3 files changed, 41 insertions, 55 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index 66c4454f7b..c55dc39605 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -222,11 +222,7 @@ Boolean nvim_buf_attach(uint64_t channel_id,
   return buf_updates_register(buf, channel_id, cb, send_buffer);
 
 error:
-  // TODO(bfredl): ASAN build should check that the ref table is empty?
-  api_free_luaref(cb.on_lines);
-  api_free_luaref(cb.on_bytes);
-  api_free_luaref(cb.on_changedtick);
-  api_free_luaref(cb.on_detach);
+  buffer_update_callbacks_free(cb);
   return false;
 }
 
@@ -1453,6 +1449,8 @@ Array nvim_buf_get_extmarks(Buffer buffer, Integer ns_id,
 ///                   the extmark end position (if it exists) will be shifted
 ///                   in when new text is inserted (true for right, false
 ///                   for left). Defaults to false.
+///               - priority: a priority value for the highlight group. For
+///                   example treesitter highlighting uses a value of 100.
 /// @param[out]  err   Error details, if any
 /// @return Id of the created/updated extmark
 Integer nvim_buf_set_extmark(Buffer buffer, Integer ns_id,
diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index d2b787a6f5..24ba6110c4 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1708,33 +1708,6 @@ const char *describe_ns(NS ns_id)
   return "(UNKNOWN PLUGIN)";
 }
 
-DecorProvider *get_provider(NS ns_id, bool force)
-{
-  ssize_t i;
-  for (i = 0; i < (ssize_t)kv_size(decor_providers); i++) {
-    DecorProvider *item = &kv_A(decor_providers, i);
-    if (item->ns_id == ns_id) {
-      return item;
-    } else if (item->ns_id > ns_id) {
-      break;
-    }
-  }
-
-  if (!force) {
-    return NULL;
-  }
-
-  for (ssize_t j = (ssize_t)kv_size(decor_providers)-1; j >= i; j++) {
-    // allocates if needed:
-    (void)kv_a(decor_providers, (size_t)j+1);
-    kv_A(decor_providers, (size_t)j+1) = kv_A(decor_providers, j);
-  }
-  DecorProvider *item = &kv_a(decor_providers, (size_t)i);
-  *item = DECORATION_PROVIDER_INIT(ns_id);
-
-  return item;
-}
-
 static bool parse_float_anchor(String anchor, FloatAnchor *out)
 {
   if (anchor.size == 0) {
@@ -1787,10 +1760,13 @@ static void parse_border_style(Object style, FloatConfig *fconfig, Error *err)
   struct {
     const char *name;
     schar_T chars[8];
+    bool shadow_color;
   } defaults[] = {
-    { "double", { "╔", "═", "╗", "║", "╝", "═", "╚", "║" } },
-    { "single", { "┌", "─", "┐", "│", "┘", "─", "└", "│" } },
-    { NULL, { { NUL } } },
+    { "double", { "╔", "═", "╗", "║", "╝", "═", "╚", "║" }, false },
+    { "single", { "┌", "─", "┐", "│", "┘", "─", "└", "│" }, false },
+    { "shadow", { "", "", " ", " ", " ", " ", " ", "" }, true },
+    { "solid", { " ", " ", " ", " ", " ", " ", " ", " " }, false },
+    { NULL, { { NUL } } , false },
   };
 
   schar_T *chars = fconfig->border_chars;
@@ -1834,13 +1810,16 @@ static void parse_border_style(Object style, FloatConfig *fconfig, Error *err)
         api_set_error(err, kErrorTypeValidation, "invalid border char");
         return;
       }
-      if (!string.size
-          || mb_string2cells_len((char_u *)string.data, string.size) != 1) {
+      if (string.size
+          && mb_string2cells_len((char_u *)string.data, string.size) > 1) {
         api_set_error(err, kErrorTypeValidation,
                       "border chars must be one cell");
+        return;
       }
       size_t len = MIN(string.size, sizeof(*chars)-1);
-      memcpy(chars[i], string.data, len);
+      if (len) {
+        memcpy(chars[i], string.data, len);
+      }
       chars[i][len] = NUL;
       hl_ids[i] = hl_id;
     }
@@ -1849,6 +1828,13 @@ static void parse_border_style(Object style, FloatConfig *fconfig, Error *err)
       memcpy(hl_ids+size, hl_ids, sizeof(*hl_ids) * size);
       size <<= 1;
     }
+    if ((chars[7][0] && chars[1][0] && !chars[0][0])
+        || (chars[1][0] && chars[3][0] && !chars[2][0])
+        || (chars[3][0] && chars[5][0] && !chars[4][0])
+        || (chars[5][0] && chars[7][0] && !chars[6][0])) {
+      api_set_error(err, kErrorTypeValidation,
+                    "corner between used edges must be specified");
+    }
   } else if (style.type == kObjectTypeString) {
     String str = style.data.string;
     if (str.size == 0 || strequal(str.data, "none")) {
@@ -1859,6 +1845,15 @@ static void parse_border_style(Object style, FloatConfig *fconfig, Error *err)
       if (strequal(str.data, defaults[i].name)) {
         memcpy(chars, defaults[i].chars, sizeof(defaults[i].chars));
         memset(hl_ids, 0, 8 * sizeof(*hl_ids));
+        if (defaults[i].shadow_color) {
+          int hl_blend = SYN_GROUP_STATIC("FloatShadow");
+          int hl_through = SYN_GROUP_STATIC("FloatShadowThrough");
+          hl_ids[2] = hl_through;
+          hl_ids[3] = hl_blend;
+          hl_ids[4] = hl_blend;
+          hl_ids[5] = hl_blend;
+          hl_ids[6] = hl_through;
+        }
         return;
       }
     }
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 787b6addc9..b5e53beabe 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1333,7 +1333,8 @@ void nvim_chan_send(Integer chan, String data, Error *err)
     return;
   }
 
-  channel_send((uint64_t)chan, data.data, data.size, &error);
+  channel_send((uint64_t)chan, data.data, data.size,
+               false, &error);
   if (error) {
     api_set_error(err, kErrorTypeValidation, "%s", error);
   }
@@ -1421,6 +1422,7 @@ void nvim_chan_send(Integer chan, String data, Error *err)
 ///     - "none" No border. This is the default
 ///     - "single" a single line box
 ///     - "double" a double line box
+///     - "shadow" a drop shadow effect by blending with the background.
 ///     If it is an array it should be an array of eight items or any divisor of
 ///     eight. The array will specifify the eight chars building up the border
 ///     in a clockwise fashion starting with the top-left corner. As, an
@@ -1431,6 +1433,9 @@ void nvim_chan_send(Integer chan, String data, Error *err)
 ///       [ "/", "-", "\\", "|" ]
 ///     or all chars the same as:
 ///       [ "x" ]
+///     An empty string can be used to turn off a specific border, for instance:
+///       [ "", "", "", ">", "", "", "", "<" ]
+///     will only make vertical borders but not horizontal ones.
 ///     By default `FloatBorder` highlight is used which links to `VertSplit`
 ///     when not defined.  It could also be specified by character:
 ///       [ {"+", "MyCorner"}, {"x", "MyBorder"} ]
@@ -2708,6 +2713,7 @@ Dictionary nvim__stats(void)
   Dictionary rv = ARRAY_DICT_INIT;
   PUT(rv, "fsync", INTEGER_OBJ(g_stats.fsync));
   PUT(rv, "redraw", INTEGER_OBJ(g_stats.redraw));
+  PUT(rv, "lua_refcount", INTEGER_OBJ(nlua_refcount));
   return rv;
 }
 
@@ -2880,19 +2886,6 @@ void nvim__screenshot(String path)
   ui_call_screenshot(path);
 }
 
-static void clear_provider(DecorProvider *p)
-{
-  if (p == NULL) {
-    return;
-  }
-  NLUA_CLEAR_REF(p->redraw_start);
-  NLUA_CLEAR_REF(p->redraw_buf);
-  NLUA_CLEAR_REF(p->redraw_win);
-  NLUA_CLEAR_REF(p->redraw_line);
-  NLUA_CLEAR_REF(p->redraw_end);
-  p->active = false;
-}
-
 /// Set or change decoration provider for a namespace
 ///
 /// This is a very general purpose interface for having lua callbacks
@@ -2937,8 +2930,8 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts,
                                   Error *err)
   FUNC_API_SINCE(7) FUNC_API_LUA_ONLY
 {
-  DecorProvider *p = get_provider((NS)ns_id, true);
-  clear_provider(p);
+  DecorProvider *p = get_decor_provider((NS)ns_id, true);
+  decor_provider_clear(p);
 
   // regardless of what happens, it seems good idea to redraw
   redraw_all_later(NOT_VALID);  // TODO(bfredl): too soon?
@@ -2981,5 +2974,5 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts,
   p->active = true;
   return;
 error:
-  clear_provider(p);
+  decor_provider_clear(p);
 }