impl size_hint for ConcurrentStream

yoshuawuyts · Mar 17, 2024 · fd72179 · fd72179
1 parent e1fab54
commit fd72179
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Showing 6 changed files with 25 additions and 0 deletions.
diff --git a/src/concurrent_stream/enumerate.rs b/src/concurrent_stream/enumerate.rs
@@ -35,6 +35,10 @@ impl<CS: ConcurrentStream> ConcurrentStream for Enumerate<CS> {
     fn concurrency_limit(&self) -> Option<std::num::NonZeroUsize> {
         self.inner.concurrency_limit()
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 struct EnumerateConsumer<C> {

diff --git a/src/concurrent_stream/into_concurrent_iterator.rs b/src/concurrent_stream/into_concurrent_iterator.rs
@@ -81,6 +81,10 @@ where
     fn concurrency_limit(&self) -> Option<std::num::NonZeroUsize> {
         None
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
 }
 
 enum State<T> {

diff --git a/src/concurrent_stream/limit.rs b/src/concurrent_stream/limit.rs
@@ -29,6 +29,10 @@ impl<CS: ConcurrentStream> ConcurrentStream for Limit<CS> {
     fn concurrency_limit(&self) -> Option<std::num::NonZeroUsize> {
         self.limit
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 struct LimitConsumer<C> {

diff --git a/src/concurrent_stream/map.rs b/src/concurrent_stream/map.rs
@@ -64,6 +64,10 @@ where
     fn concurrency_limit(&self) -> Option<std::num::NonZeroUsize> {
         self.inner.concurrency_limit()
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 // OK: validated! - all bounds should check out

diff --git a/src/concurrent_stream/mod.rs b/src/concurrent_stream/mod.rs
@@ -70,6 +70,11 @@ pub trait ConcurrentStream {
     /// How much concurrency should we apply?
     fn concurrency_limit(&self) -> Option<NonZeroUsize>;
 
+    /// How many items could we potentially end up returning?
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        (0, None)
+    }
+
     /// Creates a stream which gives the current iteration count as well as
     /// the next value.
     ///

diff --git a/src/concurrent_stream/passthrough.rs b/src/concurrent_stream/passthrough.rs
@@ -28,6 +28,10 @@ impl<CS: ConcurrentStream> ConcurrentStream for Passthrough<CS> {
     fn concurrency_limit(&self) -> Option<std::num::NonZeroUsize> {
         self.inner.concurrency_limit()
     }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.inner.size_hint()
+    }
 }
 
 struct PassthroughConsumer<C> {