Merge remote-tracking branch 'origin/master' into pr8736

Author: mcspr

doc/esp8266wifi/client-class.rst

@@ -29,6 +29,35 @@ Default input value 0 means that effective value is left at the discretion of th
 
 ``stop()`` returns ``false`` in case of an issue when closing the client (for instance a timed-out ``flush``). Depending on implementation, its parameter can be passed to ``flush()``.
 
+abort
+~~~~~
+
+.. code:: cpp
+
+ void abort();
+
+
+Originally proposed in `#8738 <https://github.com/esp8266/Arduino/pull/8738>`__
+Unlike ``stop()``, immediately shuts down internal connection object.
+
+Under usual circumstances, we either enter ``CLOSE_WAIT`` or ``TIME_WAIT`` state. But, the connection object is not freed right away, and requires us to either
+* wait until ``malloc()`` returns ``NULL`` when our TCP stack tries to allocate memory for a new connection
+* manually call ``tcp_kill_timewait()`` to forcibly stop the 'oldest' connection
+
+This API frees up resources used by the connection. Consider using it instead of ``stop()`` if your application handles a lot of clients and frequently runs out of available heap memory.
+
+*Example:*
+
+.. code:: cpp
+ # define MIN_HEAP_FREE 20000 // or whatever min available heap memory convienent for your application 
+ auto client = server.accept();
+ // ... do something with the client object ...
+ if (ESP.getFreeHeap() >= MIN_HEAP_FREE) {
+ client.stop();
+ } else {
+ client.abort();
+ }
+
 setNoDelay
 ~~~~~~~~~~
 

libraries/ESP8266WiFi/src/WiFiClient.cpp

@@ -376,6 +376,17 @@ uint16_t WiFiClient::localPort()
  return _client->getLocalPort();
 }
 
+// Api for heap saving. Optional use instead of WiFiClient::stop to systematically retreive some heap memory
+// and avoiding server crashes in case of frequent clients connections.
+void WiFiClient::abort()
+{
+ if (!_client)
+ return;
+
+ flush(0); // Flush output buffer. Don't make any use of return boolean.
+_client->abort(); // Wich in turn calls tcp_abort which calls tcp_abandon().
+}
+
 void WiFiClient::stopAll()
 {
  for (WiFiClient* it = _s_first; it; it = it->_next) {

libraries/ESP8266WiFi/src/WiFiClient.h

@@ -103,7 +103,7 @@ class WiFiClient : public Client, public SList<WiFiClient> {
  friend class WiFiServer;
 
  using Print::write;
-
+ 
  static void stopAll();
  static void stopAllExcept(WiFiClient * c);
 
@@ -148,6 +148,10 @@ class WiFiClient : public Client, public SList<WiFiClient> {
  virtual bool outputCanTimeout () override { return connected(); }
  virtual bool inputCanTimeout () override { return connected(); }
 
+ // Immediately stops this client instance.
+ // Unlike stop(), does not wait to gracefuly shutdown the connection.
+ void abort();
+
 protected:
 
  static int8_t _s_connected(void* arg, void* tpcb, int8_t err);

libraries/ESP8266httpUpdate/examples/httpUpdate/httpUpdate.ino

@@ -23,17 +23,11 @@ ESP8266WiFiMulti WiFiMulti;
 void setup() {
 
  Serial.begin(115200);
- // Serial.setDebugOutput(true);
+ // Serial.setDebugOutput(false);
 
- Serial.println();
- Serial.println();
  Serial.println();
 
- for (uint8_t t = 4; t > 0; t--) {
- Serial.printf("[SETUP] WAIT %d...\n", t);
- Serial.flush();
- delay(1000);
- }
+ ESPhttpUpdate.setClientTimeout(2000); // default was 8000
 
  WiFi.mode(WIFI_STA);
  WiFiMulti.addAP(APSSID, APPSK);

libraries/ESP8266httpUpdate/src/ESP8266httpUpdate.h

@@ -130,6 +130,9 @@ class ESP8266HTTPUpdate
  int getLastError(void);
  String getLastErrorString(void);
 
+ void setClientTimeout(int timeout) {
+ _httpClientTimeout = timeout;
+ }
 protected:
  t_httpUpdate_return handleUpdate(HTTPClient& http, const String& currentVersion, bool spiffs = false);
  bool runUpdate(Stream& in, uint32_t size, const String& md5, int command = U_FLASH);