[Memory] Fix freeing of allocated strings

src/_C008.cpp

@@ -49,7 +49,7 @@ bool CPlugin_008(CPlugin::Function function, struct EventStruct *event, String&
 
     case CPlugin::Function::CPLUGIN_PROTOCOL_TEMPLATE:
     {
-      event->String1 = String();
+      free_string(event->String1);
       event->String2 = F("demo.php?name=%sysname%&task=%tskname%&valuename=%valname%&value=%value%");
       break;
     }

src/_C010.cpp

@@ -35,7 +35,7 @@ bool CPlugin_010(CPlugin::Function function, struct EventStruct *event, String&
 
     case CPlugin::Function::CPLUGIN_PROTOCOL_TEMPLATE:
     {
-      event->String1 = String();
+      free_string(event->String1);
       event->String2 = F("%sysname%_%tskname%_%valname%=%value%");
       break;
     }

src/_C015.cpp

@@ -202,7 +202,7 @@ bool CPlugin_015(CPlugin::Function function, struct EventStruct *event, String&
 
           if (!isvalid) {
             // send empty string to Blynk in case of error
-            formattedValue = String();
+            free_string(formattedValue);
           }
 
           const String valueName = Cache.getTaskDeviceValueName(event->TaskIndex, x);

src/_C016.cpp

@@ -104,8 +104,8 @@ bool CPlugin_016(CPlugin::Function function, struct EventStruct *event, String&
 
     case CPlugin::Function::CPLUGIN_PROTOCOL_TEMPLATE:
     {
-      event->String1 = String();
-      event->String2 = String();
+      free_string(event->String1);
+      free_string(event->String2);
       break;
     }
 

src/_P055_Chiming.ino

@@ -529,7 +529,7 @@ uint8_t Plugin_055_ReadChime(const String& name, String& tokens)
     log = strformat(F("Chime: read %s "), fileName.c_str());
   }
 
-  tokens = String();
+  free_string(tokens);
   fs::File f = tryOpenFile(fileName, "r");
 
   if (f)

src/src/Commands/InternalCommands.cpp

@@ -173,7 +173,7 @@ bool do_command_case_check(command_case_data         & data,
   // The data struct is re-used on each attempt to process an internal command.
   // Re-initialize the only two members that may have been altered by a previous call.
   data.retval = false;
-  data.status = String();
+  free_string(data.status);
 
   if (!checkSourceFlags(data.event->Source, group)) {
     data.status = return_incorrect_source();

src/src/Controller_struct/C018_data_struct.cpp

@@ -25,9 +25,9 @@ void C018_data_struct::reset() {
     delete C018_easySerial;
     C018_easySerial = nullptr;
   }
-  cacheDevAddr     = String();
-  cacheHWEUI       = String();
-  cacheSysVer      = String();
+  free_string(cacheDevAddr);
+  free_string(cacheHWEUI);
+  free_string(cacheSysVer);
   autobaud_success = false;
 }
 
@@ -157,7 +157,7 @@ bool C018_data_struct::initOTAA(const String& AppEUI, const String& AppKey, cons
   if (myLora == nullptr) { return false; }
   bool success = myLora->initOTAA(AppEUI, AppKey, DevEUI);
 
-  cacheDevAddr = String();
+  free_string(cacheDevAddr);
 
   C018_logError(F("initOTAA()"));
   updateCacheOnInit();
@@ -334,7 +334,7 @@ void C018_data_struct::updateCacheOnInit() {
       cacheDevAddr = myLora->sendRawCommand(F("mac get devaddr"));
 
       if (cacheDevAddr == F("00000000")) {
-        cacheDevAddr = String();
+        free_string(cacheDevAddr);
       }
     }
   }

src/src/DataStructs/ExtendedControllerCredentialsStruct.cpp

@@ -1,6 +1,7 @@
 #include "../DataStructs/ExtendedControllerCredentialsStruct.h"
 
 #include "../Helpers/ESPEasy_Storage.h"
+#include "../Helpers/StringConverter.h"
 
 #define EXT_CONTR_CRED_USER_OFFSET 0
 #define EXT_CONTR_CRED_PASS_OFFSET 1
@@ -24,7 +25,7 @@ bool ExtendedControllerCredentialsStruct::validateChecksum() const
 
 void ExtendedControllerCredentialsStruct::clear() {
   for (size_t i = 0; i < CONTROLLER_MAX * 2; ++i) {
-    _strings[i] = String();
+    free_string(_strings[i]);
   }
 }
 

src/src/DataStructs/LogEntry.cpp

@@ -26,8 +26,9 @@ bool LogEntry_t::add(const uint8_t loglevel, const String& line)
     #endif // ifdef USE_SECOND_HEAP
 
     if (line.length() > LOG_STRUCT_MESSAGE_SIZE - 1) {
-      _message = std::move(line.substring(0, LOG_STRUCT_MESSAGE_SIZE - 1));
+      move_special(_message, line.substring(0, LOG_STRUCT_MESSAGE_SIZE - 1));
     } else {
+      reserve_special(_message, line.length());
       _message = line;
     }
   }
@@ -48,7 +49,7 @@ bool LogEntry_t::add(const uint8_t loglevel, String&& line)
     // Need to make a substring, which is a new allocation, on the 2nd heap
     HeapSelectIram ephemeral;
       #endif // ifdef USE_SECOND_HEAP
-    _message = move_special(line.substring(0, LOG_STRUCT_MESSAGE_SIZE - 1));
+    move_special(_message, line.substring(0, LOG_STRUCT_MESSAGE_SIZE - 1));
   } else {
     move_special(_message, std::move(line));
   }
@@ -59,7 +60,7 @@ bool LogEntry_t::add(const uint8_t loglevel, String&& line)
 
 void LogEntry_t::clear()
 {
-  _message   = String();
+  free_string(_message);
   _timestamp = 0;
   _loglevel  = 0;
 }

src/src/DataStructs/LogStruct.h

@@ -10,7 +10,7 @@
  * LogStruct
 \*********************************************************************************************/
 #ifdef ESP32
-  #define LOG_STRUCT_MESSAGE_LINES 60
+  #define LOG_STRUCT_MESSAGE_LINES 120
 #else
   #ifdef USE_SECOND_HEAP
     #define LOG_STRUCT_MESSAGE_LINES 60

src/src/DataStructs/Modbus.cpp

@@ -4,6 +4,7 @@
 
 #include "../DataStructs/ControllerSettingsStruct.h"
 #include "../ESPEasyCore/ESPEasy_Log.h"
+#include "../Helpers/StringConverter.h"
 
 
 Modbus::Modbus() : ModbusClient(nullptr), errcnt(0), timeout(0),
@@ -108,7 +109,7 @@ bool Modbus::handle() {
   unsigned int RXavailable = 0;
 
   #ifndef BUILD_NO_DEBUG
-  LogString = String();
+  free_string(LogString);
   #endif
   int64_t rxValue = 0;
 

src/src/DataStructs/RulesEventCache.cpp

@@ -41,6 +41,10 @@ bool RulesEventCache::addLine(const String& line, const String& filename, size_t
     # ifdef USE_SECOND_HEAP
     HeapSelectDram ephemeral;
     # endif // ifdef USE_SECOND_HEAP
+    #ifdef ESP32
+    reserve_special(event, event.length());
+    reserve_special(action, action.length());
+    #endif
 
     _eventCache.emplace_back(filename, pos, std::move(event), std::move(action));
     return true;

src/src/DataStructs/Web_StreamingBuffer.cpp

@@ -336,7 +336,7 @@ void Web_StreamingBuffer::sendContentBlocking(String& data) {
   web_server.sendContent(data);
 
   if (data.length() > (CHUNKED_BUFFER_SIZE + 1)) {
-    data = String(); // Clear also allocated memory
+    free_string(data); // Clear also allocated memory
   } else {
     data.clear();
   }

src/src/ESPEasyCore/ESPEasy_Log.cpp

@@ -17,6 +17,8 @@
 #include "../Helpers/ESPEasy_Storage.h"
 #endif
 
+#define UPDATE_LOGLEVEL_ACTIVE_CACHE_INTERVAL 5000
+
 /********************************************************************************************\
   Init critical variables for logging (important during initial factory reset stuff )
   \*********************************************************************************************/
@@ -124,6 +126,13 @@ bool loglevelActiveFor(uint8_t logLevel) {
     return false;
   }
   #endif
+  static uint32_t lastUpdateLogLevelCache = 0;
+  if (lastUpdateLogLevelCache == 0 || 
+      timePassedSince(lastUpdateLogLevelCache) > UPDATE_LOGLEVEL_ACTIVE_CACHE_INTERVAL)
+  {
+    lastUpdateLogLevelCache = millis();
+    updateLogLevelCache();
+  }
   return logLevel <= highest_active_log_level;
 }
 
@@ -143,15 +152,13 @@ uint8_t getSerialLogLevel() {
 }
 
 uint8_t getWebLogLevel() {
-  uint8_t logLevelSettings = 0;
   if (Logging.logActiveRead()) {
-    logLevelSettings = Settings.WebLogLevel;
-  } else {
-    if (Settings.WebLogLevel != 0) {
-      updateLogLevelCache();
-    }
+    return Settings.WebLogLevel;
+  } 
+  if (Settings.WebLogLevel != LOG_LEVEL_NONE) {
+    updateLogLevelCache();
   }
-  return logLevelSettings;
+  return LOG_LEVEL_NONE;
 }
 
 bool loglevelActiveFor(uint8_t destination, uint8_t logLevel) {
@@ -245,7 +252,7 @@ void addLog(uint8_t logLevel, const char *line)
       }
     }
     #else 
-    if (!copy.reserve(strlen_P((PGM_P)line))) {
+    if (!reserve_special(copy, strlen_P((PGM_P)line))) {
       return;
     }
     copy = line;
@@ -353,5 +360,5 @@ void addToLogMove(uint8_t logLevel, String&& string)
     Logging.add(logLevel, std::move(string));
   }
   // Make sure the string may no longer keep up memory
-  string = String();
+  free_string(string);
 }

src/src/Globals/RamTracker.cpp

@@ -156,7 +156,7 @@ RamTracker::RamTracker(void) {
   writePtr = 0;
 
   for (int i = 0; i < TRACES; i++) {
-    traces[i] = String();
+    free_string(traces[i]);
     tracesMemory[i] = 0xffffffff; // init with best case memory values, so they get replaced if memory goes lower
   }
 
@@ -172,7 +172,7 @@ void RamTracker::registerRamState(const String& s) {   // store function
   int bestCase = bestCaseTrace();                      // find best case memory trace
 
   if (ESP.getFreeHeap() < tracesMemory[bestCase]) {    // compare to current memory value
-    traces[bestCase] = String();
+    free_string(traces[bestCase]);
     readPtr          = writePtr + 1;                   // read out buffer, oldest value first
 
     if (readPtr >= TRACEENTRIES) { 
@@ -210,7 +210,7 @@ void RamTracker::getTraceBuffer() {
       retval += ' ';
       retval += traces[i];
       addLogMove(LOG_LEVEL_DEBUG_DEV, retval);
-      retval = String();
+      retval.clear();
     }
   }
 #endif // ifndef BUILD_NO_DEBUG

src/src/Helpers/Audio.cpp

@@ -5,6 +5,7 @@
 #include "../Globals/RamTracker.h"
 #include "../Helpers/Hardware_GPIO.h"
 #include "../Helpers/Hardware_PWM.h"
+#include "../Helpers/StringConverter.h"
 
 
 /********************************************************************************************\
@@ -53,7 +54,7 @@ void clear_rtttl_melody() {
     #   endif // if FEATURE_RTTTL_EVENTS
   }
 
-  rtttlMelody = String();
+  free_string(rtttlMelody);
 }
 
 void set_rtttl_melody(String& melody) {

src/src/Helpers/ESPEasy_checks.cpp

@@ -211,7 +211,7 @@ String ReportOffsetErrorInStruct(const String& structname, size_t offset) {
 *  Not a member function to be able to use the F-macro
 \*********************************************************************************************/
 bool SettingsCheck(String& error) {
-  error = String();
+  free_string(error);
   #ifndef LIMIT_BUILD_SIZE
 #ifdef esp8266
   size_t offset = offsetof(SettingsStruct, ResetFactoryDefaultPreference);

src/src/Helpers/Memory.h

@@ -58,4 +58,8 @@ void *special_realloc(void *ptr, size_t size);
 void *special_calloc(size_t num, size_t size);
 
 
-bool String_reserve_special(String& str, size_t size);
+// Perform a special memory allocate for the buffer pointer in the String object
+// Allocation is tried either on 2nd heap (ESP8266) or PSRAM (ESP32)
+// when possible.
+bool String_reserve_special(String& str, size_t size);
+

src/src/Helpers/Modbus_RTU.cpp

@@ -19,7 +19,7 @@ void ModbusRTU_struct::reset() {
     delete easySerial;
     easySerial = nullptr;
   }
-  detected_device_description = String();
+  free_string(detected_device_description);
 
   for (int i = 0; i < 8; ++i) {
     _sendframe[i] = 0;

src/src/Helpers/StringConverter.cpp

@@ -83,7 +83,7 @@ void move_special(String& dest, String&& source) {
     HeapSelectIram ephemeral;
     if (dest.reserve(source.length())) {
       dest = source;
-      source = String();
+      free_string(source);
       return;
     }
     // Could not allocate on 2nd heap, so just move existing string
@@ -106,6 +106,12 @@ bool reserve_special(String& str, size_t size) {
   return String_reserve_special(str, size);
 }
 
+void free_string(String& str) {
+  // This is a call specifically tailored to what is done in:
+  //  void String::move(String &rhs)
+
+  String tmp(std::move(str));
+}
 
 /********************************************************************************************\
    Format string using vsnprintf
@@ -1515,7 +1521,7 @@ bool GetArgv(const char *string, String& argvString, unsigned int argc, char sep
   int  pos_begin, pos_end;
   bool hasArgument = GetArgvBeginEnd(string, argc, pos_begin, pos_end, separator);
 
-  argvString = String();
+  free_string(argvString);
 
   if (!hasArgument) { return false; }
 

src/src/Helpers/StringConverter.h

@@ -58,6 +58,10 @@ String move_special(String&& source);
 // Try to reserve on the heap with the most space available
 bool reserve_special(String& str, size_t size);
 
+// Arduino String does not have a function to de-allocate its internal buffer
+// This is a special trick to de-allocate its internal buffer and thus free up memory.
+void free_string(String& str);
+
 /*
 template <typename T>
 bool equals(const String& str, const T &val) {

src/src/Helpers/StringParser.cpp

@@ -420,7 +420,7 @@ void transformValue(
               }
 
               if (equals(value, '0')) {
-                value = String();
+                free_string(value);
               } else {
                 const int valueLength = value.length();
 
@@ -769,7 +769,7 @@ bool findNextDevValNameInString(const String& input, int& startpos, int& endpos,
     move_special(format,    valueName.substring(hashpos + 1));
     move_special(valueName, valueName.substring(0, hashpos));
   } else {
-    format = String();
+    free_string(format);
   }
   deviceName.toLowerCase();
   valueName.toLowerCase();

src/src/Helpers/WebServer_commandHelper.cpp

@@ -23,7 +23,7 @@ HandledWebCommand_result handle_command_from_web(EventValueSource::Enum source,
 
   bool handledCmd = false;
   bool sendOK     = false;
-  printWebString = String();
+  free_string(printWebString);
   printToWeb     = false;
   printToWebJSON = false;
 

src/src/Helpers/_CPlugin_Helper.cpp

@@ -42,7 +42,8 @@ bool safeReadStringUntil(Stream     & input,
   const unsigned long timer           = start + timeout;
   unsigned long backgroundtasks_timer = start + 10;
 
-  str = String();
+  // FIXME TD-er: Should this also de-allocate internal buffer?
+  str.clear();
 
   do {
     // read character

src/src/PluginStructs/P020_data_struct.cpp

@@ -136,7 +136,7 @@ void P020_Task::discardClientIn() {
 }
 
 void P020_Task::clearBuffer() {
-  serial_buffer    = String();
+  free_string(serial_buffer);
   _maxDataGramSize = serial_processing == P020_Events::P1WiFiGateway
                     ? P020_P1_DATAGRAM_MAX_SIZE
                     : P020_DATAGRAM_MAX_SIZE;