          K::Archived: PartialEq<K>,
+{
+    pub fn insert_entry(&self, txn: &mut RwTransaction, entry: &Entry<K, A::Value>)
+        -> Result<(), A::Error>
+    {
+        let mut hasher = self.hash_builder.build_hasher();
+        entry.key.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        self.db.put(txn, &hash.to_ne_bytes(), entry, WriteFlags::empty())?;
+
+        Ok(())
+    }
+}

src/db/mod.rs

@@ -0,0 +1,164 @@
+pub use lmdb::{
+    Environment,
+
+    DatabaseFlags,
+    WriteFlags,
+    EnvironmentFlags,
+
+    Transaction,
+    RoTransaction,
+    RwTransaction,
+};
+
+mod raw;
+use raw::RawDB;
+
+mod typed;
+// re-exports
+pub use typed::{
+    DB,
+    Cursor,
+
+    Adapter,
+    OutputBuffer,
+    OutputWriter,
+};
+
+mod hash;
+pub use hash::{
+    HashDB,
+    Entry,
+};
+
+mod fix;
+pub use fix::LMDBorrow;
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::result::Result;
+    use std::ops::Deref;
+
+    use lmdb::{
+        EnvironmentFlags as EF,
+        DatabaseFlags as DF,
+        WriteFlags as WF,
+    };
+
+    pub struct TempEnv {
+        dir: tempfile::TempDir,
+        env: Arc<Environment>,
+    }
+
+    impl Deref for TempEnv {
+        type Target = Arc<Environment>;
+        fn deref(&self) -> &Self::Target {
+            &self.env
+        }
+    }
+
+    pub fn open_test_env() -> TempEnv {
+        let dir = tempfile::tempdir().expect("Failed to create tempdir for testdb");
+        let env = Environment::new()
+            .set_flags(EF::NO_SYNC | EF::WRITE_MAP)
+            .open(dir.path()).expect("Failed to open lmdb");
+        let env = Arc::new(env);
+
+        TempEnv { dir, env }
+    }
+
+    struct TestAdapter;
+
+    #[derive(Debug)]
+    enum TestErr {
+        Utf8(std::str::Utf8Error),
+        Binc(Box<bincode::ErrorKind>),
+        LMDB(lmdb::Error),
+    }
+
+    impl From<lmdb::Error> for TestErr {
+        fn from(e: lmdb::Error) -> TestErr {
+            TestErr::LMDB(e)
+        }
+    }
+
+    impl From<std::str::Utf8Error> for TestErr {
+        fn from(e: std::str::Utf8Error) -> TestErr {
+            TestErr::Utf8(e)
+        }
+    }
+
+    impl From<bincode::Error> for TestErr {
+        fn from(e: bincode::Error) -> TestErr {
+            TestErr::Binc(e)
+        }
+    }
+
+    impl DatabaseAdapter for TestAdapter {
+        type Key = str;
+        type Err = TestErr;
+
+        fn serialize_key(key: &Self::Key) -> &[u8] {
+            key.as_bytes()
+        }
+        fn deserialize_key<'de>(input: &'de [u8]) -> Result<&'de Self::Key, Self::Err> {
+            std::str::from_utf8(input).map_err(|e| e.into())
+        }
+    }
+
+    type TestDB<'txn> = Objectstore<'txn, TestAdapter, &'txn str>;
+
+    #[test]
+    fn simple_get() {
+        let e = open_test_env();
+        let ldb = e.create_db(None, DF::empty()).expect("Failed to create lmdb db");
+
+        let db = DB::new(e.env.clone(), ldb);
+
+        let testdb = TestDB::new(db.clone());
+
+        let mut val = "value";
+        let mut txn = db.begin_rw_txn().expect("Failed to being rw txn");
+        testdb.put(&mut txn, "key", &val, WF::empty()).expect("Failed to insert");
+        testdb.put(&mut txn, "key2", &val, WF::empty()).expect("Failed to insert");
+        testdb.put(&mut txn, "key3", &val, WF::empty()).expect("Failed to insert");
+        testdb.put(&mut txn, "key4", &val, WF::empty()).expect("Failed to insert");
+        testdb.put(&mut txn, "key5", &val, WF::empty()).expect("Failed to insert");
+        txn.commit().expect("commit failed");
+
+        {
+            let txn;
+            txn = db.begin_ro_txn().unwrap();
+
+            let val = testdb.get(&txn, "key").expect("Failed to retrieve");
+            assert_eq!(Some("value"), val);
+        }
+
+        {
+            let val2 = "longer_value";
+            let mut txn = db.begin_rw_txn().unwrap();
+            testdb.put(&mut txn, "key", &val2, WF::empty()).expect("Failed to update");
+            txn.commit().unwrap();
+        }
+
+        {
+            let txn = db.begin_ro_txn().unwrap();
+            let found = testdb.get_in_place(&txn, "key", &mut val).expect("Failed to retrieve update");
+            assert!(found);
+            assert_eq!("longer_value", val);
+        }
+
+        {
+            let txn = db.begin_ro_txn().unwrap();
+            let mut it = testdb.iter(&txn).unwrap();
+            assert_eq!("longer_value", it.next().unwrap().unwrap());
+            let mut i = 0;
+            while let Some(e) = it.next() {
+                assert_eq!("value", e.unwrap());
+                i += 1;
+            }
+            assert_eq!(i, 4)
+        }
+    }
+}

src/db/raw.rs

@@ -0,0 +1,62 @@
+use lmdb::{
+    Transaction,
+    RwTransaction,
+    Environment,
+    DatabaseFlags,
+    WriteFlags,
+};
+
+#[derive(Debug, Clone)]
+pub struct RawDB {
+    db: lmdb::Database,
+}
+
+impl RawDB {
+    pub fn open(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
+        env.open_db(name).map(|db| Self { db })
+    }
+    
+    pub fn create(env: &Environment, name: Option<&str>, flags: DatabaseFlags) -> lmdb::Result<Self> {
+        env.create_db(name, flags).map(|db| Self { db })
+    }
+
+    pub fn get<'txn, T: Transaction, K>(&self, txn: &'txn T, key: &K) -> lmdb::Result<Option<&'txn [u8]>>
+        where K: AsRef<[u8]>
+    {
+        match txn.get(self.db, key) {
+            Ok(buf) => Ok(Some(buf)),
+            Err(lmdb::Error::NotFound) => Ok(None),
+            Err(e) => Err(e),
+        }
+    }
+
+    pub fn put<K, V>(&self, txn: &mut RwTransaction, key: &K, value: &V, flags: WriteFlags)
+        -> lmdb::Result<()>
+        where K: AsRef<[u8]>,
+              V: AsRef<[u8]>,
+    {
+        txn.put(self.db, key, value, flags)
+    }
+
+    pub fn reserve<'txn, K>(&self, txn: &'txn mut RwTransaction, key: &K, size: usize, flags: WriteFlags) 
+        -> lmdb::Result<&'txn mut [u8]>
+        where K: AsRef<[u8]>
+    {
+        txn.reserve(self.db, key, size, flags)
+    }
+
+    pub fn del<K, V>(&self, txn: &mut RwTransaction, key: &K, value: Option<&V>) -> lmdb::Result<()>
+        where K: AsRef<[u8]>,
+              V: AsRef<[u8]>,
+    {
+        txn.del(self.db, key, value.map(AsRef::as_ref))
+    }
+
+    pub fn iter<'txn, C: lmdb::Cursor<'txn>>(&self, cursor: &'txn mut C) -> lmdb::Iter<'txn> {
+        cursor.iter_start()
+    }
+
+    pub fn open_ro_cursor<'txn, T: Transaction>(&self, txn: &'txn T) -> lmdb::Result<lmdb::RoCursor<'txn>> {
+        txn.open_ro_cursor(self.db)
+    }
+}

src/db/state.rs

@@ -1,13 +1,18 @@
-use std::fmt;
-use std::rc::Rc;
-use std::sync::Arc;
-use std::any::Any;
-use std::collections::{HashMap, hash_map::DefaultHasher};
-use std::hash::{Hash, Hasher};
-use std::default::Default;
-use std::ptr::NonNull;
-use std::alloc::Layout;
-use std::ops::Deref;
+use std::{
+    fmt,
+
+    any::Any,
+
+    collections::{
+        hash_map::DefaultHasher
+    },
+    hash::{
+        Hash, 
+        Hasher
+    },
+
+    path::Path,
+};
 
 use rkyv::{
     Archive,
@@ -16,28 +21,29 @@ use rkyv::{
     Serialize,
     Deserialize,
 
-    Fallible,
-    ser::{
-        Serializer,
-        ScratchSpace,
-        serializers::*,
-    },
-
-    string::{
-        StringResolver,
-        ArchivedString,
-    },
-
     out_field,
-    archived_root,
+
+    Fallible,
+    ser::serializers::AllocSerializer,
 };
 use rkyv_dyn::{
     archive_dyn,
 };
 use rkyv_typename::TypeName;
 
-use crate::error::Error;
-use crate::db::{DB, Environment, WriteFlags, Transaction, RoTransaction};
+use crate::db::{
+    DB,
+    Environment,
+
+    EnvironmentFlags,
+    DatabaseFlags,
+    WriteFlags,
+
+    Adapter,
+
+    Transaction,
+    RwTransaction,
+};
 
 #[archive_dyn(deserialize)]
 /// Trait to be implemented by any value in the state map.
@@ -160,122 +166,101 @@ impl StateBuilder {
     }
 }
 
-pub struct StateStorage {
-    key: u64,
-    db: StateDB
+struct StateAdapter;
+
+enum StateError {
+    LMDB(lmdb::Error),
+    RKYV(<AllocSerializer<1024> as Fallible>::Error),
 }
 
-impl StateStorage {
-    pub fn new(key: u64, db: StateDB) -> Self {
-        Self { key, db }
-    }
-
-    pub fn store(&mut self, instate: &State, outstate: &State) -> Result<(), Error> {
-        self.db.store(self.key, instate, outstate)
+impl From<lmdb::Error> for StateError {
+    fn from(e: lmdb::Error) -> Self {
+        Self::LMDB(e)
     }
 }
 
-struct SizeSerializer {
-    pos: usize,
-    scratch: FallbackScratch<HeapScratch<1024>, AllocScratch>,
+impl Fallible for StateAdapter {
+    type Error = StateError;
 }
-impl SizeSerializer {
-    pub fn new() -> Self {
-        Self { pos: 0, scratch: FallbackScratch::default() }
-    }
-}
-impl Fallible for SizeSerializer {
-    type Error = AllocScratchError;
-}
-impl Serializer for SizeSerializer {
-    fn pos(&self) -> usize {
-        self.pos
-    }
-    fn write(&mut self, bytes: &[u8]) -> Result<(), Self::Error> {
-        self.pos += bytes.len();
-        Ok(())
-    }
-}
-impl ScratchSpace for SizeSerializer {
-    unsafe fn push_scratch(
-        &mut self,
-        layout: Layout
-    ) -> Result<NonNull<[u8]>, Self::Error> {
-        self.scratch.push_scratch(layout)
+impl Adapter for StateAdapter {
+    type Serializer = AllocSerializer<1024>;
+    type Value = State;
+
+    fn new_serializer() -> Self::Serializer {
+        Self::Serializer::default()
     }
 
-    unsafe fn pop_scratch(
-        &mut self, 
-        ptr: NonNull<u8>, 
-        layout: Layout
-    ) -> Result<(), Self::Error> {
-        self.scratch.pop_scratch(ptr, layout)
+    fn from_ser_err(e: <Self::Serializer as Fallible>::Error) -> Self::Error {
+        StateError::RKYV(e)
+    }
+    fn from_db_err(e: lmdb::Error) -> Self::Error {
+        e.into()
     }
 }
 
-type LmdbSerializer<B, const N: usize> = CompositeSerializer<
-    BufferSerializer<B>, 
-    FallbackScratch<HeapScratch<N>, AllocScratch>, 
-    SharedSerializeMap,
->;
-
-
+/// State Database containing the currently set state
 pub struct StateDB {
-    input: DB,
-    output: DB,
+    /// The environment for all the databases below
+    env: Environment,
+
+    input: DB<StateAdapter>,
+    output: DB<StateAdapter>,
+
+    // TODO: Index resource name/id/uuid -> u64
 }
 
 impl StateDB {
-    pub fn new(input: DB, output: DB) -> Self {
-        Self { input, output }
+    fn open_env<P: AsRef<Path>>(path: &P) -> lmdb::Result<Environment> {
+        Environment::new()
+            .set_flags( EnvironmentFlags::WRITE_MAP 
+                      | EnvironmentFlags::NO_SUB_DIR 
+                      | EnvironmentFlags::NO_TLS
+                      | EnvironmentFlags::NO_READAHEAD)
+            .set_max_dbs(2)
+            .open(path.as_ref())
     }
 
-    fn get_size(&self, state: &State) -> usize {
-        let mut serializer = SizeSerializer::new();
-        serializer.serialize_value(state);
-        serializer.pos()
+    fn new(env: Environment, input: DB<StateAdapter>, output: DB<StateAdapter>) -> Self {
+        Self { env, input, output }
     }
 
-    pub fn store(&self, key: u64, instate: &State, outstate: &State) -> Result<(), Error> {
-        let insize = self.get_size(instate);
-        let outsize = self.get_size(outstate);
+    pub fn init<P: AsRef<Path>>(path: &P) -> lmdb::Result<Self> {
+        let env = Self::open_env(path)?;
+        let input = unsafe {
+            DB::create(&env, Some("input"), DatabaseFlags::INTEGER_KEY)?
+        };
+        let output = unsafe {
+            DB::create(&env, Some("output"), DatabaseFlags::INTEGER_KEY)?
+        };
 
-        let mut txn = self.input.begin_rw_txn()?;
+        Ok(Self::new(env, input, output))
+    }
 
-        let mut inbuf = self.input.reserve(&mut txn, &key.to_ne_bytes(), insize, WriteFlags::empty())?;
-        let bufser = BufferSerializer::new(inbuf);
-        let ser: LmdbSerializer<&mut [u8], 1024> = LmdbSerializer::new(
-            bufser,
-            FallbackScratch::default(),
-            SharedSerializeMap::default()
-        );
+    pub fn open<P: AsRef<Path>>(path: &P) -> lmdb::Result<Self> {
+        let env = Self::open_env(path)?;
+        let input = unsafe { DB::open(&env, Some("input"))?  };
+        let output = unsafe { DB::open(&env, Some("output"))?  };
 
-        let mut outbuf = self.output.reserve(&mut txn, &key.to_ne_bytes(), outsize, WriteFlags::empty())?;
-        let bufser = BufferSerializer::new(outbuf);
-        let ser: LmdbSerializer<&mut [u8], 1024> = LmdbSerializer::new(
-            bufser,
-            FallbackScratch::default(),
-            SharedSerializeMap::default()
-        );
-
-        txn.commit()?;
+        Ok(Self::new(env, input, output))
+    }
 
+    fn update_txn(&self, txn: &mut RwTransaction, key: u64, input: &State, output: &State)
+        -> Result<(), <StateAdapter as Fallible>::Error>
+    {
+        let flags = WriteFlags::empty();
+        let k = key.to_ne_bytes();
+        self.input.put(txn, &k, input, flags)?;
+        self.output.put(txn, &k, output, flags)?;
         Ok(())
     }
 
-    pub fn get_txn<'txn, T: Transaction>(&self, key: u64, txn: &'txn T)
-        -> Result<(&'txn ArchivedState, &'txn ArchivedState), Error> 
+    fn update(&self, key: u64, input: &State, output: &State) 
+        -> Result<(), <StateAdapter as Fallible>::Error>
     {
-        let inbuf = self.input.get(txn, &key.to_ne_bytes())?;
-        let outbuf = self.output.get(txn, &key.to_ne_bytes())?;
-        let instate = unsafe {
-            archived_root::<State>(inbuf.as_ref())
-        };
-        let outstate = unsafe {
-            archived_root::<State>(outbuf.as_ref())
-        };
+        let mut txn = self.env.begin_rw_txn().map_err(StateAdapter::from_db_err)?;
+        self.update_txn(&mut txn, key, input, output)?;
 
-        Ok((instate, outstate))
+        txn.commit().map_err(StateAdapter::from_db_err)
     }
 }
 

src/db/typed.rs

@@ -0,0 +1,198 @@
+use std::{
+    marker::PhantomData,
+};
+
+use rkyv::{
+    Archived,
+    archived_root,
+
+    Serialize,
+
+    ser::{
+        Serializer,
+        serializers::AllocSerializer,
+    },
+
+    util::AlignedVec,
+
+    Fallible,
+};
+
+use lmdb::{
+    Environment,
+    DatabaseFlags,
+    WriteFlags,
+
+    Transaction,
+    RwTransaction,
+};
+
+use super::RawDB;
+
+pub trait Adapter: Fallible {
+    type Serializer: rkyv::ser::Serializer;
+    type Value: Serialize<Self::Serializer>;
+
+    fn new_serializer() -> Self::Serializer;
+
+    fn from_ser_err(e: <Self::Serializer as Fallible>::Error) -> <Self as Fallible>::Error;
+    fn from_db_err(e: lmdb::Error) -> <Self as Fallible>::Error;
+}
+
+pub trait OutputBuffer {
+    type Buffer: AsRef<[u8]>;
+    fn into_slice(self) -> Self::Buffer;
+}
+
+impl<const N: usize> OutputBuffer for AllocSerializer<N> {
+    type Buffer = AlignedVec;
+    fn into_slice(self) -> Self::Buffer {
+        self.into_serializer().into_inner()
+    }
+}
+
+pub trait OutputWriter: Fallible {
+    fn write_into(&mut self, buf: &mut [u8]) -> Result<(), Self::Error>;
+}
+
+pub struct DB<A> {
+    db: RawDB,
+    phantom: PhantomData<A>,
+}
+
+impl<A> DB<A> {
+    fn new(db: RawDB) -> Self {
+        Self { db, phantom: PhantomData }
+    }
+
+    /// Open the underlying DB, creating it if necessary
+    ///
+    /// This function is unsafe since if the DB does not contain `A::Archived` we may end up doing
+    /// random memory reads or writes
+    pub unsafe fn create(env: &Environment, name: Option<&str>, flags: DatabaseFlags)
+        -> lmdb::Result<Self> 
+    {
+        RawDB::create(env, name, flags).map(Self::new)
+    }
+
+    /// Open the underlying DB
+    ///
+    /// This function is unsafe since if the DB does not contain `A::Archived` we may end up doing
+    /// random memory reads or writes
+    pub unsafe fn open(env: &Environment, name: Option<&str>) -> lmdb::Result<Self> {
+        RawDB::open(env, name).map(Self::new)
+    }
+}
+
+impl<A: Adapter> DB<A>
+{
+    pub fn del<K: AsRef<[u8]>>(&self, txn: &mut RwTransaction, key: &K) -> Result<(), A::Error> {
+        let v: Option<&Vec<u8>> = None;
+        self.db.del(txn, key, v).map_err(A::from_db_err)
+    }
+}
+
+impl<A: Adapter> DB<A>
+{
+    pub fn get<'txn, T: Transaction, K: AsRef<[u8]>>(&self, txn: &'txn T, key: &K) 
+        -> Result<Option<&'txn Archived<A::Value>>, A::Error>
+    {
+        if let Some(buf) = self.db.get(txn, key).map_err(A::from_db_err)? {
+            Ok(Some(unsafe { archived_root::<A::Value>(buf.as_ref()) }))
+        } else {
+            Ok(None)
+        }
+    }
+
+    pub fn open_ro_cursor<'txn, T: Transaction>(&self, txn: &'txn T) 
+        -> Result<Cursor<lmdb::RoCursor<'txn>, A>, A::Error>
+    {
+        let c = self.db.open_ro_cursor(txn)
+            .map_err(A::from_db_err)?;
+        // Safe because we are providing both Adapter and cursor and know it matches
+        Ok(unsafe { Cursor::new(c) })
+    }
+}
+
+impl<'a, A> DB<A>
+    where A: Adapter,
+          A::Serializer: OutputBuffer,
+{
+    pub fn put<K: AsRef<[u8]>>(&self, txn: &mut RwTransaction, key: &K, val: &A::Value, flags: WriteFlags) 
+        -> Result<usize, A::Error>
+    {
+        let mut serializer = A::new_serializer();
+        let pos = serializer.serialize_value(val)
+            .map_err(A::from_ser_err)?;
+
+        let buf = serializer.into_slice();
+        self.db.put(txn, key, &buf, flags)
+            .map_err(A::from_db_err)?;
+
+        Ok(pos)
+    }
+}
+
+impl<'a, A> DB<A>
+    where A: Adapter,
+          A::Serializer: OutputWriter,
+{
+    pub fn put_nocopy<K: AsRef<[u8]>>(&self, txn: &mut RwTransaction, key: &K, val: &A::Value, flags: WriteFlags)
+        -> Result<usize, A::Error>
+    {
+        let mut serializer = A::new_serializer();
+        let pos = serializer.serialize_value(val)
+            .map_err(A::from_ser_err)?;
+
+        let mut buf = self.db.reserve(txn, &key.as_ref(), pos, flags)
+            .map_err(A::from_db_err)?;
+        serializer.write_into(&mut buf)
+            .map_err(A::from_ser_err)?;
+
+        Ok(pos)
+    }
+}
+
+pub struct Cursor<C, A> {
+    cursor: C,
+    phantom: PhantomData<A>,
+}
+
+impl<'txn, C, A> Cursor<C, A>
+    where C: lmdb::Cursor<'txn>,
+          A: Adapter,
+{
+    // Unsafe because we don't know if the given adapter matches the given cursor
+    pub unsafe fn new(cursor: C) -> Self {
+        Self { cursor, phantom: PhantomData }
+    }
+
+    pub fn iter_dup_of<K: AsRef<[u8]>>(&mut self, key: &K) -> Iter<'txn, A> {
+        let iter = self.cursor.iter_dup_of(key);
+        // Safe because `new` isn't :P
+        unsafe { Iter::new(iter) }
+    }
+}
+
+pub struct Iter<'txn, A> {
+    iter: lmdb::Iter<'txn>,
+    phantom: PhantomData<A>,
+}
+
+impl<'txn, A: Adapter> Iter<'txn, A> {
+    pub unsafe fn new(iter: lmdb::Iter<'txn>) -> Self {
+        Self { iter, phantom: PhantomData }
+    }
+}
+
+impl<'txn, A: Adapter> Iterator for Iter<'txn, A> 
+    where Archived<A::Value>: 'txn
+{
+    type Item = Result<(&'txn [u8], &'txn Archived<A::Value>), A::Error>;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.iter.next().map(|r| r
+            .map_err(A::from_db_err)
+            .map(|(key, buf)| { (key, unsafe { archived_root::<A::Value>(buf) }) }))
+    }
+}

src/main.rs

@@ -1,11 +1,6 @@
 // FIXME: No.
 #![allow(dead_code)]
-
-#[macro_use]
-extern crate slog;
-
-#[macro_use]
-extern crate capnp_rpc;
+#![forbid(unused_imports)]
 
 extern crate async_trait;
 

src/resource.rs

@@ -1,20 +1,12 @@
 use async_trait::async_trait;
 
-use std::pin::Pin;
-use std::task::{Poll, Context};
-
-use futures::ready;
-use futures::future::{Future, BoxFuture};
 use futures::channel::oneshot;
-use futures::sink::Sink;
 use futures_signals::signal::Mutable;
 
-use smol::prelude::*;
-use smol::future::FutureExt;
-use smol::channel::{Sender, Receiver};
+use smol::channel::Receiver;
 
 use crate::error::Error;
-use crate::state::{State, StateStorage};
+use crate::state::{State, StateDB};
 
 /// A resource in BFFH has to contain several different parts;
 /// - Currently set state
@@ -60,7 +52,7 @@ pub struct Update {
 
 pub struct ResourceDriver {
     res: Box<dyn Resource>,
-    db: StateStorage,
+    db: StateDB,
 
     rx: Receiver<Update>,
     signal: Mutable<State>,
@@ -80,7 +72,7 @@ impl ResourceDriver {
                     // Not applying the new state isn't correct either since we don't know what the
                     // internal logic of the resource has done to make this happen.
                     // Another half right solution is to unwrap and recreate everything.
-                    self.db.store(&state, &outstate);
+                    //self.db.store(&state, &outstate);
                     self.signal.set_neq(outstate);
                 },
                 Err(e) => {