ClientContext: break timeout delays also on error while writing or connecting (#6454)

This PR stops the 1ms-delay loop also when a tcp error occurs (previously this was done only when tcp had just connected or a write/send had succeeded).
The tcp error can be any, in this case with pubsubclient it is "connection refused" after the mqtt server disappeared and pubsubclient tries to reconnect.

Author: d-a-v

libraries/ESP8266WiFi/src/include/ClientContext.h

@@ -128,14 +128,14 @@ class ClientContext
         if (err != ERR_OK) {
             return 0;
         }
-        _connect_pending = 1;
+        _delaying = true;
         _op_start_time = millis();
         // Following delay will be interrupted by connect callback
-        for (decltype(_timeout_ms) i = 0; _connect_pending && i < _timeout_ms; i++) {
+        for (decltype(_timeout_ms) i = 0; _delaying && i < _timeout_ms; i++) {
                // Give scheduled functions a chance to run (e.g. Ethernet uses recurrent)
                delay(1);
-       }
-        _connect_pending = 0;
+        }
+        _delaying = false;
         if (!_pcb) {
             DEBUGV(":cabrt\r\n");
             return 0;
@@ -432,15 +432,16 @@ class ClientContext
 
     void _notify_error()
     {
-        if (_connect_pending || _send_waiting) {
-            esp_schedule();
+        if (_delaying) {
+            _delaying = false;
+            esp_schedule(); // break current delay()
         }
     }
 
     size_t _write_from_source(DataSource* ds)
     {
         assert(_datasource == nullptr);
-        assert(!_send_waiting);
+        assert(!_delaying);
         _datasource = ds;
         _written = 0;
         _op_start_time = millis();
@@ -458,14 +459,14 @@ class ClientContext
                 break;
             }
 
-            _send_waiting = true;
+            _delaying = true;
             // Following delay will be interrupted by on next received ack
-            for (decltype(_timeout_ms) i = 0; _send_waiting && i < _timeout_ms; i++) {
+            for (decltype(_timeout_ms) i = 0; _delaying && i < _timeout_ms; i++) {
                // Give scheduled functions a chance to run (e.g. Ethernet uses recurrent)
                delay(1);
             }
+            _delaying = false;
         } while(true);
-        _send_waiting = false;
 
         if (_sync)
             wait_until_sent();
@@ -532,9 +533,9 @@ class ClientContext
 
     void _write_some_from_cb()
     {
-        if (_send_waiting) {
-            _send_waiting = false;
-            esp_schedule();
+        if (_delaying) {
+            _delaying = false;
+            esp_schedule(); // break current delay()
         }
     }
 
@@ -608,9 +609,9 @@ class ClientContext
         (void) err;
         (void) pcb;
         assert(pcb == _pcb);
-        assert(_connect_pending);
-        _connect_pending = 0;
-        esp_schedule();
+        assert(_delaying);
+        _delaying = false;
+        esp_schedule(); // break current delay()
         return ERR_OK;
     }
 
@@ -658,8 +659,7 @@ class ClientContext
     size_t _written = 0;
     uint32_t _timeout_ms = 5000;
     uint32_t _op_start_time = 0;
-    bool _send_waiting = false;
-    uint8_t _connect_pending = 0;
+    bool _delaying = false;
 
     int8_t _refcnt;
     ClientContext* _next;