fix metadata header parsing

[nicolasmure]

Hello,

This PR fixes the followiong metadata parsing error :

$mask = 'X-Object-Meta-';
$header = 'X-Object-Meta-Manufacturer';

echo ltrim($header, $mask); // "nufacturer"

See live example here.

Actually, ltrim does not replaces by the whole string but uses chars in the given mask instead, and stops when it encounter a char which is not in the mask.

[haphan]

Nice catch @nicolasmure! Surprisingly no one has reported this issue.

Performance wise, for this simple job, do you think we can just simply use substr instead of regex?

$name = substr($header, strlen(static::METADATA_PREFIX));

Did a small benchmark

haphan@hpbookpro:~/Projects/openstack$ php bench.php
running 1000 * 1000 iteration
regex took 1.05065107346 ms to complete
substr took 0.200830221176 ms to complete

[nicolasmure]

Sure @haphan :) I updated the code.

[haphan]

thanks @nicolasmure 🎸