Add FileAttributes.Executable as a possible FileAttribute

[kblok]

Introduction

With File.SetAttributes we can modify some file permissions, such as ReadOnly or ReadWrite, but we can't set Executable (a.k.a. 7) permission. I think we have everything we need on FileStatus.Unix.cs so we can do something like:

File.SetAttributes(path, FileAttributes.Executable);

It should call chmod setting a 7.

Usage

Some possible usage is when you need to download a zip file. You know that you have an app inside, but you need to change the mode to 7 to be able to execute it.

[danmoseley]

What should it do on Windows?

[kblok]

As FileStatus.Unix.cs ignores Windows attributes (e.g. Hidden, Directory and many others), Windows code should ignore FileAttributes.Executable.

[danmoseley]

Makes sense. Would this be for file owner only (S_IXUSR)

[kblok]

Makes sense. Would this be for file owner only (S_IXUSR)

Yes

[danmoseley]

Thanks, I think this is ready for review, they meet once a week so it may be a little bit.

[stephentoub]

As FileStatus.Unix.cs ignores Windows attributes (e.g. Hidden, Directory and many others), Windows code should ignore FileAttributes.Executable.

This was about making existing APIs work as best as possible. There's a higher bar for new APIs.

but we can't set Executable (a.k.a. 7) permission

Just as a point of order, executable is 1. 7 is Read (4) | Write (2) | Execute (1).

[kblok]

This was about making existing APIs work as best as possible. There's a higher bar for new APIs.

I don’t know if there is a concept of “Execute” permission on Windows, it’s about file extensions. What would you do in that case?

[stephentoub]

Why does it need to be on FileAttributes? Can you use the Mono.Posix nuget package and just call its Chmod (or P/Invoke to chmod directly)?

[kblok]

Why does it need to be on FileAttributes? Can you use the Mono.Posix nuget package and just call its Chmod (or P/Invoke to chmod directly)?

Yes, I could use Mono.Posix.NetStandard or P/Invoke.

When I was looking for "chmod" on this project, looking for a way to chmod 7 a file, I found that SetAttributes looked like a chmod wrapper: It validates the argument, checks if the argument is different from the current mode and then calls chmod.

On the other hand, I see that SetAttributes covers everything you need on windows, but it doesn't cover everything you need on Linux. So yeah, I could P/Invoke, but I think that a dev coding a linux app should have the same tools and level of abstraction than a guy coding a windows app. If one can set a file hidden the other should be able to make it executable.