define two weak functions defaulting to no-op

redefine them to do something useful when either spiffs or littlefs are used

Author: d-a-v

cores/esp8266/FS.h

@@ -245,6 +245,12 @@ class FS
 
 } // namespace fs
 
+extern "C"
+{
+void littlefs_weak_end(void);
+void spiffs_weak_end(void);
+}
+
 #ifndef FS_NO_GLOBALS
 using fs::FS;
 using fs::File;

cores/esp8266/spiffs_api.cpp

@@ -127,6 +127,12 @@ bool isSpiffsFilenameValid(const char* name)
 
 }; // namespace
 
+extern "C" void spiffs_weak_end(void)
+{
+    //ets_printf("debug: not weak spiffs end\n");
+    SPIFFS.end();
+}
+
 // these symbols should be defined in the linker script for each flash layout
 #ifndef CORE_MOCK
 #ifdef ARDUINO

libraries/ESP8266HTTPUpdateServer/src/ESP8266HTTPUpdateServer-impl.h

@@ -5,7 +5,6 @@
 #include <WiFiUdp.h>
 #include <flash_hal.h>
 #include <FS.h>
-#include <LittleFS.h>
 #include "StreamString.h"
 #include "ESP8266HTTPUpdateServer.h"
 
@@ -94,8 +93,8 @@ void ESP8266HTTPUpdateServerTemplate<ServerType>::setup(ESP8266WebServerTemplate
           Serial.printf("Update: %s\n", upload.filename.c_str());
         if (upload.name == "filesystem") {
           size_t fsSize = ((size_t) &_FS_end - (size_t) &_FS_start);
-          SPIFFS.end();
-          LittleFS.end();
+          spiffs_weak_end();
+          littlefs_weak_end();
           if (!Update.begin(fsSize, U_FS)){//start with max available size
             if (_serial_output) Update.printError(Serial);
           }

libraries/LittleFS/src/LittleFS.cpp

@@ -181,6 +181,12 @@ int LittleFSImpl::lfs_flash_sync(const struct lfs_config *c) {
 
 }; // namespace
 
+extern "C" void littlefs_weak_end(void)
+{
+    //ets_printf("debug: not weak littlefs end\n");
+    LittleFS.end();
+}
+
 // these symbols should be defined in the linker script for each flash layout
 #ifndef CORE_MOCK
 #ifdef ARDUINO