Makes ReadableEncodedStore::encoded_quads_for_pattern static

lib/src/sparql/plan.rs

@@ -573,13 +573,13 @@ impl<S: ReadableEncodedStore> DatasetView<S> {
         }
     }
 
-    pub fn quads_for_pattern<'a>(
-        &'a self,
+    pub fn quads_for_pattern(
+        &self,
         subject: Option<EncodedTerm>,
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a> {
+    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>>> {
         if graph_name == None {
             Box::new(
                 self.store
@@ -604,8 +604,10 @@ impl<S: ReadableEncodedStore> DatasetView<S> {
                     }),
             )
         } else {
+            Box::new(
                 self.store
-                .encoded_quads_for_pattern(subject, predicate, object, graph_name)
+                    .encoded_quads_for_pattern(subject, predicate, object, graph_name),
+            )
         }
     }
 

lib/src/store/memory.rs

@@ -5,7 +5,7 @@ use crate::model::*;
 use crate::sparql::{GraphPattern, QueryOptions, QueryResult, SimplePreparedQuery};
 use crate::store::numeric_encoder::*;
 use crate::store::{load_dataset, load_graph, ReadableEncodedStore, WritableEncodedStore};
-use crate::{DatasetSyntax, GraphSyntax};
+use crate::{DatasetSyntax, Error, GraphSyntax};
 use std::collections::hash_map::DefaultHasher;
 use std::collections::{HashMap, HashSet};
 use std::convert::Infallible;
@@ -15,6 +15,7 @@ use std::io::BufRead;
 use std::iter::FromIterator;
 use std::mem::size_of;
 use std::sync::{Arc, RwLock, RwLockReadGuard, RwLockWriteGuard};
+use std::vec::IntoIter;
 
 /// In-memory store.
 /// It encodes a [RDF dataset](https://www.w3.org/TR/rdf11-concepts/#dfn-rdf-dataset) and allows to query and update it using SPARQL.
@@ -641,18 +642,20 @@ impl StrContainer for MemoryStoreIndexes {
 }
 
 impl<'a> ReadableEncodedStore for MemoryStore {
-    fn encoded_quads_for_pattern<'b>(
-        &'b self,
+    type QuadsIter = EncodedQuadsIter;
+
+    fn encoded_quads_for_pattern(
+        &self,
         subject: Option<EncodedTerm>,
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-    ) -> Box<dyn Iterator<Item = crate::Result<EncodedQuad>> + 'b> {
-        Box::new(
-            self.encoded_quads_for_pattern_inner(subject, predicate, object, graph_name)
-                .into_iter()
-                .map(Ok),
-        )
+    ) -> EncodedQuadsIter {
+        EncodedQuadsIter {
+            iter: self
+                .encoded_quads_for_pattern_inner(subject, predicate, object, graph_name)
+                .into_iter(),
+        }
     }
 }
 
@@ -1018,6 +1021,29 @@ impl fmt::Display for MemoryStore {
     }
 }
 
+pub(crate) struct EncodedQuadsIter {
+    iter: IntoIter<EncodedQuad>,
+}
+
+impl Iterator for EncodedQuadsIter {
+    type Item = Result<EncodedQuad, Error>;
+
+    fn next(&mut self) -> Option<Result<EncodedQuad, Error>> {
+        self.iter.next().map(Ok)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+
+    fn fold<Acc, G>(self, init: Acc, mut g: G) -> Acc
+    where
+        G: FnMut(Acc, Self::Item) -> Acc,
+    {
+        self.iter.fold(init, |acc, elt| g(acc, Ok(elt)))
+    }
+}
+
 // Isomorphism implementation
 
 fn iso_canonicalize(g: &MemoryStore) -> Vec<Vec<u8>> {

lib/src/store/mod.rs

@@ -27,13 +27,15 @@ use std::io::BufRead;
 use std::iter::Iterator;
 
 pub(crate) trait ReadableEncodedStore: StrLookup {
-    fn encoded_quads_for_pattern<'a>(
-        &'a self,
+    type QuadsIter: Iterator<Item = Result<EncodedQuad>> + 'static;
+
+    fn encoded_quads_for_pattern(
+        &self,
         subject: Option<EncodedTerm>,
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a>;
+    ) -> Self::QuadsIter;
 }
 
 pub(crate) trait WritableEncodedStore: StrContainer {

lib/src/store/rocksdb.rs

@@ -273,69 +273,6 @@ impl RocksDbStore {
         Ok(self.db.get_pinned_cf(self.spog_cf(), &buffer)?.is_some())
     }
 
-    fn encoded_quads_for_pattern(
-        &self,
-        subject: Option<EncodedTerm>,
-        predicate: Option<EncodedTerm>,
-        object: Option<EncodedTerm>,
-        graph_name: Option<EncodedTerm>,
-    ) -> DecodingIndexIterator {
-        match subject {
-            Some(subject) => match predicate {
-                Some(predicate) => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => self
-                            .spog_quads(encode_term_quad(subject, predicate, object, graph_name)),
-                        None => self.quads_for_subject_predicate_object(subject, predicate, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_subject_predicate_graph(subject, predicate, graph_name)
-                        }
-                        None => self.quads_for_subject_predicate(subject, predicate),
-                    },
-                },
-                None => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_subject_object_graph(subject, object, graph_name)
-                        }
-                        None => self.quads_for_subject_object(subject, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_subject_graph(subject, graph_name),
-                        None => self.quads_for_subject(subject),
-                    },
-                },
-            },
-            None => match predicate {
-                Some(predicate) => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_predicate_object_graph(predicate, object, graph_name)
-                        }
-
-                        None => self.quads_for_predicate_object(predicate, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_predicate_graph(predicate, graph_name),
-                        None => self.quads_for_predicate(predicate),
-                    },
-                },
-                None => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => self.quads_for_object_graph(object, graph_name),
-                        None => self.quads_for_object(object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_graph(graph_name),
-                        None => self.quads(),
-                    },
-                },
-            },
-        }
-    }
-
     fn quads(&self) -> DecodingIndexIterator {
         self.spog_quads(Vec::default())
     }
@@ -503,14 +440,69 @@ impl StrLookup for RocksDbStore {
 }
 
 impl ReadableEncodedStore for RocksDbStore {
-    fn encoded_quads_for_pattern<'a>(
-        &'a self,
+    type QuadsIter = DecodingIndexIterator;
+
+    fn encoded_quads_for_pattern(
+        &self,
         subject: Option<EncodedTerm>,
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a> {
-        Box::new(self.encoded_quads_for_pattern(subject, predicate, object, graph_name))
+    ) -> DecodingIndexIterator {
+        match subject {
+            Some(subject) => match predicate {
+                Some(predicate) => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => self
+                            .spog_quads(encode_term_quad(subject, predicate, object, graph_name)),
+                        None => self.quads_for_subject_predicate_object(subject, predicate, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_subject_predicate_graph(subject, predicate, graph_name)
+                        }
+                        None => self.quads_for_subject_predicate(subject, predicate),
+                    },
+                },
+                None => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_subject_object_graph(subject, object, graph_name)
+                        }
+                        None => self.quads_for_subject_object(subject, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_subject_graph(subject, graph_name),
+                        None => self.quads_for_subject(subject),
+                    },
+                },
+            },
+            None => match predicate {
+                Some(predicate) => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_predicate_object_graph(predicate, object, graph_name)
+                        }
+
+                        None => self.quads_for_predicate_object(predicate, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_predicate_graph(predicate, graph_name),
+                        None => self.quads_for_predicate(predicate),
+                    },
+                },
+                None => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => self.quads_for_object_graph(object, graph_name),
+                        None => self.quads_for_object(object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_graph(graph_name),
+                        None => self.quads(),
+                    },
+                },
+            },
+        }
     }
 }
 
@@ -753,7 +745,7 @@ impl StaticDBRowIterator {
     }
 }
 
-struct DecodingIndexIterator {
+pub(crate) struct DecodingIndexIterator {
     iter: StaticDBRowIterator,
     prefix: Vec<u8>,
     encoding: QuadEncoding,

lib/src/store/sled.rs

@@ -127,7 +127,7 @@ impl SledStore {
         let object = object.map(|o| o.into());
         let graph_name = graph_name.map(|g| g.into());
         let this = self.clone();
-        self.encoded_quads_for_pattern_inner(subject, predicate, object, graph_name)
+        self.encoded_quads_for_pattern(subject, predicate, object, graph_name)
             .map(move |quad| this.decode_quad(&quad?))
     }
 
@@ -220,73 +220,6 @@ impl SledStore {
         Ok(self.quads.contains_key(buffer)?)
     }
 
-    fn encoded_quads_for_pattern_inner(
-        &self,
-        subject: Option<EncodedTerm>,
-        predicate: Option<EncodedTerm>,
-        object: Option<EncodedTerm>,
-        graph_name: Option<EncodedTerm>,
-    ) -> DecodingQuadIterator {
-        match subject {
-            Some(subject) => match predicate {
-                Some(predicate) => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => self.inner_quads(encode_term_quad(
-                            SPOG_PREFIX,
-                            subject,
-                            predicate,
-                            object,
-                            graph_name,
-                        )),
-                        None => self.quads_for_subject_predicate_object(subject, predicate, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_subject_predicate_graph(subject, predicate, graph_name)
-                        }
-                        None => self.quads_for_subject_predicate(subject, predicate),
-                    },
-                },
-                None => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_subject_object_graph(subject, object, graph_name)
-                        }
-                        None => self.quads_for_subject_object(subject, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_subject_graph(subject, graph_name),
-                        None => self.quads_for_subject(subject),
-                    },
-                },
-            },
-            None => match predicate {
-                Some(predicate) => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => {
-                            self.quads_for_predicate_object_graph(predicate, object, graph_name)
-                        }
-                        None => self.quads_for_predicate_object(predicate, object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_predicate_graph(predicate, graph_name),
-                        None => self.quads_for_predicate(predicate),
-                    },
-                },
-                None => match object {
-                    Some(object) => match graph_name {
-                        Some(graph_name) => self.quads_for_object_graph(object, graph_name),
-                        None => self.quads_for_object(object),
-                    },
-                    None => match graph_name {
-                        Some(graph_name) => self.quads_for_graph(graph_name),
-                        None => self.quads(),
-                    },
-                },
-            },
-        }
-    }
-
     fn quads(&self) -> DecodingQuadIterator {
         self.inner_quads(&[SPOG_PREFIX])
     }
@@ -430,14 +363,73 @@ impl StrLookup for SledStore {
 }
 
 impl ReadableEncodedStore for SledStore {
-    fn encoded_quads_for_pattern<'a>(
-        &'a self,
+    type QuadsIter = DecodingQuadIterator;
+
+    fn encoded_quads_for_pattern(
+        &self,
         subject: Option<EncodedTerm>,
         predicate: Option<EncodedTerm>,
         object: Option<EncodedTerm>,
         graph_name: Option<EncodedTerm>,
-    ) -> Box<dyn Iterator<Item = Result<EncodedQuad>> + 'a> {
-        Box::new(self.encoded_quads_for_pattern_inner(subject, predicate, object, graph_name))
+    ) -> DecodingQuadIterator {
+        match subject {
+            Some(subject) => match predicate {
+                Some(predicate) => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => self.inner_quads(encode_term_quad(
+                            SPOG_PREFIX,
+                            subject,
+                            predicate,
+                            object,
+                            graph_name,
+                        )),
+                        None => self.quads_for_subject_predicate_object(subject, predicate, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_subject_predicate_graph(subject, predicate, graph_name)
+                        }
+                        None => self.quads_for_subject_predicate(subject, predicate),
+                    },
+                },
+                None => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_subject_object_graph(subject, object, graph_name)
+                        }
+                        None => self.quads_for_subject_object(subject, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_subject_graph(subject, graph_name),
+                        None => self.quads_for_subject(subject),
+                    },
+                },
+            },
+            None => match predicate {
+                Some(predicate) => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => {
+                            self.quads_for_predicate_object_graph(predicate, object, graph_name)
+                        }
+                        None => self.quads_for_predicate_object(predicate, object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_predicate_graph(predicate, graph_name),
+                        None => self.quads_for_predicate(predicate),
+                    },
+                },
+                None => match object {
+                    Some(object) => match graph_name {
+                        Some(graph_name) => self.quads_for_object_graph(object, graph_name),
+                        None => self.quads_for_object(object),
+                    },
+                    None => match graph_name {
+                        Some(graph_name) => self.quads_for_graph(graph_name),
+                        None => self.quads(),
+                    },
+                },
+            },
+        }
     }
 }
 
@@ -723,7 +715,7 @@ fn encode_term_quad(
     vec
 }
 
-struct DecodingQuadIterator {
+pub(crate) struct DecodingQuadIterator {
     iter: Iter,
 }