add transaction stat

src/backend/impl_lmdb/transaction.rs

@@ -10,7 +10,7 @@
 
 use lmdb::Transaction;
 
-use super::{DatabaseImpl, ErrorImpl, RoCursorImpl, WriteFlagsImpl};
+use super::{DatabaseImpl, ErrorImpl, RoCursorImpl, StatImpl, WriteFlagsImpl};
 use crate::backend::traits::{
     BackendRoCursorTransaction, BackendRoTransaction, BackendRwCursorTransaction,
     BackendRwTransaction,
@@ -22,6 +22,7 @@ pub struct RoTransactionImpl<'t>(pub(crate) lmdb::RoTransaction<'t>);
 impl<'t> BackendRoTransaction for RoTransactionImpl<'t> {
     type Database = DatabaseImpl;
     type Error = ErrorImpl;
+    type Stat = StatImpl;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error> {
         self.0.get(db.0, &key).map_err(ErrorImpl::LmdbError)
@@ -30,6 +31,14 @@ impl<'t> BackendRoTransaction for RoTransactionImpl<'t> {
     fn abort(self) {
         self.0.abort()
     }
+
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error> {
+        //Err(ErrorImpl::LmdbError(lmdb::Error::Invalid))
+        self.0
+            .stat(db.0)
+            .map(StatImpl)
+            .map_err(ErrorImpl::LmdbError)
+    }
 }
 
 impl<'t> BackendRoCursorTransaction<'t> for RoTransactionImpl<'t> {
@@ -50,11 +59,20 @@ impl<'t> BackendRwTransaction for RwTransactionImpl<'t> {
     type Database = DatabaseImpl;
     type Error = ErrorImpl;
     type Flags = WriteFlagsImpl;
+    type Stat = StatImpl;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error> {
         self.0.get(db.0, &key).map_err(ErrorImpl::LmdbError)
     }
 
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error> {
+        //Err(ErrorImpl::LmdbError(lmdb::Error::Invalid))
+        self.0
+            .stat(db.0)
+            .map(StatImpl)
+            .map_err(ErrorImpl::LmdbError)
+    }
+
     fn put(
         &mut self,
         db: &Self::Database,

src/backend/impl_safe/transaction.rs

@@ -12,7 +12,8 @@
 use std::{collections::HashMap, sync::Arc};
 
 use super::{
-    snapshot::Snapshot, DatabaseImpl, EnvironmentImpl, ErrorImpl, RoCursorImpl, WriteFlagsImpl,
+    snapshot::Snapshot, DatabaseImpl, EnvironmentImpl, ErrorImpl, RoCursorImpl, StatImpl,
+    WriteFlagsImpl,
 };
 use crate::backend::traits::{
     BackendRoCursorTransaction, BackendRoTransaction, BackendRwCursorTransaction,
@@ -48,6 +49,7 @@ impl<'t> RoTransactionImpl<'t> {
 impl<'t> BackendRoTransaction for RoTransactionImpl<'t> {
     type Database = DatabaseImpl;
     type Error = ErrorImpl;
+    type Stat = StatImpl;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error> {
         let snapshot = self.snapshots.get(db).ok_or(ErrorImpl::DbIsForeignError)?;
@@ -57,6 +59,10 @@ impl<'t> BackendRoTransaction for RoTransactionImpl<'t> {
     fn abort(self) {
         // noop
     }
+
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error> {
+        Err(ErrorImpl::DbNotFoundError)
+    }
 }
 
 impl<'t> BackendRoCursorTransaction<'t> for RoTransactionImpl<'t> {
@@ -98,12 +104,17 @@ impl<'t> BackendRwTransaction for RwTransactionImpl<'t> {
     type Database = DatabaseImpl;
     type Error = ErrorImpl;
     type Flags = WriteFlagsImpl;
+    type Stat = StatImpl;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error> {
         let snapshot = self.snapshots.get(db).ok_or(ErrorImpl::DbIsForeignError)?;
         snapshot.get(key).ok_or(ErrorImpl::KeyValuePairNotFound)
     }
 
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error> {
+        Err(ErrorImpl::DbNotFoundError)
+    }
+
     #[cfg(not(feature = "db-dup-sort"))]
     fn put(
         &mut self,

src/backend/traits.rs

@@ -134,16 +134,20 @@ pub trait BackendEnvironment<'e>: Debug {
 pub trait BackendRoTransaction: Debug {
     type Error: BackendError;
     type Database: BackendDatabase;
+    type Stat: BackendStat;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error>;
 
     fn abort(self);
+
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error>;
 }
 
 pub trait BackendRwTransaction: Debug {
     type Error: BackendError;
     type Database: BackendDatabase;
     type Flags: BackendWriteFlags;
+    type Stat: BackendStat;
 
     fn get(&self, db: &Self::Database, key: &[u8]) -> Result<&[u8], Self::Error>;
 
@@ -171,6 +175,8 @@ pub trait BackendRwTransaction: Debug {
     fn commit(self) -> Result<(), Self::Error>;
 
     fn abort(self);
+
+    fn stat(&self, db: &Self::Database) -> Result<Self::Stat, Self::Error>;
 }
 
 pub trait BackendRoCursorTransaction<'t>: BackendRoTransaction {

src/readwrite.rs

@@ -11,7 +11,7 @@
 use crate::{
     backend::{
         BackendDatabase, BackendRoCursor, BackendRoCursorTransaction, BackendRoTransaction,
-        BackendRwCursorTransaction, BackendRwTransaction,
+        BackendRwCursorTransaction, BackendRwTransaction, BackendStat,
     },
     error::StoreError,
     helpers::read_transform,
@@ -24,12 +24,15 @@ pub struct Writer<T>(T);
 pub trait Readable<'r> {
     type Database: BackendDatabase;
     type RoCursor: BackendRoCursor<'r>;
+    type Stat: BackendStat;
 
     fn get<K>(&'r self, db: &Self::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
     where
         K: AsRef<[u8]>;
 
     fn open_ro_cursor(&'r self, db: &Self::Database) -> Result<Self::RoCursor, StoreError>;
+
+    fn stat(&'r self, db: &Self::Database) -> Result<Self::Stat, StoreError>;
 }
 
 impl<'r, T> Readable<'r> for Reader<T>
@@ -38,6 +41,7 @@ where
 {
     type Database = T::Database;
     type RoCursor = T::RoCursor;
+    type Stat = T::Stat;
 
     fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
     where
@@ -53,6 +57,10 @@ where
     fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
         self.0.open_ro_cursor(db).map_err(|e| e.into())
     }
+
+    fn stat(&'r self, db: &Self::Database) -> Result<Self::Stat, StoreError> {
+        self.0.stat(db).map_err(|e| e.into())
+    }
 }
 
 impl<T> Reader<T> {
@@ -76,6 +84,7 @@ where
 {
     type Database = T::Database;
     type RoCursor = T::RoCursor;
+    type Stat = T::Stat;
 
     fn get<K>(&'r self, db: &T::Database, k: &K) -> Result<Option<Value<'r>>, StoreError>
     where
@@ -91,6 +100,10 @@ where
     fn open_ro_cursor(&'r self, db: &T::Database) -> Result<T::RoCursor, StoreError> {
         self.0.open_ro_cursor(db).map_err(|e| e.into())
     }
+
+    fn stat(&'r self, db: &Self::Database) -> Result<Self::Stat, StoreError> {
+        self.0.stat(db).map_err(|e| e.into())
+    }
 }
 
 impl<T> Writer<T> {