From ab374e71787b1da37e1f885e88090bbcbd53ec47 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Wed, 8 Jun 2022 17:49:36 +0200
Subject: [PATCH] Add .clear() on db trees

---
 src/db/lib.rs            |  6 ++++++
 src/db/lmdb_adapter.rs   |  8 ++++++++
 src/db/sled_adapter.rs   |  6 ++++++
 src/db/sqlite_adapter.rs | 10 ++++++++++
 4 files changed, 30 insertions(+)

diff --git a/src/db/lib.rs b/src/db/lib.rs
index e9d3ea18..8188c715 100644
--- a/src/db/lib.rs
+++ b/src/db/lib.rs
@@ -197,6 +197,11 @@ impl Tree {
 	pub fn remove<T: AsRef<[u8]>>(&self, key: T) -> Result<Option<Value>> {
 		self.0.remove(self.1, key.as_ref())
 	}
+	/// Clears all values from the tree
+	#[inline]
+	pub fn clear(&self) -> Result<()> {
+		self.0.clear(self.1)
+	}
 
 	#[inline]
 	pub fn iter(&self) -> Result<ValueIter<'_>> {
@@ -311,6 +316,7 @@ pub(crate) trait IDb: Send + Sync {
 
 	fn insert(&self, tree: usize, key: &[u8], value: &[u8]) -> Result<Option<Value>>;
 	fn remove(&self, tree: usize, key: &[u8]) -> Result<Option<Value>>;
+	fn clear(&self, tree: usize) -> Result<()>;
 
 	fn iter(&self, tree: usize) -> Result<ValueIter<'_>>;
 	fn iter_rev(&self, tree: usize) -> Result<ValueIter<'_>>;
diff --git a/src/db/lmdb_adapter.rs b/src/db/lmdb_adapter.rs
index 74622919..30865829 100644
--- a/src/db/lmdb_adapter.rs
+++ b/src/db/lmdb_adapter.rs
@@ -139,6 +139,14 @@ impl IDb for LmdbDb {
 		Ok(old_val)
 	}
 
+	fn clear(&self, tree: usize) -> Result<()> {
+		let tree = self.get_tree(tree)?;
+		let mut tx = self.db.write_txn()?;
+		tree.clear(&mut tx)?;
+		tx.commit()?;
+		Ok(())
+	}
+
 	fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
 		let tree = self.get_tree(tree)?;
 		let tx = self.db.read_txn()?;
diff --git a/src/db/sled_adapter.rs b/src/db/sled_adapter.rs
index 982f8d82..cf61867d 100644
--- a/src/db/sled_adapter.rs
+++ b/src/db/sled_adapter.rs
@@ -113,6 +113,12 @@ impl IDb for SledDb {
 		Ok(old_val.map(|x| x.to_vec()))
 	}
 
+	fn clear(&self, tree: usize) -> Result<()> {
+		let tree = self.get_tree(tree)?;
+		tree.clear()?;
+		Ok(())
+	}
+
 	fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
 		let tree = self.get_tree(tree)?;
 		Ok(Box::new(tree.iter().map(|v| {
diff --git a/src/db/sqlite_adapter.rs b/src/db/sqlite_adapter.rs
index 14bf35ff..68d96ca0 100644
--- a/src/db/sqlite_adapter.rs
+++ b/src/db/sqlite_adapter.rs
@@ -182,6 +182,16 @@ impl IDb for SqliteDb {
 		Ok(old_val)
 	}
 
+	fn clear(&self, tree: usize) -> Result<()> {
+		trace!("clear {}: lock db", tree);
+		let this = self.0.lock().unwrap();
+		trace!("clear {}: lock acquired", tree);
+
+		let tree = this.get_tree(tree)?;
+		this.db.execute(&format!("DELETE FROM {}", tree), [])?;
+		Ok(())
+	}
+
 	fn iter(&self, tree: usize) -> Result<ValueIter<'_>> {
 		trace!("iter {}: lock db", tree);
 		let this = self.0.lock().unwrap();