extmarks/bufhl: reimplement using new marktree data structure

Add new "splice" interface for tracking buffer changes at the byte
level. This will later be reused for byte-resolution buffer updates.
(Implementation has been started, but using undocumented "_on_bytes"
option now as interface hasn't been finalized).

Use this interface to improve many edge cases of extmark adjustment.
Changed tests indicate previously incorrect behavior. Adding tests for
more edge cases will be follow-up work (overlaps on_bytes tests)

Don't consider creation/deletion of marks an undoable event by itself.
This behavior was never documented, and imposes  complexity for little gain.

Add nvim__buf_add_decoration temporary API for direct access to the new
implementation. This should be refactored into a proper API for
decorations, probably involving a huge dict.

fixes #11598

1 files changed, 9 insertions, 1 deletions

diff --git a/src/nvim/marktree.c b/src/nvim/marktree.c
index 6ad283f5dc..52e602cd94 100644
--- a/src/nvim/marktree.c
+++ b/src/nvim/marktree.c
@@ -1095,6 +1095,7 @@ static void marktree_itr_fix_pos(MarkTree *b, MarkTreeIter *itr)
 
 void marktree_check(MarkTree *b)
 {
+#ifndef NDEBUG
   if (b->root == NULL) {
     assert(b->n_keys == 0);
     assert(b->n_nodes == 0);
@@ -1107,9 +1108,15 @@ void marktree_check(MarkTree *b)
   size_t nkeys = check_node(b, b->root, &dummy, &last_right);
   assert(b->n_keys == nkeys);
   assert(b->n_keys == map_size(b->id2node));
+#else
+  // Do nothing, as assertions are required
+  (void)b;
+#endif
 }
 
-size_t check_node(MarkTree *b, mtnode_t *x, mtpos_t *last, bool *last_right)
+#ifndef NDEBUG
+static size_t check_node(MarkTree *b, mtnode_t *x,
+                         mtpos_t *last, bool *last_right)
 {
   assert(x->n <= 2 * T - 1);
   // TODO(bfredl): too strict if checking "in repair" post-delete tree.
@@ -1153,6 +1160,7 @@ size_t check_node(MarkTree *b, mtnode_t *x, mtpos_t *last, bool *last_right)
   }
   return n_keys;
 }
+#endif
 
 char *mt_inspect_rec(MarkTree *b)
 {