Add tags builtin

lua/telescope/builtin.lua

@@ -923,4 +923,30 @@ builtin.marks = function(opts)
   }):find()
 end
 
+builtin.tags = function(opts)
+  opts = opts or {}
+
+  if not vim.loop.fs_open('tags', "r", 438) then
+    print('Tags file does not exists. Create one with ctags -R')
+    return
+  end
+
+  local fd = assert(vim.loop.fs_open('tags', "r", 438))
+  local stat = assert(vim.loop.fs_fstat(fd))
+  local data = assert(vim.loop.fs_read(fd, stat.size, 0))
+  assert(vim.loop.fs_close(fd))
+
+  local lines = vim.split(data, '\n')
+
+  pickers.new(opts,{
+    prompt = 'Tags',
+    finder = finders.new_table {
+      results = lines,
+      entry_maker = make_entry.gen_from_ctags(opts),
+    },
+    previewer = previewers.ctags.new(opts),
+    sorter = conf.generic_sorter(opts),
+  }):find()
+end
+
 return builtin

lua/telescope/make_entry.lua

@@ -134,7 +134,7 @@ do
   end
 
   local execute_keys = {
-    path = function(t) 
+    path = function(t)
       return t.cwd .. path.separator .. t.filename, false
     end,
 
@@ -572,4 +572,72 @@ function make_entry.gen_from_vimoptions(opts)
   end
 end
 
+function make_entry.gen_from_ctags(opts)
+  opts = opts or {}
+
+  local cwd = vim.fn.expand(opts.cwd or vim.fn.getcwd())
+  local current_file = path.normalize(vim.fn.expand('%'), cwd)
+
+  local display_items = {
+    { width = 30 },
+    { remaining = true },
+  }
+
+  if opts.show_line then
+    table.insert(display_items, 2, { width = 30 })
+  end
+
+  local displayer = entry_display.create {
+    separator = " │ ",
+    items = display_items,
+  }
+
+  local make_display = function(entry)
+    local filename
+    if not opts.hide_filename then
+      if opts.shorten_path then
+        filename = path.shorten(entry.filename)
+      else
+        filename = entry.filename
+      end
+    end
+
+    local scode
+    if opts.show_line then
+      scode = entry.scode
+    end
+
+    return displayer {
+      filename,
+      entry.tag,
+      scode,
+    }
+  end
+
+  return function(line)
+    if line == '' or line:sub(1, 1) == '!' then
+      return nil
+    end
+
+    local tag, file, scode = string.match(line, '([^\t]+)\t([^\t]+)\t/^\t?(.*)/;"\t+.*')
+
+    if opts.only_current_file and file ~= current_file then
+      return nil
+    end
+
+    return {
+      valid = true,
+
+      ordinal = file .. ': ' .. tag .. ': ' .. scode,
+      display = make_display,
+      scode = scode,
+      tag = tag,
+
+      filename = file,
+
+      col = 1,
+    }
+  end
+end
+
 return make_entry

lua/telescope/pickers/entry_display.lua

@@ -43,8 +43,8 @@ end
 
 local function truncate(str, len)
   -- TODO: This doesn't handle multi byte chars...
-  if vim.fn.strdisplaywidth(str) > len - 1 then
-    str = str:sub(1, len)
+  if vim.fn.strdisplaywidth(str) > len then
+    str = str:sub(1, len - 1)
     str = str .. "…"
   end
   return str
@@ -68,7 +68,7 @@ entry_display.create = function(configuration)
 
   return function(self, picker)
     local results = {}
-    for k, v in ipairs(self) do
+    for k, v in pairs(self) do
       table.insert(results, generator[k](v, picker))
     end
 

lua/telescope/previewers.lua

@@ -374,6 +374,34 @@ previewers.vimgrep = defaulter(function(opts)
   }
 end, {})
 
+previewers.ctags = defaulter(function(opts)
+  local maker = get_maker(opts)
+
+  return previewers.new_termopen_previewer {
+    get_command = function(entry, status)
+      local strip_endline = string.gsub(entry.scode, '[$]$', '')
+      local strip_doubleslash = string.gsub(strip_endline, [[\\]], [[\]])
+      local strip_c_comment = string.gsub(strip_doubleslash, [[\/]], [[/]])
+
+      local cmd = 'grep -Frn --exclude=tags --exclude-dir=".git" \'' .. strip_c_comment .. '\''
+      local output = vim.split(utils.get_os_command_output(cmd), ':')
+      entry.lnum = tonumber(output[2])
+
+      local win_id = status.preview_win
+      local height = vim.api.nvim_win_get_height(win_id)
+
+      local filename = entry.filename
+      local lnum = entry.lnum or 0
+
+      local context = math.floor(height / 2)
+      local start = math.max(0, lnum - context)
+      local finish = lnum + context
+
+      return maker(filename, lnum, start, finish)
+    end,
+  }
+end, {})
+
 previewers.qflist = defaulter(function(opts)
   opts = opts or {}