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, 48 insertions, 0 deletions

diff --git a/src/nvim/buffer_updates.c b/src/nvim/buffer_updates.c
index d12527d6ac..80780a3aa3 100644
--- a/src/nvim/buffer_updates.c
+++ b/src/nvim/buffer_updates.c
@@ -281,6 +281,54 @@ void buf_updates_send_changes(buf_T *buf,
   kv_size(buf->update_callbacks) = j;
 }
 
+void buf_updates_send_splice(buf_T *buf,
+                             linenr_T start_line, colnr_T start_col,
+                             linenr_T oldextent_line, colnr_T oldextent_col,
+                             linenr_T newextent_line, colnr_T newextent_col)
+{
+  if (!buf_updates_active(buf)) {
+    return;
+  }
+
+  // notify each of the active callbakcs
+  size_t j = 0;
+  for (size_t i = 0; i < kv_size(buf->update_callbacks); i++) {
+    BufUpdateCallbacks cb = kv_A(buf->update_callbacks, i);
+    bool keep = true;
+    if (cb.on_bytes != LUA_NOREF) {
+      Array args = ARRAY_DICT_INIT;
+      Object items[8];
+      args.size = 8;
+      args.items = items;
+
+      // the first argument is always the buffer handle
+      args.items[0] = BUFFER_OBJ(buf->handle);
+
+      // next argument is b:changedtick
+      args.items[1] = INTEGER_OBJ(buf_get_changedtick(buf));
+
+      args.items[2] = INTEGER_OBJ(start_line);
+      args.items[3] = INTEGER_OBJ(start_col);
+      args.items[4] = INTEGER_OBJ(oldextent_line);
+      args.items[5] = INTEGER_OBJ(oldextent_col);
+      args.items[6] = INTEGER_OBJ(newextent_line);
+      args.items[7] = INTEGER_OBJ(newextent_col);
+
+      textlock++;
+      Object res = executor_exec_lua_cb(cb.on_bytes, "bytes", args, true, NULL);
+      textlock--;
+
+      if (res.type == kObjectTypeBoolean && res.data.boolean == true) {
+        free_update_callbacks(cb);
+        keep = false;
+      }
+    }
+    if (keep) {
+      kv_A(buf->update_callbacks, j++) = kv_A(buf->update_callbacks, i);
+    }
+  }
+  kv_size(buf->update_callbacks) = j;
+}
 void buf_updates_changedtick(buf_T *buf)
 {
   // notify each of the active channels