feat: add Modbus support

lib/eModbus/src/ModbusClient.cpp

@@ -0,0 +1,103 @@
+// =================================================================================================
+// eModbus: Copyright 2020 by Michael Harwerth, Bert Melis and the contributors to eModbus
+//               MIT license - see license.md for details
+// =================================================================================================
+#include "ModbusClient.h"
+#undef LOCAL_LOG_LEVEL
+#include "Logging.h"
+
+uint16_t ModbusClient::instanceCounter = 0;
+
+// Default constructor: set the default timeout to 2000ms, zero out all other 
+ModbusClient::ModbusClient() :
+  messageCount(0),
+  errorCount(0),
+  #if HAS_FREERTOS
+  worker(NULL),
+  #elif IS_LINUX
+  worker(0),
+  #endif
+  onData(nullptr),
+  onError(nullptr),
+  onResponse(nullptr) { instanceCounter++; }
+
+// onDataHandler: register callback for data responses
+bool ModbusClient::onDataHandler(MBOnData handler) {
+  if (onData) {
+    LOG_W("onData handler was already claimed\n");
+  } else if (onResponse) {
+    LOG_E("onData handler is unavailable with an onResponse handler\n");
+    return false;
+  }
+  onData = handler;
+  return true;
+}
+
+// onErrorHandler: register callback for error responses
+bool ModbusClient::onErrorHandler(MBOnError handler) {
+  if (onError) {
+    LOG_W("onError handler was already claimed\n");
+  } else if (onResponse) {
+    LOG_E("onError handler is unavailable with an onResponse handler\n");
+    return false;
+  } 
+  onError = handler;
+  return true;
+}
+
+// onResponseHandler: register callback for error responses
+bool ModbusClient::onResponseHandler(MBOnResponse handler) {
+  if (onError || onData) {
+    LOG_E("onResponse handler is unavailable with an onData or onError handler\n");
+    return false;
+  } 
+  onResponse = handler;
+  return true;
+}
+
+// getMessageCount: return message counter value
+uint32_t ModbusClient::getMessageCount() {
+  return messageCount;
+}
+
+// getErrorCount: return error counter value
+uint32_t ModbusClient::getErrorCount() {
+  return errorCount;
+}
+
+// resetCounts: Set both message and error counts to zero
+void ModbusClient::resetCounts() {
+  {
+    LOCK_GUARD(cntLock, countAccessM);
+    messageCount = 0;
+    errorCount = 0;
+  }
+}
+
+// waitSync: wait for response on syncRequest to arrive
+ModbusMessage ModbusClient::waitSync(uint8_t serverID, uint8_t functionCode, uint32_t token) {
+  ModbusMessage response;
+  unsigned long lostPatience = millis();
+ 
+  // Default response is TIMEOUT
+  response.setError(serverID, functionCode, TIMEOUT);
+
+  // Loop 60 seconds, if unlucky
+  while (millis() - lostPatience < 60000) {
+    {
+      LOCK_GUARD(lg, syncRespM);
+      // Look for the token
+      auto sR = syncResponse.find(token);
+      // Is it there?
+      if (sR != syncResponse.end()) {
+        // Yes. get the response, delete it from the map and return
+        response = sR->second;
+        syncResponse.erase(sR);
+        break;
+      }
+    }
+    // Give the watchdog time to act
+    delay(10);
+  }
+  return response;
+}