feat(ui): inline virtual text

vim-patch:9.0.0067: cannot show virtual text

Problem:    Cannot show virtual text.
Solution:   Initial changes for virtual text support, using text properties.

https://github.com/vim/vim/commit/7f9969c559b51446632ac7e8f76cde07e7d0078d

vim-patch:9.0.0116: virtual text not displayed if 'signcolumn' is "yes"

Problem:    Virtual text not displayed if 'signcolumn' is "yes".
Solution:   Set c_extra and c_final to NUL.
https://github.com/vim/vim/commit/711483cd1381a4ed848d783ae0a6792d5b04447b

Co-authored-by: bfredl <bjorn.linse@gmail.com>

5 files changed, 81 insertions, 11 deletions

diff --git a/src/nvim/api/extmark.c b/src/nvim/api/extmark.c
index d6f0288f94..dd256a54f0 100644
--- a/src/nvim/api/extmark.c
+++ b/src/nvim/api/extmark.c
@@ -477,6 +477,8 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id, Object start, Object e
 ///                 - "overlay": display over the specified column, without
 ///                              shifting the underlying text.
 ///                 - "right_align": display right aligned in the window.
+///                 - "inline": display at the specified column, and
+///                              shift the buffer text to the right as needed
 ///               - virt_text_win_col : position the virtual text at a fixed
 ///                                     window column (starting from the first
 ///                                     text column)
@@ -695,6 +697,8 @@ Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id, Integer line, Integer
       decor.virt_text_pos = kVTOverlay;
     } else if (strequal("right_align", str.data)) {
       decor.virt_text_pos = kVTRightAlign;
+    } else if (strequal("inline", str.data)) {
+      decor.virt_text_pos = kVTInline;
     } else {
       VALIDATE_S(false, "virt_text_pos", "", {
         goto error;
diff --git a/src/nvim/decoration.h b/src/nvim/decoration.h
index 92001d496d..95c9655742 100644
--- a/src/nvim/decoration.h
+++ b/src/nvim/decoration.h
@@ -23,9 +23,11 @@ typedef enum {
   kVTOverlay,
   kVTWinCol,
   kVTRightAlign,
+  kVTInline,
 } VirtTextPos;
 
-EXTERN const char *const virt_text_pos_str[] INIT(= { "eol", "overlay", "win_col", "right_align" });
+EXTERN const char *const virt_text_pos_str[] INIT(= { "eol", "overlay", "win_col", "right_align",
+                                                      "inline" });
 
 typedef enum {
   kHlModeUnknown,
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 863d237062..012cce7b22 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -1030,6 +1030,9 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
   int left_curline_col = 0;
   int right_curline_col = 0;
 
+  VirtText virt_inline = KV_INITIAL_VALUE;
+  size_t virt_inline_i = 0;
+
   int match_conc      = 0;              ///< cchar for match functions
   bool on_last_col    = false;
   int syntax_flags    = 0;
@@ -1706,7 +1709,9 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
       wlv.n_extra = 0;
     }
 
-    if (wlv.draw_state == WL_LINE && (area_highlighting || has_spell)) {
+    int extmark_attr = 0;
+    if (wlv.draw_state == WL_LINE
+        && (area_highlighting || has_spell || (extra_check && !has_fold))) {
       // handle Visual or match highlighting in this line
       if (wlv.vcol == wlv.fromcol
           || (wlv.vcol + 1 == wlv.fromcol && wlv.n_extra == 0
@@ -1787,6 +1792,44 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
           wlv.char_attr = 0;
         }
       }
+
+      if (has_decor && v >= 0) {
+        bool selected = (area_active || (area_highlighting && noinvcur
+                                         && wlv.vcol == wp->w_virtcol));
+        extmark_attr = decor_redraw_col(wp, (colnr_T)v, wlv.off,
+                                            selected, &decor_state);
+
+        // we could already be inside an existing virt_line with multiple chunks
+        if (!(virt_inline_i < kv_size(virt_inline))) {
+          DecorState *state = &decor_state;
+          for (size_t i = 0; i < kv_size(state->active); i++) {
+            DecorRange *item = &kv_A(state->active, i);
+            if (!(item->start_row == state->row
+                  && kv_size(item->decor.virt_text)
+                  && item->decor.virt_text_pos == kVTInline)) {
+              continue;
+            }
+            if (item->win_col >= -1 && item->start_col <= v) {
+              virt_inline = item->decor.virt_text;
+              virt_inline_i = 0;
+              item->win_col = -2;
+              break;
+            }
+          }
+        }
+
+        if (wlv.n_extra <= 0 && virt_inline_i < kv_size(virt_inline)) {
+          VirtTextChunk vtc = kv_A(virt_inline, virt_inline_i);
+          wlv.p_extra = vtc.text;
+          wlv.n_extra = (int)strlen(wlv.p_extra);
+          wlv.c_extra = NUL;
+          wlv.c_final = NUL;
+          wlv.extra_attr = vtc.hl_id ? syn_id2attr(vtc.hl_id) : 0;
+          n_attr = wlv.n_extra;
+          extmark_attr = 0;
+          virt_inline_i++;
+        }
+      }
     }
 
     // Get the next character to put on the screen.
@@ -2019,10 +2062,6 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
         }
 
         if (has_decor && v > 0) {
-          bool selected = (area_active || (area_highlighting && noinvcur
-                                           && wlv.vcol == wp->w_virtcol));
-          int extmark_attr = decor_redraw_col(wp, (colnr_T)v - 1, wlv.off,
-                                              selected, &decor_state);
           if (extmark_attr != 0) {
             if (!attr_pri) {
               wlv.char_attr = hl_combine_attr(wlv.char_attr, extmark_attr);
diff --git a/src/nvim/plines.c b/src/nvim/plines.c
index 3e69e547cb..738057b696 100644
--- a/src/nvim/plines.c
+++ b/src/nvim/plines.c
@@ -295,17 +295,25 @@ unsigned     linetabsize(win_T *wp, linenr_T lnum)
 /// Prepare the structure passed to chartabsize functions.
 ///
 /// "line" is the start of the line, "ptr" is the first relevant character.
-/// When "lnum" is zero do not use text properties that insert text.
-void init_chartabsize_arg(chartabsize_T *cts, win_T *wp, linenr_T lnum FUNC_ATTR_UNUSED,
-                          colnr_T col, char *line, char *ptr)
+/// When "lnum" is zero do not use inline virtual text.
+void init_chartabsize_arg(chartabsize_T *cts, win_T *wp, linenr_T lnum, colnr_T col, char *line,
+                          char *ptr)
 {
   cts->cts_win = wp;
   cts->cts_vcol = col;
   cts->cts_line = line;
   cts->cts_ptr = ptr;
   cts->cts_cur_text_width = 0;
-  // TODO(bfredl): actually lookup inline virtual text here
   cts->cts_has_virt_text = false;
+  cts->cts_row = lnum - 1;
+
+  if (cts->cts_row >= 0) {
+    marktree_itr_get(wp->w_buffer->b_marktree, cts->cts_row, 0, cts->cts_iter);
+    mtkey_t mark = marktree_itr_current(cts->cts_iter);
+    if (mark.pos.row == cts->cts_row) {
+      cts->cts_has_virt_text = true;
+    }
+  }
 }
 
 /// Free any allocated item in "cts".
@@ -383,7 +391,22 @@ int win_lbr_chartabsize(chartabsize_T *cts, int *headp)
   // First get normal size, without 'linebreak' or virtual text
   int size = win_chartabsize(wp, s, vcol);
   if (cts->cts_has_virt_text) {
-    // TODO(bfredl): inline virtual text
+    int col = (int)(s - line);
+    while (true) {
+      mtkey_t mark = marktree_itr_current(cts->cts_iter);
+      if (mark.pos.row != cts->cts_row || mark.pos.col > col) {
+        break;
+      } else if (mark.pos.col == col) { // TODO: or maybe unconditionally, what if byte-misaligned?
+        if (!mt_end(mark)) {
+          Decoration decor = get_decor(mark);
+          if (decor.virt_text_pos == kVTInline) {
+            cts->cts_cur_text_width = decor.virt_text_width;
+            size += cts->cts_cur_text_width;
+          }
+        }
+      }
+      marktree_itr_next(wp->w_buffer->b_marktree, cts->cts_iter);
+    }
   }
 
   int c = (uint8_t)(*s);
diff --git a/src/nvim/plines.h b/src/nvim/plines.h
index 808f6d284e..a15c234bba 100644
--- a/src/nvim/plines.h
+++ b/src/nvim/plines.h
@@ -11,9 +11,11 @@ typedef struct {
   win_T *cts_win;
   char *cts_line;    // start of the line
   char *cts_ptr;     // current position in line
+  int cts_row;
 
   bool cts_has_virt_text;  // true if if a property inserts text
   int cts_cur_text_width;     // width of current inserted text
+  MarkTreeIter cts_iter[1];
   // TODO(bfredl): iterator in to the marktree for scanning virt text
 
   int cts_vcol;    // virtual column at current position