fix #1002 ::Flush() wait for empty send buffer

Author: d-a-v

libraries/ESP8266WiFi/src/WiFiClient.cpp

@@ -259,7 +259,7 @@ size_t WiFiClient::peekBytes(uint8_t *buffer, size_t length) {
 void WiFiClient::flush()
 {
     if (_client)
-        _client->flush();
+        _client->arduinoFlush();
 }
 
 void WiFiClient::stop()

libraries/ESP8266WiFi/src/WiFiUdp.cpp

@@ -243,8 +243,7 @@ int WiFiUDP::peek()
 
 void WiFiUDP::flush()
 {
-    if (_ctx)
-        _ctx->flush();
+    endPacket();
 }
 
 IPAddress WiFiUDP::remoteIP()

libraries/ESP8266WiFi/src/include/ClientContext.h

@@ -290,6 +290,17 @@ class ClientContext
         _rx_buf_offset = 0;
     }
 
+    void arduinoFlush()
+    {
+#if 1
+	// this is useless since _write_from_source() always exits with _datasource==NULL
+        while (state() == ESTABLISHED && _datasource && _datasource->available()) {
+            _write_some();
+            delay(1); // esp_ schedule+yield
+        }
+#endif
+    }
+
     uint8_t state() const
     {
         if(!_pcb) {

libraries/Ethernet/src/EthernetUdp.cpp

@@ -118,7 +118,7 @@ size_t EthernetUDP::write(const uint8_t *buffer, size_t size)
 int EthernetUDP::parsePacket()
 {
   // discard any remaining bytes in the last packet
-  flush();
+  clear_incoming();
 
   if (recvAvailable(_sock) > 0)
   {
@@ -204,7 +204,7 @@ int EthernetUDP::peek()
   return b;
 }
 
-void EthernetUDP::flush()
+void EthernetUDP::clear_remaining()
 {
   // could this fail (loop endlessly) if _remaining > 0 and recv in read fails?
   // should only occur if recv fails after telling us the data is there, lets
@@ -216,3 +216,8 @@ void EthernetUDP::flush()
   }
 }
 
+void EthernetUDP::flush()
+{
+  endPacket();  
+}
+

libraries/Ethernet/src/EthernetUdp.h

@@ -49,6 +49,9 @@ class EthernetUDP : public UDP {
   uint16_t _remotePort; // remote port for the incoming packet whilst it's being processed
   uint16_t _offset; // offset into the packet being sent
   uint16_t _remaining; // remaining bytes of incoming packet yet to be processed
+  
+protected:
+  void clear_remaining();
 
 public:
   EthernetUDP();  // Constructor