[4.2] Allow Setting The Default Crypt Cost Factor

[miclf]

As suggested by @jasonlewis in #6500.

[jasonlewis]

As you mentioned in the referenced issue the service provider will probably need to be changed as well so that it's a shared binding. Otherwise you won't be able to globally set the cost factor.

[miclf]

Never mind, I think it’s not needed. The Closure is currently bound via bindShared:

/**
* Register the service provider.
*
* @return void
*/
public function register()
{
    $this->app->bindShared('hash', function() { return new BcryptHasher; });
}

Looking at the IoC, what I understand from this is: the Closure is wrapped into another one and is executed only once because its return value is stored as a static property of the outer, shared Closure (see Container.php#L203). So I guess the IoC always gives the same instance of the Hasher.

Does this sound right?