Add FS::format (#702)

cores/esp8266/FS.cpp

@@ -167,6 +167,13 @@ bool FS::begin() {
     return _impl->begin();
 }
 
+bool FS::format() {
+    if (!_impl) {
+        return false;
+    }
+    return _impl->format();
+}
+
 File FS::open(const String& path, const char* mode) {
     return open(path.c_str(), mode);
 }

cores/esp8266/FS.h

@@ -92,6 +92,8 @@ public:
 
     bool begin();
 
+    bool format();
+
     File open(const char* path, const char* mode);
     File open(const String& path, const char* mode);
 

cores/esp8266/FSImpl.h

@@ -63,6 +63,7 @@ public:
 class FSImpl {
 public:
     virtual bool begin() = 0;
+    virtual bool format() = 0;
     virtual FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) = 0;
     virtual DirImplPtr openDir(const char* path) = 0;
     virtual bool rename(const char* pathFrom, const char* pathTo) = 0;

cores/esp8266/spiffs_api.cpp

@@ -102,6 +102,25 @@ public:
         return _tryMount();
     }
 
+    bool format() override {
+        bool wasMounted = (SPIFFS_mounted(&_fs) != 0);
+
+        if (_tryMount()) {
+            SPIFFS_unmount(&_fs);
+        }
+        auto rc = SPIFFS_format(&_fs);
+        if (rc != SPIFFS_OK) {
+            DEBUGV("SPIFFS_format: rc=%d, err=%d\r\n", rc, _fs.err_code);
+            return false;
+        }
+
+        if (wasMounted) {
+            return _tryMount();
+        }
+
+        return true;
+    }
+
 protected:
     friend class SPIFFSFileImpl;
     friend class SPIFFSDirImpl;