Adds Store::drop_graph

CHANGELOG.md

@@ -1,12 +1,13 @@
 ## Master
 
 ### Added
-- [SPARQL 1.1 Update](https://www.w3.org/TR/sparql11-update/) support for Rust, Python and JavaScript.
+- [SPARQL 1.1 Update](https://www.w3.org/TR/sparql11-update/) support for Rust, Python and JavaScript. All store-like classes now provide an `update` method.
 - [SPARQL 1.1 Query Results CSV and TSV Formats](https://www.w3.org/TR/sparql11-results-csv-tsv/) serializers and TSV format parser.
 - The SPARQL Query and Update algebra is now public.
 - 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`.
 
 ### Removed
 - The `default_graph_uris` and `named_graph_uris` parameters from `pyoxigraph` `query` methods.

lib/src/store/memory.rs

@@ -455,6 +455,35 @@ impl MemoryStore {
         dump_dataset(self.iter().map(Ok), writer, format)
     }
 
+    /// Removes a graph from this 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.clone());
+    /// let store = MemoryStore::new();
+    /// store.insert(quad.clone());    
+    /// assert_eq!(1, store.len());
+    ///
+    /// store.drop_graph(&ex);
+    /// assert_eq!(0, store.len());
+    /// # Result::<_,Box<dyn std::error::Error>>::Ok(())
+    /// ```
+    pub fn drop_graph<'a>(&self, graph_name: impl Into<GraphNameRef<'a>>) {
+        if let Some(graph_name) = self
+            .get_encoded_graph_name(graph_name.into())
+            .unwrap_infallible()
+        {
+            for quad in self.encoded_quads_for_pattern_inner(None, None, None, Some(graph_name)) {
+                let mut this = self;
+                this.remove_encoded(&quad).unwrap_infallible();
+            }
+        }
+    }
+
     #[allow(clippy::expect_used)]
     fn indexes(&self) -> RwLockReadGuard<'_, MemoryStoreIndexes> {
         self.indexes

lib/src/store/rocksdb.rs

@@ -352,6 +352,21 @@ impl RocksDbStore {
         dump_dataset(self.iter(), writer, syntax)
     }
 
+    /// Removes a graph from this store.
+    ///
+    /// See [`MemoryStore`](super::memory::MemoryStore::drop_graph()) for a usage example.
+    pub fn drop_graph<'a>(&self, graph_name: impl Into<GraphNameRef<'a>>) -> Result<(), io::Error> {
+        if let Some(graph_name) = self.get_encoded_graph_name(graph_name.into())? {
+            let mut transaction = self.auto_batch_writer();
+            for quad in self.encoded_quads_for_pattern(None, None, None, Some(graph_name)) {
+                transaction.remove_encoded(&quad?)?;
+            }
+            transaction.apply()
+        } else {
+            Ok(())
+        }
+    }
+
     fn id2str_cf(&self) -> &ColumnFamily {
         get_cf(&self.db, ID2STR_CF)
     }

lib/src/store/sled.rs

@@ -385,6 +385,19 @@ impl SledStore {
         dump_dataset(self.iter(), writer, format)
     }
 
+    /// Removes a graph from this store.
+    ///
+    /// See [`MemoryStore`](super::memory::MemoryStore::drop_graph()) for a usage example.
+    pub fn drop_graph<'a>(&self, graph_name: impl Into<GraphNameRef<'a>>) -> Result<(), io::Error> {
+        if let Some(graph_name) = self.get_encoded_graph_name(graph_name.into())? {
+            for quad in self.encoded_quads_for_pattern(None, None, None, Some(graph_name)) {
+                let mut this = self;
+                this.remove_encoded(&quad?)?;
+            }
+        }
+        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() {