Refactored

MQTTCallbackHandlers.cpp

@@ -0,0 +1,180 @@
+/*
+ *  © 2021, Gregor Baues, All rights reserved.
+ *  
+ *  This file is part of DCC-EX/CommandStation-EX
+ *
+ *  This 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
+ *  (at your option) any later version.
+ *
+ *  It 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 CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ * 
+ */
+
+#if __has_include("config.h")
+#include "config.h"
+#else
+#warning config.h not found. Using defaults from config.example.h
+#include "config.example.h"
+#endif
+#include "defines.h"
+
+#include <errno.h>
+#include <limits.h>
+
+#include "MQTTInterface.h"
+
+
+// Fwd decl for the callback handlers
+void mqttDCCEXCallback(MQTTInterface *mqtt, csmsg_t &tm);
+void mqttProtocolCallback(MQTTInterface *mqtt, csmsg_t &tm);
+void mqttMCallback(MQTTInterface *mqtt, csmsg_t &tm);
+
+typedef void (*CallbackFunc)(MQTTInterface *mqtt, csmsg_t &tm);
+
+template<class M, class N>
+struct CallbackFunction {
+	M first;
+	N second;
+};
+using CallbackFunctions = CallbackFunction<char, CallbackFunc>[MAX_CALLBACKS];
+
+// lookup table for the protocol handle functions
+constexpr CallbackFunctions vec = {
+		{'<', mqttDCCEXCallback},
+		{'{', mqttProtocolCallback},
+        {'m', mqttMCallback}
+};
+
+long cantorEncode(long a, long b)
+{
+    return (((a + b) * (a + b + 1)) / 2) + b;
+}
+
+void cantorDecode(int32_t c, int *a, int *b)
+{
+    int w = floor((sqrt(8 * c + 1) - 1) / 2);
+    int t = (w * (w + 1)) / 2;
+    *b = c - t;
+    *a = w - *b;
+}
+
+/**
+ * @brief lookup of the proper function for < or { based commands 
+ *  
+ * @param c 
+ * @return CallbackFunc 
+ */
+auto protocolDistributor(const char c) -> CallbackFunc {
+	for (auto &&f : vec)
+	{
+		if (f.first == c)
+			return f.second;
+	}
+	return nullptr;
+}
+
+void protocolHandler(MQTTInterface *mqtt, csmsg_t &tm) {
+	protocolDistributor(tm.cmd[0])(mqtt, tm);  
+}
+
+/**
+ * @brief Callback for handling 'm' MQTT Protocol commands (deprecated)
+ * @deprecated to be replaced by '{' commands in simple JSON format
+ */
+void mqttMCallback(MQTTInterface *mqtt, csmsg_t &tm)
+{
+    auto clients = mqtt->getClients();
+    DIAG(F("MQTT m - Callback"));
+    switch (tm.cmd[1])
+        {
+        case 'i': // Inital handshake message to create the tunnel
+        {
+            char buffer[MAXPAYLOAD];
+            char *tmp = tm.cmd + 3;
+            auto length = strlen(tm.cmd);
+            strlcpy(buffer, tmp, length);
+            buffer[length - 4] = '\0';
+
+            DIAG(F("MQTT buffer %s - %s - %s - %d"), tm.cmd, tmp, buffer, length);
+
+            auto distantid = strtol(buffer, NULL, 10);
+
+            if (errno == ERANGE || distantid > UCHAR_MAX)
+            {
+                DIAG(F("MQTT Invalid Handshake ID; must be between 0 and 255"));
+                return;
+            }
+            if (distantid == 0)
+            {
+                DIAG(F("MQTT Invalid Handshake ID"));
+                return;
+            }
+
+            // Create a new MQTT client
+
+            auto subscriberid = mqtt->obtainSubscriberID(); // to be used in the parsing process for the clientid in the ringbuffer
+
+            if (subscriberid == 0)
+            {
+                DIAG(F("MQTT no more connections are available"));
+                return;
+            }
+
+            auto topicid = cantorEncode((long)subscriberid, (long)distantid);
+            DIAG(F("MQTT Client connected : subscriber [%d] : distant [%d] : topic: [%d]"), subscriberid, (int)distantid, topicid);
+
+            // extract the number delivered from & initalize the new mqtt client object
+            clients[subscriberid] = {(int)distantid, subscriberid, topicid, false}; // set to true once the channels are available
+
+            auto sq = mqtt->getSubscriptionQueue();
+            sq->push(subscriberid);
+
+            return;
+        }
+        default:
+        {
+            return;
+        }
+        }
+}
+
+/**
+ * @brief Callback for handling '{' MQTT Protocol commands
+ */
+void mqttProtocolCallback(MQTTInterface *mqtt, csmsg_t &tm)
+{
+    DIAG(F("MQTT Protocol - Callback"));
+}
+
+/**
+ * @brief Callback for handling '<' DccEX commands
+ */
+void mqttDCCEXCallback(MQTTInterface *mqtt, csmsg_t &tm)
+// void mqttDCCEXCallback(MQTTInterface *mqtt, char *topic, char *payload, unsigned int length)
+{
+    DIAG(F("MQTT DCCEX - Callback"));
+    if (!tm.mqsocket)
+    {
+        DIAG(F("MQTT Can't identify sender; command send on wrong topic"));
+        return;
+    }
+    int idx = mqtt->getPool()->setItem(tm); // Add the recieved command to the pool
+    if (idx == -1)
+    {
+        DIAG(F("MQTT Command pool full. Could not handle recieved command."));
+        return;
+    }
+    mqtt->getIncomming()->push(idx); // Add the index of the pool item to the incomming queue
+
+    // don't show the topic as we would have to save it also just like the payload
+    if (Diag::MQTT)
+        DIAG(F("MQTT Message arrived: [%s]"), tm.cmd);
+}

MQTTInterface.cpp

@@ -33,23 +33,11 @@
 #include "MQTTBrokers.h"
 #include "DCCTimer.h"
 #include "CommandDistributor.h"
-// #include "MemoryFree.h"
 #include "freeMemory.h"
 
 MQTTInterface *MQTTInterface::singleton = NULL;
 
-long cantorEncode(long a, long b)
+void protocolHandler(MQTTInterface *mqtt, csmsg_t &tm); 
-{
-    return (((a + b) * (a + b + 1)) / 2) + b;
-}
-
-void cantorDecode(int32_t c, int *a, int *b)
-{
-    int w = floor((sqrt(8 * c + 1) - 1) / 2);
-    int t = (w * (w + 1)) / 2;
-    *b = c - t;
-    *a = w - *b;
-}
 
 /**
  * @brief callback used from DIAG to send diag messages to the broker / clients
@@ -148,6 +136,7 @@ byte senderMqSocket(MQTTInterface *mqtt, char *topic)
     // if mqsocket == 0 here we haven't got any Id in the topic string
     return mqsocket;
 }
+
 /**
  * @brief MQTT Interface callback recieving all incomming messages from the PubSubClient
  * 
@@ -171,8 +160,6 @@ void mqttCallback(char *topic, byte *pld, unsigned int length)
     }
 
     MQTTInterface *mqtt = MQTTInterface::get();
-    auto clients = mqtt->getClients();
-    errno = 0;
     csmsg_t tm; // topic message
 
     // FOR DIAGS and MQTT ON in the callback we need to copy the payload buffer
@@ -188,87 +175,7 @@ void mqttCallback(char *topic, byte *pld, unsigned int length)
     if (Diag::MQTT)
         DIAG(F("MQTT Callback:[%s/%d] [%s] [%d] on interface [%x]"), topic, tm.mqsocket, tm.cmd, length, mqtt);
 
-    switch (tm.cmd[0])
+    protocolHandler(mqtt, tm); 
-    {
-    case '<': // Recieved a DCC-EX Command
-    {
-        if (!tm.mqsocket)
-        {
-            DIAG(F("MQTT Can't identify sender; command send on wrong topic"));
-            return;
-        }
-        int idx = mqtt->getPool()->setItem(tm); // Add the recieved command to the pool
-        if (idx == -1)
-        {
-            DIAG(F("MQTT Command pool full. Could not handle recieved command."));
-            return;
-        }
-        mqtt->getIncomming()->push(idx); // Add the index of the pool item to the incomming queue
-
-        // don't show the topic as we would have to save it also just like the payload
-        if (Diag::MQTT)
-            DIAG(F("MQTT Message arrived: [%s]"), tm.cmd);
-
-        break;
-    }
-    case 'm': // Recieved an MQTT Connection management message
-    {
-        switch (tm.cmd[1])
-        {
-        case 'i': // Inital handshake message to create the tunnel
-        {
-            char buffer[MAXPAYLOAD];
-            char *tmp = tm.cmd + 3;
-            strlcpy(buffer, tmp, length);
-            buffer[length - 4] = '\0';
-
-            // DIAG(F("MQTT buffer %s - %s - %s - %d"), payload, tmp, buffer, length);
-
-            auto distantid = strtol(buffer, NULL, 10);
-
-            if (errno == ERANGE || distantid > UCHAR_MAX)
-            {
-                DIAG(F("MQTT Invalid Handshake ID; must be between 0 and 255"));
-                return;
-            }
-            if (distantid == 0)
-            {
-                DIAG(F("MQTT Invalid Handshake ID"));
-                return;
-            }
-
-            // Create a new MQTT client
-
-            auto subscriberid = mqtt->obtainSubscriberID(); // to be used in the parsing process for the clientid in the ringbuffer
-
-            if (subscriberid == 0)
-            {
-                DIAG(F("MQTT no more connections are available"));
-                return;
-            }
-
-            auto topicid = cantorEncode((long)subscriberid, (long)distantid);
-            DIAG(F("MQTT Client connected : subscriber [%d] : distant [%d] : topic: [%d]"), subscriberid, (int)distantid, topicid);
-
-            // extract the number delivered from & initalize the new mqtt client object
-            clients[subscriberid] = {(int)distantid, subscriberid, topicid, false}; // set to true once the channels are available
-
-            auto sq = mqtt->getSubscriptionQueue();
-            sq->push(subscriberid);
-
-            return;
-        }
-        default:
-        {
-            return;
-        }
-        }
-    }
-    default:
-    {
-        break;
-    }
-    }
 }
 
 /**