Reduce stack usage

CHANGELOG.md

@@ -18,7 +18,7 @@ All notable changes to this project will be documented in this file.
 - Command `SetOption162 1` to disable adding export energy to energy today (#22578)
 - ESP32 support for WPA2/3 Enterprise conditional in core v3.1.0.241206 (#22600)
 - Support for Sonoff POWCT Energy Export Active (#22596)
-- Improved auto-selection of LED hardware support (RMT, SPI)
+- Improved auto-selection of LED hardware support (RMT, SPI) (#22618)
 
 ### Breaking Changed
 - ESP32 ArtNet switches from GRB to RGB encoding (#22556)

tasmota/tasmota_support/support.ino

@@ -1148,6 +1148,8 @@ int GetCommandCode(char* destination, size_t destination_size, const char* needl
 
 bool DecodeCommand(const char* haystack, void (* const MyCommand[])(void), const uint8_t *synonyms = nullptr);
 bool DecodeCommand(const char* haystack, void (* const MyCommand[])(void), const uint8_t *synonyms) {
+  SHOW_FREE_MEM(PSTR("DecodeCommand"));
+
   GetTextIndexed(XdrvMailbox.command, CMDSZ, 0, haystack);  // Get prefix if available
   int prefix_length = strlen(XdrvMailbox.command);
   if (prefix_length) {
@@ -2680,9 +2682,7 @@ void AddLogData(uint32_t loglevel, const char* log_data, const char* log_data_pa
     }
     snprintf_P(TasmotaGlobal.log_buffer, LOG_BUFFER_SIZE, PSTR("%s%c%c%s%s%s%s\1"),
       TasmotaGlobal.log_buffer, TasmotaGlobal.log_buffer_pointer++, '0'+loglevel, mxtime, log_data, log_data_payload, log_data_retained);
-    if (too_long) {
-      free(too_long);
-    }
+    if (too_long) { free(too_long); }
     TasmotaGlobal.log_buffer_pointer &= 0xFF;
     if (!TasmotaGlobal.log_buffer_pointer) {
       TasmotaGlobal.log_buffer_pointer++;  // Index 0 is not allowed as it is the end of char string

tasmota/tasmota_xdrv_driver/xdrv_02_9_mqtt.ino

@@ -702,15 +702,14 @@ void MqttPublishLoggingAsync(bool refresh) {
 
 void MqttPublishPayload(const char* topic, const char* payload, uint32_t binary_length, bool retained) {
   // Publish <topic> payload string or binary when binary_length set with optional retained
-
-  SHOW_FREE_MEM(PSTR("MqttPublish"));
+  SHOW_FREE_MEM(PSTR("MqttPublishPayload"));
 
   bool binary_data = (binary_length > 0);
   if (!binary_data) {
     binary_length = strlen(payload);
   }
 
-  if (Settings->flag4.mqtt_no_retain) {                   // SetOption104 - Disable all MQTT retained messages, some brokers don't support it: AWS IoT, Losant
+  if (Settings->flag4.mqtt_no_retain) {                  // SetOption104 - Disable all MQTT retained messages, some brokers don't support it: AWS IoT, Losant
     retained = false;                                    // Some brokers don't support retained, they will disconnect if received
   }
 
@@ -794,14 +793,30 @@ void MqttPublishPayloadPrefixTopic_P(uint32_t prefix, const char* subtopic, cons
   prefix 5 = stat using subtopic or RESULT
   prefix 6 = tele using subtopic or RESULT
 */
-  char romram[64];
+  SHOW_FREE_MEM(PSTR("MqttPublishPayloadPrefixTopic_P"));
+/*
+  char romram[64];                      // Claim 64 bytes from 4k stack
   snprintf_P(romram, sizeof(romram), ((prefix > 3) && !Settings->flag.mqtt_response) ? S_RSLT_RESULT : subtopic);  // SetOption4 - Switch between MQTT RESULT or COMMAND
   UpperCase(romram, romram);
 
   prefix &= 3;
-  char stopic[TOPSZ];
+  char stopic[TOPSZ];                   // Claim TOPSZ bytes from 4k stack
   GetTopic_P(stopic, prefix, TasmotaGlobal.mqtt_topic, romram);
   MqttPublishPayload(stopic, payload, binary_length, retained);
+*/
+  // Reduce important stack usage by 200 bytes but adding 52 bytes code
+  char *romram = (char*)malloc(64);     // Claim 64 bytes from 20k heap
+  strcpy_P(romram, ((prefix > 3) && !Settings->flag.mqtt_response) ? S_RSLT_RESULT : subtopic);
+  UpperCase(romram, romram);
+
+  prefix &= 3;
+  char *htopic = (char*)malloc(TOPSZ);  // Claim TOPSZ bytes from 16k heap
+  GetTopic_P(htopic, prefix, TasmotaGlobal.mqtt_topic, romram);
+  char stopic[strlen_P(htopic) +1];     // Claim only strlen_P bytes from 4k stack
+  strcpy_P(stopic, htopic);
+  free(htopic);                         // Free 16k heap from TOPSZ bytes
+  free(romram);                         // Free 16k heap from 64 bytes
+  MqttPublishPayload(stopic, payload, binary_length, retained);
 
 #if defined(USE_MQTT_AWS_IOT) || defined(USE_MQTT_AWS_IOT_LIGHT)
   if ((prefix > 0) && (Settings->flag4.awsiot_shadow) && (Mqtt.connected)) {    // placeholder for SetOptionXX
@@ -857,6 +872,8 @@ void MqttPublishPayloadPrefixTopicRulesProcess_P(uint32_t prefix, const char* su
 
 void MqttPublishPrefixTopic_P(uint32_t prefix, const char* subtopic, bool retained) {
   // Publish <prefix>/<device>/<RESULT or <subtopic>> default ResponseData string with optional retained
+  SHOW_FREE_MEM(PSTR("MqttPublishPrefixTopic_P"));
+
   MqttPublishPayloadPrefixTopic_P(prefix, subtopic, ResponseData(), 0, retained);
 }
 
@@ -868,6 +885,8 @@ void MqttPublishPrefixTopic_P(uint32_t prefix, const char* subtopic) {
 void MqttPublishPrefixTopicRulesProcess_P(uint32_t prefix, const char* subtopic, bool retained) {
   // Publish <prefix>/<device>/<RESULT or <subtopic>> default ResponseData string with optional retained
   //   then process rules
+  SHOW_FREE_MEM(PSTR("MqttPublishPrefixTopicRulesProcess_P"));
+
   MqttPublishPrefixTopic_P(prefix, subtopic, retained);
   XdrvRulesProcess(0);
 }

tasmota/tasmota_xx2c_global/xdrv_interface.ino

@@ -1105,10 +1105,10 @@ bool XdrvRulesProcess(bool teleperiod) {
 
 #ifdef USE_DEBUG_DRIVER
 void ShowFreeMem(const char *where) {
-  char stemp[30];
-  snprintf_P(stemp, sizeof(stemp), where);
-  XdrvMailbox.data = stemp;
+  char *XdrvMailboxData = XdrvMailbox.data;
+  XdrvMailbox.data = (char*)where;
   XdrvCall(FUNC_FREE_MEM);
+  XdrvMailbox.data = XdrvMailboxData;
 }
 #endif