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-rw-r--r--vendor/rayon/src/delegate.rs109
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+//! Macros for delegating newtype iterators to inner types.
+
+// Note: these place `impl` bounds at the end, as token gobbling is the only way
+// I know how to consume an arbitrary list of constraints, with `$($args:tt)*`.
+
+/// Creates a parallel iterator implementation which simply wraps an inner type
+/// and delegates all methods inward. The actual struct must already be
+/// declared with an `inner` field.
+///
+/// The implementation of `IntoParallelIterator` should be added separately.
+macro_rules! delegate_iterator {
+ ($iter:ty => $item:ty ,
+ impl $( $args:tt )*
+ ) => {
+ impl $( $args )* ParallelIterator for $iter {
+ type Item = $item;
+
+ fn drive_unindexed<C>(self, consumer: C) -> C::Result
+ where C: UnindexedConsumer<Self::Item>
+ {
+ self.inner.drive_unindexed(consumer)
+ }
+
+ fn opt_len(&self) -> Option<usize> {
+ self.inner.opt_len()
+ }
+ }
+ }
+}
+
+/// Creates an indexed parallel iterator implementation which simply wraps an
+/// inner type and delegates all methods inward. The actual struct must already
+/// be declared with an `inner` field.
+macro_rules! delegate_indexed_iterator {
+ ($iter:ty => $item:ty ,
+ impl $( $args:tt )*
+ ) => {
+ delegate_iterator!{
+ $iter => $item ,
+ impl $( $args )*
+ }
+
+ impl $( $args )* IndexedParallelIterator for $iter {
+ fn drive<C>(self, consumer: C) -> C::Result
+ where C: Consumer<Self::Item>
+ {
+ self.inner.drive(consumer)
+ }
+
+ fn len(&self) -> usize {
+ self.inner.len()
+ }
+
+ fn with_producer<CB>(self, callback: CB) -> CB::Output
+ where CB: ProducerCallback<Self::Item>
+ {
+ self.inner.with_producer(callback)
+ }
+ }
+ }
+}
+
+#[test]
+fn unindexed_example() {
+ use crate::collections::btree_map::IntoIter;
+ use crate::iter::plumbing::*;
+ use crate::prelude::*;
+
+ use std::collections::BTreeMap;
+
+ struct MyIntoIter<T: Ord + Send, U: Send> {
+ inner: IntoIter<T, U>,
+ }
+
+ delegate_iterator! {
+ MyIntoIter<T, U> => (T, U),
+ impl<T: Ord + Send, U: Send>
+ }
+
+ let map = BTreeMap::from([(1, 'a'), (2, 'b'), (3, 'c')]);
+ let iter = MyIntoIter {
+ inner: map.into_par_iter(),
+ };
+ let vec: Vec<_> = iter.map(|(k, _)| k).collect();
+ assert_eq!(vec, &[1, 2, 3]);
+}
+
+#[test]
+fn indexed_example() {
+ use crate::iter::plumbing::*;
+ use crate::prelude::*;
+ use crate::vec::IntoIter;
+
+ struct MyIntoIter<T: Send> {
+ inner: IntoIter<T>,
+ }
+
+ delegate_indexed_iterator! {
+ MyIntoIter<T> => T,
+ impl<T: Send>
+ }
+
+ let iter = MyIntoIter {
+ inner: vec![1, 2, 3].into_par_iter(),
+ };
+ let mut vec = vec![];
+ iter.collect_into_vec(&mut vec);
+ assert_eq!(vec, &[1, 2, 3]);
+}