- "Open a network stream to HOST.
-The first four parameters have the same meaning as in
-`open-network-stream'. The function returns a list where the
-first element is the stream, the second element is the greeting
-the server replied with after connecting, and the third element
-is a string representing the capabilities of the server (if any).
-
-The PARAMETERS is a keyword list that can have the following
-values:
-
-:type -- either `network', `tls', `shell' or `starttls'. If
-omitted, the default is `network'.
-
-:end-of-command -- a regexp saying what the end of a command is.
-This defaults to \"\\n\".
-
-:success -- a regexp saying whether the STARTTLS command was
-successful or not. For instance, for NNTP this is \"^3\".
-
-:capability-command -- a string representing the command used to
-query server for capabilities. For instance, for IMAP this is
-\"1 CAPABILITY\\r\\n\".
-
-:starttls-function -- a function that takes one parameter, which
-is the response to the capaibility command. It should return nil
-if it turns out that the server doesn't support STARTTLS, or the
-command to switch on STARTTLS otherwise."
- (let ((type (or (cadr (memq :type parameters)) 'network)))
- (when (and (eq type 'starttls)
- (fboundp 'open-gnutls-stream))
- (setq type 'network))
- (when (eq type 'ssl)
- (setq type 'tls))
- (destructuring-bind (stream greeting capabilities)
- (funcall (intern (format "proto-stream-open-%s" type) obarray)
- name buffer host service parameters)
- (list (and stream
- (memq (process-status stream)
- '(open run))
- stream)
- greeting capabilities))))
-
-(defun proto-stream-open-network (name buffer host service parameters)
+ "Open a network stream to HOST, possibly with encryption.
+Normally, return a network process object; with a non-nil
+:return-list parameter, return a list instead (see below).
+
+The first four parameters, NAME, BUFFER, HOST, and SERVICE, have
+the same meanings as in `open-network-stream'. The remaining
+PARAMETERS should be a sequence of keywords and values:
+
+:type specifies the connection type, one of the following:
+ nil or `network'
+ -- Begin with an ordinary network connection, and if
+ the parameters :success and :capability-command
+ are also supplied, try to upgrade to an encrypted
+ connection via STARTTLS. Even if that
+ fails (e.g. if HOST does not support TLS), retain
+ an unencrypted connection.
+ `plain' -- An ordinary, unencrypted network connection.
+ `starttls' -- Begin with an ordinary connection, and try
+ upgrading via STARTTLS. If that fails for any
+ reason, drop the connection; in that case the
+ returned object is a killed process.
+ `tls' -- A TLS connection.
+ `ssl' -- Equivalent to `tls'.
+ `shell' -- A shell connection.
+
+:return-list specifies this function's return value.
+ If omitted or nil, return a process object. A non-nil means to
+ return (PROC . PROPS), where PROC is a process object and PROPS
+ is a plist of connection properties, with these keywords:
+ :greeting -- the greeting returned by HOST (a string), or nil.
+ :capabilities -- a string representing HOST's capabilities,
+ or nil if none could be found.
+ :type -- the resulting connection type; `plain' (unencrypted)
+ or `tls' (TLS-encrypted).
+
+:end-of-command specifies a regexp matching the end of a command.
+ If non-nil, it defaults to \"\\n\".
+
+:end-of-capability specifies a regexp matching the end of the
+ response to the command specified for :capability-command.
+ It defaults to the regexp specified for :end-of-command.
+
+:success specifies a regexp matching a message indicating a
+ successful STARTTLS negotiation. For instance, the default
+ should be \"^3\" for an NNTP connection.
+
+:capability-command specifies a command used to query the HOST
+ for its capabilities. For instance, for IMAP this should be
+ \"1 CAPABILITY\\r\\n\".
+
+:starttls-function specifies a function for handling STARTTLS.
+ This function should take one parameter, the response to the
+ capability command, and should return the command to switch on
+ STARTTLS if the server supports STARTTLS, and nil otherwise."
+ (let ((type (plist-get parameters :type))
+ (return-list (plist-get parameters :return-list)))
+ (if (and (not return-list)
+ (or (eq type 'plain)
+ (and (memq type '(nil network))
+ (not (and (plist-get parameters :success)
+ (plist-get parameters :capability-command))))))
+ ;; The simplest case is equivalent to `open-network-stream'.
+ (open-network-stream name buffer host service)
+ ;; For everything else, refer to proto-stream-open-*.
+ (unless (plist-get parameters :end-of-command)
+ (setq parameters (append '(:end-of-command "\r\n") parameters)))
+ (let* ((connection-function
+ (cond
+ ((eq type 'plain) 'proto-stream-open-plain)
+ ((memq type '(nil network starttls))
+ 'proto-stream-open-starttls)
+ ((memq type '(tls ssl)) 'proto-stream-open-tls)
+ ((eq type 'shell) 'proto-stream-open-shell)
+ (t (error "Invalid connection type %s" type))))
+ (result (funcall connection-function
+ name buffer host service parameters)))
+ (if return-list
+ (list (car result)
+ :greeting (nth 1 result)
+ :capabilities (nth 2 result)
+ :type (nth 3 result))
+ (car result))))))
+
+(defun proto-stream-open-plain (name buffer host service parameters)
+ (let ((start (with-current-buffer buffer (point)))
+ (stream (open-network-stream name buffer host service)))
+ (list stream
+ (proto-stream-get-response stream start
+ (plist-get parameters :end-of-command))
+ nil
+ 'plain)))
+
+(defun proto-stream-open-starttls (name buffer host service parameters)