refactor(renderer): remove set_folder_hl function from icons

This greatly simplifies the folder highlighting logic. It wasn't clear
before and the code was probably doing more than it should. The logic
with highlight_opened_file wasn't working at all, so i just removed it.
This should allow us to greatly extend the order in which the components
are rendered.

lua/nvim-tree/renderer/builder.lua

@@ -6,7 +6,7 @@ local icons = require "nvim-tree.renderer.components.icons"
 
 -- TODO(refactor): the builder abstraction is not perfect yet. We shouldn't leak data in components.
 -- Components should return only and icon / highlight group pair at most.
--- The code was mostly moved from renderer/init.lua and rearranged, so it's still under construction.
+-- Only missing git refactoring
 
 local Builder = {}
 Builder.__index = Builder
@@ -84,39 +84,28 @@ function Builder:_build_folder(node, padding, git_hl)
   local has_children = #node.nodes ~= 0 or node.has_children
   local icon = icons.get_folder_icon(node.open, node.link_to ~= nil, has_children)
   local git_icon = git.get_icons(node, self.index, offset, #icon, self.highlights) or ""
+  local line = padding .. icon .. git_icon .. name .. self.trailing_slash
 
-  local folder_hl = "NvimTreeFolderName"
+  self:_insert_line(line)
+
+  if #icon > 0 then
+    self:_insert_highlight("NvimTreeFolderIcon", offset, offset + #icon)
+  end
+
+  local foldername_hl = "NvimTreeFolderName"
   if self.special_map[node.absolute_path] then
-    folder_hl = "NvimTreeSpecialFolderName"
+    foldername_hl = "NvimTreeSpecialFolderName"
   elseif node.open then
-    folder_hl = "NvimTreeOpenedFolderName"
+    foldername_hl = "NvimTreeOpenedFolderName"
   elseif not has_children then
-    folder_hl = "NvimTreeEmptyFolderName"
+    foldername_hl = "NvimTreeEmptyFolderName"
   end
 
-  icons.set_folder_hl(
-    self.index,
-    offset,
-    #icon + #git_icon,
-    #name,
-    "NvimTreeFolderIcon",
-    folder_hl,
-    self.highlights,
-    self.open_file_highlight
-  )
+  self:_insert_highlight(foldername_hl, offset + #icon + #git_icon, #line)
+
   if git_hl then
-    icons.set_folder_hl(
-      self.index,
-      offset,
-      #icon + #git_icon,
-      #name,
-      git_hl,
-      git_hl,
-      self.highlights,
-      self.open_file_highlight
-    )
+    self:_insert_highlight(git_hl, offset + #icon + #git_icon, #line)
   end
-  self:_insert_line(padding .. icon .. git_icon .. name .. self.trailing_slash)
 end
 
 -- TODO: missing git icon for symlinks

lua/nvim-tree/renderer/components/icons.lua

@@ -11,14 +11,6 @@ local function empty()
   return ""
 end
 
-local function get_trailing_length()
-  return vim.g.nvim_tree_add_trailing and 1 or 0
-end
-
-local function set_folder_hl_default(line, depth, git_icon_len, _, hl_group, _, hl)
-  table.insert(hl, { hl_group, line, depth + git_icon_len, -1 })
-end
-
 local function get_folder_icon(open, is_symlink, has_children)
   local n
   if is_symlink and open then
@@ -41,12 +33,6 @@ local function get_folder_icon(open, is_symlink, has_children)
   return n .. M.padding
 end
 
-local function set_folder_hl(line, depth, icon_len, name_len, hl_icongroup, hl_fnamegroup, hl, should_hl_opened_files)
-  local hl_icon = should_hl_opened_files and hl_icongroup or "NvimTreeFolderIcon"
-  table.insert(hl, { hl_icon, line, depth, depth + icon_len })
-  table.insert(hl, { hl_fnamegroup, line, depth + icon_len, depth + icon_len + name_len + get_trailing_length() })
-end
-
 local function get_file_icon_default()
   local hl_group = "NvimTreeFileIcon"
   local icon = M.icons.default
@@ -95,10 +81,8 @@ end
 local function config_folder_icon()
   if M.configs.show_folder_icon then
     M.get_folder_icon = get_folder_icon
-    M.set_folder_hl = set_folder_hl
   else
     M.get_folder_icon = empty
-    M.set_folder_hl = set_folder_hl_default
   end
 end