things

6 files changed, 134 insertions, 16 deletions

diff --git a/database/src/indices/key.rs b/database/src/indices/key.rs
new file mode 100644
index 0000000..ab56f76
--- /dev/null
+++ b/database/src/indices/key.rs
@@ -0,0 +1,42 @@
+/*
+    This file is part of jellything (https://codeberg.org/metamuffin/jellything)
+    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
+    Copyright (C) 2025 metamuffin <metamuffin.org>
+*/
+
+use crate::{
+    backends::WriteTransaction,
+    indices::Index,
+    table::{RowNum, Table, TableNum},
+};
+use anyhow::Result;
+
+pub struct KeyIndex<T> {
+    id: TableNum,
+    key: fn(&T) -> &[u8],
+}
+
+impl<T: 'static> KeyIndex<T> {
+    pub fn new(table: &mut Table<T>, id: TableNum, key: fn(&T) -> &[u8]) -> Self {
+        table.indices.push(Box::new(Self { id, key }));
+        Self { id, key }
+    }
+    pub fn key(&self, id: RowNum, val: &T) -> Vec<u8> {
+        let mut v = Vec::new();
+        v.extend(self.id.to_be_bytes());
+        v.extend((self.key)(val));
+        v.extend(id.to_be_bytes());
+        v
+    }
+}
+impl<T: 'static> Index<T> for KeyIndex<T> {
+    fn add(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
+        db.set(&self.key(id, val), &[])
+    }
+    fn remove(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
+        db.del(&self.key(id, val))
+    }
+    fn compare(&self, before: &T, after: &T) -> bool {
+        (self.key)(before) == (self.key)(after)
+    }
+}
diff --git a/database/src/indices/mod.rs b/database/src/indices/mod.rs
index 523235e..e291c91 100644
--- a/database/src/indices/mod.rs
+++ b/database/src/indices/mod.rs
@@ -8,6 +8,7 @@ use crate::{backends::WriteTransaction, table::RowNum};
 use anyhow::Result;
 
 pub mod order;
+pub mod key;
 
 pub trait Index<T> {
     fn add(&self, db: &mut dyn WriteTransaction, row: RowNum, val: &T) -> Result<()>;
diff --git a/database/src/indices/order.rs b/database/src/indices/order.rs
index 5b7924b..25ab01b 100644
--- a/database/src/indices/order.rs
+++ b/database/src/indices/order.rs
@@ -4,34 +4,35 @@
     Copyright (C) 2025 metamuffin <metamuffin.org>
 */
 
-use crate::{backends::WriteTransaction, indices::Index, table::Table};
+use crate::{
+    backends::WriteTransaction,
+    indices::Index,
+    table::{RowNum, Table, TableNum},
+};
 use anyhow::Result;
+use bytemuck::{NoUninit, bytes_of};
 
 pub struct OrderIndex<T> {
-    id: u32,
+    id: TableNum,
     value: fn(&T) -> [u8; 8],
 }
+
+#[repr(C)]
+#[derive(NoUninit, Clone, Copy)]
+struct Key(TableNum, [u8; 8], RowNum);
+
 impl<T: 'static> OrderIndex<T> {
-    pub fn new(table: &mut Table<T>, id: u32, value: fn(&T) -> [u8; 8]) -> Self {
+    pub fn new(table: &mut Table<T>, id: TableNum, value: fn(&T) -> [u8; 8]) -> Self {
         table.indices.push(Box::new(Self { id, value }));
         Self { id, value }
     }
-    fn key(&self, id: u64, val: &T) -> Vec<u8> {
-        let mut key = Vec::new();
-        key.extend(self.id.to_be_bytes());
-        key.extend((self.value)(val));
-        key.extend(id.to_be_bytes());
-        key
-    }
 }
 impl<T: 'static> Index<T> for OrderIndex<T> {
-    fn add(&self, db: &mut dyn WriteTransaction, id: u64, val: &T) -> Result<()> {
-        db.set(&self.key(id, val), &[])?;
-        Ok(())
+    fn add(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
+        db.set(bytes_of(&Key(self.id, (self.value)(val), id)), &[])
     }
-    fn remove(&self, db: &mut dyn WriteTransaction, id: u64, val: &T) -> Result<()> {
-        db.del(&self.key(id, val))?;
-        Ok(())
+    fn remove(&self, db: &mut dyn WriteTransaction, id: RowNum, val: &T) -> Result<()> {
+        db.del(bytes_of(&Key(self.id, (self.value)(val), id)))
     }
     fn compare(&self, before: &T, after: &T) -> bool {
         (self.value)(before) == (self.value)(after)
diff --git a/database/src/iterator.rs b/database/src/iterator.rs
new file mode 100644
index 0000000..2db349b
--- /dev/null
+++ b/database/src/iterator.rs
@@ -0,0 +1,70 @@
+/*
+    This file is part of jellything (https://codeberg.org/metamuffin/jellything)
+    which is licensed under the GNU Affero General Public License (version 3); see /COPYING.
+    Copyright (C) 2025 metamuffin <metamuffin.org>
+*/
+
+use crate::backends::ReadTransaction;
+use anyhow::Result;
+use std::{borrow::Cow, ops::Range};
+
+pub struct PrefixIterator<'a> {
+    db: &'a dyn ReadTransaction,
+    prefix: &'a [u8],
+    cursor: Cow<'a, [u8]>,
+}
+impl Iterator for PrefixIterator<'_> {
+    type Item = Result<Vec<u8>>;
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.db.next(&self.cursor) {
+            Err(e) => Some(Err(e)),
+            Ok(None) => None,
+            Ok(Some(next)) => {
+                if next.starts_with(self.prefix) {
+                    self.cursor = next.clone().into();
+                    Some(Ok(next))
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
+
+pub struct RangeIterator<'a> {
+    db: &'a dyn ReadTransaction,
+    range: Range<Cow<'a, [u8]>>,
+}
+impl Iterator for RangeIterator<'_> {
+    type Item = Result<Vec<u8>>;
+    fn next(&mut self) -> Option<Self::Item> {
+        match self.db.next(&self.range.start) {
+            Err(e) => Some(Err(e)),
+            Ok(None) => None,
+            Ok(Some(next)) => {
+                if next.as_slice() < self.range.end.as_ref() {
+                    self.range.start = next.clone().into();
+                    Some(Ok(next))
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
+impl DoubleEndedIterator for RangeIterator<'_> {
+    fn next_back(&mut self) -> Option<Self::Item> {
+        match self.db.prev(&self.range.end) {
+            Err(e) => Some(Err(e)),
+            Ok(None) => None,
+            Ok(Some(prev)) => {
+                if prev.as_slice() >= self.range.start.as_ref() {
+                    self.range.end = prev.clone().into();
+                    Some(Ok(prev))
+                } else {
+                    None
+                }
+            }
+        }
+    }
+}
diff --git a/database/src/lib.rs b/database/src/lib.rs
index 6c70e51..87baae1 100644
--- a/database/src/lib.rs
+++ b/database/src/lib.rs
@@ -6,3 +6,6 @@
 pub mod backends;
 pub mod indices;
 pub mod table;
+pub mod iterator;
+
+pub type Pad32 = u32;
diff --git a/database/src/table.rs b/database/src/table.rs
index e2f6196..1f44571 100644
--- a/database/src/table.rs
+++ b/database/src/table.rs
@@ -11,6 +11,7 @@ use crate::{
 use anyhow::Result;
 use serde::{Serialize, de::DeserializeOwned};
 
+pub type TableNum = u64;
 pub type RowNum = u64;
 
 pub struct Table<T> {