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-rw-r--r--src/db/counted_tree_hack.rs127
1 files changed, 0 insertions, 127 deletions
diff --git a/src/db/counted_tree_hack.rs b/src/db/counted_tree_hack.rs
deleted file mode 100644
index a4ce12e0..00000000
--- a/src/db/counted_tree_hack.rs
+++ /dev/null
@@ -1,127 +0,0 @@
-//! This hack allows a db tree to keep in RAM a counter of the number of entries
-//! it contains, which is used to call .len() on it. This is usefull only for
-//! the sled backend where .len() otherwise would have to traverse the whole
-//! tree to count items. For sqlite and lmdb, this is mostly useless (but
-//! hopefully not harmfull!). Note that a CountedTree cannot be part of a
-//! transaction.
-
-use std::sync::{
- atomic::{AtomicUsize, Ordering},
- Arc,
-};
-
-use crate::{Result, Tree, TxError, Value, ValueIter};
-
-#[derive(Clone)]
-pub struct CountedTree(Arc<CountedTreeInternal>);
-
-struct CountedTreeInternal {
- tree: Tree,
- len: AtomicUsize,
-}
-
-impl CountedTree {
- pub fn new(tree: Tree) -> Result<Self> {
- let len = tree.len()?;
- Ok(Self(Arc::new(CountedTreeInternal {
- tree,
- len: AtomicUsize::new(len),
- })))
- }
-
- pub fn len(&self) -> usize {
- self.0.len.load(Ordering::SeqCst)
- }
-
- pub fn is_empty(&self) -> bool {
- self.len() == 0
- }
-
- pub fn get<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<Value>> {
- self.0.tree.get(key)
- }
-
- pub fn first(&self) -> Result<Option<(Value, Value)>> {
- self.0.tree.first()
- }
-
- pub fn iter(&self) -> Result<ValueIter<'_>> {
- self.0.tree.iter()
- }
-
- // ---- writing functions ----
-
- pub fn insert<K, V>(&self, key: K, value: V) -> Result<Option<Value>>
- where
- K: AsRef<[u8]>,
- V: AsRef<[u8]>,
- {
- let old_val = self.0.tree.insert(key, value)?;
- if old_val.is_none() {
- self.0.len.fetch_add(1, Ordering::SeqCst);
- }
- Ok(old_val)
- }
-
- pub fn remove<K: AsRef<[u8]>>(&self, key: K) -> Result<Option<Value>> {
- let old_val = self.0.tree.remove(key)?;
- if old_val.is_some() {
- self.0.len.fetch_sub(1, Ordering::SeqCst);
- }
- Ok(old_val)
- }
-
- pub fn compare_and_swap<K, OV, NV>(
- &self,
- key: K,
- expected_old: Option<OV>,
- new: Option<NV>,
- ) -> Result<bool>
- where
- K: AsRef<[u8]>,
- OV: AsRef<[u8]>,
- NV: AsRef<[u8]>,
- {
- let old_some = expected_old.is_some();
- let new_some = new.is_some();
-
- let tx_res = self.0.tree.db().transaction(|tx| {
- let old_val = tx.get(&self.0.tree, &key)?;
- let is_same = match (&old_val, &expected_old) {
- (None, None) => true,
- (Some(x), Some(y)) if x == y.as_ref() => true,
- _ => false,
- };
- if is_same {
- match &new {
- Some(v) => {
- tx.insert(&self.0.tree, &key, v)?;
- }
- None => {
- tx.remove(&self.0.tree, &key)?;
- }
- }
- Ok(())
- } else {
- Err(TxError::Abort(()))
- }
- });
-
- match tx_res {
- Ok(()) => {
- match (old_some, new_some) {
- (false, true) => {
- self.0.len.fetch_add(1, Ordering::SeqCst);
- }
- (true, false) => {
- self.0.len.fetch_sub(1, Ordering::SeqCst);
- }
- _ => (),
- }
- Ok(true)
- }
- Err(TxError::Abort(())) => Ok(false),
- Err(TxError::Db(e)) => Err(e),
- }
- }
-}