highlight: expose builtin highlight groups using hl_group_set event

5 files changed, 24 insertions, 7 deletions

diff --git a/src/nvim/api/ui.c b/src/nvim/api/ui.c
index 4f28ea5af3..20ed77afad 100644
--- a/src/nvim/api/ui.c
+++ b/src/nvim/api/ui.c
@@ -123,6 +123,7 @@ void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
   ui->mode_change = remote_ui_mode_change;
   ui->grid_scroll = remote_ui_grid_scroll;
   ui->hl_attr_define = remote_ui_hl_attr_define;
+  ui->hl_group_set = remote_ui_hl_group_set;
   ui->raw_line = remote_ui_raw_line;
   ui->bell = remote_ui_bell;
   ui->visual_bell = remote_ui_visual_bell;
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index a1d25766fe..41bf0af65b 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -73,6 +73,8 @@ void default_colors_set(Integer rgb_fg, Integer rgb_bg, Integer rgb_sp,
 void hl_attr_define(Integer id, HlAttrs rgb_attrs, HlAttrs cterm_attrs,
                     Array info)
   FUNC_API_SINCE(5) FUNC_API_REMOTE_IMPL FUNC_API_BRIDGE_IMPL;
+void hl_group_set(String name, Integer id)
+  FUNC_API_SINCE(6) FUNC_API_BRIDGE_IMPL;
 void grid_resize(Integer grid, Integer width, Integer height)
   FUNC_API_SINCE(5) FUNC_API_REMOTE_IMPL FUNC_API_COMPOSITOR_IMPL;
 void grid_clear(Integer grid)
diff --git a/src/nvim/highlight.c b/src/nvim/highlight.c
index e5cbb4f944..f11880cb2b 100644
--- a/src/nvim/highlight.c
+++ b/src/nvim/highlight.c
@@ -106,14 +106,19 @@ static int get_attr_entry(HlEntry entry)
 /// When a UI connects, we need to send it the table of highlights used so far.
 void ui_send_all_hls(UI *ui)
 {
-  if (!ui->hl_attr_define) {
-    return;
+  if (ui->hl_attr_define) {
+    for (size_t i = 1; i < kv_size(attr_entries); i++) {
+      Array inspect = hl_inspect((int)i);
+      ui->hl_attr_define(ui, (Integer)i, kv_A(attr_entries, i).attr,
+                         kv_A(attr_entries, i).attr, inspect);
+      api_free_array(inspect);
+    }
   }
-  for (size_t i = 1; i < kv_size(attr_entries); i++) {
-    Array inspect = hl_inspect((int)i);
-    ui->hl_attr_define(ui, (Integer)i, kv_A(attr_entries, i).attr,
-                       kv_A(attr_entries, i).attr, inspect);
-    api_free_array(inspect);
+  if (ui->hl_group_set) {
+    for (size_t hlf = 0; hlf < HLF_COUNT; hlf++) {
+      ui->hl_group_set(ui, cstr_as_string((char *)hlf_names[hlf]),
+                       highlight_attr[hlf]);
+    }
   }
 }
 
@@ -251,6 +256,7 @@ void clear_hl_tables(bool reinit)
     map_clear(int, int)(combine_attr_entries);
     map_clear(int, int)(blend_attr_entries);
     map_clear(int, int)(blendthrough_attr_entries);
+    memset(highlight_attr_last, -1, sizeof(highlight_attr_last));
     highlight_attr_set_all();
     highlight_changed();
     screen_invalidate_highlights();
diff --git a/src/nvim/highlight_defs.h b/src/nvim/highlight_defs.h
index 25d859c55d..afccf9e6f6 100644
--- a/src/nvim/highlight_defs.h
+++ b/src/nvim/highlight_defs.h
@@ -150,6 +150,7 @@ EXTERN const char *hlf_names[] INIT(= {
 
 
 EXTERN int highlight_attr[HLF_COUNT];       // Highl. attr for each context.
+EXTERN int highlight_attr_last[HLF_COUNT];  // copy for detecting changed groups
 EXTERN int highlight_user[9];                   // User[1-9] attributes
 EXTERN int highlight_stlnc[9];                  // On top of user
 EXTERN int cterm_normal_fg_color INIT(= 0);
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index e39075739c..bcb18b6e67 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -14,6 +14,7 @@
 
 #include "nvim/vim.h"
 #include "nvim/ascii.h"
+#include "nvim/api/private/helpers.h"
 #include "nvim/syntax.h"
 #include "nvim/charset.h"
 #include "nvim/cursor_shape.h"
@@ -7500,6 +7501,12 @@ void highlight_changed(void)
 
     highlight_attr[hlf] = hl_get_ui_attr(hlf, final_id,
                                          hlf == (int)HLF_INACTIVE);
+
+    if (highlight_attr[hlf] != highlight_attr_last[hlf]) {
+      ui_call_hl_group_set(cstr_as_string((char *)hlf_names[hlf]),
+                           highlight_attr[hlf]);
+      highlight_attr_last[hlf] = highlight_attr[hlf];
+    }
   }
 
   /* Setup the user highlights