Rationalize File timestamp callback (#7785)

Fixes #7775

Clean up the passing/setting of custom File time callbacks and add a
host test verifying they work.  Existing core was not passing custom
timeCallbacks set at the FS level down to open()ed files, resulting in
them calling the default time(nullptr) and reporting wrong file modify
times.

cores/esp8266/FS.cpp

@@ -206,6 +206,7 @@ void File::setTimeCallback(time_t (*cb)(void)) {
     if (!_p)
         return;
     _p->setTimeCallback(cb);
+    _timeCallback = cb;
 }
 
 File Dir::openFile(const char* mode) {
@@ -221,7 +222,7 @@ File Dir::openFile(const char* mode) {
     }
 
     File f(_impl->openFile(om, am), _baseFS);
-    f.setTimeCallback(timeCallback);
+    f.setTimeCallback(_timeCallback);
     return f;
 }
 
@@ -287,7 +288,7 @@ void Dir::setTimeCallback(time_t (*cb)(void)) {
     if (!_impl)
         return;
     _impl->setTimeCallback(cb);
-    timeCallback = cb;
+    _timeCallback = cb;
 }
 
 
@@ -304,7 +305,7 @@ bool FS::begin() {
         DEBUGV("#error: FS: no implementation");
         return false;
     }
-    _impl->setTimeCallback(timeCallback);
+    _impl->setTimeCallback(_timeCallback);
     bool ret = _impl->begin();
     DEBUGV("%s\n", ret? "": "#error: FS could not start");
     return ret;
@@ -367,7 +368,7 @@ File FS::open(const char* path, const char* mode) {
         return File();
     }
     File f(_impl->open(path, om, am), this);
-    f.setTimeCallback(timeCallback);
+    f.setTimeCallback(_timeCallback);
     return f;
 }
 
@@ -388,7 +389,7 @@ Dir FS::openDir(const char* path) {
     }
     DirImplPtr p = _impl->openDir(path);
     Dir d(p, this);
-    d.setTimeCallback(timeCallback);
+    d.setTimeCallback(_timeCallback);
     return d;
 }
 
@@ -444,6 +445,7 @@ void FS::setTimeCallback(time_t (*cb)(void)) {
     if (!_impl)
         return;
     _impl->setTimeCallback(cb);
+    _timeCallback = cb;
 }
 
 

cores/esp8266/FS.h

@@ -118,6 +118,7 @@ public:
 
 protected:
     FileImplPtr _p;
+    time_t (*_timeCallback)(void) = nullptr;
 
     // Arduino SD class emulation
     std::shared_ptr<Dir> _fakeDir;
@@ -145,7 +146,7 @@ public:
 protected:
     DirImplPtr _impl;
     FS       *_baseFS;
-    time_t (*timeCallback)(void) = nullptr;
+    time_t (*_timeCallback)(void) = nullptr;
 };
 
 // Backwards compatible, <4GB filesystem usage
@@ -198,7 +199,7 @@ public:
 class FS
 {
 public:
-    FS(FSImplPtr impl) : _impl(impl) { timeCallback = _defaultTimeCB; }
+    FS(FSImplPtr impl) : _impl(impl) { _timeCallback = _defaultTimeCB; }
 
     bool setConfig(const FSConfig &cfg);
 
@@ -240,7 +241,7 @@ public:
 protected:
     FSImplPtr _impl;
     FSImplPtr getImpl() { return _impl; }
-    time_t (*timeCallback)(void);
+    time_t (*_timeCallback)(void) = nullptr;
     static time_t _defaultTimeCB(void) { return time(NULL); }
 };
 

cores/esp8266/FSImpl.h

@@ -45,8 +45,8 @@ public:
 
     // Filesystems *may* support a timestamp per-file, so allow the user to override with
     // their own callback for *this specific* file (as opposed to the FSImpl call of the
-    // same name.  The default implementation simply returns time(&null)
-    virtual void setTimeCallback(time_t (*cb)(void)) { timeCallback = cb; }
+    // 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
@@ -56,7 +56,7 @@ public:
     virtual time_t getCreationTime() { return 0; } // Default is to not support timestamps
 
 protected:
-    time_t (*timeCallback)(void) = nullptr;
+    time_t (*_timeCallback)(void) = nullptr;
 };
 
 enum OpenMode {
@@ -90,11 +90,11 @@ public:
 
     // Filesystems *may* support a timestamp per-file, so allow the user to override with
     // their own callback for *this specific* file (as opposed to the FSImpl call of the
-    // same name.  The default implementation simply returns time(&null)
-    virtual void setTimeCallback(time_t (*cb)(void)) { timeCallback = cb; }
+    // same name.  The default implementation simply returns time(null)
+    virtual void setTimeCallback(time_t (*cb)(void)) { _timeCallback = cb; }
 
 protected:
-    time_t (*timeCallback)(void) = nullptr;
+    time_t (*_timeCallback)(void) = nullptr;
 };
 
 class FSImpl {
@@ -118,11 +118,11 @@ public:
 
     // Filesystems *may* support a timestamp per-file, so allow the user to override with
     // their own callback for all files on this FS.  The default implementation simply
-    // returns the present time as reported by time(&null)
-    virtual void setTimeCallback(time_t (*cb)(void)) { timeCallback = cb; }
+    // returns the present time as reported by time(null)
+    virtual void setTimeCallback(time_t (*cb)(void)) { _timeCallback = cb; }
 
 protected:
-    time_t (*timeCallback)(void) = nullptr;
+    time_t (*_timeCallback)(void) = nullptr;
 };
 
 } // namespace fs