Implement iter() and range() on db

src/db/lib.rs

@@ -18,6 +18,7 @@ pub struct Transaction<'a>(pub(crate) &'a dyn ITx<'a>);
 pub struct Tree(pub(crate) Arc<dyn IDb>, pub(crate) usize);
 
 pub type Value<'a> = Cow<'a, [u8]>;
+pub type ValueIter<'a> = Box<dyn std::iter::Iterator<Item = Result<(Value<'a>, Value<'a>)>> + 'a>;
 
 // ----
 
@@ -89,6 +90,14 @@ impl Tree {
 	pub fn put<T: AsRef<[u8]>, U: AsRef<[u8]>>(&self, key: T, value: U) -> Result<()> {
 		self.0.put(self.1, key.as_ref(), value.as_ref())
 	}
+
+	pub fn iter<'a>(&'a self, reverse: bool) -> Result<ValueIter<'a>> {
+		self.0.range(self.1, None, reverse)
+	}
+
+	pub fn range<'a, T: AsRef<[u8]>>(&'a self, start: T, reverse: bool) -> Result<ValueIter<'a>> {
+		self.0.range(self.1, Some(start.as_ref()), reverse)
+	}
 }
 
 impl<'a> Transaction<'a> {
@@ -126,6 +135,12 @@ pub(crate) trait IDb: Send + Sync {
 
 	fn get<'a>(&'a self, tree: usize, key: &[u8]) -> Result<Option<Value<'a>>>;
 	fn put(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<()>;
+	fn range<'a>(
+		&'a self,
+		tree: usize,
+		start: Option<&[u8]>,
+		reverse: bool,
+	) -> Result<ValueIter<'a>>;
 
 	fn transaction(&self, f: &dyn ITxFn) -> TxResult<(), ()>;
 }

src/db/sled_adapter.rs

@@ -4,10 +4,11 @@ use std::sync::{Arc, RwLock};
 use arc_swap::ArcSwapOption;
 
 use sled::transaction::{
-	ConflictableTransactionError, TransactionError, Transactional, TransactionalTree, UnabortableTransactionError
+	ConflictableTransactionError, TransactionError, Transactional, TransactionalTree,
+	UnabortableTransactionError,
 };
 
-use crate::{Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxResult, Value, Db};
+use crate::{Db, Error, IDb, ITx, ITxFn, Result, TxError, TxFnResult, TxResult, Value, ValueIter};
 
 impl From<sled::Error> for Error {
 	fn from(e: sled::Error) -> Error {
@@ -58,12 +59,45 @@ impl IDb for SledDb {
 		let tree = self.get_tree(tree)?;
 		Ok(tree.get(key)?.map(|v| v.to_vec().into()))
 	}
+
 	fn put(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<()> {
 		let tree = self.get_tree(tree)?;
 		tree.insert(key, value)?;
 		Ok(())
 	}
 
+	fn range<'a>(
+		&'a self,
+		tree: usize,
+		start: Option<&[u8]>,
+		reverse: bool,
+	) -> Result<ValueIter<'a>> {
+		let tree = self.get_tree(tree)?;
+		if reverse {
+			match start {
+				Some(start) => Ok(Box::new(tree.range(..=start).rev().map(|v| {
+					v.map(|(x, y)| (x.to_vec().into(), y.to_vec().into()))
+						.map_err(Into::into)
+				}))),
+				None => Ok(Box::new(tree.iter().rev().map(|v| {
+					v.map(|(x, y)| (x.to_vec().into(), y.to_vec().into()))
+						.map_err(Into::into)
+				}))),
+			}
+		} else {
+			match start {
+				Some(start) => Ok(Box::new(tree.range(start..).map(|v| {
+					v.map(|(x, y)| (x.to_vec().into(), y.to_vec().into()))
+						.map_err(Into::into)
+				}))),
+				None => Ok(Box::new(tree.iter().map(|v| {
+					v.map(|(x, y)| (x.to_vec().into(), y.to_vec().into()))
+						.map_err(Into::into)
+				}))),
+			}
+		}
+	}
+
 	fn transaction(&self, f: &dyn ITxFn) -> TxResult<(), ()> {
 		let trees = self.trees.read().unwrap();
 		let res = trees.0.transaction(|txtrees| {
@@ -76,7 +110,10 @@ impl IDb for SledDb {
 					assert!(tx.err.into_inner().is_none());
 					Ok(())
 				}
-				TxFnResult::Abort => Err(ConflictableTransactionError::Abort(())),
+				TxFnResult::Abort => {
+					assert!(tx.err.into_inner().is_none());
+					Err(ConflictableTransactionError::Abort(()))
+				}
 				TxFnResult::Err => {
 					let err_arc = tx
 						.err
@@ -117,14 +154,18 @@ impl<'a> SledTx<'a> {
 
 impl<'a> ITx<'a> for SledTx<'a> {
 	fn get(&self, tree: usize, key: &[u8]) -> Result<Option<Value<'a>>> {
-		let tree = self.trees.get(tree)
+		let tree = self
+			.trees
+			.get(tree)
 			.ok_or(Error("invalid tree id".into()))?;
 		let tmp = self.save_error(tree.get(key))?;
 		Ok(tmp.map(|v| v.to_vec().into()))
 	}
 
 	fn put(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<()> {
-		let tree = self.trees.get(tree)
+		let tree = self
+			.trees
+			.get(tree)
 			.ok_or(Error("invalid tree id".into()))?;
 		self.save_error(tree.insert(key, value))?;
 		Ok(())

src/db/test.rs

@@ -5,36 +5,63 @@ use crate::sled_adapter::SledDb;
 fn test_suite(db: Db) -> Result<()> {
 	let tree = db.tree("tree")?;
 
+	let ka: &[u8] = &b"test"[..];
+	let kb: &[u8] = &b"zwello"[..];
 	let va: &[u8] = &b"plop"[..];
 	let vb: &[u8] = &b"plip"[..];
 	let vc: &[u8] = &b"plup"[..];
 
-	tree.put(b"test", va)?;
+	tree.put(ka, va)?;
-	assert_eq!(tree.get(b"test")?, Some(va.into()));
+	assert_eq!(tree.get(ka)?, Some(va.into()));
 
 	let res = db.transaction::<_, (), _>(|tx| {
-		assert_eq!(tx.get(&tree, b"test")?, Some(va.into()));
+		assert_eq!(tx.get(&tree, ka)?, Some(va.into()));
 
-		tx.put(&tree, b"test", vb)?;
+		tx.put(&tree, ka, vb)?;
 
-		assert_eq!(tx.get(&tree, b"test")?, Some(vb.into()));
+		assert_eq!(tx.get(&tree, ka)?, Some(vb.into()));
 
 		tx.commit(12)
 	});
 	assert!(matches!(res, Ok(12)));
-	assert_eq!(tree.get(b"test")?, Some(vb.into()));
+	assert_eq!(tree.get(ka)?, Some(vb.into()));
 
 	let res = db.transaction::<(), _, _>(|tx| {
-		assert_eq!(tx.get(&tree, b"test")?, Some(vb.into()));
+		assert_eq!(tx.get(&tree, ka)?, Some(vb.into()));
 
-		tx.put(&tree, b"test", vc)?;
+		tx.put(&tree, ka, vc)?;
 
-		assert_eq!(tx.get(&tree, b"test")?, Some(vc.into()));
+		assert_eq!(tx.get(&tree, ka)?, Some(vc.into()));
 
 		tx.abort(42)
 	});
 	assert!(matches!(res, Err(TxError::Abort(42))));
-	assert_eq!(tree.get(b"test")?, Some(vb.into()));
+	assert_eq!(tree.get(ka)?, Some(vb.into()));
+
+	let mut iter = tree.iter(false)?;
+	assert_eq!(iter.next().unwrap().unwrap(), (ka.into(), vb.into()));
+	assert!(iter.next().is_none());
+
+	tree.put(kb, vc)?;
+	assert_eq!(tree.get(kb)?, Some(vc.into()));
+
+	let mut iter = tree.iter(false)?;
+	assert_eq!(iter.next().unwrap().unwrap(), (ka.into(), vb.into()));
+	assert_eq!(iter.next().unwrap().unwrap(), (kb.into(), vc.into()));
+	assert!(iter.next().is_none());
+
+	let mut iter = tree.range("tz", false)?;
+	assert_eq!(iter.next().unwrap().unwrap(), (kb.into(), vc.into()));
+	assert!(iter.next().is_none());
+
+	let mut iter = tree.range("tz", true)?;
+	assert_eq!(iter.next().unwrap().unwrap(), (ka.into(), vb.into()));
+	assert!(iter.next().is_none());
+
+	let mut iter = tree.iter(true)?;
+	assert_eq!(iter.next().unwrap().unwrap(), (kb.into(), vc.into()));
+	assert_eq!(iter.next().unwrap().unwrap(), (ka.into(), vb.into()));
+	assert!(iter.next().is_none());
 
 	Ok(())
 }