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, 37 insertions, 22 deletions

diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 0612575e67..24ad012201 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -87,6 +87,7 @@
 #include "nvim/highlight.h"
 #include "nvim/main.h"
 #include "nvim/mark.h"
+#include "nvim/mark_extended.h"
 #include "nvim/mbyte.h"
 #include "nvim/memline.h"
 #include "nvim/memory.h"
@@ -622,6 +623,9 @@ bool win_cursorline_standout(const win_T *wp)
     || (wp->w_p_cole > 0 && (VIsual_active || !conceal_cursor_line(wp)));
 }
 
+static DecorationState decorations;
+bool decorations_active = false;
+
 /*
  * Update a single window.
  *
@@ -1221,6 +1225,7 @@ static void win_update(win_T *wp)
                          : (wp->w_topline + wp->w_height_inner));
     args.items[0] = WINDOW_OBJ(wp->handle);
     args.items[1] = BUFFER_OBJ(buf->handle);
+    // TODO(bfredl): we are not using this, but should be first drawn line?
     args.items[2] = INTEGER_OBJ(wp->w_topline-1);
     args.items[3] = INTEGER_OBJ(knownmax);
     // TODO(bfredl): we could allow this callback to change mod_top, mod_bot.
@@ -1232,6 +1237,8 @@ static void win_update(win_T *wp)
     }
   }
 
+  decorations_active = extmark_decorations_reset(buf, &decorations);
+
   for (;; ) {
     /* stop updating when reached the end of the window (check for _past_
      * the end of the window is at the end of the loop) */
@@ -2250,8 +2257,7 @@ win_line (
   int prev_c1 = 0;                      // first composing char for prev_c
 
   bool search_attr_from_match = false;  // if search_attr is from :match
-  BufhlLineInfo bufhl_info;             // bufhl data for this line
-  bool has_bufhl = false;               // this buffer has highlight matches
+  bool has_decorations = false;         // this buffer has decorations
   bool do_virttext = false;             // draw virtual text for this line
 
   /* draw_state: items that are drawn in sequence: */
@@ -2315,14 +2321,12 @@ win_line (
       }
     }
 
-    if (bufhl_start_line(wp->w_buffer, lnum, &bufhl_info)) {
-      if (kv_size(bufhl_info.line->items)) {
-        has_bufhl = true;
+    if (decorations_active) {
+      has_decorations = extmark_decorations_line(wp->w_buffer, lnum-1,
+                                                 &decorations);
+      if (has_decorations) {
         extra_check = true;
       }
-      if (kv_size(bufhl_info.line->virt_text)) {
-        do_virttext = true;
-      }
     }
 
     // Check for columns to display for 'colorcolumn'.
@@ -3515,19 +3519,25 @@ win_line (
             char_attr = hl_combine_attr(spell_attr, char_attr);
         }
 
-        if (has_bufhl && v > 0) {
-          int bufhl_attr = bufhl_get_attr(&bufhl_info, (colnr_T)v);
-          if (bufhl_attr != 0) {
+        if (has_decorations && v > 0) {
+          int extmark_attr = extmark_decorations_col(wp->w_buffer, (colnr_T)v-1,
+                                                     &decorations);
+          if (extmark_attr != 0) {
             if (!attr_pri) {
-              char_attr = hl_combine_attr(char_attr, bufhl_attr);
+              char_attr = hl_combine_attr(char_attr, extmark_attr);
             } else {
-              char_attr = hl_combine_attr(bufhl_attr, char_attr);
+              char_attr = hl_combine_attr(extmark_attr, char_attr);
             }
           }
         }
 
+        // TODO(bfredl): luahl should reuse the "active decorations" buffer
         if (buf->b_luahl && v > 0 && v < (long)lua_attr_bufsize+1) {
-          char_attr = hl_combine_attr(char_attr, lua_attr_buf[v-1]);
+          if (!attr_pri) {
+            char_attr = hl_combine_attr(char_attr, lua_attr_buf[v-1]);
+          } else {
+            char_attr = hl_combine_attr(lua_attr_buf[v-1], char_attr);
+          }
         }
 
         if (wp->w_buffer->terminal) {
@@ -4008,6 +4018,19 @@ win_line (
       if (draw_color_col)
         draw_color_col = advance_color_col(VCOL_HLC, &color_cols);
 
+      VirtText virt_text = KV_INITIAL_VALUE;
+      if (luatext) {
+        kv_push(virt_text, ((VirtTextChunk){ .text = luatext, .hl_id = 0 }));
+        do_virttext = true;
+      } else if (has_decorations) {
+        VirtText *vp = extmark_decorations_virt_text(wp->w_buffer,
+                                                     &decorations);
+        if (vp) {
+          virt_text = *vp;
+          do_virttext = true;
+        }
+      }
+
       if (((wp->w_p_cuc
             && (int)wp->w_virtcol >= VCOL_HLC - eol_hl_off
             && (int)wp->w_virtcol <
@@ -4018,14 +4041,6 @@ win_line (
         int rightmost_vcol = 0;
         int i;
 
-        VirtText virt_text;
-        if (luatext) {
-          virt_text = (VirtText)KV_INITIAL_VALUE;
-          kv_push(virt_text, ((VirtTextChunk){ .text = luatext, .hl_id = 0 }));
-        } else {
-          virt_text = do_virttext ? bufhl_info.line->virt_text
-                                  : (VirtText)KV_INITIAL_VALUE;
-        }
         size_t virt_pos = 0;
         LineState s = LINE_STATE((char_u *)"");
         int virt_attr = 0;