On going effort, now load and support LUA+C plugin

12 files changed, 653 insertions, 8 deletions

diff --git a/conf.d/cmake/config.cmake b/conf.d/cmake/config.cmake
index b1bfa96..a8bce3d 100644
--- a/conf.d/cmake/config.cmake
+++ b/conf.d/cmake/config.cmake
@@ -18,7 +18,7 @@
 
 # Project Info
 # ------------------
-set(PROJECT_NAME 4a-softmixer-afbd)
+set(PROJECT_NAME 4a-softmixer)
 set(PROJECT_PRETTY_NAME "Audio SoftMixer")
 set(PROJECT_DESCRIPTION "Soft Mixer for 4A (AGL Advanced Audio Architecture)")
 set(PROJECT_URL "https://github.com/iotbzh/4a-softmixer")
@@ -73,6 +73,7 @@ set (PKG_REQUIRED_LIST
 	afb-daemon>=4.0
 	libmicrohttpd>=0.9.55
 	uuid
+        alsa>=1.1.2
 )
 
 # Prefix path where will be installed the files
@@ -130,7 +131,7 @@ list(APPEND link_libraries afb-helpers)
 set(CONTROL_SUPPORT_LUA 1)
 add_definitions(-DCONTROL_PLUGIN_PATH="${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}/lib/plugins:${CMAKE_BINARY_DIR}/package/lib/plugins")
 add_definitions(-DCONTROL_CONFIG_PATH="${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}/etc:${CMAKE_BINARY_DIR}/package/etc")
-add_definitions(-DCONTROL_LUA_PATH="${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}/data:${CMAKE_BINARY_DIR}/package/data")
+add_definitions(-DCONTROL_LUA_PATH="${CMAKE_INSTALL_PREFIX}/${PROJECT_NAME}/data:${CMAKE_SOURCE_DIR}/conf.d/project/lua.d")
 add_definitions(-DCTL_PLUGIN_MAGIC=987456123)
 add_definitions(-DUSE_API_DYN=1 -DAFB_BINDING_VERSION=dyn)
 
@@ -197,7 +198,7 @@ set(AFB_REMPORT "1234" CACHE PATH "Default binder listening port")
 
 # Print a helper message when every thing is finished
 # ----------------------------------------------------
-set(CLOSING_MESSAGE "Typical binding launch: afb-daemon --name afbd-${PROJECT_NAME} --port=${AFB_REMPORT} --workdir=${CMAKE_BINARY_DIR}/. --ldpath=package/lib --roothttp=package  --token=\"${AFB_TOKEN}\" --tracereq=common --verbose")
+set(CLOSING_MESSAGE "Typical binding launch: afb-daemon --name ${PROJECT_NAME}-afbd --port=${AFB_REMPORT} --workdir=${CMAKE_BINARY_DIR} --binding=package/lib/softmixer-binding.so --ldpath=${CMAKE_INSTALL_PREFIX}/4a-alsa-core/lib --roothttp=package/htdocs --token=\"${AFB_TOKEN}\" --tracereq=common --verbose")
 set(PACKAGE_MESSAGE "Install widget file using in the target : afm-util install ${PROJECT_NAME}.wgt")
 
 # Optional schema validator about now only XML, LUA and JSON
diff --git a/conf.d/project/etc/4a-softmixer-config.json b/conf.d/project/etc/4a-softmixer-config.json
index 9d89f07..db13705 100644
--- a/conf.d/project/etc/4a-softmixer-config.json
+++ b/conf.d/project/etc/4a-softmixer-config.json
@@ -3,18 +3,27 @@
     "metadata": {
         "uid": "Soft Mixer",
         "version": "1.0",
-        "api": "soft-mixer",
+        "api": "softmixer",
         "info": "Soft Mixer emulating hardware mixer",
-        "require": ["alsa-core"]
+        "require": ["alsacore"]
     },
     "plugins": [
         {
             "uid": "alsa-router",
             "ldpath": "package/lib/plugins",
+            "lua2c": ["AlsaDmix", "AlsaRouter"],
             "info": "Map alsa-loop subdevices to 4A HAL streams"
         }
     ],
 
+    "onload": [
+        {
+            "uid": "init-soft-mixer",
+            "info": "Initialise Audio Router",
+            "lua": "_init_softmixer_"
+        }
+    ],
+
     "sndcards": [
         {
             "uid": "Focusrite_Scarlett_18i8",
@@ -72,11 +81,17 @@
     "controls": [
         {
             "uid": "stream",
-            "function": "plugin://alsa-router/stream_ctl"
+            "callback": {
+                "plugin": "alsa-router",
+                "function": "stream_ctl"
+            }
         },
         {
             "uid": "zone",
-            "function": "plugin://alsa-router/zone_ctl"
+            "callback": {
+                "plugin": "alsa-router",
+                "function": "zone_ctl"
+            }
         }
     ]
 }
diff --git a/conf.d/project/etc/CMakeLists.txt b/conf.d/project/etc/CMakeLists.txt
index 378effc..2e7daa7 100644
--- a/conf.d/project/etc/CMakeLists.txt
+++ b/conf.d/project/etc/CMakeLists.txt
@@ -19,7 +19,7 @@
 ##################################################
 # Control Policy Config file
 ##################################################
-PROJECT_TARGET_ADD(soft-mixer-config)
+PROJECT_TARGET_ADD(softmixer-config)
 
 	file(GLOB CONF_FILES "*.json")
 
diff --git a/conf.d/project/htdocs/AFB-websock.js b/conf.d/project/htdocs/AFB-websock.js
new file mode 100644
index 0000000..99ab3b8
--- /dev/null
+++ b/conf.d/project/htdocs/AFB-websock.js
@@ -0,0 +1,177 @@
+var urlws;
+var urlhttp;
+
+AFB = function(base, initialtoken){
+
+urlws = "ws://"+window.location.host+"/"+base;
+urlhttp = "http://"+window.location.host+"/"+base;
+
+/*********************************************/
+/****                                     ****/
+/****             AFB_context             ****/
+/****                                     ****/
+/*********************************************/
+var AFB_context;
+{
+	var UUID = undefined;
+	var TOKEN = initialtoken;
+
+	var context = function(token, uuid) {
+		this.token = token;
+		this.uuid = uuid;
+	}
+
+	context.prototype = {
+		get token() {return TOKEN;},
+		set token(tok) {if(tok) TOKEN=tok;},
+		get uuid() {return UUID;},
+		set uuid(id) {if(id) UUID=id;}
+	};
+
+	AFB_context = new context();
+}
+/*********************************************/
+/****                                     ****/
+/****             AFB_websocket           ****/
+/****                                     ****/
+/*********************************************/
+var AFB_websocket;
+{
+	var CALL = 2;
+	var RETOK = 3;
+	var RETERR = 4;
+	var EVENT = 5;
+
+	var PROTO1 = "x-afb-ws-json1";
+
+	AFB_websocket = function(onopen, onabort) {
+		var u = urlws;
+		if (AFB_context.token) {
+			u = u + '?x-afb-token=' + AFB_context.token;
+			if (AFB_context.uuid)
+				u = u + '&x-afb-uuid=' + AFB_context.uuid;
+		}
+		this.ws = new WebSocket(u, [ PROTO1 ]);
+		this.pendings = {};
+		this.awaitens = {};
+		this.counter = 0;
+		this.ws.onopen = onopen.bind(this);
+		this.ws.onerror = onerror.bind(this);
+		this.ws.onclose = onclose.bind(this);
+		this.ws.onmessage = onmessage.bind(this);
+		this.onopen = onopen;
+		this.onabort = onabort;
+		this.onclose = onabort;
+	}
+
+	function onerror(event) {
+		var f = this.onabort;
+		if (f) {
+			delete this.onopen;
+			delete this.onabort;
+			f && f(this);
+		}
+		this.onerror && this.onerror(this);
+	}
+
+	function onopen(event) {
+		var f = this.onopen;
+		delete this.onopen;
+		delete this.onabort;
+		f && f(this);
+	}
+
+	function onclose(event) {
+		for (var id in this.pendings) {
+			var ferr = this.pendings[id].onerror;
+			ferr && ferr(null, this);
+		}
+		this.pendings = {};
+		this.onclose && this.onclose();
+	}
+
+	function fire(awaitens, name, data) {
+		var a = awaitens[name];
+		if (a)
+			a.forEach(function(handler){handler(data);});
+		var i = name.indexOf("/");
+		if (i >= 0) {
+			a = awaitens[name.substring(0,i)];
+			if (a)
+				a.forEach(function(handler){handler(data);});
+		}
+		a = awaitens["*"];
+		if (a)
+			a.forEach(function(handler){handler(data);});
+	}
+
+	function reply(pendings, id, ans, offset) {
+		if (id in pendings) {
+			var p = pendings[id];
+			delete pendings[id];
+			var f = p[offset];
+			f(ans);
+		}
+	}
+
+	function onmessage(event) {
+		var obj = JSON.parse(event.data);
+		var code = obj[0];
+		var id = obj[1];
+		var ans = obj[2];
+		AFB_context.token = obj[3];
+		switch (code) {
+		case RETOK:
+			reply(this.pendings, id, ans, 0);
+			break;
+		case RETERR:
+			reply(this.pendings, id, ans, 1);
+			break;
+		case EVENT:
+		default:
+			fire(this.awaitens, id, ans);
+			break;
+		}
+	}
+
+	function close() {
+		this.ws.close();
+                this.onabort();
+	}
+
+	function call(method, request) {
+		return new Promise((function(resolve, reject){
+			var id, arr;
+			do {
+			   id = String(this.counter = 4095 & (this.counter + 1));
+			} while (id in this.pendings);
+			this.pendings[id] = [ resolve, reject ];
+			arr = [CALL, id, method, request ];
+			if (AFB_context.token) arr.push(AFB_context.token);
+			this.ws.send(JSON.stringify(arr));
+		}).bind(this));
+	}
+
+	function onevent(name, handler) {
+		var id = name;
+		var list = this.awaitens[id] || (this.awaitens[id] = []);
+		list.push(handler);
+	}
+
+	AFB_websocket.prototype = {
+		close: close,
+		call: call,
+		onevent: onevent
+	};
+}
+/*********************************************/
+/****                                     ****/
+/****                                     ****/
+/****                                     ****/
+/*********************************************/
+return {
+	context: AFB_context,
+	ws: AFB_websocket
+};
+};
+
diff --git a/conf.d/project/htdocs/AudioBinding.css b/conf.d/project/htdocs/AudioBinding.css
new file mode 100644
index 0000000..1052aa7
--- /dev/null
+++ b/conf.d/project/htdocs/AudioBinding.css
@@ -0,0 +1,7 @@
+pre {outline: 1px solid #ccc; padding: 5px; margin: 5px; }
+.string { color: green; }
+.number { color: darkorange; }
+.boolean { color: blue; }
+.null { color: magenta; }
+.key { color: red; }
+
diff --git a/conf.d/project/htdocs/AudioBinding.js b/conf.d/project/htdocs/AudioBinding.js
new file mode 100644
index 0000000..0f5caf9
--- /dev/null
+++ b/conf.d/project/htdocs/AudioBinding.js
@@ -0,0 +1,197 @@
+    var afb = new AFB("api", "mysecret");
+    var ws;
+    var sndcard="HALNotSelected";
+    var evtidx=0;
+    var numid=0;
+
+    function syntaxHighlight(json) {
+        if (typeof json !== 'string') {
+             json = JSON.stringify(json, undefined, 2);
+        }
+        json = json.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
+        return json.replace(/("(\\u[a-zA-Z0-9]{4}|\\[^u]|[^\\"])*"(\s*:)?|\b(true|false|null)\b|-?\d+(?:\.\d*)?(?:[eE][+\-]?\d+)?)/g, function (match) {
+            var cls = 'number';
+            if (/^"/.test(match)) {
+                if (/:$/.test(match)) {
+                    cls = 'key';
+                } else {
+                    cls = 'string';
+                }
+            } else if (/true|false/.test(match)) {
+                cls = 'boolean';
+            } else if (/null/.test(match)) {
+                cls = 'null';
+            }
+            return '<span class="' + cls + '">' + match + '</span>';
+        });
+    }
+
+    function getParameterByName(name, url) {
+        if (!url) {
+          url = window.location.href;
+        }
+        name = name.replace(/[\[\]]/g, "\\$&");
+        var regex = new RegExp("[?&]" + name + "(=([^&#]*)|&|#|$)"),
+            results = regex.exec(url);
+        if (!results) return null;
+        if (!results[2]) return '';
+        return decodeURIComponent(results[2].replace(/\+/g, " "));
+    }
+
+    // default soundcard is "PCH"
+    var devid=getParameterByName("devid");
+    if (!devid) devid="hw:1";
+
+    var haldev=getParameterByName("haldev");
+    if (!haldev) haldev="scarlett-usb";
+
+    var sndname=getParameterByName("sndname");
+    if (!sndname) sndname="PCH";
+
+    var mode=getParameterByName("mode");
+    if (!mode) mode="0";
+
+
+
+
+    function replyok(obj) {
+            console.log("replyok:" + JSON.stringify(obj));
+            document.getElementById("output").innerHTML = "OK: "+ syntaxHighlight(obj);
+    }
+
+    function replyerr(obj) {
+            console.log("replyerr:" + JSON.stringify(obj));
+            document.getElementById("output").innerHTML = "ERROR: "+ syntaxHighlight(obj);
+    }
+
+    function gotevent(obj) {
+            console.log("gotevent:" + JSON.stringify(obj));
+            document.getElementById("outevt").innerHTML = (evtidx++) +": "+JSON.stringify(obj);
+    }
+
+    function send(message) {
+            var api = document.getElementById("api").value;
+            var verb = document.getElementById("verb").value;
+            document.getElementById("question").innerHTML = "subscribe: "+api+"/"+verb + " (" + JSON.stringify(message) +")";
+            ws.call(api+"/"+verb, {data:message}).then(replyok, replyerr);
+    }
+
+
+     // On button click from HTML page
+    function callbinder(api, verb, query) {
+            console.log ("subscribe api="+api+" verb="+verb+" query=" +query);
+            var question = urlws +"/" +api +"/" +verb + "?query=" + JSON.stringify(query);
+            document.getElementById("question").innerHTML = syntaxHighlight(question);
+            ws.call(api+"/"+verb, query).then(replyok, replyerr);
+    }
+
+
+    // Retreive Select value and Text from the binder
+    // Note: selection of value/text for a given context is huggly!!!
+    function querySelectList (elemid, api, verb, query) {
+
+        console.log("querySelectList elemid=%s api=%s verb=%s query=%s", elemid, api, verb, query);
+
+        var selectobj = document.getElementById(elemid);
+        if (!selectobj) {
+            return;
+        }
+
+        // onlick update selected HAL api
+        selectobj.onclick=function(){
+           sndcard= this.value;
+           console.log ("Default Selection=" + sndcard);
+        };
+
+        function gotit (result) {
+
+            // display response as for normal onclick action
+            replyok(result);
+            var response=result.response;
+
+            // fulfill select with avaliable active HAL
+            for (idx=0; idx<response.length; idx++) {
+                var opt = document.createElement('option');
+
+                // Alsa LowLevel selection mode
+                if (response[idx].name)  opt.text   = response[idx].name;
+                if (response[idx].devid) opt.value  = response[idx].devid;
+
+                // HAL selection mode
+                if (response[idx].shortname) opt.text  = response[idx].shortname;
+                if (response[idx].api) opt.value = response[idx].api;
+
+                selectobj.appendChild(opt);
+            }
+
+           sndcard= selectobj.value;
+        }
+
+        var question = urlws +"/"+api +"/" +verb + "?query=" + JSON.stringify(query);
+        document.getElementById("question").innerHTML = syntaxHighlight(question);
+
+        // request lowlevel ALSA to get API list
+        ws.call(api+"/"+verb, query).then(gotit, replyerr);
+    }
+
+    function refresh_list (self, api, verb, query) {
+        console.log("refresh_list id=%s api=%s verb=%s query=%s", self.id, api, verb, query);
+
+        if (self.value > 0) return;
+
+        // onlick update selected HAL api
+        self.onclick=function(){
+           numid = parseInt(self.value);
+           console.log ("Default numid=%d", numid);
+        };
+
+        function gotit (result) {
+
+            // display response as for normal onclick action
+            replyok(result);
+            var response=result.response;
+
+
+
+            // fulfill select with avaliable active HAL
+            for (idx=0; idx<response.length; idx++) {
+                var opt = document.createElement('option');
+
+                // Alsa LowLevel selection mode
+                opt.text   = response[idx].name + ' id=' + response[idx].id;
+                opt.value  = response[idx].id;
+
+                self.appendChild(opt);
+            }
+            self.selectedIndex=2;
+            numid = parseInt (self.value);
+        }
+
+        var question = urlws +"/"+api +"/" +verb + "?query=" + JSON.stringify(query);
+        document.getElementById("question").innerHTML = syntaxHighlight(question);
+
+        // request lowlevel ALSA to get API list
+        ws.call(api+"/"+verb, query).then(gotit, replyerr);
+    }
+
+
+    function init(elemid, api, verb, query) {
+
+        function onopen() {
+                // check for active HALs
+                querySelectList (elemid, api, verb, query);
+
+                document.getElementById("main").style.visibility = "visible";
+                document.getElementById("connected").innerHTML = "Binder WS Active";
+                document.getElementById("connected").style.background  = "lightgreen";
+                ws.onevent("*", gotevent);
+        }
+
+        function onabort() {
+                document.getElementById("main").style.visibility = "hidden";
+                document.getElementById("connected").innerHTML = "Connected Closed";
+                document.getElementById("connected").style.background  = "red";
+
+        }
+        ws = new afb.ws(onopen, onabort);
+    }
diff --git a/conf.d/project/htdocs/CMakeLists.txt b/conf.d/project/htdocs/CMakeLists.txt
new file mode 100644
index 0000000..ce916fa
--- /dev/null
+++ b/conf.d/project/htdocs/CMakeLists.txt
@@ -0,0 +1,34 @@
+###########################################################################
+# Copyright 2015, 2016, 2017 IoT.bzh
+#
+# author: Fulup Ar Foll <fulup@iot.bzh>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+###########################################################################
+
+
+
+##################################################
+# HTML Testing Files
+##################################################
+PROJECT_TARGET_ADD(softmixer-html5)
+
+    file(GLOB SOURCE_FILES "*.html" "*.js" "*.jpg" "*.css")
+
+	add_input_files("${SOURCE_FILES}")
+
+    SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+	LABELS "HTDOCS"
+	OUTPUT_NAME ${TARGET_NAME}
+    )
+
diff --git a/conf.d/project/htdocs/README.md b/conf.d/project/htdocs/README.md
new file mode 100644
index 0000000..7aafea0
--- /dev/null
+++ b/conf.d/project/htdocs/README.md
@@ -0,0 +1,7 @@
+------------------------------------------------------------------------
+   Basic HTML & WS test
+------------------------------------------------------------------------
+
+  # Load bindings directly from development tree for debug
+  AFB_BINDER_NAME='sample' afb-daemon --verbose --verbose --token="" --ldpaths=build --port=1234 --roothttp=htdocs
+
diff --git a/conf.d/project/htdocs/index.html b/conf.d/project/htdocs/index.html
new file mode 100644
index 0000000..9a7d66f
--- /dev/null
+++ b/conf.d/project/htdocs/index.html
@@ -0,0 +1,43 @@
+<html>
+<head>
+    <title>Simple COntroller Test</title>
+    <link rel="stylesheet" href="AudioBinding.css">
+    <script type="text/javascript" src="AFB-websock.js"></script>
+    <script type="text/javascript" src="AudioBinding.js"></script>
+</head>
+
+<body onload="init('hal_registry','alsacore', 'hallist')">
+
+    <h1>Simple Control Test</h1>
+    <button id="connected" onclick="init()">Binder WS Fail</button> 
+    <button id="mnitoring" onclick="window.open('/monitoring/monitor.html','_monitor_ctl')">Debug/Monitoring</a></button>
+    <br><br>
+
+    <h2>V2 API CALL</h2>
+    <ol>
+	    <li><button onclick="callbinder('pol4a','request', {'uid':'navigation-role'});">Navigation Open</button></li>
+	    <li><button onclick="callbinder('pol4a','request', {'uid':'emergency-role'});">Emergency Open</button></li>
+    <br>
+    <li><button onclick="callbinder('pol4a', 'request', {'uid':'release-current'});">Release Current Role</button></li>
+    </ol>
+
+    <h2>V3 API CALL</h2>
+    <ol>
+    <li><button onclick="callbinder('pol4a','navigation-role');">Navigation Open</button></li>
+    <li><button onclick="callbinder('pol4a','emergency-role');">Emergency Open</button></li>
+    <br>
+    <li><button onclick="callbinder('pol4a','release-current');">Release Current Role</button></li>
+    </ol>
+
+    <h2>Signal/Timeout</h2>
+    <ol>
+    <li><button onclick="callbinder('pol4a','signal-timeout', {'timeout':3, 'data':'state', 'event':'quit'});">Get Signal in 3s</button></li>
+    </ol>
+
+    <div id="main" style="visibility:hidden">
+    <ol>
+    <li>Question <pre id="question"></pre>
+    <li>Response <pre id="output"></pre>
+    <li>Events: <pre id="outevt"></pre>
+    </ol>
+    </div>
diff --git a/conf.d/project/lua.d/CMakeLists.txt b/conf.d/project/lua.d/CMakeLists.txt
new file mode 100644
index 0000000..5171349
--- /dev/null
+++ b/conf.d/project/lua.d/CMakeLists.txt
@@ -0,0 +1,32 @@
+###########################################################################
+# Copyright 2017 IoT.bzh
+#
+# author: Fulup Ar Foll <fulup@iot.bzh>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+###########################################################################
+
+
+##################################################
+# Soft Mixer Lua Scripts
+##################################################
+PROJECT_TARGET_ADD(softmixer-lua)
+
+    file(GLOB LUA_FILES "*.lua")
+
+	add_input_files("${LUA_FILES}")
+
+    SET_TARGET_PROPERTIES(${TARGET_NAME} PROPERTIES
+	LABELS "DATA"
+	OUTPUT_NAME ${TARGET_NAME}
+    )
diff --git a/conf.d/project/lua.d/softmixer-00.lua b/conf.d/project/lua.d/softmixer-00.lua
new file mode 100644
index 0000000..29d2c70
--- /dev/null
+++ b/conf.d/project/lua.d/softmixer-00.lua
@@ -0,0 +1,86 @@
+--[[
+  Copyright (C) 2016 "IoT.bzh"
+  Author Fulup Ar Foll <fulup@iot.bzh>
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+  Note: this file should be called before any other to assert declare function
+  is loaded before anything else.
+
+  References:
+    http://lua-users.org/wiki/DetectingUndefinedVariables
+
+--]]
+
+
+--===================================================
+--=  Niklas Frykholm
+-- basically if user tries to create global variable
+-- the system will not let them!!
+-- call GLOBAL_lock(_G)
+--
+--===================================================
+function GLOBAL_lock(t)
+  local mt = getmetatable(t) or {}
+  mt.__newindex = lock_new_index
+  setmetatable(t, mt)
+end
+
+--===================================================
+-- call GLOBAL_unlock(_G)
+-- to change things back to normal.
+--===================================================
+function GLOBAL_unlock(t)
+  local mt = getmetatable(t) or {}
+  mt.__newindex = unlock_new_index
+  setmetatable(t, mt)
+end
+
+function lock_new_index(t, k, v)
+  if (string.sub(k,1,1) ~= "_") then
+    GLOBAL_unlock(_G)
+    error("GLOBALS are locked -- " .. k ..
+          " must be declared local or prefix with '_' for globals.", 2)
+  else
+    rawset(t, k, v)
+  end
+end
+
+function unlock_new_index(t, k, v)
+  rawset(t, k, v)
+end
+
+-- return serialised version of printable table
+function Dump_Table(o)
+   if type(o) == 'table' then
+      local s = '{ '
+      for k,v in pairs(o) do
+         if type(k) ~= 'number' then k = '"'..k..'"' end
+         s = s .. '['..k..'] = ' .. Dump_Table(v) .. ','
+      end
+      return s .. '} '
+   else
+      return tostring(o)
+   end
+end
+
+
+-- simulate C prinf function
+printf = function(s,...)
+    io.write(s:format(...))
+    io.write("\n")
+    return
+end
+
+-- lock global variable
+GLOBAL_lock(_G)
diff --git a/conf.d/project/lua.d/softmixer-01.lua b/conf.d/project/lua.d/softmixer-01.lua
new file mode 100644
index 0000000..d4ae580
--- /dev/null
+++ b/conf.d/project/lua.d/softmixer-01.lua
@@ -0,0 +1,46 @@
+--[[
+  Copyright (C) 2016 "IoT.bzh"
+  Author Fulup Ar Foll <fulup@iot.bzh>
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+
+  NOTE: strict mode: every global variables should be prefixed by '_'
+--]]
+
+-- Static variables should be prefixed with _
+_EventHandle={}
+
+-- Call when AlsaCore return HAL active list
+function _AlsaPingCB_ (source, result, context)
+
+    AFB:notice (source, "--InLua-- PingCB: result='%s'", Dump_Table(result))
+
+end
+
+-- Display receive arguments and echo them to caller
+function _init_softmixer_ (source, args)
+
+    -- create event to push change audio roles to potential listeners
+    _EventHandle=AFB:evtmake(source, "control")
+
+    -- get list of supported HAL devices
+    AFB:service(source, "alsacore","ping", {}, "_AlsaPingCB_", {})
+
+    -- test Lua2C plugin
+    L2C:alsadmix(source, {})
+
+    AFB:notice (source, "--InLua-- _init_softmixer_ done")
+
+    return 0 -- happy end
+end