ext/spl: DirectoryIterator to support modern filesytems.

With filesystems with builtin large capacity such as ZFS, Btfrs, NTFS
 or even ext4 with large_dir feature enabled, an int to represent an
entry index is falling short, thus risking overflows.

A zend_long however should cover this need without  increasing out
internal data structure.

close GH-20705

NEWS

@@ -50,6 +50,10 @@ PHP                                                                        NEWS
   . Soap::__setCookie() when cookie name is a digit is now not stored and represented
     as a string anymore but a int. (David Carlier)
 
+- SPL:
+  . DirectoryIterator key can now work better with filesystem supporting larger
+    directory indexing. (David Carlier)
+
 - Standard:
   . Fixed bug GH-19926 (reset internal pointer earlier while splicing array
     while COW violation flag is still set). (alexandre-daubois)

ext/spl/spl_directory.c

@@ -414,7 +414,7 @@ static zend_object *spl_filesystem_object_clone(zend_object *old_object)
 			spl_filesystem_dir_open(intern, source->path);
 			/* read until we hit the position in which we were before */
 			bool skip_dots = SPL_HAS_FLAG(source->flags, SPL_FILE_DIR_SKIPDOTS);
-			int index;
+			zend_long index;
 			for (index = 0; index < source->u.dir.index; ++index) {
 				do {
 					spl_filesystem_dir_read(intern);

ext/spl/spl_directory.h

@@ -62,7 +62,7 @@ struct _spl_filesystem_object {
 		struct {
 			php_stream         *dirp;
 			zend_string        *sub_path;
-			int                index;
+			zend_long          index;
 			zend_function      *func_rewind;
 			zend_function      *func_next;
 			zend_function      *func_valid;