From d27d62f973a6879c5b9671356ab1cbf74e7845f4 Mon Sep 17 00:00:00 2001
From: Tpt <thomaspt@hotmail.fr>
Date: Wed, 13 Oct 2021 21:14:21 +0200
Subject: [PATCH] Evaluation: Adds size_hint to iterators

Removes some iterators that could be written as filter
---
 lib/src/sparql/eval.rs | 135 +++++++++++++++++++++--------------------
 1 file changed, 69 insertions(+), 66 deletions(-)

diff --git a/lib/src/sparql/eval.rs b/lib/src/sparql/eval.rs
index 5a4a12ce..64e4b1a7 100644
--- a/lib/src/sparql/eval.rs
+++ b/lib/src/sparql/eval.rs
@@ -303,12 +303,15 @@ impl SimpleEvaluator {
                     Rc::new(move |from| {
                         let mut errors = Vec::default();
                         let mut right_values = EncodedTupleSet::new(join_keys.clone());
-                        for result in right(from.clone()) {
-                            match result {
-                                Ok(result) => right_values.insert(result),
-                                Err(error) => errors.push(Err(error)),
-                            }
-                        }
+                        right_values.extend(right(from.clone()).filter_map(
+                            |result| match result {
+                                Ok(result) => Some(result),
+                                Err(error) => {
+                                    errors.push(Err(error));
+                                    None
+                                }
+                            },
+                        ));
                         Box::new(HashJoinIterator {
                             left_iter: left(from),
                             right: right_values,
@@ -341,21 +344,30 @@ impl SimpleEvaluator {
                         let right: Vec<_> = right(from.clone())
                             .filter_map(std::result::Result::ok)
                             .collect();
-                        Box::new(CartesianProductAntiJoinIterator {
-                            left_iter: left(from),
-                            right,
-                        })
+                        Box::new(left(from).filter(move |left_tuple| {
+                            if let Ok(left_tuple) = left_tuple {
+                                !right.iter().any(|right_tuple| {
+                                    are_compatible_and_not_disjointed(left_tuple, right_tuple)
+                                })
+                            } else {
+                                true
+                            }
+                        }))
                     })
                 } else {
                     Rc::new(move |from| {
                         let mut right_values = EncodedTupleSet::new(join_keys.clone());
-                        for result in right(from.clone()).filter_map(std::result::Result::ok) {
-                            right_values.insert(result);
-                        }
-                        Box::new(HashAntiJoinIterator {
-                            left_iter: left(from),
-                            right: right_values,
-                        })
+                        right_values
+                            .extend(right(from.clone()).filter_map(std::result::Result::ok));
+                        Box::new(left(from).filter(move |left_tuple| {
+                            if let Ok(left_tuple) = left_tuple {
+                                !right_values.get(left_tuple).iter().any(|right_tuple| {
+                                    are_compatible_and_not_disjointed(left_tuple, right_tuple)
+                                })
+                            } else {
+                                true
+                            }
+                        }))
                     })
                 }
             }
@@ -2974,6 +2986,11 @@ impl Iterator for CartesianProductJoinIterator {
             }
         }
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (min, max) = self.left_iter.size_hint();
+        (min * self.right.len(), max.map(|v| v * self.right.len()))
+    }
 }
 
 struct HashJoinIterator {
@@ -3001,56 +3018,12 @@ impl Iterator for HashJoinIterator {
             }
         }
     }
-}
-
-struct CartesianProductAntiJoinIterator {
-    left_iter: EncodedTuplesIterator,
-    right: Vec<EncodedTuple>,
-}
-
-impl Iterator for CartesianProductAntiJoinIterator {
-    type Item = Result<EncodedTuple, EvaluationError>;
-
-    fn next(&mut self) -> Option<Result<EncodedTuple, EvaluationError>> {
-        loop {
-            match self.left_iter.next()? {
-                Ok(left_tuple) => {
-                    let exists_compatible_right = self.right.iter().any(|right_tuple| {
-                        are_compatible_and_not_disjointed(&left_tuple, right_tuple)
-                    });
-                    if !exists_compatible_right {
-                        return Some(Ok(left_tuple));
-                    }
-                }
-                Err(error) => return Some(Err(error)),
-            }
-        }
-    }
-}
 
-struct HashAntiJoinIterator {
-    left_iter: EncodedTuplesIterator,
-    right: EncodedTupleSet,
-}
-
-impl Iterator for HashAntiJoinIterator {
-    type Item = Result<EncodedTuple, EvaluationError>;
-
-    fn next(&mut self) -> Option<Result<EncodedTuple, EvaluationError>> {
-        loop {
-            match self.left_iter.next()? {
-                Ok(left_tuple) => {
-                    let exists_compatible_right =
-                        self.right.get(&left_tuple).iter().any(|right_tuple| {
-                            are_compatible_and_not_disjointed(&left_tuple, right_tuple)
-                        });
-                    if !exists_compatible_right {
-                        return Some(Ok(left_tuple));
-                    }
-                }
-                Err(error) => return Some(Err(error)),
-            }
-        }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (
+            0,
+            self.left_iter.size_hint().1.map(|v| v * self.right.len()),
+        )
     }
 }
 
@@ -3187,6 +3160,11 @@ impl Iterator for ConsecutiveDeduplication {
             }
         }
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (min, max) = self.inner.size_hint();
+        (if min == 0 { 0 } else { 1 }, max)
+    }
 }
 
 struct ConstructIterator {
@@ -3228,6 +3206,14 @@ impl Iterator for ConstructIterator {
             }
         }
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (min, max) = self.iter.size_hint();
+        (
+            min * self.template.len(),
+            max.map(|v| v * self.template.len()),
+        )
+    }
 }
 
 fn get_triple_template_value<'a>(
@@ -3771,6 +3757,7 @@ pub enum ComparatorFunction {
 struct EncodedTupleSet {
     key: Vec<usize>,
     map: HashMap<u64, Vec<EncodedTuple>>,
+    len: usize,
 }
 
 impl EncodedTupleSet {
@@ -3778,6 +3765,7 @@ impl EncodedTupleSet {
         Self {
             key,
             map: HashMap::new(),
+            len: 0,
         }
     }
     fn insert(&mut self, tuple: EncodedTuple) {
@@ -3785,6 +3773,7 @@ impl EncodedTupleSet {
             .entry(self.tuple_key(&tuple))
             .or_default()
             .push(tuple);
+        self.len += 1;
     }
 
     fn get(&self, tuple: &EncodedTuple) -> &[EncodedTuple] {
@@ -3800,6 +3789,20 @@ impl EncodedTupleSet {
         }
         hasher.finish()
     }
+
+    fn len(&self) -> usize {
+        self.len
+    }
+}
+
+impl Extend<EncodedTuple> for EncodedTupleSet {
+    fn extend<T: IntoIterator<Item = EncodedTuple>>(&mut self, iter: T) {
+        let iter = iter.into_iter();
+        self.map.reserve(iter.size_hint().0);
+        for tuple in iter {
+            self.insert(tuple);
+        }
+    }
 }
 
 #[test]