The output buffer was on the data stack, which leads to big trouble when the
buffer needs to grow in a deeper stack level.

lib-sieve: imap4flags extension: Fix binary corruption occurring when setflag/addflag/removeflag flag-list is a variable.

The original implementation checked the first operand for being a variable.
Obviously, when the assigned flag string is just a variable, this doesn't work.
This causes the flag list to be recognized erroneously as a variable flags
string. Fixed the problem by explicitly emitting an omitted operand when there
is no second argument for a setflag/addflag/removeflag.

Because the new byte code format is incompatible, the extension version is
bumped to 1.

This was caused by recent lib-smtp changes.
There is no envelope in IMAPSieve context, so the rcpt parameters are NULL, causing the segfault.

The session ID is now already added by Dovecot.

lib-sieve: vacation extension: Use the correct address for "From:" outgoing header when original envelope recipient is found.

Caused by earlier adjustments for Dovecot lib-smtp.
Copy-paste problem detected by Coverity.

It is a remnant from debugging.

Only calls that require space allocation are to be changed.

It erroneously applied another layer of MIME header encoding.
The problem is that existing Sieve scripts may rely on this behaviour; i.e. scripts may contain addresesses with literal UTF8 in the phrase part.
Therefore, this change allows both behaviors.

lib-sieve: util: rfc2822: Added rfc2822_header_write_address() which allows adding a header with one or more addresses.

It applies UTF8 encoding only when the address string somehow contains 8-bit characters.
Sieve addresses are supposed to have any UTF8 characters in the phase MIME-encoded, not literal 8-bit characters.
However, this has been allowed from the beginning, so disabling the old behavior may break existing installations.
This function allows supporting both options.

Also dropped the single-letter identifier for most fields to prevent conflicts with mail user variables; these were undocumented anyway.

A few were still omitted.

Cleanup performed with the following semantic patch:

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	i_stream_unref(&E);
	- }
	+ i_stream_unref(&E);

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	o_stream_unref(&E);
	- }
	+ o_stream_unref(&E);

Cleanup performed with the following semantic patch:

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	timeout_remove(&E);
	- }
	+ timeout_remove(&E);

Cleanup performed with the following semantic patch:

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	io_remove(&E);
	- }
	+ io_remove(&E);

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	io_remove_closed(&E);
	- }
	+ io_remove_closed(&E);

Error handling is delayed, so that we need to explicitly handle the error in Sieve.
This is now implemented by handling the error before executing the scritpt and placing the parsed address in struct sieve_script_env.

lib-sieve: Added sieve_script_env_init() to initialize struct sieve_script_env from struct mail_user.

Most code was put in an unnecessary else block.

If a home directory is given, it's assumed that it will be autocreated even
if it doesn't initially exist. Earlier the autocreation may have been done
by lib-storage as it created the mail root directory, but this no longer
happens.

The parent event doesn't really matter here, so NULL is used.

This follows the following commits in Dovecot:
lib-storage: Moved connection information in struct mail_user into separate struct mail_user_connection_data.
lib-storage: mail-user: Added more information about the client connection.

lib-sieve: vnd.dovecot.report extension: Fixed creation of "Original-Mail-From" and original "Original-Rcpt-To" headers.

Recent changes relating to lib-smtp caused the paths to have duplicate '<' '>'.

Now using struct smtp_address rather than sieve_address.
In some cases, struct message_address may prove to be more suitable, but this is the best fit for now.
Adjusted to the renamed fields in struct mail_deliver_context.

It doesn't serve a purpose either, since parsing "from" address from URI is not allowed for notify mailto.

lib-sieve: store action: Avoid NULL pointer dereference during rollback when transaction context is somehow unassigned.

This change matches the other transaction stages.
This will not currently happen though.
Reported by Coverity.

Otherwise the error status is overwritten.
Problem found by Coverity.

Used the stream's cur_header field, rather than the local variable.
Problem found by Coverity.

The merge_from_parent() function may not actually read anything, potentially leaving the stream buffer unassigned.
Problem found by Coverity.

This makes the implementation easier to understand and amend once Dovecot APIs changes.
This implicitly makes the implementation suitable for the new istream snapshot handling.

Added assertions on subtractions.
Restructured the code for clarity.
Added comments.

Ported Dovecot's istream-jsonstr for ManageSieve syntax.