1 files changed, 27 insertions, 33 deletions

diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index d2b787a6f5..c73a9195c3 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 +1760,12 @@ 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 },
+    { NULL, { { NUL } } , false },
   };
 
   schar_T *chars = fconfig->border_chars;
@@ -1834,13 +1809,16 @@ 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 +1827,13 @@ 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 +1844,15 @@ 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;
       }
     }