fix: Termux compatible is_readable_directory function

lua/battery/battery.lua

@@ -1,12 +1,8 @@
 local M = {}
 
 local L = require('plenary.log')
-local powershell = require('battery.powershell')
-local pmset = require('battery.pmset')
-local powersupply = require('battery.powersupply')
-local acpi = require('battery.acpi')
 local config = require('battery.config')
-local file = require('util.file')
+local parsers = require('battery.parsers')
 local icons = require('battery.icons')
 
 -- TODO check for icons and if not available fallback to text
@@ -33,25 +29,21 @@ end
 -- can reload the battery module and we can detect the old job is still running.
 local timer = nil
 
--- Select the battery info job to run based on platform and what programs
--- are available
+---Select the battery info job to run based on platform and what programs
+---are available
+---@return (fun(battery_status: table): any)?
+---@return string?
 local function select_job()
-  if vim.fn.has('win32') and vim.fn.executable('powershell') == 1 then
-    log.debug('windows powershell battery job')
-    return powershell.get_battery_info_job, 'powershell'
-  elseif vim.fn.executable('pmset') == 1 then
-    log.debug('pmset battery job')
-    return pmset.get_battery_info_job, 'pmset'
-  elseif file.is_readable_directory('/sys/class/power_supply/') then
-    log.debug('power_supply battery job')
-    return powersupply.get_battery_info_job, 'powersupply'
-  elseif vim.fn.executable('acpi') == 1 then
-    log.debug('acpi battery job')
-    return acpi.get_battery_info_job, 'acpi'
-  else
-    log.debug('no battery job')
-    return nil, 'none'
+  for method, parser_module in pairs(parsers.parsers) do
+    if parser_module.check() then
+      log.debug('using '..method..' method')
+      return parser_module.get_battery_info_job, method
+    end
   end
+
+  -- No suitable parser was found.
+  log.debug('no parser found')
+  return nil, nil
 end
 
 -- This is used for the health check
@@ -68,7 +60,7 @@ local function timer_loop()
     log.debug(timer .. ' is running now')
     local job_function, method = select_job()
     battery_status.method = method
-    log.debug('using method ' .. method)
+    log.debug('using method ' .. (method or 'nil'))
 
     if job_function then
       job_function(battery_status):start()
@@ -98,7 +90,7 @@ local function start_timer()
   -- Always call the job immediately before starting the timed loop
   local job_function, method = select_job()
   battery_status.method = method
-  log.debug('using method ' .. method)
+  log.debug('using method: ' .. (method or 'nil'))
 
   if job_function then
     job_function(battery_status):start()

lua/battery/acpi.lua → lua/battery/parsers/acpi.lua

@@ -84,4 +84,10 @@ function M.get_battery_info_job(battery_status)
   })
 end
 
+---Check if this parser would work in the current environment
+---@return boolean
+function M.check()
+  return vim.fn.executable('acpi') == 1
+end
+
 return M

lua/battery/parsers/init.lua

@@ -0,0 +1,15 @@
+local M = {}
+
+---@class ParserModule
+---@field check fun(): boolean
+---@field get_battery_info_job fun(battery_status: table): any
+
+---@type table<string, ParserModule>
+M.parsers = {
+  powershell = require('battery.parsers.powershell'),
+  pmset = require('battery.parsers.pmset'),
+  powersupply = require('battery.parsers.powersupply'),
+  acpi = require('battery.parsers.acpi'),
+}
+
+return M

lua/battery/pmset.lua → lua/battery/parsers/pmset.lua

@@ -81,4 +81,10 @@ function M.get_battery_info_job(battery_status)
   })
 end
 
+---Check if this parser would work in the current environment
+---@return boolean
+function M.check()
+  return vim.fn.executable('pmset') == 1
+end
+
 return M

lua/battery/powershell.lua → lua/battery/parsers/powershell.lua

@@ -87,4 +87,10 @@ function M.get_battery_info_job(battery_status)
   })
 end
 
+---Check if this parser would work in the current environment
+---@return boolean
+function M.check()
+  return vim.fn.has('win32') and vim.fn.executable('powershell') == 1
+end
+
 return M

lua/battery/powersupply.lua → lua/battery/parsers/powersupply.lua

@@ -6,6 +6,7 @@ local J = require('plenary.job')
 local L = require('plenary.log')
 local BC = require('util.chooser')
 local config = require('battery.config')
+local file = require('util.file')
 local log = L.new({ plugin = 'battery' })
 
 -- Convert lowercase status from `/sys/class/power_supply/BAT?/status`
@@ -84,4 +85,10 @@ function M.get_battery_info_job(battery_status)
   })
 end
 
+---Check if this parser would work in the current environment
+---@return boolean
+function M.check()
+  return file.is_readable_directory('/sys/class/power_supply/')
+end
+
 return M

lua/util/file.lua

@@ -2,9 +2,24 @@ local M = {}
 
 local bit = require('bit')
 
-function M.is_readable_directory(file)
-  local s = vim.loop.fs_stat(file)
-  return s ~= nil and s.type == 'directory' and bit.band(s.mode, 4) == 4
+---Check if there is a readable directory at the given file path.
+---Warning: the `path` may be substituted onto the command line,
+---so the input _must_ be trusted.
+---@param path string
+---@return boolean
+function M.is_readable_directory(path)
+  if not os.getenv('TERMUX_VERSION') then
+    -- When not running in Termux
+    local s = vim.loop.fs_stat(path)
+    return (
+      s ~= nil -- File exists
+      and s.type == 'directory' -- File is a directory
+      and bit.band(s.mode, 4) == 4 -- File is readable (Minimum permissions: ------r--)
+    )
+  else
+    -- In Termux, use the `test` command
+    return os.execute('test -d \''..path..'\' && test -r \''..path..'\'') == 0
+  end
 end
 
 return M