1 files changed, 142 insertions, 0 deletions
diff --git a/src/iter/filter_map.rs b/src/iter/filter_map.rs
new file mode 100644
index 0000000..f19c385
--- /dev/null
+++ b/src/iter/filter_map.rs
@@ -0,0 +1,142 @@
+use super::plumbing::*;
+use super::*;
+
+use std::fmt::{self, Debug};
+
+/// `FilterMap` creates an iterator that uses `filter_op` to both filter and map elements.
+/// This struct is created by the [`filter_map()`] method on [`ParallelIterator`].
+///
+/// [`filter_map()`]: trait.ParallelIterator.html#method.filter_map
+/// [`ParallelIterator`]: trait.ParallelIterator.html
+#[must_use = "iterator adaptors are lazy and do nothing unless consumed"]
+#[derive(Clone)]
+pub struct FilterMap<I: ParallelIterator, P> {
+    base: I,
+    filter_op: P,
+}
+
+impl<I: ParallelIterator + Debug, P> Debug for FilterMap<I, P> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("FilterMap")
+            .field("base", &self.base)
+            .finish()
+    }
+}
+
+impl<I: ParallelIterator, P> FilterMap<I, P> {
+    /// Creates a new `FilterMap` iterator.
+    pub(super) fn new(base: I, filter_op: P) -> Self {
+        FilterMap { base, filter_op }
+    }
+}
+
+impl<I, P, R> ParallelIterator for FilterMap<I, P>
+where
+    I: ParallelIterator,
+    P: Fn(I::Item) -> Option<R> + Sync + Send,
+    R: Send,
+{
+    type Item = R;
+
+    fn drive_unindexed<C>(self, consumer: C) -> C::Result
+    where
+        C: UnindexedConsumer<Self::Item>,
+    {
+        let consumer = FilterMapConsumer::new(consumer, &self.filter_op);
+        self.base.drive_unindexed(consumer)
+    }
+}
+
+/// ////////////////////////////////////////////////////////////////////////
+/// Consumer implementation
+
+struct FilterMapConsumer<'p, C, P> {
+    base: C,
+    filter_op: &'p P,
+}
+
+impl<'p, C, P: 'p> FilterMapConsumer<'p, C, P> {
+    fn new(base: C, filter_op: &'p P) -> Self {
+        FilterMapConsumer { base, filter_op }
+    }
+}
+
+impl<'p, T, U, C, P> Consumer<T> for FilterMapConsumer<'p, C, P>
+where
+    C: Consumer<U>,
+    P: Fn(T) -> Option<U> + Sync + 'p,
+{
+    type Folder = FilterMapFolder<'p, C::Folder, P>;
+    type Reducer = C::Reducer;
+    type Result = C::Result;
+
+    fn split_at(self, index: usize) -> (Self, Self, Self::Reducer) {
+        let (left, right, reducer) = self.base.split_at(index);
+        (
+            FilterMapConsumer::new(left, self.filter_op),
+            FilterMapConsumer::new(right, self.filter_op),
+            reducer,
+        )
+    }
+
+    fn into_folder(self) -> Self::Folder {
+        let base = self.base.into_folder();
+        FilterMapFolder {
+            base,
+            filter_op: self.filter_op,
+        }
+    }
+
+    fn full(&self) -> bool {
+        self.base.full()
+    }
+}
+
+impl<'p, T, U, C, P> UnindexedConsumer<T> for FilterMapConsumer<'p, C, P>
+where
+    C: UnindexedConsumer<U>,
+    P: Fn(T) -> Option<U> + Sync + 'p,
+{
+    fn split_off_left(&self) -> Self {
+        FilterMapConsumer::new(self.base.split_off_left(), &self.filter_op)
+    }
+
+    fn to_reducer(&self) -> Self::Reducer {
+        self.base.to_reducer()
+    }
+}
+
+struct FilterMapFolder<'p, C, P> {
+    base: C,
+    filter_op: &'p P,
+}
+
+impl<'p, T, U, C, P> Folder<T> for FilterMapFolder<'p, C, P>
+where
+    C: Folder<U>,
+    P: Fn(T) -> Option<U> + Sync + 'p,
+{
+    type Result = C::Result;
+
+    fn consume(self, item: T) -> Self {
+        let filter_op = self.filter_op;
+        if let Some(mapped_item) = filter_op(item) {
+            let base = self.base.consume(mapped_item);
+            FilterMapFolder { base, filter_op }
+        } else {
+            self
+        }
+    }
+
+    // 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()
+    }
+
+    fn full(&self) -> bool {
+        self.base.full()
+    }
+}