Add fileCreation/getCreation create-time accessors (#7000)

* Add fileCreation/getCreation create-time accessors

For SDFS and LittleFS, enable a creation time accessor for files and Dir
iterators, similar to the existing fileTime/getLastWrite calls.

Remove spurious Dir::getLastWrite method (the proper and only documented
way is really Dir::fileTime).

Update json to point to new mklittlefs which copies the creation date of
files to the image.

Fixes #6992

* Remove malloc(), use stack vars for temp names

LFS filenames are limited in size and generally very small.  Use a stack
variable instead of a dynamic allocation when performing full-path
computations.

* Replace "Creation" w/"CreationTime" in FS accessor

Per review, `getCreation` -> `getCreationTime`, `fileCreation` ->
`fileCreationTime`.

The names `fileTime()` and `getLastWrite()` are inherited from ESP32
implementation and unchanged.

* Add creation time to listfiles SD example

* Enable SdFat's sateTime callback for timestamping

SdFat requries the dateTimeCallback call (global for everything) to
update dates and times on created files.

Because the callback signature doesn't have space for us to provide
any parameters, we cannot get the the File, Dir, or FS object's
dateTimeCB member.  Instead, just go with `time(null)` as the callback
function which is right in all but the most esoteric cases.

* Correct DOS year/month offset in dateTime callback

* Fix docs to match new xxxCreationTime() API names

Co-authored-by: Develo <deveyes@gmail.com>

cores/esp8266/FS.cpp

@@ -187,6 +187,13 @@ time_t File::getLastWrite() {
     return _p->getLastWrite();
 }
 
+time_t File::getCreationTime() {
+    if (!_p)
+        return 0;
+
+    return _p->getCreationTime();
+}
+
 void File::setTimeCallback(time_t (*cb)(void)) {
     if (!_p)
         return;
@@ -224,6 +231,12 @@ time_t Dir::fileTime() {
     return _impl->fileTime();
 }
 
+time_t Dir::fileCreationTime() {
+    if (!_impl)
+        return 0;
+    return _impl->fileCreationTime();
+}
+
 size_t Dir::fileSize() {
     if (!_impl) {
         return 0;
@@ -262,17 +275,11 @@ bool Dir::rewind() {
     return _impl->rewind();
 }
 
-time_t Dir::getLastWrite() {
-    if (!_impl)
-        return 0;
-
-    return _impl->getLastWrite();
-}
-
 void Dir::setTimeCallback(time_t (*cb)(void)) {
     if (!_impl)
         return;
     _impl->setTimeCallback(cb);
+    timeCallback = cb;
 }
 
 
@@ -289,6 +296,7 @@ bool FS::begin() {
         DEBUGV("#error: FS: no implementation");
         return false;
     }
+    _impl->setTimeCallback(timeCallback);
     bool ret = _impl->begin();
     DEBUGV("%s\n", ret? "": "#error: FS could not start");
     return ret;

cores/esp8266/FS.h

@@ -112,6 +112,7 @@ public:
     String readString() override;
 
     time_t getLastWrite();
+    time_t getCreationTime();
     void setTimeCallback(time_t (*cb)(void));
 
 protected:
@@ -120,7 +121,6 @@ protected:
     // Arduino SD class emulation
     std::shared_ptr<Dir> _fakeDir;
     FS                  *_baseFS;
-    time_t (*timeCallback)(void) = nullptr;
 };
 
 class Dir {
@@ -132,20 +132,19 @@ public:
     String fileName();
     size_t fileSize();
     time_t fileTime();
+    time_t fileCreationTime();
     bool isFile() const;
     bool isDirectory() const;
 
     bool next();
     bool rewind();
 
-    time_t getLastWrite();
     void setTimeCallback(time_t (*cb)(void));
 
 protected:
     DirImplPtr _impl;
     FS       *_baseFS;
     time_t (*timeCallback)(void) = nullptr;
-
 };
 
 // Backwards compatible, <4GB filesystem usage

cores/esp8266/FSImpl.h

@@ -51,6 +51,8 @@ public:
     // as the FS is allowed to return either the time of the last write() operation or the
     // time present in the filesystem metadata (often the last time the file was closed)
     virtual time_t getLastWrite() { return 0; } // Default is to not support timestamps
+    // Same for creation time.
+    virtual time_t getCreationTime() { return 0; } // Default is to not support timestamps
 
 protected:
     time_t (*timeCallback)(void) = nullptr;
@@ -75,7 +77,11 @@ public:
     virtual FileImplPtr openFile(OpenMode openMode, AccessMode accessMode) = 0;
     virtual const char* fileName() = 0;
     virtual size_t fileSize() = 0;
+    // Return the last written time for a file.  Undefined when called on a writable file
+    // as the FS is allowed to return either the time of the last write() operation or the
+    // time present in the filesystem metadata (often the last time the file was closed)
     virtual time_t fileTime() { return 0; } // By default, FS doesn't report file times
+    virtual time_t fileCreationTime() { return 0; } // By default, FS doesn't report file times
     virtual bool isFile() const = 0;
     virtual bool isDirectory() const = 0;
     virtual bool next() = 0;
@@ -86,11 +92,6 @@ public:
     // same name.  The default implementation simply returns time(&null)
     virtual void setTimeCallback(time_t (*cb)(void)) { timeCallback = cb; }
 
-    // Return the last written time for a file.  Undefined when called on a writable file
-    // as the FS is allowed to return either the time of the last write() operation or the
-    // time present in the filesystem metadata (often the last time the file was closed)
-    virtual time_t getLastWrite() { return 0; } // Default is to not support timestamps
-
 protected:
     time_t (*timeCallback)(void) = nullptr;
 };