perf: improve headline loading speed

Using the internal file API of nvim orgmode increases initial loading
speed drastically with larger Orgfile collections from multiple seconds
of delay to nearly instand loading.

Author: Sebastian Flügge

lua/telescope-orgmode/entry_maker/headlines.lua

@@ -2,23 +2,16 @@ require('telescope-orgmode.entry_maker.types')
 local org = require('telescope-orgmode.org')
 local entry_display = require('telescope.pickers.entry_display')
 
----@param file_results { file: OrgApiFile, filename: string }[]
+---@param headline_results { filename: string, title: string, level: number, line_number: number, all_tags: string[], is_archived: boolean }[]
 ---@return OrgHeadlineEntry[]
-local function index_headlines(file_results, opts)
+local function index_headlines(headline_results, opts)
   local results = {}
-  for _, file_entry in ipairs(file_results) do
-    for _, headline in ipairs(file_entry.file.headlines) do
-      local allowed_depth = opts.max_depth == nil or headline.level <= opts.max_depth
-      local allowed_archive = opts.archived or not headline.is_archived
-      if allowed_depth and allowed_archive then
-        local entry = {
-          file = file_entry.file,
-          filename = file_entry.filename,
-          headline = headline,
-        }
-        table.insert(results, entry)
-      end
-    end
+  for _, headline in ipairs(headline_results) do
+    local entry = {
+      filename = headline.filename,
+      headline = headline,
+    }
+    table.insert(results, entry)
   end
 
   return results
@@ -29,7 +22,7 @@ local M = {}
 ---@param opts any
 ---@return OrgHeadlineEntry[]
 M.get_entries = function(opts)
-  return index_headlines(org.load_files(opts), opts)
+  return index_headlines(org.load_headlines(opts), opts)
 end
 
 ---Entry-Maker for Telescope
@@ -39,8 +32,8 @@ M.make_entry = function(opts)
   local displayer = entry_display.create({
     separator = ' ',
     items = {
-      { width = vim.F.if_nil(opts.location_width, 16) },
       { width = vim.F.if_nil(opts.location_width, 24) },
+      { width = vim.F.if_nil(opts.tags_width, 20) },
       { remaining = true },
     },
   })
@@ -56,7 +49,7 @@ M.make_entry = function(opts)
 
   return function(entry)
     local headline = entry.headline
-    local lnum = headline.position.start_line
+    local lnum = headline.line_number
     local location = string.format('%s:%i', vim.fn.fnamemodify(entry.filename, ':t'), lnum)
     local line = string.format('%s %s', string.rep('*', headline.level), headline.title)
     local tags = table.concat(headline.all_tags, ':')

lua/telescope-orgmode/mappings.lua

@@ -4,6 +4,7 @@ local M = {}
 
 function M.attach_mappings(map, opts)
   map('i', '<c-space>', to_actions.toggle_headlines_orgfiles(opts), { desc = 'Toggle headline/orgfile' })
+  map('n', '<c-space>', to_actions.toggle_headlines_orgfiles(opts), { desc = 'Toggle headline/orgfile' })
   M.attach_custom(map, opts)
 end
 

lua/telescope-orgmode/org.lua

@@ -5,7 +5,7 @@ local M = {}
 function M.load_files(opts)
   ---@type { filename: string, last_used: number, title: string }[]
   local file_results = vim.tbl_map(function(file)
-    return { filename = file.filename, last_used = file.metadata.mtime, title = file:get_title()   }
+    return { filename = file.filename, last_used = file.metadata.mtime, title = file:get_title() }
   end, require('orgmode').files:all())
 
   if not opts.archived then
@@ -21,6 +21,44 @@ function M.load_files(opts)
   return file_results
 end
 
+function M.load_headlines(opts)
+  ---@type { filename: string, title: string, level: number, line_number: number, all_tags: string[], is_archived: boolean }[]
+  local results = {}
+
+  -- Get files sorted by modification time (most recent first)
+  local files = require('orgmode').files:all()
+  if not opts.archived then
+    files = vim.tbl_filter(function(file)
+      return not (vim.fn.fnamemodify(file.filename, ':e') == 'org_archive')
+    end, files)
+  end
+
+  table.sort(files, function(a, b)
+    return a.metadata.mtime < b.metadata.mtime
+  end)
+
+  for _, file in ipairs(files) do
+    -- Skip archive files unless explicitly requested
+    local headlines = opts.archived and file:get_headlines_including_archived() or file:get_headlines()
+    for _, headline in ipairs(headlines) do
+      if
+        (not opts.max_depth or headline:get_level() <= opts.max_depth) and (opts.archived or not headline:is_archived())
+      then
+        table.insert(results, {
+          filename = file.filename,
+          title = headline:get_title(),
+          level = headline:get_level(),
+          line_number = headline:get_range().start_line,
+          all_tags = headline:get_tags(),
+          is_archived = headline:is_archived(),
+        })
+      end
+    end
+  end
+
+  return results
+end
+
 function M.refile(opts)
   return OrgApi.refile(opts)
 end

tests/plenary/lightweight_headlines_spec.lua

@@ -0,0 +1,64 @@
+local OrgFile = require('orgmode.files.file')
+local org = require('telescope-orgmode.org')
+
+describe('Telescope Orgmode Integration', function()
+  ---@return OrgFile
+  local load_file_sync = function(content, filename)
+    content = content or {}
+    filename = filename or vim.fn.tempname() .. '.org'
+    vim.fn.writefile(content, filename)
+    return OrgFile.load(filename):wait()
+  end
+
+  describe('org.load_headlines integration', function()
+    it('should return headlines from multiple files', function()
+      -- Create test files
+      local file1 = load_file_sync({ '* File1 Headline' })
+      local file2 = load_file_sync({ '* File2 Headline' })
+
+      -- Mock orgmode.files:all() to return our test files
+      local original_require = require
+      package.loaded['orgmode'] = {
+        files = {
+          all = function()
+            return { file1, file2 }
+          end,
+        },
+      }
+
+      local headlines = org.load_headlines({})
+
+      -- Restore original require
+      require = original_require
+
+      assert.are.same(2, #headlines)
+      assert.are.same('File1 Headline', headlines[1].title)
+      assert.are.same('File2 Headline', headlines[2].title)
+    end)
+
+    it('should respect archive filtering across files', function()
+      local regular_file = load_file_sync({ '* Regular Headline' })
+      local archive_filename = vim.fn.tempname() .. '.org_archive'
+      local archive_file = load_file_sync({ '* Archive Headline' }, archive_filename)
+
+      -- Mock orgmode.files:all()
+      local original_require = require
+      package.loaded['orgmode'] = {
+        files = {
+          all = function()
+            return { regular_file, archive_file }
+          end,
+        },
+      }
+
+      local headlines_no_archive = org.load_headlines({})
+      local headlines_with_archive = org.load_headlines({ archived = true })
+
+      -- Restore
+      require = original_require
+
+      assert.are.same(1, #headlines_no_archive) -- only regular file
+      assert.are.same(2, #headlines_with_archive) -- both files
+    end)
+  end)
+end)