-
---[[
-
- 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