Initial public release of Warp.

Repo-Sync-Origin: warpdotdev/warp-internal@12af1d983b

crates/editor/src/parallel_util.rs

@@ -0,0 +1,46 @@
+//! Parallelism utilities.
+
+use rayon::iter::{FromParallelIterator, IntoParallelIterator, ParallelExtend, ParallelIterator};
+
+/// `Last` is a helper to extract the last value of a [`ParallelIterator`].
+///
+/// It can be used with [`ParallelIterator::collect`], [`ParallelIterator::unzip`], and similar
+/// methods.
+pub struct Last<T> {
+    result: Option<T>,
+}
+
+impl<T> Last<T> {
+    /// Extract the collected value.
+    pub fn into_inner(self) -> Option<T> {
+        self.result
+    }
+}
+
+impl<T> Default for Last<T> {
+    fn default() -> Self {
+        Self { result: None }
+    }
+}
+
+impl<T: Send> FromParallelIterator<T> for Last<T> {
+    fn from_par_iter<I>(par_iter: I) -> Self
+    where
+        I: IntoParallelIterator<Item = T>,
+    {
+        let mut last = Self::default();
+        last.par_extend(par_iter);
+        last
+    }
+}
+
+impl<T: Send> ParallelExtend<T> for Last<T> {
+    fn par_extend<I>(&mut self, par_iter: I)
+    where
+        I: IntoParallelIterator<Item = T>,
+    {
+        // The find_last implementation does a bunch of bookkeeping to short-circuit once it finds
+        // the most-last match, so rely on that here.
+        self.result = par_iter.into_par_iter().find_last(|_| true)
+    }
+}