I'm trying to set up a view permission based on a webform field.  I've been able to get to my custom module using hook_webform_submission_access().

So I have an email field in the webform, and I want to check that based on the current user's email address.  Should be pretty simple, I just can't get the field data.  Anyone know?

if ($submission->data['field_email'] == $user->mail)

What is the correct syntax instead of $submission->data['field_email']

I'm on Drupal 7 and Webform 4.x branch.