implement first stages of active mode communication

htdocs/index.html

@@ -33,6 +33,7 @@
         <script src="static/lib/Measurement.js"></script>
         <script src="static/lib/FrequencyDisplay.js"></script>
         <script src="static/lib/Js8Threads.js"></script>
+        <script src="static/lib/Modes.js"></script>
         <link rel="stylesheet" type="text/css" href="static/lib/nanoscroller.css" />
         <link rel="stylesheet" type="text/css" href="static/css/openwebrx.css" />
         <meta charset="utf-8">

htdocs/lib/Modes.js

@@ -0,0 +1,28 @@
+var Modes = {
+    modes: [],
+    features: {},
+    setModes:function(json){
+        this.modes = json.map(function(m){ return new Mode(m); });
+    },
+    setFeatures:function(features){
+        this.features = features;
+    },
+    findByModulation:function(modulation){
+        matches = this.modes.filter(function(m) { return m.modulation === modulation; });
+        if (matches.length) return matches[0]
+    }
+}
+
+var Mode = function(json){
+    this.modulation = json.modulation;
+    this.name = json.name;
+    this.requirements = json.requirements;
+};
+
+Mode.prototype.isAvailable = function(){
+    return this.requirements.map(function(r){
+        return Modes.features[r];
+    }).reduce(function(a, b){
+        return a && b;
+    }, true);
+}

htdocs/openwebrx.js

@@ -1177,6 +1177,10 @@ function on_ws_recv(evt) {
                         // set a higher reconnection timeout right away to avoid additional load
                         reconnect_timeout = 16000;
                         break;
+                    case 'modes':
+                        Modes.setModes(json['value']);
+                        console.info(Modes);
+                        break;
                     default:
                         console.warn('received message of unknown type: ' + json['type']);
                 }
@@ -2014,6 +2018,11 @@ function demodulator_digital_replace_last() {
 
 function demodulator_digital_replace(subtype) {
     if (secondary_demod === subtype) return;
+    var mode = Modes.findByModulation(subtype);
+    if (mode && !mode.isAvailable()) {
+        divlog('Digital mode "' + mode.name + '" not supported. Please check requirements', true);
+        return;
+    }
     switch (subtype) {
         case "bpsk31":
         case "bpsk63":