Added imap_custom(), which initiates the custom command processing,
and an associated response handler imap_state_custom_resp(), which
handles any responses by sending them to the client as body data.
All untagged responses with the same name as the first word of the
custom request string are accepted, with the exception of SELECT and
EXAMINE which have responses that cannot be easily identified. An
extra check has been provided for them so that any untagged responses
are accepted for them.
Added imap_parse_custom_request() for parsing the CURLOPT_CUSTOMREQUEST
parameter which URL decodes the value and separates the request from
any parameters - This makes it easier to filter untagged responses
by the request command.
For consistency changed the logic of the imap_state_append_resp()
function to test for an unsucessful continuation response rather than a
succesful one.
The APPEND operation needs to be performed in several steps:
1) We send "<tag> APPEND <mailbox> <flags> {<size>}\r\n"
2) Server responds with continuation respose "+ ...\r\n"
3) We start the transfer and send <size> bytes of data
4) Only now we end the request command line by sending "\r\n"
5) Server responds with "<tag> OK ...\r\n"
This commit performs steps 4 and 5, in the DONE phase, as more
processing is required after the transfer.
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.
Not processing the final FETCH responses was not optimal, not only
because the response code would be ignored but it would also leave data
unread on the socket which would prohibit connection reuse.
A typical FETCH response can be broken down into four parts:
1) "* <uid> FETCH (<what> {<size>}\r\n", using continuation syntax
2) <size> bytes of the actual message
3) ")\r\n", finishing the untagged response
4) "<tag> OK ...", finishing the command
Part 1 is read in imap_fetch_resp(), part 2 is consumed in the PERFORM
phase by the transfer subsystem, parts 3 and 4 are currently ignored.
Added a loop to imap_statemach_act() in which Curl_pp_readresp() is
called until the cache is drained. Without this multiple responses
received in a single packet could result in a hang or delay.
RFC 3501 states that "the client MUST be prepared to accept any response
at all times" yet we assume anything received with "* " at the beginning
is the untagged response we want.
Introduced a helper function that checks whether the input looks like a
response to specified command, so that we may filter the ones we are
interested in according to the current state.
Introduced similar handling to the FETCH responses, where even the
untagged data responses are handled by the response handler of the
individual state.
Removed this pointer to a downloaded bytes counter because it was set in
imap_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.
From a maintenance point of view the code reads better to view tagged
responses, then untagged followed by continuation responses.
Additionally, this matches the order of responses in POP3.
