- Rework ExpiringTimeTracker to be based on PolledTimeout.

- Ensure espnowDelay and floodingMeshDelay always performs maintenance.

- Rework MutexTracker to use shared_ptr.

- Change enums to enum class.

- Change typedef to using.

- Add HeapMonitor class.

- Make _messageIDs be a map instead of an unordered_map to reduce heap usage.

- Use the possibly broken wifi_country ESP8266 API to check for legal WiFi channels when setting WiFi channels.

- Make MessageData, RequestData and ResponseData contain a TimeTracker rather than inherit from TimeTracker.

- Add deprecated attribute to TransmissionResult.

- Remove superfluous elses.

- Reduce cyclomatic complexity.

- Change postfix ++ and -- to prefix.

- Generalize getEncryptedConnectionIterator method.

- Increase code NRVO compatibility.

- Change _connectionAttemptTimeoutMs type from int32_t to uint32_t.

- Add deprecated attribute to ESP8266WiFiMesh.

- Add some constness to TypeConversionFunctions.

- Move base36 arrays to PROGMEM in TypeConversionFunctions.cpp.

- Add deprecated atttribute to SHA1 and MD5 hashes.

- Remove _warningsEnabled in CryptoInterface since this has been replaced by the deprecated attribute.

- Prefix all TypeConversion getters with "get".

- Improve comments.

- Fix merge conflict.

libraries/ESP8266WiFiMesh/src/HeapMonitor.h

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2020 Anders Löfgren
+ *
+ * License (MIT license):
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef __ESPHEAPMONITOR_H__
+#define __ESPHEAPMONITOR_H__
+
+#include <Arduino.h>
+
+class HeapMonitor {
+
+public:
+
+  enum class HeapStatus
+  {
+    NOMINAL    = 0,
+    LIMITED    = 1,
+    CRITICAL   = 2
+  };
+
+  HeapMonitor(const uint32_t criticalHeapLevel, const uint32_t criticalHeapLevelBuffer);
+
+  virtual ~HeapMonitor() = default; 
+
+  /**
+   * Set the maximum free heap level in bytes within which free heap size is considered critical. 
+   */
+  void setCriticalHeapLevel(const uint32_t freeHeapInBytes);
+  uint32_t getCriticalHeapLevel() const;
+
+  /**
+   * Set the buffer of the critical heap level, within which free heap size is considered limited. 
+   */
+  void setCriticalHeapLevelBuffer(const uint32_t bufferInBytes);
+  uint32_t getCriticalHeapLevelBuffer() const;
+
+  HeapStatus getHeapStatus() const;
+
+private:
+
+  uint32_t _criticalHeapLevel;
+  uint32_t _criticalHeapLevelBuffer;
+
+};
+
+#endif