It should be possible to check exists and isDir/isFile with a single stat call

[dlangBugzillaToGithub]

code (@MartinNowak) reported this on 2013-06-02T05:25:01Z

Transfered from https://issues.dlang.org/show_bug.cgi?id=10240

CC List

• petar.p.kirov
• razvan.nitu1305

Description

In std.file the functions isDir, isFile and dirEntry all throw if a path does not exist.
Therefor one needs a separate stat call to test for existence.
Also dirEntry does enforce again that a path exists.

[dlangBugzillaToGithub]

razvan.nitu1305 commented on 2017-10-05T08:28:47Z

There are 2 ways to solve this:

1. Either check that the file or directory exists inside the isDir/isFile functions and return false if the path does not exist or the input string doesn't designate a directory/file. This is troublesome since you have one value for 2 different semantics.

2. Create a function existsAndIsDir/File where you can call stat a single time. This means adding 2 new functions that add no extra functionality for the benefit of a micro-optimization.

In my opinion we should close this as WONTFIX.

[dlangBugzillaToGithub]

petar.p.kirov commented on 2017-10-05T09:47:27Z

I believe the right solution add a function akin to C++17's file_status (http://en.cppreference.com/w/cpp/experimental/fs/file_status) which would return a struct essentially being union of

https://msdn.microsoft.com/en-us/library/windows/desktop/aa364946(v=vs.85).aspx on Windows

and 

http://pubs.opengroup.org/onlinepubs/009695399/functions/stat.html on Posix.

That way users would be to obtain more information in a single call.

Unfortunately we have all kinds of functions defined in https://dlang.org/phobos-prerelease/std_file General, Attributes, Timestamp

while a single function returning a struct would be much more useful.

[dlangBugzillaToGithub]

petar.p.kirov commented on 2017-10-05T09:47:59Z

> while a single function returning a struct would be much more useful...

... and more type-safe.

[dlangBugzillaToGithub]

petar.p.kirov commented on 2017-10-05T09:54:04Z

> I believe the right solution add a function akin to C++17's file_status (http://en.cppreference.com/w/cpp/experimental/fs/file_status)

Here I meant this function:
http://en.cppreference.com/w/cpp/experimental/fs/status

as file_status is a struct.