Merging upstream version 1.75.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 107 insertions, 56 deletions

diff --git a/vendor/itertools/src/merge_join.rs b/vendor/itertools/src/merge_join.rs
index f2fbdea2c..84f7d0333 100644
--- a/vendor/itertools/src/merge_join.rs
+++ b/vendor/itertools/src/merge_join.rs
@@ -2,19 +2,23 @@ use std::cmp::Ordering;
 use std::iter::Fuse;
 use std::fmt;
 
+use either::Either;
+
 use super::adaptors::{PutBack, put_back};
 use crate::either_or_both::EitherOrBoth;
+use crate::size_hint::{self, SizeHint};
 #[cfg(doc)]
 use crate::Itertools;
 
 /// Return an iterator adaptor that merge-joins items from the two base iterators in ascending order.
 ///
 /// [`IntoIterator`] enabled version of [`Itertools::merge_join_by`].
-pub fn merge_join_by<I, J, F>(left: I, right: J, cmp_fn: F)
+pub fn merge_join_by<I, J, F, T>(left: I, right: J, cmp_fn: F)
     -> MergeJoinBy<I::IntoIter, J::IntoIter, F>
     where I: IntoIterator,
           J: IntoIterator,
-          F: FnMut(&I::Item, &J::Item) -> Ordering
+          F: FnMut(&I::Item, &J::Item) -> T,
+          T: OrderingOrBool<I::Item, J::Item>,
 {
     MergeJoinBy {
         left: put_back(left.into_iter().fuse()),
@@ -30,7 +34,66 @@ pub fn merge_join_by<I, J, F>(left: I, right: J, cmp_fn: F)
 pub struct MergeJoinBy<I: Iterator, J: Iterator, F> {
     left: PutBack<Fuse<I>>,
     right: PutBack<Fuse<J>>,
-    cmp_fn: F
+    cmp_fn: F,
+}
+
+pub trait OrderingOrBool<L, R> {
+    type MergeResult;
+    fn left(left: L) -> Self::MergeResult;
+    fn right(right: R) -> Self::MergeResult;
+    // "merge" never returns (Some(...), Some(...), ...) so Option<Either<I::Item, J::Item>>
+    // is appealing but it is always followed by two put_backs, so we think the compiler is
+    // smart enough to optimize it. Or we could move put_backs into "merge".
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult);
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint;
+}
+
+impl<L, R> OrderingOrBool<L, R> for Ordering {
+    type MergeResult = EitherOrBoth<L, R>;
+    fn left(left: L) -> Self::MergeResult {
+        EitherOrBoth::Left(left)
+    }
+    fn right(right: R) -> Self::MergeResult {
+        EitherOrBoth::Right(right)
+    }
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult) {
+        match self {
+            Ordering::Equal => (None, None, EitherOrBoth::Both(left, right)),
+            Ordering::Less => (None, Some(right), EitherOrBoth::Left(left)),
+            Ordering::Greater => (Some(left), None, EitherOrBoth::Right(right)),
+        }
+    }
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint {
+        let (a_lower, a_upper) = left;
+        let (b_lower, b_upper) = right;
+        let lower = ::std::cmp::max(a_lower, b_lower);
+        let upper = match (a_upper, b_upper) {
+            (Some(x), Some(y)) => x.checked_add(y),
+            _ => None,
+        };
+        (lower, upper)
+    }
+}
+
+impl<L, R> OrderingOrBool<L, R> for bool {
+    type MergeResult = Either<L, R>;
+    fn left(left: L) -> Self::MergeResult {
+        Either::Left(left)
+    }
+    fn right(right: R) -> Self::MergeResult {
+        Either::Right(right)
+    }
+    fn merge(self, left: L, right: R) -> (Option<L>, Option<R>, Self::MergeResult) {
+        if self {
+            (None, Some(right), Either::Left(left))
+        } else {
+            (Some(left), None, Either::Right(right))
+        }
+    }
+    fn size_hint(left: SizeHint, right: SizeHint) -> SizeHint {
+        // Not ExactSizeIterator because size may be larger than usize
+        size_hint::add(left, right)
+    }
 }
 
 impl<I, J, F> Clone for MergeJoinBy<I, J, F>
@@ -52,49 +115,34 @@ impl<I, J, F> fmt::Debug for MergeJoinBy<I, J, F>
     debug_fmt_fields!(MergeJoinBy, left, right);
 }
 
-impl<I, J, F> Iterator for MergeJoinBy<I, J, F>
+impl<I, J, F, T> Iterator for MergeJoinBy<I, J, F>
     where I: Iterator,
           J: Iterator,
-          F: FnMut(&I::Item, &J::Item) -> Ordering
+          F: FnMut(&I::Item, &J::Item) -> T,
+          T: OrderingOrBool<I::Item, J::Item>,
 {
-    type Item = EitherOrBoth<I::Item, J::Item>;
+    type Item = T::MergeResult;
 
     fn next(&mut self) -> Option<Self::Item> {
         match (self.left.next(), self.right.next()) {
             (None, None) => None,
-            (Some(left), None) =>
-                Some(EitherOrBoth::Left(left)),
-            (None, Some(right)) =>
-                Some(EitherOrBoth::Right(right)),
+            (Some(left), None) => Some(T::left(left)),
+            (None, Some(right)) => Some(T::right(right)),
             (Some(left), Some(right)) => {
-                match (self.cmp_fn)(&left, &right) {
-                    Ordering::Equal =>
-                        Some(EitherOrBoth::Both(left, right)),
-                    Ordering::Less => {
-                        self.right.put_back(right);
-                        Some(EitherOrBoth::Left(left))
-                    },
-                    Ordering::Greater => {
-                        self.left.put_back(left);
-                        Some(EitherOrBoth::Right(right))
-                    }
+                let (left, right, next) = (self.cmp_fn)(&left, &right).merge(left, right);
+                if let Some(left) = left {
+                    self.left.put_back(left);
+                }
+                if let Some(right) = right {
+                    self.right.put_back(right);
                 }
+                Some(next)
             }
         }
     }
 
-    fn size_hint(&self) -> (usize, Option<usize>) {
-        let (a_lower, a_upper) = self.left.size_hint();
-        let (b_lower, b_upper) = self.right.size_hint();
-
-        let lower = ::std::cmp::max(a_lower, b_lower);
-
-        let upper = match (a_upper, b_upper) {
-            (Some(x), Some(y)) => x.checked_add(y),
-            _ => None,
-        };
-
-        (lower, upper)
+    fn size_hint(&self) -> SizeHint {
+        T::size_hint(self.left.size_hint(), self.right.size_hint())
     }
 
     fn count(mut self) -> usize {
@@ -106,10 +154,12 @@ impl<I, J, F> Iterator for MergeJoinBy<I, J, F>
                 (None, Some(_right)) => break count + 1 + self.right.into_parts().1.count(),
                 (Some(left), Some(right)) => {
                     count += 1;
-                    match (self.cmp_fn)(&left, &right) {
-                        Ordering::Equal => {}
-                        Ordering::Less => self.right.put_back(right),
-                        Ordering::Greater => self.left.put_back(left),
+                    let (left, right, _) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
                     }
                 }
             }
@@ -122,27 +172,24 @@ impl<I, J, F> Iterator for MergeJoinBy<I, J, F>
             match (self.left.next(), self.right.next()) {
                 (None, None) => break previous_element,
                 (Some(left), None) => {
-                    break Some(EitherOrBoth::Left(
+                    break Some(T::left(
                         self.left.into_parts().1.last().unwrap_or(left),
                     ))
                 }
                 (None, Some(right)) => {
-                    break Some(EitherOrBoth::Right(
+                    break Some(T::right(
                         self.right.into_parts().1.last().unwrap_or(right),
                     ))
                 }
                 (Some(left), Some(right)) => {
-                    previous_element = match (self.cmp_fn)(&left, &right) {
-                        Ordering::Equal => Some(EitherOrBoth::Both(left, right)),
-                        Ordering::Less => {
-                            self.right.put_back(right);
-                            Some(EitherOrBoth::Left(left))
-                        }
-                        Ordering::Greater => {
-                            self.left.put_back(left);
-                            Some(EitherOrBoth::Right(right))
-                        }
+                    let (left, right, elem) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
                     }
+                    previous_element = Some(elem);
                 }
             }
         }
@@ -156,13 +203,17 @@ impl<I, J, F> Iterator for MergeJoinBy<I, J, F>
             n -= 1;
             match (self.left.next(), self.right.next()) {
                 (None, None) => break None,
-                (Some(_left), None) => break self.left.nth(n).map(EitherOrBoth::Left),
-                (None, Some(_right)) => break self.right.nth(n).map(EitherOrBoth::Right),
-                (Some(left), Some(right)) => match (self.cmp_fn)(&left, &right) {
-                    Ordering::Equal => {}
-                    Ordering::Less => self.right.put_back(right),
-                    Ordering::Greater => self.left.put_back(left),
-                },
+                (Some(_left), None) => break self.left.nth(n).map(T::left),
+                (None, Some(_right)) => break self.right.nth(n).map(T::right),
+                (Some(left), Some(right)) => {
+                    let (left, right, _) = (self.cmp_fn)(&left, &right).merge(left, right);
+                    if let Some(left) = left {
+                        self.left.put_back(left);
+                    }
+                    if let Some(right) = right {
+                        self.right.put_back(right);
+                    }
+                }
             }
         }
     }