feat: optimization of highlights using global highlight-group cache

lua/bubbly/factories/bubble.lua

@@ -4,6 +4,7 @@
 -- Created by datwaft <github.com/datwaft>
 
 local gethighlight = require'bubbly.utils.highlight'.gethighlight
+local ensure_highlight_exists = require'bubbly.utils.highlight'.ensure_highlight_exists
 
 local settings = {
   left_character = vim.g.bubbly_characters.left,
@@ -32,9 +33,9 @@ return function(list)
   -- Render delimiter of the bubble
   local function render_delimiter(delimiter, color)
     if type(color) == 'string' then
-      return '%#'..gethighlight(nil, color) ..'Delimiter#'..delimiter
+      return '%#'..ensure_highlight_exists(gethighlight(nil, color)..'Delimiter')..'#'..delimiter
     else
-      return '%#'..gethighlight(color.foreground, color.background)..'Delimiter#'..delimiter
+      return '%#'..ensure_highlight_exists(gethighlight(color.foreground, color.background)..'Delimiter')..'#'..delimiter
     end
   end
   -- Auxiliar function to know if data is last in the list
@@ -73,16 +74,16 @@ return function(list)
       if isfirst then bubble = bubble..render_delimiter(e.left, e.color) end
       -- render data style
       if type(e.color) == 'string' then
-        bubble = bubble..'%#'..gethighlight(nil, e.color, e.style) ..'#'
+        bubble = bubble..'%#'..ensure_highlight_exists(gethighlight(nil, e.color, e.style))..'#'
       else
-        bubble = bubble..'%#'..gethighlight(e.color.foreground, e.color.background, e.style)..'#'
+        bubble = bubble..'%#'..ensure_highlight_exists(gethighlight(e.color.foreground, e.color.background, e.style))..'#'
       end
       -- render data
       if not isfirst then bubble = bubble..' ' end
       bubble = bubble..e.data:gsub('^%s*(.-)%s*$', '%1')
       if not islast then bubble = bubble..' ' end
       -- render right delimiter
-      if islast then bubble = bubble..render_delimiter(e.right, e.color)..'%#BubblyStatusLine#' end
+      if islast then bubble = bubble..render_delimiter(e.right, e.color)..'%#'..ensure_highlight_exists('BubblyStatusLine')..'#' end
       -- render post
       bubble = bubble..e.post
       -- disable isfirst

lua/bubbly/factories/highlight.lua

@@ -16,36 +16,50 @@ local function execute_command(name, foreground, background, style)
   vim.cmd(highlight(name, foreground, background, style))
 end
 
--- Executes highlight vim command for normal, bold, italic and delimiter highlight
+-- Creates highlight config to be used in global highlight cache
+---@param command string - vim highlight command
+local function highlight_config(command)
+  return { exists = false, cmd = command }
+end
+
+-- Returns highlight configs wrapping vim commands for normal, bold, italic and
+-- delimiter highlight
 ---@param name string
 ---@param foreground string
 ---@param background string
 ---@param default_background string
 local function define_bubble_highlight(name, foreground, background, default_background)
-  execute_command(name, background, foreground)
-  execute_command(name..'Bold', background, foreground, 'bold')
-  execute_command(name..'Italic', background, foreground, 'italic')
-  execute_command(name..'Delimiter', foreground, default_background)
+  return {
+    [name] = highlight_config(highlight(name, background, foreground)),
+    [name..'Bold'] = highlight_config(highlight(name..'Bold', background, foreground, 'bold')),
+    [name..'Italic'] = highlight_config(highlight(name..'Italic', background, foreground, 'italic')),
+    [name..'Delimiter'] = highlight_config(highlight(name..'Delimiter', foreground, default_background)),
+  }
 end
 
--- Generates all vim highlights following :help :highlight for a palette
+-- Generates all vim highlight configs following :help :highlight for a palette
+-- and saves them in a global variable
 ---@param palette table<string, string>
 return function(palette)
   local fg = hlparser(palette.foreground)
   local bg = hlparser(palette.background)
+  local highlights = {}
   for k1, v1 in pairs(palette) do
     v1 = hlparser(v1)
     for k2, v2 in pairs(palette) do
       if k1 ~= k2 then
         v2 = hlparser(v2)
         local name = 'Bubbly'..titlecase(k2)..titlecase(k1)
-        define_bubble_highlight(name, v1, v2, bg)
+        local bubble_highlights = define_bubble_highlight(name, v1, v2, bg)
+        highlights = vim.tbl_extend('force', highlights, bubble_highlights)
       end
     end
     if k1 ~= 'background' then
-      define_bubble_highlight('Bubbly'..titlecase(k1), v1, bg, bg)
+      local bubble_highlights = define_bubble_highlight('Bubbly'..titlecase(k1), v1, bg, bg)
+      highlights = vim.tbl_extend('force', highlights, bubble_highlights)
     end
   end
-  execute_command('BubblyStatusLine', fg, bg)
+  highlights['BubblyStatusLine'] = highlight_config(highlight('BubblyStatusLine', fg, bg))
   execute_command('BubblyTabLine', fg, bg)
+  vim.g._bubbly_highlight_cache = highlights
 end

lua/bubbly/utils/highlight.lua

@@ -34,6 +34,22 @@ function M.gethighlight(foreground, background, special)
     titlecase(special)
 end
 
+-- Ensures that a highlight with given name exists.
+---@param name string | nil
+---@return string
+function M.ensure_highlight_exists(name)
+  local highlight_cache = vim.g._bubbly_highlight_cache or {}
+  local highlight = highlight_cache[name]
+  if highlight and not highlight.exists then
+    vim.cmd(highlight.cmd)
+    highlight.exists = true
+    highlight_cache[name] = highlight
+    vim.g._bubbly_highlight_cache = highlight_cache
+  end
+  -- Return the highlight name to be able to wrap 'name' with this function call
+  return name
+end
+
 -- Parses a palette value
 ---@param usercolor string
 ---@return string