Re: dirEntries() and exceptions

[rjframe via Digitalmars-d-learn]

On Fri, 24 Nov 2017 12:02:47 +, doc wrote:

> I'm trying recursively find files, and have some trouble to catch
> exceptions if have no permission to read directory.
> 
...
> 
> std.file.FileException@std/file.d(3798):
> /tmp/systemd-private-8338348a306b4d589e3f6ba2bfd0c8fe-systemd-
timesyncd.service-3374MK:
> Permission denied 
> 
> [code]
> void main() {
> import std.stdio, std.file;
> 
> try {
> auto farray = dirEntries("/tmp", "*.{d,py,ph,sh}",
> SpanMode.breadth);
> foreach (f; farray) {
> writeln(f);
> }
> catch (FileException e) {
> writeln(e.msg);
> }
> }
> [/code]
> 
> This not work, after writeln(e.msg); program is exit.

The exception for dirEntries was reported as a bug here[1]; there is a 
workaround listed on that page that silently skips directories it can't 
read, but you'll need to modify it a bit to maintain a breadth search.

As to why your code stops after catching the exception, the try/catch 
block does not place you back in the block that threw the exception, but 
drops you off in the outer scope. You would need to place the code in some 
sort of loop to run until all input was consumed in order continue past 
the exception.


[1]: https://issues.dlang.org/show_bug.cgi?id=12391

dirEntries() and exceptions

[doc via Digitalmars-d-learn]

I'm trying recursively find files, and have some trouble to catch 
exceptions if have no permission to read directory.


[code]
void main() {
import std.file,std.stdio;
auto farray = dirEntries("/tmp", "*.{d,py,pl,sh}", 
SpanMode.breadth);

foreach (f; farray){writeln(f);}}
[/code]

std.file.FileException@std/file.d(3798): 
/tmp/systemd-private-8338348a306b4d589e3f6ba2bfd0c8fe-systemd-timesyncd.service-3374MK: Permission denied


??:? @safe core.sys.posix.dirent.DIR* 
std.file.cenforce!(core.sys.posix.dirent.DIR*).cenforce(core.sys.posix.dirent.DIR*, lazy const(char)[], immutable(char)[], ulong) [0xd31f7ce7]
??:? bool std.file.DirIteratorImpl.stepIn(immutable(char)[]) 
[0xd31f7119]

??:? void std.file.DirIteratorImpl.popFront() [0xd31f7641]
??:? void std.file.DirIterator.popFront() [0xd31f78dc]
??:? _Dmain [0xd31f1ff2]


Example structure /tmp

.
├── 374e60aa-296f-4499-9d12-36626a105069
├── 6787feed-013f-4907-bf86-b18a5a7c966f
├── dub_platform_probe-0d2aed9d-4a4f-4da3-a9fe-af705fb4914c.d
├── dub_platform_probe-3e5246ea-7158-4184-865e-8f15ec149b6f.d
├── dub_platform_probe-724ee4cf-bdc9-4137-b25a-4893323922ac.d
├── dub_platform_probe-9a0c98e4-3077-460c-9309-b8066be1b353.d
├── dub_platform_probe-be30fcdc-3eb2-4a0c-88bd-49a8507eb48b.d
├── dub_platform_probe-dc6d01e2-4f5d-4e71-adde-70131b8a0587.d
├── dub_platform_probe-dcd282e3-1b9c-486a-84ee-5eee5c60790f.d
├── dub_platform_probe-e2dfd83f-5f21-401c-a450-20bf5e73a678.d
├── ls
├── ls.d
├── ls.o
├── 
systemd-private-8338348a306b4d589e3f6ba2bfd0c8fe-systemd-timesyncd.service-3374MK [error opening dir]

├── vscode-e6da53a1363a02042f56966c5464593959886044.sock

drwx-- 3 root root60 ноя 24 08:32  
systemd-private-8338348a306b4d589e3f6ba2bfd0c8fe-systemd-timesyncd.service-3374MK


This dir have permission 0700, only root can read in this dir. 
Also, in /tmp I'm create at root a new dir /tmp/www with 0700 
perm. But my program has exit when exception on 
/tmp/systed-private... and can't write any messages when can't 
read /tmp/www.


So, how I can skip any exceptions and continue program?

[code]
void main() {
import std.stdio, std.file;

try {
auto farray = dirEntries("/tmp", "*.{d,py,ph,sh}", 
SpanMode.breadth);

foreach (f; farray) {
writeln(f);
}
catch (FileException e) {
writeln(e.msg);
}
}
[/code]

This not work, after writeln(e.msg); program is exit.