Add basic XOAUTH2 support.

This still relies on an external script to obtain the resource access
token.  Since XOAUTH2 should be slowly going away, use the same
refresh_commands as with OAUTHBEARER.

Unlike OAUTHBEARER, XOAUTH2 must be explicitly added to the
$imap/smtp/pop_authenticators list.

To keep the shared functions simpler, convert them to use buffers.

RFC 7628 indicates that upon authentication failure the clients should
be sending an BASE 64 encoded '^a' ("AQ=="), to terminate the SASL
session, so change all the handlers to do that and read the following
response.  The RFC doesn't comment about a line terminator being
required, but I assume it is, so add that too.

1 files changed, 1 insertions, 1 deletions

diff --git a/account.h b/account.h
index 943da839..2eccb7f4 100644
--- a/account.h
+++ b/account.h
@@ -57,6 +57,6 @@ int mutt_account_getuser (ACCOUNT* account);
 int mutt_account_getlogin (ACCOUNT* account);
 int mutt_account_getpass (ACCOUNT* account);
 void mutt_account_unsetpass (ACCOUNT* account);
-char* mutt_account_getoauthbearer (ACCOUNT* account);
+int mutt_account_getoauthbearer (ACCOUNT* account, BUFFER *authbearer, int xoauth2);
 
 #endif /* _MUTT_ACCOUNT_H_ */