Specialize more consume_iters

src/iter/cloned.rs

@@ -205,6 +205,14 @@ where
         }
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where
+        I: IntoIterator<Item = &'a T>
+    {
+        self.base = self.base.consume_iter(iter.into_iter().cloned());
+        self
+    }
+
     fn complete(self) -> F::Result {
         self.base.complete()
     }

src/iter/filter.rs

@@ -136,6 +136,10 @@ where
         }
     }
 
+    // This cannot easily specialize `consume_iter` to be better than
+    // the default, because that requires checking `self.base.full()`
+    // during a call to `self.base.consume_iter()`. (#632)
+
     fn complete(self) -> Self::Result {
         self.base.complete()
     }

src/iter/filter_map.rs

@@ -140,6 +140,10 @@ where
         }
     }
 
+    // This cannot easily specialize `consume_iter` to be better than
+    // the default, because that requires checking `self.base.full()`
+    // during a call to `self.base.consume_iter()`. (#632)
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

src/iter/find.rs

@@ -86,6 +86,20 @@ where
         self
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where I: IntoIterator<Item = T>
+    {
+        self.item = iter
+            .into_iter()
+            // stop iterating if another thread has found something
+            .take_while(|_| !self.full())
+            .find(self.find_op);
+        if self.item.is_some() {
+            self.found.store(true, Ordering::Relaxed)
+        }
+        self
+    }
+
     fn complete(self) -> Self::Result {
         self.item
     }

src/iter/fold.rs

@@ -141,6 +141,20 @@ where
         }
     }
 
+    fn consume_iter<I>(self, iter: I) -> Self
+    where
+        I: IntoIterator<Item = T>
+    {
+        let base = self.base;
+        let item = iter
+            .into_iter()
+            // stop iterating if another thread has finished
+            .take_while(|_| !base.full())
+            .fold(self.item, self.fold_op);
+
+        FoldFolder { base: base, item: item, fold_op: self.fold_op }
+    }
+
     fn complete(self) -> C::Result {
         self.base.consume(self.item).complete()
     }

src/iter/inspect.rs

@@ -243,6 +243,14 @@ where
         }
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where
+        I: IntoIterator<Item = T>
+    {
+        self.base = self.base.consume_iter(iter.into_iter().inspect(self.inspect_op));
+        self
+    }
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

src/iter/intersperse.rs

@@ -1,7 +1,7 @@
 use super::plumbing::*;
 use super::*;
 use std::cell::Cell;
-use std::iter::Fuse;
+use std::iter::{self, Fuse};
 
 /// `Intersperse` is an iterator that inserts a particular item between each
 /// item of the adapted iterator.  This struct is created by the
@@ -382,6 +382,30 @@ where
         self
     }
 
+    fn consume_iter<I>(self, iter: I) -> Self
+    where I: IntoIterator<Item = T>
+    {
+        let mut clone_first = self.clone_first;
+        let between_item = self.item;
+        let base = self.base.consume_iter(
+            iter.into_iter()
+                .flat_map(|item| {
+                    let first = if clone_first {
+                        Some(between_item.clone())
+                    } else {
+                        clone_first = true;
+                        None
+                    };
+                    first.into_iter().chain(iter::once(item))
+                })
+        );
+        IntersperseFolder {
+            base: base,
+            item: between_item,
+            clone_first: clone_first,
+        }
+    }
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

src/iter/map.rs

@@ -247,6 +247,14 @@ where
         }
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where
+        I: IntoIterator<Item = T>,
+    {
+        self.base = self.base.consume_iter(iter.into_iter().map(self.map_op));
+        self
+    }
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

src/iter/update.rs

@@ -245,6 +245,20 @@ where
         }
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where
+        I: IntoIterator<Item = T>
+    {
+        let update_op = self.update_op;
+        self.base = self.base.consume_iter(
+            iter.into_iter().map(|mut item| {
+                update_op(&mut item);
+                item
+            })
+        );
+        self
+    }
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

src/iter/while_some.rs

@@ -122,6 +122,26 @@ where
         self
     }
 
+    fn consume_iter<I>(mut self, iter: I) -> Self
+    where I: IntoIterator<Item = Option<T>>
+    {
+        let full = self.full;
+        self.base = self.base.consume_iter(
+            iter.into_iter()
+                .take_while(|x| {
+                    match *x {
+                        Some(_) => !full.load(Ordering::Relaxed),
+                        None => {
+                            full.store(true, Ordering::Relaxed);
+                            false
+                        }
+                    }
+                })
+                .map(|x| x.unwrap())
+        );
+        self
+    }
+
     fn complete(self) -> C::Result {
         self.base.complete()
     }

tests/octillion.rs

@@ -42,27 +42,57 @@ fn find_first_octillion_flat() {
     assert_eq!(x, Some(0));
 }
 
-#[test]
-fn find_last_octillion() {
+fn two_threads<F: Send + FnOnce() -> R, R: Send>(f: F) -> R {
     // FIXME: If we don't use at least two threads, then we end up walking
     // through the entire iterator sequentially, without the benefit of any
     // short-circuiting.  We probably don't want testing to wait that long. ;)
-    // It would be nice if `find_last` could prioritize the later splits,
-    // basically flipping the `join` args, without needing indexed `rev`.
-    // (or could we have an unindexed `rev`?)
     let builder = rayon::ThreadPoolBuilder::new().num_threads(2);
     let pool = builder.build().unwrap();
 
-    let x = pool.install(|| octillion().find_last(|_| true));
+    pool.install(f)
+}
+
+#[test]
+fn find_last_octillion() {
+    // It would be nice if `find_last` could prioritize the later splits,
+    // basically flipping the `join` args, without needing indexed `rev`.
+    // (or could we have an unindexed `rev`?)
+    let x = two_threads(|| octillion().find_last(|_| true));
     assert_eq!(x, Some(OCTILLION - 1));
 }
 
 #[test]
 fn find_last_octillion_flat() {
-    // FIXME: Ditto, need two threads.
-    let builder = rayon::ThreadPoolBuilder::new().num_threads(2);
-    let pool = builder.build().unwrap();
-
-    let x = pool.install(|| octillion_flat().find_last(|_| true));
+    let x = two_threads(|| octillion_flat().find_last(|_| true));
     assert_eq!(x, Some(OCTILLION - 1));
 }
+
+#[test]
+fn find_any_octillion() {
+    let x = two_threads(|| octillion().find_any(|x| *x > OCTILLION / 2));
+    assert!(x.is_some());
+}
+
+#[test]
+fn find_any_octillion_flat() {
+    let x = two_threads(|| octillion_flat().find_any(|x| *x > OCTILLION / 2));
+    assert!(x.is_some());
+}
+
+#[test]
+fn filter_find_any_octillion() {
+    let x = two_threads(|| octillion().filter(|x| *x > OCTILLION / 2).find_any(|_| true));
+    assert!(x.is_some());
+}
+
+#[test]
+fn filter_find_any_octillion_flat() {
+    let x = two_threads(|| octillion_flat().filter(|x| *x > OCTILLION / 2).find_any(|_| true));
+    assert!(x.is_some());
+}
+
+#[test]
+fn fold_find_any_octillion_flat() {
+    let x = two_threads(|| octillion_flat().fold(|| (), |_, _| ()).find_any(|_| true));
+    assert!(x.is_some());
+}