iterate over a directory, dealing with permission errors

[John Colvin via Digitalmars-d]

On Friday, 18 September 2015 at 12:27:37 UTC, Robert burner 
Schadek wrote:
> On Friday, 18 September 2015 at 12:17:25 UTC, John Colvin wrote:
>> That's neat, didn't know about std.exception.handle
>
> It is at least a year old. I created it because I had a range 
> that threw, and there was nothing to keep a range going or 
> reenter it.
>
>>
>> Unfortunately, I think there are two problems with your 
>> solution:
>>
>> 1) DirIteratorImpl will throw on popFront, not front. I had to 
>> look at source to find out. Is this a failure of documentation 
>> or is it actually an implementation detail?
>
> That one is trivial RangePrimitive.popFront
>
> foreach(file; dirEntries(args[1], SpanMode.depth)
>          .handle!(Exception, RangePrimitive.popFront, (e, r) =>
>  DirEntry())) {
>      writeln(file.name);
>  }

Yes, but implicit in this being an OK solution for people is that 
no-one ever reorganises the internals of DirIteratorImpl. I guess 
One could use handle to deal with *all* the range primitives as a 
defensive countermeasure.

>> 2) it doesn't cover the case where args[1] itself is 
>> unreadable, because dirEntries will throw when it's created.
>
> well, creating a DirEntry is not a range operation. handle 
> can't help you there.

Yup :(