fc6a13c · dodrio · git.iko.soy

git.iko.soy/dodrio

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Add comments clarifying logic about change list stack in `diff_non_keyed_children`

fc6a13cNick Fitzgerald8 years ago

src/diff.rs+16

compare with master

unifiedsplit

@@ -793,9 +793,13 @@ fn diff_non_keyed_children(

793

794 for (i, (new_child, old_child)) in new.iter().zip(old.iter()).enumerate() {

795 if i == 0 {

796+ // [... parent]

796 change_list.push_first_child();

797 change_list.push_first_child();

798+ // [... parent first_child]

797 } else {

799 } else {

800+ // [... parent prev_sibling]

798 change_list.pop_push_next_sibling();

801 change_list.pop_push_next_sibling();

802+ // [... parent next_sibling]

799 }

803 }

800

804

801 diff(

805 diff(

@@ -808,13 +812,23 @@ fn diff_non_keyed_children(

808 );

812 );

809 }

813 }

810

814

815+ // Note that because `new` and `old` are not empty, the previous loop always

816+ // executes at least once, so the change list stack is now:

817+ //

818+ // [... parent child]

819+

811 match old.len().cmp(&new.len()) {

820 match old.len().cmp(&new.len()) {

812 Ordering::Greater => {

821 Ordering::Greater => {

822+ // [... parent last_shared_child]

813 change_list.pop_push_next_sibling();

823 change_list.pop_push_next_sibling();

824+ // [... parent first_child_to_remove]

814 remove_self_and_next_siblings(change_list, registry, &old[new.len()..]);

825 remove_self_and_next_siblings(change_list, registry, &old[new.len()..]);

826+ // [... parent]

815 }

827 }

816 Ordering::Less => {

828 Ordering::Less => {

829+ // [... parent last_child]

817 change_list.pop();

830 change_list.pop();

831+ // [... parent]

818 create_and_append_children(

832 create_and_append_children(

819 cached_set,

833 cached_set,

820 change_list,

834 change_list,

@@ -824,7 +838,9 @@ fn diff_non_keyed_children(

824 );

838 );

825 }

839 }

826 Ordering::Equal => {

840 Ordering::Equal => {

841+ // [... parent child]

827 change_list.pop();

842 change_list.pop();

843+ // [... parent]

828 }

844 }

829 }

845 }

830}

846}