Automatically call yield() in WiFiClient::available if called more than once

cores/esp8266/core_esp8266_main.cpp

@@ -49,6 +49,13 @@ extern void (*__init_array_end)(void);
 static cont_t g_cont;
 static os_event_t g_loop_queue[LOOP_QUEUE_SIZE];
 
+static uint32_t g_micros_at_task_start;
+
+extern "C" uint32_t esp_micros_at_task_start()
+{
+    return g_micros_at_task_start;
+}
+
 extern "C" void abort()
 {
     while(1){}
@@ -86,6 +93,7 @@ static void loop_wrapper()
 
 static void loop_task(os_event_t *events)
 {
+    g_micros_at_task_start = system_get_time();
     cont_run(&g_cont, &loop_wrapper);
     if (cont_check(&g_cont) != 0)
     {

libraries/ESP8266WiFi/src/WiFiClient.cpp

@@ -46,7 +46,8 @@ extern "C"
  static int g_localPort = MIN_LOCAL_PORT;
 
 ICACHE_FLASH_ATTR WiFiClient::WiFiClient() 
-: _client(0) 
+: _client(0)
+, _lastPollTime(0)
 {
 }
 
@@ -153,12 +154,20 @@ size_t ICACHE_FLASH_ATTR WiFiClient::write(const uint8_t *buf, size_t size)
     return _client->write(reinterpret_cast<const char*>(buf), size);
 }
 
+extern "C" uint32_t esp_micros_at_task_start();
+
 int ICACHE_FLASH_ATTR WiFiClient::available()
 {
     if (!_client)
         return 0;
 
-    return _client->getSize();
+    if (_lastPollTime > esp_micros_at_task_start())
+        yield();
+
+    _lastPollTime = micros();
+
+    int result = _client->getSize();
+    return result;
 }
 
 int ICACHE_FLASH_ATTR WiFiClient::read() 

libraries/ESP8266WiFi/src/WiFiClient.h

@@ -66,6 +66,8 @@ private:
   void _err(int8_t err);
 
   ClientContext* _client;
+  uint32_t _lastPollTime;
+  
 };
 
 #endif