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Re: [PATCH] posix: if glob has a trailing slash match directories only.

From: Paul Eggert <eggert at cs dot ucla dot edu>
To: Dmitry Goncharov <dgoncharov at users dot sf dot net>
Cc: libc-alpha at sourceware dot org
Date: Wed, 29 Nov 2017 22:03:02 -0800
Subject: Re: [PATCH] posix: if glob has a trailing slash match directories only.
Authentication-results: sourceware.org; auth=none
References: <20171128210857.GC2745@madrid> <a97c9749-5bcd-0292-9eae-bd7c4c59ab09@cs.ucla.edu> <20171129042114.GA2702@madrid> <dec247a8-a079-ccde-89da-f7dd6b572604@cs.ucla.edu> <CAG+Z0CsgP0sMTtaurAF8kXJ0HSqhPMC-BxS36=OB05GNUo9xSQ@mail.gmail.com> <CAG+Z0CsvFWv+JGauq3=PAV8=pcD9YHi8p1k9yTbsdT8iNU9AZw@mail.gmail.com> <c6f24b4a-9681-bb87-16c4-6ba8535c45c9@cs.ucla.edu> <20171130053212.GB21476@madrid>

Dmitry Goncharov wrote:

Paul, i am missing where you see the performance hit.
The current contract makes the caller check after the library by calling stat
on each entry.

No, these callers need not call stat. glob itself doesn't call stat, when itcalls itself recursively with this flag. Instead, glob simply charges ahead andgets an ENOTDIR (or whatever( in the next level of recursion. For this sort ofusage, it is a win for glob to filter out directories if that is easy (becausethere is then no need even to issue the syscalls that result in ENOTDIR), but itcan be a loss for glob to filter out directories via stat calls.

References:
- [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Dmitry Goncharov
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Paul Eggert
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Dmitry Goncharov
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Paul Eggert
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Dmitry Goncharov
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Paul Eggert
- Re: [PATCH] posix: if glob has a trailing slash match directories only.
  - From: Dmitry Goncharov

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