Implement SPIFFS.exists

cores/esp8266/FS.cpp

@@ -193,6 +193,17 @@ File FS::open(const char* path, const char* mode) {
     return File(_impl->open(path, om, am));
 }
 
+bool FS::exists(const char* path) {
+    if (!_impl) {
+        return false;
+    }
+    return _impl->exists(path);
+}
+
+bool FS::exists(const String& path) {
+    return exists(path.c_str());
+}
+
 Dir FS::openDir(const char* path) {
     if (!_impl) {
         return Dir();

cores/esp8266/FS.h

@@ -97,6 +97,9 @@ public:
     File open(const char* path, const char* mode);
     File open(const String& path, const char* mode);
 
+    bool exists(const char* path);
+    bool exists(const String& path);
+
     Dir openDir(const char* path);
     Dir openDir(const String& path);
 

cores/esp8266/FSImpl.h

@@ -65,6 +65,7 @@ public:
     virtual bool begin() = 0;
     virtual bool format() = 0;
     virtual FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) = 0;
+    virtual bool exists(const char* path) = 0;
     virtual DirImplPtr openDir(const char* path) = 0;
     virtual bool rename(const char* pathFrom, const char* pathTo) = 0;
     virtual bool remove(const char* path) = 0;

cores/esp8266/spiffs_api.cpp

@@ -59,7 +59,7 @@ public:
     }
 
     FileImplPtr open(const char* path, OpenMode openMode, AccessMode accessMode) override;
-
+    bool exists(const char* path) override;
     DirImplPtr openDir(const char* path) override;
 
     bool rename(const char* pathFrom, const char* pathTo) override {
@@ -404,6 +404,14 @@ FileImplPtr SPIFFSImpl::open(const char* path, OpenMode openMode, AccessMode acc
     return std::make_shared<SPIFFSFileImpl>(this, fd);
 }
 
+bool SPIFFSImpl::exists(const char* path) {
+    char tmpName[SPIFFS_OBJ_NAME_LEN];
+    strlcpy(tmpName, path, sizeof(tmpName));
+    spiffs_stat stat;
+    int rc = SPIFFS_stat(&_fs, tmpName, &stat);
+    return rc == SPIFFS_OK;
+}
+
 DirImplPtr SPIFFSImpl::openDir(const char* path) {
     spiffs_DIR dir;
     char tmpName[SPIFFS_OBJ_NAME_LEN];

doc/reference.md

@@ -191,6 +191,14 @@ if (!f) {
 }
 ```
 
+#### exists
+
+```c++
+SPIFFS.exists(path)
+```
+
+Returns *true* if a file with given path exists, *false* otherwise.
+
 #### openDir
 
 ```c++