[RFC i-g-t 2/5] lib/igt_dir_explorer: Add function to recursively read all files in a directory

[Peter Senna Tschudin]

On 5/15/2025 10:51 AM, Zbigniew Kempczyński wrote:
> On Wed, May 14, 2025 at 07:51:34PM +0200, Peter Senna Tschudin wrote:
>> Introduces igt_dir_explorer_read_and_discard_all(), a function that
>> performs a recursive scan of all files within a directory. Each file is
>> read, and its content is discarded.
>>
>> This functionality is utilized in the following tests:
>> - core_debugfs
>> - core_debugfs_display_on_off
>> - core_sysfs
>>
>> This addition enhances the ability to efficiently handle directory
>> traversal and file processing in tests.
>>
>> Cc: marcin.bernatowicz at intel.com
>> Cc: himanshu.girotra at intel.com
>> Cc: aditya.chauhan at intel.com
>> Cc: pravalika.gurram at intel.com
>> Cc: sai.gowtham.ch at intel.com
>> Cc: ramadevi.gandi at intel.com
>> Cc: lucas.demarchi at intel.com
>> Cc: rodrigo.vivi at intel.com
>> Cc: kamil.konieczny at linux.intel.com
>> Cc: katarzyna.piecielska at intel.com
>> Signed-off-by: Peter Senna Tschudin <peter.senna at linux.intel.com>
>> ---
>>  lib/igt_dir_explorer.c | 72 ++++++++++++++++++++++++++++++++++++++++++
>>  lib/igt_dir_explorer.h | 10 ++++++
>>  lib/meson.build        |  1 +
>>  3 files changed, 83 insertions(+)
>>  create mode 100644 lib/igt_dir_explorer.c
>>  create mode 100644 lib/igt_dir_explorer.h
>>
>> diff --git a/lib/igt_dir_explorer.c b/lib/igt_dir_explorer.c
>> new file mode 100644
>> index 000000000..d47e08535
>> --- /dev/null
>> +++ b/lib/igt_dir_explorer.c
>> @@ -0,0 +1,72 @@
>> +// SPDX-License-Identifier: MIT
>> +/*
>> + * Copyright © 2025 Intel Corporation
>> + */
>> +
>> +#include <dirent.h>
>> +#include <fcntl.h>
>> +
>> +#include "igt.h"
>> +#include "igt_dir_explorer.h"
>> +
>> +void igt_dir_explorer_read_and_discard_all(int path_fd, int indent)
> 
> Just loose thought - if you're doing recursive directory traversal,
> wouldn't be better to pass function (kind of callback) which would be
> called for each file/dir entry? I mean single traversal code, and
> multiple callbacks for different use cases.

I like the idea. Can you help me create a spec for it? There is more than
just what to do. There are cases where we may want to test only specific
files, and cases where we do not want to test specific files. Ideas:
 - Accept a callback that performs the action on each file. Read or write
   for example
 - Accept specification for which files to read, and which not to read.
 - Maybe an optional blocking callback? do not proceed to the next file
   until this one returns. This is useful for an async reset for example.
 - Limits? Depth, number of files, wait between reads?
 - Concurrency? Try read them all at the same time?
 - Random order for doing the action on the file?

Which ones of these make sense, and what else can we customize?

Would it be ok to delay these improvements to a next iteration? There is
some urgency in solving the issues I created with intel_sysfs_debugfs.