Merge pull request #377 from sim590/menu-iterator

[etc/awesome.git] / helpers.lua

diff --git a/helpers.lua b/helpers.lua
index 81910d21b206bc2b151cdb9214b84e8bb80e4b3b..313579f8a3d28368b4918faf5e0a32f4b9ca9e37 100644 (file)
--- a/helpers.lua
+++ b/helpers.lua
@@ -1,17 +1,17 @@
-
 --[[
-                                                      
-     Licensed under GNU General Public License v2     
-      * (c) 2013,      Luke Bonham                    
-      * (c) 2010-2012, Peter Hofmann                  
-                                                      
---]]
 
-local debug  = require("debug")
+     Licensed under GNU General Public License v2
+      * (c) 2013, Luca CPZ
 
-local capi   = { timer = timer }
-local io     = { open = io.open }
-local rawget = rawget
+--]]
+
+local spawn      = require("awful.spawn")
+local timer      = require("gears.timer")
+local debug      = require("debug")
+local io         = { lines = io.lines,
+                     open  = io.open }
+local rawget     = rawget
+local table      = { sort  = table.sort }
 
 -- Lain helper functions for internal use
 -- lain.helpers
@@ -30,33 +30,107 @@ end
 
 -- }}}
 
--- {{{ Read the first line of a file or return nil.
+-- {{{ File operations
+
+-- see if the file exists and is readable
+function helpers.file_exists(file)
+  local f = io.open(file)
+  if f then
+      local s = f:read()
+      f:close()
+      f = s
+  end
+  return f ~= nil
+end
 
-function helpers.first_line(f)
-    local fp = io.open(f)
-    if not fp
-    then
-        return nil
-    end
+-- get all lines from a file, returns an empty
+-- list/table if the file does not exist
+function helpers.lines_from(file)
+  if not helpers.file_exists(file) then return {} end
+  local lines = {}
+  for line in io.lines(file) do
+    lines[#lines + 1] = line
+  end
+  return lines
+end
+
+-- match all lines from a file, returns an empty
+-- list/table if the file or match does not exist
+function helpers.lines_match(regexp, file)
+       local lines = {}
+       for index,line in pairs(helpers.lines_from(file)) do
+               if string.match(line, regexp) then
+                       lines[index] = line
+               end
+       end
+       return lines
+end
 
-    local content = fp:read("*l")
-    fp:close()
-    return content
+-- get first line of a file, return nil if
+-- the file does not exist
+function helpers.first_line(file)
+    return helpers.lines_from(file)[1]
+end
+
+-- get first non empty line from a file,
+-- returns nil otherwise
+function helpers.first_nonempty_line(file)
+  for k,v in pairs(helpers.lines_from(file)) do
+    if #v then return v end
+  end
+  return nil
 end
 
 -- }}}
 
--- {{{ Timer maker 
+-- {{{ Timer maker
 
 helpers.timer_table = {}
 
-function helpers.newtimer(name, timeout, fun, nostart)
-    helpers.timer_table[name] = capi.timer({ timeout = timeout })
+function helpers.newtimer(name, timeout, fun, nostart, stoppable)
+    if not name or #name == 0 then return end
+    name = (stoppable and name) or timeout
+    if not helpers.timer_table[name] then
+        helpers.timer_table[name] = timer({ timeout = timeout })
+        helpers.timer_table[name]:start()
+    end
     helpers.timer_table[name]:connect_signal("timeout", fun)
-    helpers.timer_table[name]:start()
     if not nostart then
         helpers.timer_table[name]:emit_signal("timeout")
     end
+    return stoppable and helpers.timer_table[name]
+end
+
+-- }}}
+
+-- {{{ Pipe operations
+
+-- run a command and execute a function on its output (asynchronous pipe)
+-- @param cmd the input command
+-- @param callback function to execute on cmd output
+-- @return cmd PID
+function helpers.async(cmd, callback)
+    return spawn.easy_async(cmd,
+    function (stdout, stderr, reason, exit_code)
+        callback(stdout, exit_code)
+    end)
+end
+
+-- like above, but call spawn.easy_async with a shell
+function helpers.async_with_shell(cmd, callback)
+    return spawn.easy_async_with_shell(cmd,
+    function (stdout, stderr, reason, exit_code)
+        callback(stdout, exit_code)
+    end)
+end
+
+-- run a command and execute a function on its output line by line
+function helpers.line_callback(cmd, callback)
+    return spawn.with_line_callback(cmd, {
+        stdout = function (line)
+            callback(line)
+        end,
+    })
 end
 
 -- }}}
@@ -75,4 +149,59 @@ end
 
 -- }}}
 
+-- {{{ Misc
+
+-- check if an element exist on a table
+function helpers.element_in_table(element, tbl)
+    for _, i in pairs(tbl) do
+        if i == element then
+            return true
+        end
+    end
+    return false
+end
+
+-- iterate over table of records sorted by keys
+function helpers.spairs(t)
+    -- collect the keys
+    local keys = {}
+    for k in pairs(t) do keys[#keys+1] = k end
+
+    table.sort(keys)
+
+    -- return the iterator function
+    local i = 0
+    return function()
+        i = i + 1
+        if keys[i] then
+            return keys[i], t[keys[i]]
+        end
+    end
+end
+
+-- create trivial partition of a set. The trivial partition set is the simplest
+-- partition of a set. For e.g., the trivial partition set of {a, b, c}, is
+-- simply {{a}, {b}, {c}}.
+function helpers.trivial_partition_set(set)
+    local ss = {}
+    for _,e in pairs(set) do
+        ss[#ss+1] = {e}
+    end
+    return ss
+end
+
+-- creates the powerset of a given set
+function helpers.powerset(s)
+    if not s then return {} end
+    local t = {{}}
+    for i = 1, #s do
+        for j = 1, #t do
+            t[#t+1] = {s[i],unpack(t[j])}
+        end
+    end
+    return t
+end
+
+-- }}}
+
 return helpers