Make SPIFFS and LittleFS stay out of link when not needed (#6699)

* define two weak functions defaulting to no-op
redefine them to do something useful when either spiffs or littlefs are used

* noop

* single entry point for closing FSes

* rename functions, override when instanciated, add link to explanation

* spiffs: call end on destructor

Author: d-a-v

cores/esp8266/FS.h

@@ -245,6 +245,13 @@ class FS
 
 } // namespace fs
 
+extern "C"
+{
+void close_all_fs(void);
+void littlefs_request_end(void);
+void spiffs_request_end(void);
+}
+
 #ifndef FS_NO_GLOBALS
 using fs::FS;
 using fs::File;

cores/esp8266/FSnoop.cpp

@@ -0,0 +1,33 @@
+/*
+ *  no-op implementations
+ *  used/linked when no strong implementation already exists elsewhere
+ */
+
+#include <FS.h>
+
+extern "C"
+{
+
+void close_all_fs(void)
+{
+    littlefs_request_end();
+    spiffs_request_end();
+}
+
+// default weak definitions
+// they are overriden in their respective real implementation
+// hint: https://github.com/esp8266/Arduino/pull/6699#issuecomment-549085382
+
+void littlefs_request_end(void) __attribute__((weak));
+void littlefs_request_end(void)
+{
+    //ets_printf("debug: noop: littlefs_request_end\n");
+}
+
+void spiffs_request_end(void) __attribute__((weak));
+void spiffs_request_end(void)
+{
+    //ets_printf("debug: noop: spiffs_request_end\n");
+}
+
+}

cores/esp8266/spiffs_api.cpp

@@ -141,6 +141,14 @@ FS SPIFFS = FS(FSImplPtr(new spiffs_impl::SPIFFSImpl(
                              FS_PHYS_PAGE,
                              FS_PHYS_BLOCK,
                              SPIFFS_MAX_OPEN_FILES)));
+
+extern "C" void spiffs_request_end(void)
+{
+    // override default weak function
+    //ets_printf("debug: not weak spiffs end\n");
+    SPIFFS.end();
+}
+
 #endif // ARDUINO
 #endif // !CORE_MOCK
 

cores/esp8266/spiffs_api.h

@@ -80,6 +80,11 @@ class SPIFFSImpl : public FSImpl
         memset(&_fs, 0, sizeof(_fs));
     }
 
+    ~SPIFFSImpl()
+    {
+        end();
+    }
+
     FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) override;
     bool exists(const char* path) override;
     DirImplPtr openDir(const char* path) override;

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 +93,7 @@ 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();
+          close_all_fs();
           if (!Update.begin(fsSize, U_FS)){//start with max available size
             if (_serial_output) Update.printError(Serial);
           }

libraries/LittleFS/src/LittleFS.cpp

@@ -190,6 +190,14 @@ int LittleFSImpl::lfs_flash_sync(const struct lfs_config *c) {
 
 #if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_LITTLEFS)
 FS LittleFS = FS(FSImplPtr(new littlefs_impl::LittleFSImpl(FS_PHYS_ADDR, FS_PHYS_SIZE, FS_PHYS_PAGE, FS_PHYS_BLOCK, FS_MAX_OPEN_FILES)));
+
+extern "C" void littlefs_request_end(void)
+{
+    // override default weak function
+    //ets_printf("debug: not weak littlefs end\n");
+    LittleFS.end();
+}
+
 #endif
 
 #endif // !CORE_MOCK