1 files changed, 79 insertions, 0 deletions
diff --git a/lain/asyncshell.lua b/lain/asyncshell.lua
new file mode 100644
index 0000000..0aafa17
--- /dev/null
+++ b/lain/asyncshell.lua
@@ -0,0 +1,79 @@
+
+--[[
+                                                  
+     Licensed under GNU General Public License v2 
+      * (c) 2013, Alexander Yakushev              
+                                                  
+--]]
+
+-- Asynchronous io.popen for Awesome WM.
+-- How to use...
+-- ...asynchronously:
+-- asyncshell.request('wscript -Kiev', function(f) wwidget.text = f:read("*l") end)
+-- ...synchronously:
+-- widget:set_text(asyncshell.demand('wscript -Kiev', 5):read("*l") or "Error")
+
+local spawn = require('awful.util').spawn
+
+asyncshell               = {}
+asyncshell.request_table = {}
+asyncshell.id_counter    = 0
+asyncshell.folder        = "/tmp/asyncshell"
+asyncshell.file_template = asyncshell.folder .. '/req'
+
+-- Create a directory for asynchell response files
+os.execute("mkdir -p " .. asyncshell.folder)
+
+-- Returns next tag - unique identifier of the request
+local function next_id()
+   asyncshell.id_counter = (asyncshell.id_counter + 1) % 100000
+   return asyncshell.id_counter
+end
+
+-- Sends an asynchronous request for an output of the shell command.
+-- @param command Command to be executed and taken output from
+-- @param callback Function to be called when the command finishes
+-- @return Request ID
+function asyncshell.request(command, callback)
+   local id = next_id()
+   local tmpfname = asyncshell.file_template .. id
+   asyncshell.request_table[id] = { callback = callback }
+   local req =
+      string.format("sh -c '%s > %s; " ..
+                    'echo "asyncshell.deliver(%s)" | ' ..
+                    "awesome-client' 2> /dev/null",
+                    string.gsub(command, "'", "'\\''"), tmpfname, id)
+   spawn(req, false)
+   return id
+end
+
+-- Calls the remembered callback function on the output of the shell
+-- command.
+-- @param id Request ID
+-- @param output The output file of the shell command to be delievered
+function asyncshell.deliver(id)
+   if asyncshell.request_table[id] and
+      asyncshell.request_table[id].callback then
+      local output = io.open(asyncshell.file_template .. id, 'r')
+      asyncshell.request_table[id].callback(output)
+   end
+end
+
+-- Sends a synchronous request for an output of the command. Waits for
+-- the output, but if the given timeout expires returns nil.
+-- @param command Command to be executed and taken output from
+-- @param timeout Maximum amount of time to wait for the result
+-- @return File handler on success, nil otherwise
+function asyncshell.demand(command, timeout)
+   local id = next_id()
+   local tmpfname = asyncshell.file_template .. id
+   local f = io.popen(string.format("(%s > %s; echo asyncshell_done) & " ..
+                                    "(sleep %s; echo asynchell_timeout)",
+                                    command, tmpfname, timeout))
+   local result = f:read("*line")
+   if result == "asyncshell_done" then
+      return io.open(tmpfname)
+   end
+end
+
+return asyncshell