Add SPIFFS::end (esp8266#1657)

Author: igrr

cores/esp8266/FS.cpp

@@ -167,6 +167,12 @@ bool FS::begin() {
     return _impl->begin();
 }
 
+void FS::end() {
+    if (_impl) {
+        _impl->end();
+    }
+}
+
 bool FS::format() {
     if (!_impl) {
         return false;

cores/esp8266/FS.h

@@ -102,7 +102,8 @@ class FS
     FS(FSImplPtr impl) : _impl(impl) { }
 
     bool begin();
-
+    void end();
+    
     bool format();
     bool info(FSInfo& info);
 

cores/esp8266/FSImpl.h

@@ -63,6 +63,7 @@ class DirImpl {
 class FSImpl {
 public:
     virtual bool begin() = 0;
+    virtual void end() = 0;
     virtual bool format() = 0;
     virtual bool info(FSInfo& info) = 0;
     virtual FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) = 0;

cores/esp8266/spiffs_api.h

@@ -132,6 +132,14 @@ class SPIFFSImpl : public FSImpl
         return _tryMount();
     }
 
+    void end() override
+    {
+        if (SPIFFS_mounted(&_fs) == 0) {
+            return;
+        }
+        SPIFFS_unmount(&_fs);
+    }
+
     bool format() override
     {
         if (_size == 0) {

doc/filesystem.md

@@ -7,6 +7,7 @@ title: File System
   * [Uploading files to file system](#uploading-files-to-file-system)
   * [File system object (SPIFFS)](#file-system-object-spiffs)
     * [begin](#begin)
+    * [end](#end)
     * [format](#format)
     * [open](#open)
     * [exists](#exists)
@@ -86,6 +87,14 @@ This method mounts SPIFFS file system. It must be called before any other
 FS APIs are used. Returns *true* if file system was mounted successfully, false
 otherwise.
 
+### end
+
+```c++
+SPIFFS.end()
+```
+
+This method unmounts SPIFFS file system. Use this method before updating SPIFFS using OTA.
+
 ### format
 
 ```c++