properly process packets until you get the one you want (prep for callback w/good retain support)

Adafruit_MQTT.cpp

@@ -191,7 +191,7 @@ int8_t Adafruit_MQTT::connect() {
     // TODO: The Server is permitted to start sending PUBLISH packets matching the
     // Subscription before the Server sends the SUBACK Packet. (will really need to use callbacks - ada)
     if(MQTT_PROTOCOL_LEVEL > 3) {
-       len = readPacket(buffer, 5, CONNECT_TIMEOUT_MS);
+       len = processPacketsUntil(buffer, MQTT_CTRL_SUBACK, CONNECT_TIMEOUT_MS);
        DEBUG_PRINT(F("SubAck:\t"));
        DEBUG_PRINTBUFFER(buffer, len);
        if ((len != 5) || (buffer[0] != (MQTT_CTRL_SUBACK << 4))) {
@@ -204,6 +204,61 @@ int8_t Adafruit_MQTT::connect() {
   return 0;
 }
 
+uint16_t Adafruit_MQTT::processPacketsUntil(uint8_t *buffer, uint8_t waitforpackettype, uint16_t timeout) {
+  uint16_t len;
+  while (len = readFullPacket(buffer, timeout)) {
+
+    // TODO: add subscription reading & processing here
+
+    if ((buffer[0] >> 4) == waitforpackettype) {
+      //DEBUG_PRINTLN(F("Found right packet")); 
+      return len;
+    }
+  }
+  return 0;
+}
+
+uint16_t Adafruit_MQTT::readFullPacket(uint8_t *buffer, uint16_t timeout) {
+  // will read a packet and Do The Right Thing with length
+  uint8_t *pbuff = buffer;
+
+  uint8_t rlen;
+
+  // read the packet type:
+  rlen = readPacket(pbuff, 1, timeout);
+  if (rlen != 1) return 0;
+
+  //DEBUG_PRINT(F("Packet Type:\t")); DEBUG_PRINTBUFFER(pbuff, rlen);
+  pbuff++;
+
+  uint32_t value = 0;
+  uint32_t multiplier = 1;
+  uint8_t encodedByte;
+
+  do {
+    rlen = readPacket(pbuff, 1, timeout);
+    if (rlen != 1) return 0;
+    encodedByte = pbuff[0]; // save the last read val
+    pbuff++; // get ready for reading the next byte
+
+    uint32_t intermediate = encodedByte & 0x7F;
+    intermediate *= multiplier;
+    value += intermediate;
+    multiplier *= 128;
+    if (multiplier > 128*128*128) {
+      DEBUG_PRINT(F("Malformed packet len\n"));
+      return 0;
+    }
+  } while (encodedByte & 0x80);
+
+  //DEBUG_PRINT(F("Packet Length:\t")); DEBUG_PRINTLN(value);
+  
+  rlen = readPacket(pbuff, value, timeout);
+  //DEBUG_PRINT(F("Remaining packet:\t")); DEBUG_PRINTBUFFER(pbuff, rlen);
+
+  return ((pbuff - buffer)+rlen);
+}
+
 const __FlashStringHelper* Adafruit_MQTT::connectErrorString(int8_t code) {
    switch (code) {
       case 1: return F("Wrong protocol");
@@ -415,7 +470,7 @@ void Adafruit_MQTT::flushIncoming(uint16_t timeout) {
 }
 
 bool Adafruit_MQTT::ping(uint8_t num) {
-  flushIncoming(100);
+  //flushIncoming(100);
 
   while (num--) {
     // Construct and send ping packet.
@@ -424,7 +479,7 @@ bool Adafruit_MQTT::ping(uint8_t num) {
       continue;
 
     // Process ping reply.
-    len = readPacket(buffer, 2, PING_TIMEOUT_MS);
+    len = processPacketsUntil(buffer, MQTT_CTRL_PINGRESP, PING_TIMEOUT_MS);
     if (buffer[0] == (MQTT_CTRL_PINGRESP << 4))
       return true;
   }
@@ -692,6 +747,7 @@ Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
   mqtt = mqttserver;
   topic = feed;
   qos = q;
+  callback = 0;
 }
 
 Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
@@ -699,4 +755,13 @@ Adafruit_MQTT_Subscribe::Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver,
   mqtt = mqttserver;
   topic = (const char *)feed;
   qos = q;
+  callback = 0;
+}
+
+void Adafruit_MQTT_Subscribe::setCallback(SubscribeCallbackType cb) {
+  callback = cb;
+}
+
+void Adafruit_MQTT_Subscribe::removeCallback(void) {
+  callback = 0;
 }

Adafruit_MQTT.h

@@ -95,6 +95,9 @@
 // eg max-subscription-payload-size
 #define SUBSCRIPTIONDATALEN 20
 
+//Function pointer called CallbackType that takes a float
+//and returns an int
+typedef void (*SubscribeCallbackType)(char *);  
 
 extern void printBuffer(uint8_t *buffer, uint8_t len);
 
@@ -202,6 +205,11 @@ class Adafruit_MQTT {
   virtual uint16_t readPacket(uint8_t *buffer, uint8_t maxlen, int16_t timeout,
                               bool checkForValidPubPacket = false) = 0;
 
+  // Read a full packet, keeping note of the correct length
+  uint16_t readFullPacket(uint8_t *buffer, uint16_t timeout);
+  // Properly process packets until you get to one you want
+  uint16_t processPacketsUntil(uint8_t *buffer, uint8_t waitforpackettype, uint16_t timeout);
+
   // Shared state that subclasses can use:
   const char *servername;
   int16_t portnum;
@@ -255,7 +263,8 @@ class Adafruit_MQTT_Subscribe {
   Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver, const char *feedname, uint8_t q=0);
   Adafruit_MQTT_Subscribe(Adafruit_MQTT *mqttserver, const __FlashStringHelper *feedname, uint8_t q=0);
 
-  bool setCallback(void (*callback)(char *));
+  void setCallback(SubscribeCallbackType callb);
+  void removeCallback(void);
 
   const char *topic;
   uint8_t qos;
@@ -265,6 +274,7 @@ class Adafruit_MQTT_Subscribe {
   // ensure nul terminating lastread.
   uint8_t datalen;
  private:
+  SubscribeCallbackType callback;
   Adafruit_MQTT *mqtt;
 };