feat: add filepermissions component

Author: alichtman

README.md

@@ -257,6 +257,7 @@ sections = {lualine_a = {'mode'}}
 - `diff` (git diff status)
 - `encoding` (file encoding)
 - `fileformat` (file format)
+- `filepermissions`
 - `filename`
 - `filesize`
 - `filetype`
@@ -630,6 +631,20 @@ sections = {
 }
 ```
 
+#### filepermissions component options
+
+```lua
+sections = {
+  lualine_a = {
+    {
+      'filepermissions',
+        octal = false, -- Displays file permissions in octal format if set to true
+      }
+    }
+  }
+}
+```
+
 #### filename component options
 
 ```lua

lua/lualine/components/filepermissions.lua

@@ -0,0 +1,32 @@
+-- Copyright (c) 2020-2021 shadmansaleh
+-- MIT license, see LICENSE for more details.
+local M = require('lualine.component'):extend()
+local bit = require('bit')
+
+-- Initializer
+function M:init(options)
+  -- Run super()
+  M.super.init(self, options)
+end
+
+-- Function that runs every time statusline is updated
+function M:update_status()
+  local curr_filepath = vim.fn.expand('%')
+  if curr_filepath == '' then
+    return ''
+  end
+
+  if not self.options.octal then
+    return vim.fn.getfperm(curr_filepath)
+  else
+    local stat_results = vim.uv.fs_stat(curr_filepath)
+    if stat_results == nil then
+      return ''
+    end
+    local bitmask = 0b111111111
+    local octal_perm = bit.band(stat_results.mode, bitmask)
+    return string.format('o%o', octal_perm)
+  end
+end
+
+return M

tests/spec/component_spec.lua

@@ -585,6 +585,30 @@ describe('FileSize component', function()
   end)
 end)
 
+describe('Filepermissions componnet', function()
+  it('can show octal permissions', function()
+    local opts = build_component_opts {
+      octal = true,
+    }
+    vim.cmd(':e test-file.txt')
+    assert_component('filepermissions', opts, '')
+    vim.cmd(':w')
+    vim.fn.setfperm("test-file.txt", "rwxrwxrwx")
+    assert_component('filename', opts, 'o777')
+  end)
+
+  it('can show regular permissions', function()
+    local opts = build_component_opts {
+      octal = false,
+    }
+    vim.cmd(':e test-file.txt')
+    assert_component('filepermissions', opts, '')
+    vim.cmd(':w')
+    vim.fn.setfperm("test-file.txt", "rwxrwxrwx")
+    assert_component('filename', opts, 'rwxrwxrwx')
+  end)
+end)
+
 describe('Filename component', function()
   it('works', function()
     local opts = build_component_opts {