Issue 7819 - setTimes should support folders on Windows

[ghost]

http://d.puremagic.com/issues/show_bug.cgi?id=7819

• Moved setTimes implementation closer to getTimes.
• Added FILE_FLAG_BACKUP_SEMANTICS and FILE_ATTRIBUTE_DIRECTORY flags to enable setting folder times on Windows (See MSDN docs for these here).
• Updated getTimes docs to reflect it works on folders.
• Changed enforce to cenforce for Posix in setTimes since the function claimed it only threw FileException's.

Credits to Jay Norwood for the patch for setTimes fix.

[CyberShadow]

Should we really be using FILE_FLAG_BACKUP_SEMANTICS in a library function for setting directory times? It seems like that flag was created for a very specific purpose (backup software).

Also it should be noted that FILE_FLAG_BACKUP_SEMANTICS requires SE_BACKUP_NAME and SE_RESTORE_NAME privileges, so I believe this won't work for unprivileged processes (the default execution level for programs on Windows Vista and newer).

[ghost]

Hmm I see. Is there any other way we can implement this? It doesn't work if there's only FILE_ATTRIBUTE_DIRECTORY | FILE_ATTRIBUTE_NORMAL.

[CyberShadow]

The logical conclusion is that the Windows API was designed such that setting directory times directly should not be possible with usual flags.

[ghost]

Heh, "designed" :). I can't find a flag which could help, tried looking in here, and various other places (GENERIC_WRITE doesn't work either).

Tried to look on SO, only thing I've found is http://stackoverflow.com/a/279944 and it says FILE_FLAG_BACKUP_SEMANTICS has to be used. And a file/dir time modifier from codeproject also uses this flag.

[CyberShadow]

And a file/dir time modifier from codeproject also uses this flag.

I don't think that has any weight - unless the project author argumented their decision using arguments not mentioned in this discussion, the use of the flag is as uninformed as we are.

A better idea would be to check what standard libraries of other language implementations do.

[ghost]

A better idea would be to check what standard libraries of other language implementations do.

I'll get to it later, for now closing this. Thanks for the review, we avoided making a mistake.

[ghost]

Eeeehh, at the very bottom of CreateFile:

To open a directory using CreateFile, specify the FILE_FLAG_BACKUP_SEMANTICS 
flag as part of dwFlagsAndAttributes. Appropriate security checks still apply when
this flag is used without SE_BACKUP_NAME and SE_RESTORE_NAME privileges.

PHP also uses it, and everywhere I look that flag is used.

[alexrp]

LGTM. @CyberShadow ?

[CyberShadow]

I'm fine with it if other languages do it. At least we have something to point a finger at :)