Fix for wifi disconnect handling (#431)

Author: igrr

hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/WiFiUdp.cpp

@@ -124,9 +124,10 @@ int WiFiUDP::available() {
 /* Release any resources being used by this WiFiUDP instance */
 void WiFiUDP::stop()
 {
-    if (_ctx)
+    if (_ctx) {
         _ctx->disconnect();
-    _ctx->unref();
+        _ctx->unref();
+    }
     _ctx = 0;
 }
 
@@ -271,6 +272,7 @@ uint16_t WiFiUDP::localPort()
 void WiFiUDP::stopAll()
 {
     for (WiFiUDP* it = _s_first; it; it = it->_next) {
+        DEBUGV("%s %08x %08x\n", __func__, (uint32_t) it, (uint32_t) _s_first);
         it->stop();
     }
 }

hardware/esp8266com/esp8266/libraries/ESP8266WiFi/src/include/slist.h

@@ -9,19 +9,21 @@ class SList {
 protected:
 
   static void _add(T* self) {
+    DEBUGV("%s %08x %08x\n", __func__, (uint32_t) self, (uint32_t) _s_first);
     T* tmp = _s_first;
     _s_first = self;
     self->_next = tmp;
   }
 
   static void _remove(T* self) {
+    DEBUGV("%s %08x %08x\n", __func__, (uint32_t) self, (uint32_t) _s_first);
     if (_s_first == self) {
       _s_first = self->_next;
       self->_next = 0;
       return;
     }
 
-    for (T* prev = _s_first; prev->_next; _s_first = _s_first->_next) {
+    for (T* prev = _s_first; prev->_next; prev = prev->_next) {
       if (prev->_next == self) {
         prev->_next = self->_next;
         self->_next = 0;