More generic lifetimes for iter_changes and added iter_all_changes

src/text/inline.rs

@@ -174,12 +174,15 @@ impl<'s, T: DiffableStr + ?Sized> fmt::Display for InlineChange<'s, T> {
     }
 }
 
-pub(crate) fn iter_inline_changes<'diff, T>(
-    diff: &'diff TextDiff<'_, '_, '_, T>,
+pub(crate) fn iter_inline_changes<'x, 'diff, 'old, 'new, 'bufs, T>(
+    diff: &'diff TextDiff<'old, 'new, 'bufs, T>,
     op: &DiffOp,
-) -> impl Iterator<Item = InlineChange<'diff, T>>
+) -> impl Iterator<Item = InlineChange<'x, T>> + 'diff
 where
     T: DiffableStr + ?Sized,
+    'x: 'diff,
+    'old: 'x,
+    'new: 'x,
 {
     let (tag, old_range, new_range) = op.as_tag_tuple();
 

src/text/mod.rs

@@ -294,7 +294,15 @@ impl<'old, 'new, 'bufs, T: DiffableStr + ?Sized + 'old + 'new> TextDiff<'old, 'n
     /// ways in which a change could be encoded (insert/delete vs replace), look
     /// up the value from the appropriate slice and also handle correct index
     /// handling.
-    pub fn iter_changes(&self, op: &DiffOp) -> impl Iterator<Item = Change<'_, T>> {
+    pub fn iter_changes<'x, 'slf>(
+        &'slf self,
+        op: &DiffOp,
+    ) -> impl Iterator<Item = Change<'x, T>> + 'slf
+    where
+        'x: 'slf,
+        'old: 'x,
+        'new: 'x,
+    {
         op.iter_changes(self.old_slices(), self.new_slices())
     }
 
@@ -310,6 +318,22 @@ impl<'old, 'new, 'bufs, T: DiffableStr + ?Sized + 'old + 'new> TextDiff<'old, 'n
         group_diff_ops(self.ops().to_vec(), n)
     }
 
+    /// Flattens out the diff into all changes.
+    ///
+    /// This is a shortcut for combining [`TextDiff::ops`] with
+    /// [`TextDiff::iter_changes`].
+    pub fn iter_all_changes<'x, 'slf>(&'slf self) -> impl Iterator<Item = Change<'x, T>> + 'slf
+    where
+        'x: 'slf,
+        'old: 'x,
+        'new: 'x,
+    {
+        // unclear why this needs Box::new here.  It seems to infer some really
+        // odd lifetimes I can't figure out how to work with.
+        Box::new(self.ops().iter().flat_map(move |op| self.iter_changes(&op)))
+            as Box<dyn Iterator<Item = _>>
+    }
+
     /// Utility to return a unified diff formatter.
     pub fn unified_diff<'diff>(&'diff self) -> UnifiedDiff<'diff, 'old, 'new, 'bufs, T> {
         UnifiedDiff::from_text_diff(self)
@@ -322,7 +346,15 @@ impl<'old, 'new, 'bufs, T: DiffableStr + ?Sized + 'old + 'new> TextDiff<'old, 'n
     /// this function with regards to how it detects those inline changes
     /// is currently not defined and will likely change over time.
     #[cfg(feature = "inline")]
-    pub fn iter_inline_changes(&self, op: &DiffOp) -> impl Iterator<Item = InlineChange<'_, T>> {
+    pub fn iter_inline_changes<'x, 'slf>(
+        &'slf self,
+        op: &DiffOp,
+    ) -> impl Iterator<Item = InlineChange<'x, T>> + 'slf
+    where
+        'x: 'slf,
+        'old: 'x,
+        'new: 'x,
+    {
         inline::iter_inline_changes(self, op)
     }
 }
@@ -492,3 +524,18 @@ fn test_get_close_matches() {
     );
     assert_eq!(matches, vec!["aulo", "hulu", "uulo", "zulo"]);
 }
+
+#[test]
+fn test_lifetimes_on_iter() {
+    fn diff_lines<'x, T>(old: &'x T, new: &'x T) -> Vec<Change<'x, T::Output>>
+    where
+        T: DiffableStrRef + ?Sized,
+    {
+        TextDiff::from_lines(old, new).iter_all_changes().collect()
+    }
+
+    let a = "1\n2\n3\n".to_string();
+    let b = "1\n99\n3\n".to_string();
+    let changes = diff_lines(&a, &b);
+    insta::assert_debug_snapshot!(&changes);
+}

src/types.rs

@@ -247,15 +247,16 @@ impl DiffOp {
     ///
     /// `old` and `new` are two indexable objects like the types you pass to
     /// the diffing algorithm functions.
-    pub fn iter_changes<'x, Old, New, T>(
+    pub fn iter_changes<'x, 'lookup, Old, New, T>(
         &self,
-        old: &'x Old,
-        new: &'x New,
-    ) -> impl Iterator<Item = Change<'x, T>>
+        old: &'lookup Old,
+        new: &'lookup New,
+    ) -> impl Iterator<Item = Change<'x, T>> + 'lookup
     where
         Old: Index<usize, Output = &'x T> + ?Sized,
         New: Index<usize, Output = &'x T> + ?Sized,
         T: 'x + ?Sized,
+        'x: 'lookup,
     {
         let (tag, old_range, new_range) = self.as_tag_tuple();
         let mut old_index = old_range.start;

src/udiff.rs

@@ -240,11 +240,11 @@ impl<'diff, 'old, 'new, 'bufs, T: DiffableStr + ?Sized>
     pub fn iter_changes(&self) -> impl Iterator<Item = Change<'_, T>> + '_ {
         // unclear why this needs Box::new here.  It seems to infer some really
         // odd lifetimes I can't figure out how to work with.
-        (Box::new(
+        Box::new(
             self.ops()
                 .iter()
                 .flat_map(move |op| self.diff.iter_changes(op)),
-        )) as Box<dyn Iterator<Item = _>>
+        ) as Box<dyn Iterator<Item = _>>
     }
 
     /// Write the hunk as bytes to the output stream.