lib-imap-client: Support sending IMAP ID command including unique x-session-ext-id

imapc: Change auth_failed boolean to more specific auth_failed_state Since we now rely on auth_failed_state being initialized to zero, explicitly set IMAPC_COMMAND_STATE_OK to be defined as 0.

imapc: Fix infinite reconnection when server keeps sending corrupted state When corrupted state was found, imapc_client_mailbox_reconnect() is called to reconnect. This call skipped the normal "is it safe to reconnect?" checks causing potentially infinite reconnections.

lib-imap-client: Avoid infinite reconnection loops when retrying command fails reconnect_command_count wasn't calculated correctly, because the SELECT and potentially other following sync commands weren't included in it.

quota: Add imapc backend This allows using imapc storage with imapc quota. The quota acts as read-only, so it's used only when the current quota usage is explicitly asked. The quota can be looked up using either a mailbox name or quota root name. By default INBOX's quota is looked up. If there are multiple quota roots returned for the mailbox, only the first quota root returned by the QUOTAROOT reply is used.

imapc: Make sure client is logged in when checking capabilities Especially with imapc_features=delay-login the capability could have been looked at before the client was even connected.

lib-imap-client: Add unit test Initially this tests some connection and reconnection problems.

lib-imap-client: Disconnection during LOGIN should still have state=disconnected It's not an authentication failure, which would imply that the user or password was wrong.

lib-imap-client: Call the public login callback exactly once. Previously it was also called only once, as long as there were only a single imap connection. (The current imapc code wouldn't create more than one connection.) It was a bit confusing what the expectation was, so now the callback is never called more than once.

lib-imap-client: Change connect_retry_interval_secs to _msecs This allows caller to provide better precision.

imapc: Use IMAPC_COMMAND_STATE_AUTH_FAILED to indicate auth failure

global: Fix imapc_client_login usage

lib-imap-client: Add login_callback setter This way it can be set before actually calling login which might happen some time later.

lib-imap-client: Make retry count and interval configurable

imapc: Use LOGOUT to cleanly disconnect from server. This makes it clearer in the remote server's logs whether the disconnection was intentional or not. Use a hardcoded 5 second timeout for LOGOUT. It should be enough time for the server to finish sending the tagged reply.

lib-imap-client: invoke state change callback on "authentication success"

lib-imap-client: add callback to notify consumers about state changes Add a callback to notify imapc users about failures. Currently, the only failure defined is "authentication failed".

imapc: Added imapc_max_line_length to limit maximum memory usage. The default is still unlimited, but this should be set to something smaller for untrusted servers.

imapc: Added support for PROXYAUTH command by setting imapc_features = proxyauth This can be useful when talking to Sun/Oracle IMAP server, which wants you to use LOGIN+PROXYAUTH to perform master user logins, instead of supporting the standard SASL PLAIN authentication.

Changed type of internet port values to in_port_t everywhere. Created special SET_IN_PORT setting type for internet port values. Created net_str2port() for parsing internet port values. Removed several atoi() invocations in the process.

imapc: Don't write SEARCH YOUNGER/OLDER queries if server doesn't support WITHIN extension

lib-imap-client: If we get disconnected and reconnect, log it as warning instead of as error.

imapc: Added throttling settings to imapc_features=throttle:a:b:c This change could be reverted once good settings are found.

imapc: Added imapc_features=search support for sending SEARCH commands. Currently requires the remote server to support ESEARCH (but this would be easy to avoid). This is only minimally tested for now, so bugs may exist (especially related to sub-queries).

lib-imap-client: Added imapc_command_get_tag()

imapc: Added imapc_sasl_mechanisms setting The first supported SASL mechanism is used, otherwise the login fails entirely.

imapc: If connection isn't in selected state when deleting mailbox, don't try to UNSELECT it.

imapc: Abort pending commands before any deinitialization to avoid crashes.

lib-imap-client: Added support for UNSELECT capability.

lib-imap-client: Connect and command timeouts are now configurable. Also use the same connect timeout for the DNS lookup's timeout.

Added ssl_client_ca_file to specify the CA certs as a file instead of as a dir. This is required for Redhat-based systems where there isn't a CA directory like in Debian/Ubuntu.

imapc: Added IMAPC_DEFAULT_MAX_IDLE_TIME macro.

lib-imap-client: Added support for NAMESPACE capability Required by previous imapc commit

imapc: Added imapc_max_idle_time setting to force activity on connection. Reducing this from the default 29 minutes should help when there's a stateful firewall between imapc and the backend server.

imapc: Added X-GM-EXT-1 and CONDSTORE to capabilities.

imapc: Pass ssl_crypto_device setting to lib-ssl-iostream.

Compile fixes.

imapc: Added imapc_ssl_verify setting.

imapc: Initial support for automatically reconnecting to remote server.

imapc: Removed unused "stop now" functionality.

imapc: Changed mailbox opening API to be more extensible.

imapc: Command sending API changed to be more extensible.

imapc: Changed imapc_client_mailbox_cmd() parameter order to be same as in _cmdf().

Moved imapc-client into its own lib-imap-client library.