added command queue

git-svn-id: https://svn.spreadspace.org/gcsd/trunk@27 ac14a137-c7f1-4531-abe0-07747231d213

5 files changed, 116 insertions, 20 deletions

diff --git a/src/Makefile b/src/Makefile
index abad7a5..91461fd 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -53,6 +53,7 @@ C_SRCS := $(C_OBJS:%.o=%.c)
 
 LUA_SRCS := client_list.lua \
             module_list.lua \
+            command_queue.lua \
             main_loop.lua
 
 LUA_BYTECODE := $(EXECUTABLE).lc
diff --git a/src/command_queue.lua b/src/command_queue.lua
new file mode 100644
index 0000000..a7ed70b
--- /dev/null
+++ b/src/command_queue.lua
@@ -0,0 +1,77 @@
+--
+--  gcsd
+--
+--  gcsd the generic command sequencer daemon can be used to serialize 
+--  commands sent over various paralell communication channels to a
+--  single command output. It can be seen as a multiplexer for any
+--  kind of communication between a single resource and various clients
+--  which want to submit commands to it or query information from it.
+--  gcsd is written in C and Lua. The goal is to provide an easy to 
+--  understand high level API based on Lua which can be used to
+--  implement the business logic of the so formed multiplexer daemon.
+--  
+--
+--  Copyright (C) 2009-2010 Markus Grueneis <gimpf@spreadspace.org>
+--                          Christian Pointner <equinox@spreadspace.org>
+--
+--  This file is part of gcsd.
+--
+--  gcsd is free software: you can redistribute it and/or modify
+--  it under the terms of the GNU General Public License as published by
+--  the Free Software Foundation, either version 3 of the License, or
+--  any later version.
+--
+--  gcsd is distributed in the hope that it will be useful,
+--  but WITHOUT ANY WARRANTY; without even the implied warranty of
+--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+--  GNU General Public License for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with gcsd. If not, see <http://www.gnu.org/licenses/>.
+--
+
+local defines = require("defines")
+
+command_queue = {}
+
+command_queue.commands = {}
+command_queue.current = nil
+
+function command_queue:enqueue(command, expected_response, timeout)
+   local new_cmd = {}
+   new_cmd.command = command
+   new_cmd.sent = false
+   new_cmd.expected_response = expected_response
+   new_cmd.timeout = timeout
+   
+   table.insert(self.commands, new_cmd)
+end
+
+function command_queue:command_pending()
+   return (self.current == nil and #self.commands > 0)
+end
+
+function command_queue:get_current_command()
+   return self.current
+end
+
+function command_queue:get_next_command() 
+   if(self.current ~= nil) then return nil end
+
+   self.current = self.commands[1]
+   return self.current.command
+end
+
+function command_queue:command_sent()
+   if(self.current == nil) then return end
+   
+   self.current.sent = true
+   return self.current.expected_response
+end
+
+function command_queue:command_completed()
+   if(self.current == nil) then return end
+   
+   table.remove(self.commands, 1)
+   self.current = nil
+end
diff --git a/src/main_loop.lua b/src/main_loop.lua
index 5540dee..ebe42fa 100644
--- a/src/main_loop.lua
+++ b/src/main_loop.lua
@@ -35,7 +35,7 @@ local defines = require("defines")
 
 function get_readables()
    local readables = {}
-   for _, module in ipairs(module_list.modules) do
+   for _, module in ipairs(module_list.inputs) do
       for _, fd  in ipairs(module:get_read_handles()) do
          table.insert(readables, fd)
       end
@@ -45,13 +45,13 @@ function get_readables()
          table.insert(readables, fd)
       end
    end
-   
+
    return readables
 end
 
 function get_writeables()
    local writeables = { }
-   for _, module in ipairs(module_list.modules) do
+   for _, module in ipairs(module_list.inputs) do
       for _, fd  in ipairs(module:get_write_handles()) do
          table.insert(writeables, fd)
       end
@@ -61,11 +61,11 @@ function get_writeables()
          table.insert(writeables, fd)
       end
    end
-   
+
    return writeables
 end
 
-function main_loop(opt) 
+function main_loop(opt)
    log.printf(log.NOTICE, "main_loop started")
    local sig = signal.init()
 
@@ -85,7 +85,7 @@ function main_loop(opt)
                if(return_value == 1) then break end
             else
                local ret = reader:read()
-               if(ret == defines.KILL_DAEMON) then 
+               if(ret == defines.KILL_DAEMON) then
                   return_value = 2
                   break 
                elseif(ret == defines.KILL_MODULE_CLASS) then
@@ -103,6 +103,11 @@ function main_loop(opt)
                client_list:unregister(writer.client_instance)
             end
          end
+         if(command_queue:command_pending()) then
+            log.printf(log.DEBUG, "sending pending command: %s", command_queue:get_next_command())
+            command_queue:command_sent()
+            command_queue:command_completed()
+         end
       end
    end
 
diff --git a/src/module_list.lua b/src/module_list.lua
index 7c1feae..7683e27 100644
--- a/src/module_list.lua
+++ b/src/module_list.lua
@@ -32,7 +32,8 @@
 
 module_list = {}
 
-module_list.modules = {}
+module_list.inputs = {}
+module_list.output = nil
 
 function module_list:init(opt)
    log.printf(log.DEBUG, "gcsd output = %s", opt.cmd_out)
@@ -50,19 +51,20 @@ function module_list:init(opt)
    end
    package.path = old_path
 
-   table.insert(self.modules, dummy:new({}))
+   self.output = dummy:new({})
+   table.insert(self.inputs, dummy:new({}))
    if(opt.debug) then
-      table.insert(self.modules, debug_shell:new({["host"]="127.0.0.1", ["port"]="9000"}))
-      table.insert(self.modules, debug_shell:new({["host"]="127.0.0.1", ["port"]="9001"}))
+      table.insert(self.inputs, debug_shell:new({["host"]="127.0.0.1", ["port"]="9000"}))
+      table.insert(self.inputs, debug_shell:new({["host"]="127.0.0.1", ["port"]="9001"}))
    end
 end
 
 function module_list:unregister(module)
-   for i, m in ipairs(self.modules) do
+   for i, m in ipairs(self.inputs) do
       if(m == module) then
-         log.printf(log.INFO, "removing module: " .. module.name)
+         log.printf(log.INFO, "removing input module: " .. module.name)
          module:cleanup()
-         table.remove(self.modules, i)
+         table.remove(self.inputs, i)
          break
       end
    end
@@ -71,23 +73,27 @@ end
 function module_list:unregister_by_class(class)
    local free_list = {}
 
-   for i, m in ipairs(self.modules) do
+   for i, m in ipairs(self.inputs) do
       if(m.class == class) then
          table.insert(free_list, 1, i)
       end
    end
 
    for _, i in ipairs(free_list) do
-      log.printf(log.INFO, "removing module: " .. self.modules[i].name)
-      self.modules[i]:cleanup()
-      table.remove(self.modules, i)
+      log.printf(log.INFO, "removing input module: " .. self.inputs[i].name)
+      self.inputs[i]:cleanup()
+      table.remove(self.inputs, i)
    end
 end
 
 function module_list:cleanup()
-   for _, module in ipairs(self.modules) do
-      log.printf(log.INFO, "removing module: " .. module.name)
+   for _, module in ipairs(self.inputs) do
+      log.printf(log.INFO, "removing input module: " .. module.name)
       module:cleanup()
    end
-   self.modules = {}
+   if(self.output ~= nil) then
+      log.printf(log.INFO, "removing output module: " .. self.output.name)
+      self.output:cleanup()
+   end
+   self.inputs = {}
 end
diff --git a/src/modules/debug_shell.lua b/src/modules/debug_shell.lua
index 72be4e7..291fc0f 100644
--- a/src/modules/debug_shell.lua
+++ b/src/modules/debug_shell.lua
@@ -232,6 +232,7 @@ function debug_shell:exec_cmd(socket)
       elseif(cmd == 'help') then
          if(sep and sep ~= "") then socket.out_buffer = socket.out_buffer .. "unknown command\n" end
          socket.out_buffer = socket.out_buffer .. "!<lua code>     execute lua code\n" ..
+                                   "cmd <cmd>       add the command to the command queue\n" ..
                                    "quit            quit this debug session\n" ..
                                    "ping[ <data>]   echo request (response will be 'pong[ <data>]')\n" ..
                                    "disable         close this debug shell instance and close all connections\n" ..
@@ -240,6 +241,12 @@ function debug_shell:exec_cmd(socket)
       elseif(cmd == 'ping') then
          if(sep == ' ') then socket.out_buffer = socket.out_buffer .. "pong " .. (param or "") .. "\n"
          else socket.out_buffer = socket.out_buffer .. "pong\n" end
+      elseif(cmd == 'cmd') then
+        if(not param or param == '') then socket.out_buffer = socket.out_buffer .. "Error: please specify a command\n"
+        else 
+           socket.out_buffer = socket.out_buffer .. "enqueing command: " .. param .. "\n"
+           command_queue:enqueue(param, nil, nil)
+        end
       else 
          socket.out_buffer = socket.out_buffer .. "unknown command\n"
       end