Adds support of OPTIONAL

lib/src/sparql/eval.rs

@@ -124,6 +124,12 @@ impl<S: EncodedQuadsStore> SimpleEvaluator<S> {
                         }),
                 )
             }
+            PlanNode::LeftJoin { left, right } => Box::new(LeftJoinIterator {
+                eval: self.clone(),
+                right_plan: *right,
+                left_iter: self.eval_plan(*left, from),
+                current_right_iter: None,
+            }),
             PlanNode::Filter { child, expression } => {
                 let eval = self.clone();
                 Box::new(self.eval_plan(*child, from).filter(move |tuple| {
@@ -136,23 +142,12 @@ impl<S: EncodedQuadsStore> SimpleEvaluator<S> {
                     }
                 }))
             }
-            PlanNode::Union { entry, children } => {
+            PlanNode::Union { entry, children } => Box::new(UnionIterator {
-                //TODO: avoid clones
+                eval: self.clone(),
-                let eval = self.clone();
+                children_plan: children,
-                Box::new(self.eval_plan(*entry, from).flat_map(move |tuple| {
+                input_iter: self.eval_plan(*entry, from),
-                    let eval = eval.clone();
+                current_iters: Vec::default(),
-                    let iter: EncodedTuplesIterator = match tuple {
+            }),
-                        Ok(tuple) => Box::new(
-                            children
-                                .clone()
-                                .into_iter()
-                                .flat_map(move |child| eval.eval_plan(child, tuple.clone())),
-                        ),
-                        Err(error) => Box::new(once(Err(error))),
-                    };
-                    iter
-                }))
-            }
             PlanNode::Extend {
                 child,
                 position,
@@ -302,7 +297,7 @@ impl<S: EncodedQuadsStore> SimpleEvaluator<S> {
                 _ => None,
             },
             PlanExpression::Datatype(e) => self.eval_expression(e, tuple)?.datatype(),
-            PlanExpression::Bound(v) => Some((*v >= tuple.len() && tuple[*v].is_some()).into()),
+            PlanExpression::Bound(v) => Some((*v < tuple.len() && tuple[*v].is_some()).into()),
             PlanExpression::IRI(e) => match self.eval_expression(e, tuple)? {
                 EncodedTerm::NamedNode { iri_id } => Some(EncodedTerm::NamedNode { iri_id }),
                 EncodedTerm::SimpleLiteral { value_id }
@@ -586,12 +581,76 @@ fn put_pattern_value(selector: &PatternValue, value: EncodedTerm, tuple: &mut En
 }
 
 fn put_value(position: usize, value: EncodedTerm, tuple: &mut EncodedTuple) {
-    if tuple.len() > position {
+    if position < tuple.len() {
         tuple[position] = Some(value)
     } else {
-        if tuple.len() < position {
+        if position > tuple.len() {
             tuple.resize(position, None);
         }
         tuple.push(Some(value))
     }
 }
+
+struct LeftJoinIterator<S: EncodedQuadsStore> {
+    eval: SimpleEvaluator<S>,
+    right_plan: PlanNode,
+    left_iter: EncodedTuplesIterator,
+    current_right_iter: Option<EncodedTuplesIterator>,
+}
+
+impl<S: EncodedQuadsStore> Iterator for LeftJoinIterator<S> {
+    type Item = Result<EncodedTuple>;
+
+    fn next(&mut self) -> Option<Result<EncodedTuple>> {
+        if let Some(ref mut right_iter) = self.current_right_iter {
+            if let Some(tuple) = right_iter.next() {
+                return Some(tuple);
+            }
+        }
+        match self.left_iter.next()? {
+            Ok(left_tuple) => {
+                let mut right_iter = self
+                    .eval
+                    .eval_plan(self.right_plan.clone(), left_tuple.clone());
+                match right_iter.next() {
+                    Some(right_tuple) => {
+                        self.current_right_iter = Some(right_iter);
+                        Some(right_tuple)
+                    }
+                    None => Some(Ok(left_tuple)),
+                }
+            }
+            Err(error) => Some(Err(error)),
+        }
+    }
+}
+
+struct UnionIterator<S: EncodedQuadsStore> {
+    eval: SimpleEvaluator<S>,
+    children_plan: Vec<PlanNode>,
+    input_iter: EncodedTuplesIterator,
+    current_iters: Vec<EncodedTuplesIterator>,
+}
+
+impl<S: EncodedQuadsStore> Iterator for UnionIterator<S> {
+    type Item = Result<EncodedTuple>;
+
+    fn next(&mut self) -> Option<Result<EncodedTuple>> {
+        while let Some(mut iter) = self.current_iters.pop() {
+            if let Some(tuple) = iter.next() {
+                self.current_iters.push(iter);
+                return Some(tuple);
+            }
+        }
+        match self.input_iter.next()? {
+            Ok(input_tuple) => {
+                for plan in &self.children_plan {
+                    self.current_iters
+                        .push(self.eval.eval_plan(plan.clone(), input_tuple.clone()));
+                }
+            }
+            Err(error) => return Some(Err(error)),
+        }
+        self.next()
+    }
+}

lib/src/sparql/plan.rs

@@ -1,4 +1,5 @@
 use model::vocab::xsd;
+use model::Literal;
 use sparql::algebra::*;
 use store::encoded::EncodedQuadsStore;
 use store::numeric_encoder::EncodedTerm;
@@ -27,6 +28,10 @@ pub enum PlanNode {
         entry: Box<PlanNode>,
         children: Vec<PlanNode>,
     },
+    LeftJoin {
+        left: Box<PlanNode>,
+        right: Box<PlanNode>,
+    },
     Extend {
         child: Box<PlanNode>,
         position: usize,
@@ -203,7 +208,25 @@ impl<'a, S: EncodedQuadsStore> PlanBuilder<'a, S> {
                 variables,
                 graph_name,
             )?,
-            GraphPattern::LeftJoin(a, b, e) => unimplemented!(),
+            GraphPattern::LeftJoin(a, b, e) => {
+                let right = Box::new(self.build_for_graph_pattern(
+                    b,
+                    PlanNode::Init,
+                    variables,
+                    graph_name,
+                )?);
+                PlanNode::LeftJoin {
+                    left: Box::new(self.build_for_graph_pattern(a, input, variables, graph_name)?),
+                    right: if *e == Expression::from(Literal::from(true)) {
+                        right
+                    } else {
+                        Box::new(PlanNode::Filter {
+                            child: right,
+                            expression: self.build_for_expression(e, variables)?,
+                        })
+                    },
+                }
+            }
             GraphPattern::Filter(e, p) => PlanNode::Filter {
                 child: Box::new(self.build_for_graph_pattern(p, input, variables, graph_name)?),
                 expression: self.build_for_expression(e, variables)?,
@@ -220,7 +243,7 @@ impl<'a, S: EncodedQuadsStore> PlanBuilder<'a, S> {
                             stack.push(b);
                         }
                         Some(p) => children.push(self.build_for_graph_pattern(
-                            a,
+                            p,
                             PlanNode::Init,
                             variables,
                             graph_name,

lib/tests/sparql_test_cases.rs

@@ -88,6 +88,11 @@ fn sparql_w3c_query_evaluation_testsuite() {
         Url::parse("http://www.w3.org/2001/sw/DataAccess/tests/data-r2/cast/manifest.ttl").unwrap(),
         Url::parse("http://www.w3.org/2001/sw/DataAccess/tests/data-r2/distinct/manifest.ttl")
             .unwrap(),
+        Url::parse(
+            "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/optional-filter/manifest.ttl",
+        ).unwrap(),
+        Url::parse("http://www.w3.org/2001/sw/DataAccess/tests/data-r2/optional/manifest.ttl")
+            .unwrap(),
     ];
     let test_blacklist = vec![
         //Multiple writing of the same xsd:integer. Our system does strong normalization.
@@ -97,12 +102,9 @@ fn sparql_w3c_query_evaluation_testsuite() {
         NamedNode::from_str(
             "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/distinct/manifest#distinct-9",
         ).unwrap(),
-        //With LeftJoin
+        //Test on curly brace scoping with OPTIONAL filter
-        NamedNode::from_str(
-            "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/distinct/manifest#distinct-4",
-        ).unwrap(),
         NamedNode::from_str(
-            "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/distinct/manifest#no-distinct-4",
+            "http://www.w3.org/2001/sw/DataAccess/tests/data-r2/optional-filter/manifest#dawg-optional-filter-005-not-simplified",
         ).unwrap(),
     ];
     let client = RDFClient::default();
@@ -130,6 +132,17 @@ fn sparql_w3c_query_evaluation_testsuite() {
                 }
                 None => MemoryDataset::default(),
             };
+            for graph_data in &test.graph_data {
+                let named_graph = data
+                    .named_graph(&NamedNode::from(graph_data.clone()).into())
+                    .unwrap();
+                client
+                    .load_graph(graph_data.clone())
+                    .unwrap()
+                    .iter()
+                    .unwrap()
+                    .for_each(|triple| named_graph.insert(&triple.unwrap()).unwrap());
+            }
             match data.query(client.get(&test.query).unwrap()) {
                 Err(error) => assert!(
                     false,
@@ -143,7 +156,7 @@ fn sparql_w3c_query_evaluation_testsuite() {
                         .unwrap();
                     assert!(
                             actual_graph.is_isomorphic(&expected_graph).unwrap(),
-                        "Failure on {}. Expected file:\n{}\nOutput file:\n{}\nParsed query:\n{}\nData:\n{}\n",
+                            "Failure on {}.\nExpected file:\n{}\nOutput file:\n{}\nParsed query:\n{}\nData:\n{}\n",
                             test,
                             expected_graph,
                             actual_graph,
@@ -296,6 +309,7 @@ pub struct Test {
     pub comment: Option<String>,
     pub query: Url,
     pub data: Option<Url>,
+    pub graph_data: Vec<Url>,
     pub result: Option<Url>,
 }
 
@@ -312,6 +326,9 @@ impl fmt::Display for Test {
         for data in &self.data {
             write!(f, " with data {}", data)?;
         }
+        for data in &self.graph_data {
+            write!(f, " and graph data {}", data)?;
+        }
         for result in &self.result {
             write!(f, " and expected result {}", result)?;
         }
@@ -371,6 +388,9 @@ pub mod qt {
         pub static ref DATA: NamedNode =
             NamedNode::from_str("http://www.w3.org/2001/sw/DataAccess/tests/test-query#data")
                 .unwrap();
+        pub static ref GRAPH_DATA: NamedNode =
+            NamedNode::from_str("http://www.w3.org/2001/sw/DataAccess/tests/test-query#graphData")
+                .unwrap();
     }
 }
 
@@ -408,12 +428,12 @@ impl<'a> Iterator for TestManifest<'a> {
                     Some(Term::Literal(c)) => Some(c.value().to_string()),
                     _ => None,
                 };
-                let (query, data) = match self
+                let (query, data, graph_data) = match self
                     .graph
                     .object_for_subject_predicate(&test_subject, &*mf::ACTION)
                     .unwrap()
                 {
-                    Some(Term::NamedNode(n)) => (n.into(), None),
+                    Some(Term::NamedNode(n)) => (n.into(), None, vec![]),
                     Some(Term::BlankNode(n)) => {
                         let n = n.into();
                         let query = match self
@@ -433,7 +453,15 @@ impl<'a> Iterator for TestManifest<'a> {
                             Some(Term::NamedNode(q)) => Some(q.into()),
                             _ => None,
                         };
-                        (query, data)
+                        let graph_data = self
+                            .graph
+                            .objects_for_subject_predicate(&n, &qt::GRAPH_DATA)
+                            .unwrap()
+                            .filter_map(|g| match g {
+                                Ok(Term::NamedNode(q)) => Some(q.into()),
+                                _ => None,
+                            }).collect();
+                        (query, data, graph_data)
                     }
                     Some(_) => return Some(Err("invalid action".into())),
                     None => {
@@ -458,6 +486,7 @@ impl<'a> Iterator for TestManifest<'a> {
                     comment,
                     query,
                     data,
+                    graph_data,
                     result,
                 }))
             }