Adds Store::clear

CHANGELOG.md

@@ -7,7 +7,7 @@
 - A simple built-in HTTP client. In the Rust library, is disabled by default behind the `http_client` feature. It powers SPARQL federation and SPARQL UPDATE `LOAD` operations.
 - `std::str::FromStr` implementations to `NamedNode`, `BlankNode`, `Literal`, `Term` and `Variable` allowing to easily parse Turtle/SPARQL serialization of these terms.
 - Optional Sled storage for `oxigraph_server`.
-- `(Memory|RocksDB|Sled)Store::drop_graph`.
+- `(Memory|RocksDB|Sled)Store::drop_graph` and `(Memory|RocksDB|Sled)Store::clear`.
 
 ### Removed
 - The `default_graph_uris` and `named_graph_uris` parameters from `pyoxigraph` `query` methods.

lib/src/store/memory.rs

@@ -484,6 +484,27 @@ impl MemoryStore {
         }
     }
 
+    /// Clears the store.
+    ///
+    /// Usage example:
+    /// ```
+    /// use oxigraph::MemoryStore;
+    /// use oxigraph::model::{NamedNode, Quad};
+    ///
+    /// let ex = NamedNode::new("http://example.com")?;
+    /// let quad = Quad::new(ex.clone(), ex.clone(), ex.clone(), ex);
+    /// let store = MemoryStore::new();
+    /// store.insert(quad.clone());    
+    /// assert_eq!(1, store.len());
+    ///
+    /// store.clear();
+    /// assert_eq!(0, store.len());
+    /// # Result::<_,Box<dyn std::error::Error>>::Ok(())
+    /// ```
+    pub fn clear(&self) {
+        *self.indexes_mut() = MemoryStoreIndexes::default();
+    }
+
     #[allow(clippy::expect_used)]
     fn indexes(&self) -> RwLockReadGuard<'_, MemoryStoreIndexes> {
         self.indexes
@@ -900,6 +921,7 @@ impl StrEncodingAware for MemoryStoreIndexes {
     type Error = Infallible;
     type StrId = LargeSpur;
 }
+
 impl WritableEncodedStore for MemoryStoreIndexes {
     fn insert_encoded(&mut self, quad: &EncodedQuad) -> Result<(), Infallible> {
         if quad.graph_name.is_default_graph() {

lib/src/store/rocksdb.rs

@@ -367,6 +367,23 @@ impl RocksDbStore {
         }
     }
 
+    /// Clears the store.
+    ///
+    /// See [`MemoryStore`](super::memory::MemoryStore::clear()) for a usage example.
+    pub fn clear(&self) -> Result<(), io::Error> {
+        self.clear_cf(self.id2str_cf())?;
+        self.clear_cf(self.spog_cf())?;
+        self.clear_cf(self.posg_cf())?;
+        self.clear_cf(self.ospg_cf())?;
+        self.clear_cf(self.gspo_cf())?;
+        self.clear_cf(self.gpos_cf())?;
+        self.clear_cf(self.gosp_cf())?;
+        self.clear_cf(self.dspo_cf())?;
+        self.clear_cf(self.dpos_cf())?;
+        self.clear_cf(self.dosp_cf())?;
+        Ok(())
+    }
+
     fn id2str_cf(&self) -> &ColumnFamily {
         get_cf(&self.db, ID2STR_CF)
     }
@@ -655,6 +672,34 @@ impl RocksDbStore {
             encoding,
         }
     }
+
+    fn clear_cf(&self, cf: &ColumnFamily) -> Result<(), io::Error> {
+        self.db
+            .delete_range_cf(
+                cf,
+                [
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                    u8::MIN,
+                ],
+                [
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                    u8::MAX,
+                ],
+            )
+            .map_err(map_err)
+    }
 }
 
 impl fmt::Display for RocksDbStore {

lib/src/store/sled.rs

@@ -398,6 +398,23 @@ impl SledStore {
         Ok(())
     }
 
+    /// Clears the store.
+    ///
+    /// See [`MemoryStore`](super::memory::MemoryStore::clear()) for a usage example.
+    pub fn clear(&self) -> Result<(), io::Error> {
+        self.dspo.clear()?;
+        self.dpos.clear()?;
+        self.dosp.clear()?;
+        self.gspo.clear()?;
+        self.gpos.clear()?;
+        self.gosp.clear()?;
+        self.spog.clear()?;
+        self.posg.clear()?;
+        self.ospg.clear()?;
+        self.id2str.clear()?;
+        Ok(())
+    }
+
     fn contains_encoded(&self, quad: &EncodedQuad) -> Result<bool, io::Error> {
         let mut buffer = Vec::with_capacity(4 * WRITTEN_TERM_MAX_SIZE);
         if quad.graph_name.is_default_graph() {