Following commit e450f66a02 and the changes in the multi interface
being used internally, from 7.29.0, the transfer cancellation in
pop3_dophase_done() is no longer required.
Moved the blocking state machine to the disconnect functions so that the
logout / quit functions are only responsible for sending the actual
command needed to logout or quit.
Additionally removed the hard return on failure.
Some state changes would be performed after a failure test that
performed a hard return, whilst others would be performed within a test
for success. Updated the code, for consistency, so all instances are
performed within a success test.
Removed this pointer to a downloaded bytes counter because it was set in
pop3_init() to point to the same variable the transfer functions keep
the count in (k->bytecount), effectively making the code in transfer.c
"*k->bytecountp = k->bytecount" a no-op.
Updated the mailbox variable to correctly reflect it's purpose. The
name mailbox was a leftover from when IMAP and POP3 support was
initially added to curl.
Removed user and passwd from the POP3 struct as these cannot be set on
a per-request basis and are leftover from legacy FTP code.
Changed some comments still using FTP terminology.
Moved the mailbox and custom request variables from the per-connection
struct pop3_conn to the new per-request struct and fixed references
accordingly.
... since they're not used by the easy interface really, I wanted to
remove the association. Also, I unified the pingpong statemachine driver
into a single function with a 'wait' argument: Curl_pp_statemach.
A call to Curl_ssl_connect() was accidentally left in when the SSL/TLS
connection layer was reworked in 7.29. Not only would this cause the
connection to block but had the additional overhead of calling the
non-blocking connect a little bit later.
Reworked the pp->endofresp() function so that the conndata, line and
line length are passed down to it just as with Curl_client_write()
rather than each implementation of the function having to query
these values.
Additionally changed the int return type to bool as this is more
representative of the function's usage.
Corrected the order of the upgrade_tls() functions and moved the handler
upgrade and getsock() functions out from the middle of the state related
functions.
Corrected the order of the pop3_state_capa() / imap_state_capability()
and the pop3_state_capa_resp() / imap_state_capability_resp() functions
to match the execution order.
Added honoring of the tls_supported flag when starting a TLS upgrade
rather than unconditionally attempting it. If the use_ssl flag is set
to CURLUSESSL_TRY and the server doesn't support TLS upgrades then the
connection will continue to authenticate. If this flag is set to
CURLUSESSL_ALL then the connection will complete with a failure as it
did previously.
