class Mail::IMAP

def find(options=nil, &block)


search_charset: charset to pass to IMAP server search. Omitted by default. Example: 'UTF-8' or 'ASCII'.
The default is 'ALL'
or a single-dimension array of search keywords and arguments. Refer to [IMAP] section 6.4.4 for a full list
keys: are passed as criteria to the SEARCH command. They can either be a string holding the entire search string,
is false. Use #find_and_delete if you would like this to default to true.
delete_after_find: flag for whether to delete each retreived email after find. Default
This is helpful when you don't want your messages to be set to read automatically. Default is false.
is the default, a SELECT command will be used to retrieve the mail
set to true, the code will use the EXAMINE command to retrieve the mail. If set to false, which
read_only: will ensure that no writes are made to the inbox during the session. Specifically, if this is
instance of Message, not an array of Message instances.
count: number of emails to retrieve. The default value is 10. A value of 1 returns an
order: order of emails returned. Possible values are :asc or :desc. Default value is :asc.
what: last or first emails. The default is :first.
mailbox: mailbox to search the email(s) in. The default is 'INBOX'.
Possible options:

Find emails in a IMAP mailbox. Without any options, the 10 last received emails are returned. 
def find(options=nil, &block)
  options = validate_options(options)
  start do |imap|
    options[:read_only] ? imap.examine(options[:mailbox]) : imap.select(options[:mailbox])
    uids = imap.uid_search(options[:keys], options[:search_charset])
    uids.reverse! if options[:what].to_sym == :last
    uids = uids.first(options[:count]) if options[:count].is_a?(Integer)
    uids.reverse! if (options[:what].to_sym == :last && options[:order].to_sym == :asc) ||
                            (options[:what].to_sym != :last && options[:order].to_sym == :desc)
    if block_given?
      uids.each do |uid|
        uid = options[:uid].to_i unless options[:uid].nil?
        fetchdata = imap.uid_fetch(uid, ['RFC822', 'FLAGS'])[0]
        new_message = Mail.new(fetchdata.attr['RFC822'])
        new_message.mark_for_delete = true if options[:delete_after_find]
        if block.arity == 4
          yield new_message, imap, uid, fetchdata.attr['FLAGS']
        elsif block.arity == 3
          yield new_message, imap, uid
        else
          yield new_message
        end
        imap.uid_store(uid, "+FLAGS", [Net::IMAP::DELETED]) if options[:delete_after_find] && new_message.is_marked_for_delete?
        break unless options[:uid].nil?
      end
      imap.expunge if options[:delete_after_find]
    else
      emails = []
      uids.each do |uid|
        uid = options[:uid].to_i unless options[:uid].nil?
        fetchdata = imap.uid_fetch(uid, ['RFC822'])[0]
        emails << Mail.new(fetchdata.attr['RFC822'])
        imap.uid_store(uid, "+FLAGS", [Net::IMAP::DELETED]) if options[:delete_after_find]
        break unless options[:uid].nil?
      end
      imap.expunge if options[:delete_after_find]
      emails.size == 1 && options[:count] == 1 ? emails.first : emails
    end
  end
end