1 files changed, 1040 insertions, 0 deletions

diff --git a/src/imap/imap-fetch.c b/src/imap/imap-fetch.c
new file mode 100644
index 0000000..db811f7
--- /dev/null
+++ b/src/imap/imap-fetch.c
@@ -0,0 +1,1040 @@
+/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */
+
+#include "imap-common.h"
+#include "array.h"
+#include "buffer.h"
+#include "istream.h"
+#include "ostream.h"
+#include "str.h"
+#include "message-size.h"
+#include "imap-date.h"
+#include "imap-utf7.h"
+#include "mail-search-build.h"
+#include "imap-commands.h"
+#include "imap-quote.h"
+#include "imap-fetch.h"
+#include "imap-util.h"
+
+#include <ctype.h>
+
+#define BODY_NIL_REPLY \
+	"\"text\" \"plain\" NIL NIL NIL \"7bit\" 0 0"
+#define ENVELOPE_NIL_REPLY \
+	"(NIL NIL NIL NIL NIL NIL NIL NIL NIL NIL)"
+
+static ARRAY(struct imap_fetch_handler) fetch_handlers;
+
+static int imap_fetch_handler_cmp(const struct imap_fetch_handler *h1,
+				  const struct imap_fetch_handler *h2)
+{
+	return strcmp(h1->name, h2->name);
+}
+
+void imap_fetch_handlers_register(const struct imap_fetch_handler *handlers,
+				  size_t count)
+{
+	array_append(&fetch_handlers, handlers, count);
+	array_sort(&fetch_handlers, imap_fetch_handler_cmp);
+}
+
+void imap_fetch_handler_unregister(const char *name)
+{
+	const struct imap_fetch_handler *handler, *first_handler;
+
+	first_handler = array_front(&fetch_handlers);
+	handler = imap_fetch_handler_lookup(name);
+	i_assert(handler != NULL);
+	array_delete(&fetch_handlers, handler - first_handler, 1);
+}
+
+static int
+imap_fetch_handler_bsearch(const char *name, const struct imap_fetch_handler *h)
+{
+	return strcmp(name, h->name);
+}
+
+const struct imap_fetch_handler *imap_fetch_handler_lookup(const char *name)
+{
+	return array_bsearch(&fetch_handlers, name, imap_fetch_handler_bsearch);
+}
+
+bool imap_fetch_init_handler(struct imap_fetch_init_context *init_ctx)
+{
+	const struct imap_fetch_handler *handler;
+	const char *lookup_name, *p;
+
+	for (p = init_ctx->name; i_isalnum(*p) || *p == '-'; p++) ;
+	lookup_name = t_strdup_until(init_ctx->name, p);
+
+	handler = array_bsearch(&fetch_handlers, lookup_name,
+				imap_fetch_handler_bsearch);
+	if (handler == NULL) {
+		init_ctx->error = t_strdup_printf("Unknown parameter: %s",
+						  init_ctx->name);
+		return FALSE;
+	}
+	if (!handler->init(init_ctx)) {
+		i_assert(init_ctx->error != NULL);
+		return FALSE;
+	}
+	return TRUE;
+}
+
+void imap_fetch_init_nofail_handler(struct imap_fetch_context *ctx,
+				    bool (*init)(struct imap_fetch_init_context *))
+{
+	struct imap_fetch_init_context init_ctx;
+
+	i_zero(&init_ctx);
+	init_ctx.fetch_ctx = ctx;
+	init_ctx.pool = ctx->ctx_pool;
+
+	if (!init(&init_ctx))
+		i_unreached();
+}
+
+int imap_fetch_att_list_parse(struct client *client, pool_t pool,
+			      const struct imap_arg *list,
+			      struct imap_fetch_context **fetch_ctx_r,
+			      const char **client_error_r)
+{
+	struct imap_fetch_init_context init_ctx;
+	const char *str;
+
+	i_zero(&init_ctx);
+	init_ctx.fetch_ctx = imap_fetch_alloc(client, pool, "NOTIFY");
+	init_ctx.pool = pool;
+	init_ctx.args = list;
+
+	while (imap_arg_get_atom(init_ctx.args, &str)) {
+		init_ctx.name = t_str_ucase(str);
+		init_ctx.args++;
+		if (!imap_fetch_init_handler(&init_ctx)) {
+			*client_error_r = t_strconcat("Invalid fetch-att list: ",
+						      init_ctx.error, NULL);
+			imap_fetch_free(&init_ctx.fetch_ctx);
+			return -1;
+		}
+	}
+	if (!IMAP_ARG_IS_EOL(init_ctx.args)) {
+		*client_error_r = "fetch-att list contains non-atoms.";
+		imap_fetch_free(&init_ctx.fetch_ctx);
+		return -1;
+	}
+	*fetch_ctx_r = init_ctx.fetch_ctx;
+	return 0;
+}
+
+struct imap_fetch_context *
+imap_fetch_alloc(struct client *client, pool_t pool, const char *reason)
+{
+	struct imap_fetch_context *ctx;
+
+	ctx = p_new(pool, struct imap_fetch_context, 1);
+	ctx->client = client;
+	ctx->ctx_pool = pool;
+	ctx->reason = p_strdup(pool, reason);
+	pool_ref(pool);
+
+	p_array_init(&ctx->all_headers, pool, 64);
+	p_array_init(&ctx->handlers, pool, 16);
+	p_array_init(&ctx->tmp_keywords, pool,
+		     client->keywords.announce_count + 8);
+	return ctx;
+}
+
+#undef imap_fetch_add_handler
+void imap_fetch_add_handler(struct imap_fetch_init_context *ctx,
+			    enum imap_fetch_handler_flags flags,
+			    const char *nil_reply,
+			    imap_fetch_handler_t *handler, void *context)
+{
+	/* partially because of broken clients, but also partially because
+	   it potentially can make client implementations faster, we have a
+	   buffered parameter which basically means that the handler promises
+	   to write the output in fetch_ctx->state.cur_str. The cur_str is then
+	   sent to client before calling any non-buffered handlers.
+
+	   We try to keep the handler registration order the same as the
+	   client requested them. This is especially useful to get UID
+	   returned first, which some clients rely on..
+	*/
+	const struct imap_fetch_context_handler *ctx_handler;
+	struct imap_fetch_context_handler h;
+
+	if (context == NULL) {
+		/* don't allow duplicate handlers */
+		array_foreach(&ctx->fetch_ctx->handlers, ctx_handler) {
+			if (ctx_handler->handler == handler &&
+			    ctx_handler->context == NULL)
+				return;
+		}
+	}
+
+	i_zero(&h);
+	h.handler = handler;
+	h.context = context;
+	h.buffered = (flags & IMAP_FETCH_HANDLER_FLAG_BUFFERED) != 0;
+	h.want_deinit = (flags & IMAP_FETCH_HANDLER_FLAG_WANT_DEINIT) != 0;
+	h.name = p_strdup(ctx->pool, ctx->name);
+	h.nil_reply = p_strdup(ctx->pool, nil_reply);
+
+	if (!h.buffered)
+		array_push_back(&ctx->fetch_ctx->handlers, &h);
+	else {
+		array_insert(&ctx->fetch_ctx->handlers,
+			     ctx->fetch_ctx->buffered_handlers_count, &h, 1);
+                ctx->fetch_ctx->buffered_handlers_count++;
+	}
+}
+
+static void
+expunges_drop_known(struct mailbox *box,
+		    const struct imap_fetch_qresync_args *qresync_args,
+		    struct mailbox_transaction_context *trans,
+		    ARRAY_TYPE(seq_range) *expunged_uids)
+{
+	struct mailbox_status status;
+	struct mail *mail;
+	const uint32_t *seqs, *uids;
+	unsigned int i, count;
+
+	seqs = array_get(qresync_args->qresync_sample_seqset, &count);
+	uids = array_front(qresync_args->qresync_sample_uidset);
+	i_assert(array_count(qresync_args->qresync_sample_uidset) == count);
+	i_assert(count > 0);
+
+	mailbox_get_open_status(box, STATUS_MESSAGES, &status);
+	mail = mail_alloc(trans, 0, NULL);
+
+	/* FIXME: we could do removals from the middle as well */
+	for (i = 0; i < count && seqs[i] <= status.messages; i++) {
+		mail_set_seq(mail, seqs[i]);
+		if (uids[i] != mail->uid)
+			break;
+	}
+	if (i > 0)
+		seq_range_array_remove_range(expunged_uids, 1, uids[i-1]);
+	mail_free(&mail);
+}
+
+static int
+get_expunges_fallback(struct mailbox *box,
+		      const struct imap_fetch_qresync_args *qresync_args,
+		      const ARRAY_TYPE(seq_range) *uid_filter_arr,
+		      ARRAY_TYPE(seq_range) *expunged_uids)
+{
+	struct mailbox_transaction_context *trans;
+	struct mail_search_args *search_args;
+	struct mail_search_context *search_ctx;
+	struct mail *mail;
+	const struct seq_range *uid_filter;
+	struct mailbox_status status;
+	unsigned int i, count;
+	uint32_t next_uid;
+	int ret = 0;
+
+	uid_filter = array_get(uid_filter_arr, &count);
+	i_assert(count > 0);
+	i = 0;
+	next_uid = uid_filter[0].seq1;
+
+	/* search UIDs only in given range */
+	search_args = mail_search_build_init();
+	search_args->args = p_new(search_args->pool, struct mail_search_arg, 1);
+	search_args->args->type = SEARCH_UIDSET;
+	p_array_init(&search_args->args->value.seqset, search_args->pool, count);
+	array_append_array(&search_args->args->value.seqset, uid_filter_arr);
+
+	trans = mailbox_transaction_begin(box, 0, "FETCH send VANISHED");
+	search_ctx = mailbox_search_init(trans, search_args, NULL, 0, NULL);
+	mail_search_args_unref(&search_args);
+
+	while (mailbox_search_next(search_ctx, &mail)) {
+		if (mail->uid == next_uid) {
+			if (next_uid < uid_filter[i].seq2)
+				next_uid++;
+			else if (++i < count)
+				next_uid = uid_filter[i].seq1;
+			else
+				break;
+		} else {
+			/* next_uid .. mail->uid-1 are expunged */
+			i_assert(mail->uid > next_uid);
+			while (mail->uid > uid_filter[i].seq2) {
+				seq_range_array_add_range(expunged_uids,
+							  next_uid,
+							  uid_filter[i].seq2);
+				i++;
+				i_assert(i < count);
+				next_uid = uid_filter[i].seq1;
+			}
+			if (next_uid != mail->uid) {
+				seq_range_array_add_range(expunged_uids,
+							  next_uid,
+							  mail->uid - 1);
+			}
+			if (uid_filter[i].seq2 != mail->uid)
+				next_uid = mail->uid + 1;
+			else if (++i < count)
+				next_uid = uid_filter[i].seq1;
+			else
+				break;
+		}
+	}
+	if (i < count) {
+		i_assert(next_uid <= uid_filter[i].seq2);
+		seq_range_array_add_range(expunged_uids, next_uid,
+					  uid_filter[i].seq2);
+		i++;
+	}
+	for (; i < count; i++) {
+		seq_range_array_add_range(expunged_uids, uid_filter[i].seq1,
+					  uid_filter[i].seq2);
+	}
+
+	mailbox_get_open_status(box, STATUS_UIDNEXT, &status);
+	seq_range_array_remove_range(expunged_uids, status.uidnext,
+				     (uint32_t)-1);
+
+	if (mailbox_search_deinit(&search_ctx) < 0)
+		ret = -1;
+
+	if (ret == 0 && qresync_args->qresync_sample_seqset != NULL &&
+	    array_is_created(qresync_args->qresync_sample_seqset))
+		expunges_drop_known(box, qresync_args, trans, expunged_uids);
+
+	(void)mailbox_transaction_commit(&trans);
+	return ret;
+}
+
+int imap_fetch_send_vanished(struct client *client, struct mailbox *box,
+			     const struct mail_search_args *search_args,
+			     const struct imap_fetch_qresync_args *qresync_args)
+{
+	const struct mail_search_arg *uidarg = search_args->args;
+	const struct mail_search_arg *modseqarg = uidarg->next;
+	const ARRAY_TYPE(seq_range) *uid_filter;
+	uint64_t modseq;
+	ARRAY_TYPE(seq_range) expunged_uids_range;
+	string_t *str;
+	int ret = 0;
+
+	i_assert(uidarg->type == SEARCH_UIDSET);
+	i_assert(modseqarg->type == SEARCH_MODSEQ);
+
+	uid_filter = &uidarg->value.seqset;
+	modseq = modseqarg->value.modseq->modseq - 1;
+
+	i_array_init(&expunged_uids_range, array_count(uid_filter));
+	if (!mailbox_get_expunged_uids(box, modseq, uid_filter, &expunged_uids_range)) {
+		/* return all expunged UIDs */
+		if (get_expunges_fallback(box, qresync_args, uid_filter,
+					  &expunged_uids_range) < 0) {
+			array_clear(&expunged_uids_range);
+			ret = -1;
+		}
+	}
+	if (array_count(&expunged_uids_range) > 0) {
+		str = str_new(default_pool, 128);
+		str_append(str, "* VANISHED (EARLIER) ");
+		imap_write_seq_range(str, &expunged_uids_range);
+		str_append(str, "\r\n");
+		o_stream_nsend(client->output, str_data(str), str_len(str));
+		str_free(&str);
+	}
+	array_free(&expunged_uids_range);
+	return ret;
+}
+
+static void imap_fetch_init(struct imap_fetch_context *ctx)
+{
+	if (ctx->initialized)
+		return;
+	ctx->initialized = TRUE;
+
+	if (ctx->flags_update_seen && !ctx->flags_have_handler) {
+		ctx->flags_show_only_seen_changes = TRUE;
+		imap_fetch_init_nofail_handler(ctx, imap_fetch_flags_init);
+	}
+	if ((ctx->fetch_data &
+	     (MAIL_FETCH_STREAM_HEADER | MAIL_FETCH_STREAM_BODY)) != 0)
+		ctx->fetch_data |= MAIL_FETCH_NUL_STATE;
+}
+
+void imap_fetch_begin(struct imap_fetch_context *ctx, struct mailbox *box,
+		      struct mail_search_args *search_args)
+{
+	enum mailbox_transaction_flags trans_flags =
+		MAILBOX_TRANSACTION_FLAG_REFRESH;
+	struct mailbox_header_lookup_ctx *wanted_headers = NULL;
+	const char *const *headers;
+
+	i_assert(!ctx->state.fetching);
+
+        imap_fetch_init(ctx);
+        i_zero(&ctx->state);
+
+	if (array_count(&ctx->all_headers) > 0 &&
+	    ((ctx->fetch_data & (MAIL_FETCH_STREAM_HEADER |
+				 MAIL_FETCH_STREAM_BODY)) == 0)) {
+		array_append_zero(&ctx->all_headers);
+
+		headers = array_front(&ctx->all_headers);
+		wanted_headers = mailbox_header_lookup_init(box, headers);
+		array_pop_back(&ctx->all_headers);
+	}
+
+	if (ctx->flags_update_seen) {
+		/* Hide the implicit \Seen flag addition. Otherwise a separate
+		   untagged FETCH FLAGS (\Seen) would be sent on top of the
+		   one FLAGS (\Seen) already added in the main FETCH reply.
+
+		   We don't set this always, because some plugins might want
+		   to do their own flag changes which we don't want hidden.
+		   (Of course this isn't perfect since if implicit \Seen flags
+		   are added, other flag changes are also hidden.) */
+		trans_flags |= MAILBOX_TRANSACTION_FLAG_HIDE;
+	}
+	ctx->state.trans = mailbox_transaction_begin(box, trans_flags,
+						     ctx->reason);
+
+	mail_search_args_init(search_args, box, TRUE,
+			      &ctx->client->search_saved_uidset);
+	ctx->state.search_ctx =
+		mailbox_search_init(ctx->state.trans, search_args, NULL,
+				    ctx->fetch_data, wanted_headers);
+	ctx->state.cur_str = str_new(default_pool, 8192);
+	ctx->state.fetching = TRUE;
+
+	mailbox_header_lookup_unref(&wanted_headers);
+}
+
+static int imap_fetch_flush_buffer(struct imap_fetch_context *ctx)
+{
+	const unsigned char *data;
+	size_t len;
+
+	data = str_data(ctx->state.cur_str);
+	len = str_len(ctx->state.cur_str);
+
+	if (len == 0)
+		return 0;
+
+	/* there's an extra space at the end if we added any fetch items
+	   to buffer */
+	if (data[len-1] == ' ') {
+		len--;
+		ctx->state.cur_first = FALSE;
+	}
+	ctx->state.line_partial = TRUE;
+
+	if (o_stream_send(ctx->client->output, data, len) < 0)
+		return -1;
+
+	str_truncate(ctx->state.cur_str, 0);
+	return 0;
+}
+
+static int imap_fetch_send_nil_reply(struct imap_fetch_context *ctx)
+{
+	const struct imap_fetch_context_handler *handler;
+
+	if (!ctx->state.cur_first)
+		str_append_c(ctx->state.cur_str, ' ');
+
+	handler = array_idx(&ctx->handlers, ctx->state.cur_handler);
+	str_printfa(ctx->state.cur_str, "%s %s ",
+		    handler->name, handler->nil_reply);
+
+	if (!handler->buffered) {
+		if (imap_fetch_flush_buffer(ctx) < 0)
+			return -1;
+	}
+	return 0;
+}
+
+static void imap_fetch_fix_empty_reply(struct imap_fetch_context *ctx)
+{
+	if (ctx->state.line_partial && ctx->state.cur_first) {
+		/* we've flushed an empty "FETCH (" reply so
+		   far. we can't take it back, but RFC 3501
+		   doesn't allow returning empty "FETCH ()"
+		   either, so just add the current message's
+		   UID there. */
+		str_printfa(ctx->state.cur_str, "UID %u ",
+			    ctx->state.cur_mail->uid);
+	}
+}
+
+static bool imap_fetch_cur_failed(struct imap_fetch_context *ctx)
+{
+	ctx->failures = TRUE;
+	if (ctx->client->set->parsed_fetch_failure ==
+	    IMAP_CLIENT_FETCH_FAILURE_DISCONNECT_IMMEDIATELY)
+		return FALSE;
+
+	if (!array_is_created(&ctx->fetch_failed_uids))
+		p_array_init(&ctx->fetch_failed_uids, ctx->ctx_pool, 8);
+	seq_range_array_add(&ctx->fetch_failed_uids, ctx->state.cur_mail->uid);
+
+	if (ctx->error == MAIL_ERROR_NONE) {
+		/* preserve the first error, since it may change in storage. */
+		ctx->errstr = p_strdup(ctx->ctx_pool,
+			mailbox_get_last_error(ctx->state.cur_mail->box, &ctx->error));
+	}
+	return TRUE;
+}
+
+static int imap_fetch_more_int(struct imap_fetch_context *ctx, bool cancel)
+{
+	struct imap_fetch_state *state = &ctx->state;
+	struct client *client = ctx->client;
+	const struct imap_fetch_context_handler *handlers;
+	unsigned int count;
+	int ret;
+
+	if (state->cont_handler != NULL) {
+		ret = state->cont_handler(ctx);
+		if (ret == 0)
+			return 0;
+
+		if (ret < 0) {
+			if (client->output->closed)
+				return -1;
+
+			if (state->cur_mail->expunged) {
+				/* not an error, just lost it. */
+				state->skipped_expunged_msgs = TRUE;
+				if (imap_fetch_send_nil_reply(ctx) < 0)
+					return -1;
+			} else {
+				if (!imap_fetch_cur_failed(ctx))
+					return -1;
+			}
+		}
+
+		state->cont_handler = NULL;
+                state->cur_handler++;
+		if (state->cur_input != NULL)
+			i_stream_unref(&state->cur_input);
+	}
+
+	handlers = array_get(&ctx->handlers, &count);
+	for (;;) {
+		if (o_stream_get_buffer_used_size(client->output) >=
+		    CLIENT_OUTPUT_OPTIMAL_SIZE) {
+			ret = o_stream_flush(client->output);
+			if (ret <= 0)
+				return ret;
+		}
+
+		if (state->cur_mail == NULL) {
+			if (cancel)
+				return 1;
+
+			if (!mailbox_search_next(state->search_ctx,
+						 &state->cur_mail))
+				break;
+
+			str_printfa(state->cur_str, "* %u FETCH (",
+				    state->cur_mail->seq);
+			ctx->fetched_mails_count++;
+			state->cur_first = TRUE;
+			state->cur_str_prefix_size = str_len(state->cur_str);
+			i_assert(!state->line_partial);
+		}
+
+		for (; state->cur_handler < count; state->cur_handler++) {
+			if (str_len(state->cur_str) > 0 &&
+			    !handlers[state->cur_handler].buffered) {
+				/* first non-buffered handler.
+				   flush the buffer. */
+				if (imap_fetch_flush_buffer(ctx) < 0)
+					return -1;
+			}
+
+			i_assert(state->cur_input == NULL);
+			T_BEGIN {
+				const struct imap_fetch_context_handler *h =
+					&handlers[state->cur_handler];
+
+				ret = h->handler(ctx, state->cur_mail,
+						 h->context);
+			} T_END;
+
+			if (ret == 0)
+				return 0;
+
+			if (ret < 0) {
+				if (state->cur_mail->expunged) {
+					/* not an error, just lost it. */
+					state->skipped_expunged_msgs = TRUE;
+					if (imap_fetch_send_nil_reply(ctx) < 0)
+						return -1;
+				} else {
+					i_assert(ret < 0 ||
+						 state->cont_handler != NULL);
+					if (!imap_fetch_cur_failed(ctx))
+						return -1;
+				}
+			}
+
+			state->cont_handler = NULL;
+			if (state->cur_input != NULL)
+				i_stream_unref(&state->cur_input);
+		}
+
+		imap_fetch_fix_empty_reply(ctx);
+		if (str_len(state->cur_str) > 0 &&
+		    (state->line_partial ||
+		     str_len(state->cur_str) != state->cur_str_prefix_size)) {
+			/* no non-buffered handlers */
+			if (imap_fetch_flush_buffer(ctx) < 0)
+				return -1;
+		}
+
+		if (state->line_partial)
+			o_stream_nsend(client->output, ")\r\n", 3);
+		client->last_output = ioloop_time;
+
+		state->cur_mail = NULL;
+		state->cur_handler = 0;
+		state->line_partial = FALSE;
+	}
+
+	return ctx->failures ? -1 : 1;
+}
+
+int imap_fetch_more(struct imap_fetch_context *ctx,
+		    struct client_command_context *cmd)
+{
+	int ret;
+
+	i_assert(ctx->client->output_cmd_lock == NULL ||
+		 ctx->client->output_cmd_lock == cmd);
+
+	ret = imap_fetch_more_int(ctx, cmd->cancel);
+	if (ret < 0)
+		ctx->state.failed = TRUE;
+	if (ctx->state.line_partial) {
+		/* nothing can be sent until FETCH is finished */
+		ctx->client->output_cmd_lock = cmd;
+	}
+	if (cmd->cancel && ctx->client->output_cmd_lock != NULL) {
+		/* canceling didn't really work. we must not output
+		   anything anymore. */
+		if (!ctx->client->destroyed)
+			client_disconnect(ctx->client, "Failed to cancel FETCH");
+		ctx->client->output_cmd_lock = NULL;
+	}
+	return ret;
+}
+
+int imap_fetch_more_no_lock_update(struct imap_fetch_context *ctx)
+{
+	int ret;
+
+	ret = imap_fetch_more_int(ctx, FALSE);
+	if (ret < 0) {
+		ctx->state.failed = TRUE;
+		if (ctx->state.line_partial) {
+			/* we can't send any more replies to client, because
+			   the FETCH reply wasn't fully sent. */
+			client_disconnect(ctx->client,
+				"NOTIFY failed in the middle of FETCH reply");
+		}
+	}
+	return ret;
+}
+
+int imap_fetch_end(struct imap_fetch_context *ctx)
+{
+	struct imap_fetch_state *state = &ctx->state;
+
+	if (ctx->state.fetching) {
+		ctx->state.fetching = FALSE;
+		if (state->line_partial) {
+			imap_fetch_fix_empty_reply(ctx);
+			if (imap_fetch_flush_buffer(ctx) < 0)
+				state->failed = TRUE;
+			if (o_stream_send(ctx->client->output, ")\r\n", 3) < 0)
+				state->failed = TRUE;
+		}
+	}
+	ctx->client->output_cmd_lock = NULL;
+
+	str_free(&state->cur_str);
+
+	i_stream_unref(&state->cur_input);
+
+	if (state->search_ctx != NULL) {
+		if (mailbox_search_deinit(&state->search_ctx) < 0)
+			state->failed = TRUE;
+	}
+
+	if (state->trans != NULL) {
+		/* even if something failed, we want to commit changes to
+		   cache, as well as possible \Seen flag changes for FETCH
+		   replies we returned so far. */
+		if (mailbox_transaction_commit(&state->trans) < 0)
+			state->failed = TRUE;
+	}
+	return state->failed ? -1 : 0;
+}
+
+void imap_fetch_free(struct imap_fetch_context **_ctx)
+{
+	struct imap_fetch_context *ctx = *_ctx;
+	const struct imap_fetch_context_handler *handler;
+
+	*_ctx = NULL;
+
+	(void)imap_fetch_end(ctx);
+
+	array_foreach(&ctx->handlers, handler) {
+		if (handler->want_deinit)
+			handler->handler(ctx, NULL, handler->context);
+	}
+	pool_unref(&ctx->ctx_pool);
+}
+
+static int fetch_body(struct imap_fetch_context *ctx, struct mail *mail,
+		      void *context ATTR_UNUSED)
+{
+	const char *body;
+
+	if (mail_get_special(mail, MAIL_FETCH_IMAP_BODY, &body) < 0)
+		return -1;
+
+	if (ctx->state.cur_first)
+		ctx->state.cur_first = FALSE;
+	else {
+		if (o_stream_send(ctx->client->output, " ", 1) < 0)
+			return -1;
+	}
+
+	if (o_stream_send(ctx->client->output, "BODY (", 6) < 0 ||
+	    o_stream_send_str(ctx->client->output, body) < 0 ||
+	    o_stream_send(ctx->client->output, ")", 1) < 0)
+		return -1;
+	return 1;
+}
+
+static bool fetch_body_init(struct imap_fetch_init_context *ctx)
+{
+	if (ctx->name[4] == '\0') {
+		ctx->fetch_ctx->fetch_data |= MAIL_FETCH_IMAP_BODY;
+		imap_fetch_add_handler(ctx, 0, "("BODY_NIL_REPLY")",
+				       fetch_body, NULL);
+		return TRUE;
+	}
+	return imap_fetch_body_section_init(ctx);
+}
+
+static int fetch_bodystructure(struct imap_fetch_context *ctx,
+			       struct mail *mail, void *context ATTR_UNUSED)
+{
+	const char *bodystructure;
+
+	if (mail_get_special(mail, MAIL_FETCH_IMAP_BODYSTRUCTURE,
+			     &bodystructure) < 0)
+		return -1;
+
+	if (ctx->state.cur_first)
+		ctx->state.cur_first = FALSE;
+	else {
+		if (o_stream_send(ctx->client->output, " ", 1) < 0)
+			return -1;
+	}
+
+	if (o_stream_send(ctx->client->output, "BODYSTRUCTURE (", 15) < 0 ||
+	    o_stream_send_str(ctx->client->output, bodystructure) < 0 ||
+	    o_stream_send(ctx->client->output, ")", 1) < 0)
+		return -1;
+
+	return 1;
+}
+
+static bool fetch_bodystructure_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_IMAP_BODYSTRUCTURE;
+	imap_fetch_add_handler(ctx, 0, "("BODY_NIL_REPLY" NIL NIL NIL NIL)",
+			       fetch_bodystructure, NULL);
+	return TRUE;
+}
+
+static int fetch_envelope(struct imap_fetch_context *ctx, struct mail *mail,
+			  void *context ATTR_UNUSED)
+{
+	const char *envelope;
+
+	if (mail_get_special(mail, MAIL_FETCH_IMAP_ENVELOPE, &envelope) < 0)
+		return -1;
+
+	if (ctx->state.cur_first)
+		ctx->state.cur_first = FALSE;
+	else {
+		if (o_stream_send(ctx->client->output, " ", 1) < 0)
+			return -1;
+	}
+
+	if (o_stream_send(ctx->client->output, "ENVELOPE (", 10) < 0 ||
+	    o_stream_send_str(ctx->client->output, envelope) < 0 ||
+	    o_stream_send(ctx->client->output, ")", 1) < 0)
+		return -1;
+	return 1;
+}
+
+static bool fetch_envelope_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_IMAP_ENVELOPE;
+	imap_fetch_add_handler(ctx, 0, ENVELOPE_NIL_REPLY,
+			       fetch_envelope, NULL);
+	return TRUE;
+}
+
+static int fetch_flags(struct imap_fetch_context *ctx, struct mail *mail,
+		       void *context ATTR_UNUSED)
+{
+	enum mail_flags flags;
+	const char *const *keywords;
+
+	flags = mail_get_flags(mail);
+	if (ctx->flags_update_seen && (flags & MAIL_SEEN) == 0 &&
+	    !mailbox_is_readonly(mail->box)) {
+		/* Add \Seen flag */
+		ctx->state.seen_flags_changed = TRUE;
+		flags |= MAIL_SEEN;
+		mail_update_flags(mail, MODIFY_ADD, MAIL_SEEN);
+	} else if (ctx->flags_show_only_seen_changes) {
+		return 1;
+	}
+
+	keywords = client_get_keyword_names(ctx->client, &ctx->tmp_keywords,
+			mail_get_keyword_indexes(mail));
+
+	str_append(ctx->state.cur_str, "FLAGS (");
+	imap_write_flags(ctx->state.cur_str, flags, keywords);
+	str_append(ctx->state.cur_str, ") ");
+	return 1;
+}
+
+bool imap_fetch_flags_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->flags_have_handler = TRUE;
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_FLAGS;
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       "()", fetch_flags, NULL);
+	return TRUE;
+}
+
+static int fetch_internaldate(struct imap_fetch_context *ctx, struct mail *mail,
+			      void *context ATTR_UNUSED)
+{
+	time_t date;
+
+	if (mail_get_received_date(mail, &date) < 0)
+		return -1;
+
+	str_printfa(ctx->state.cur_str, "INTERNALDATE \"%s\" ",
+		    imap_to_datetime(date));
+	return 1;
+}
+
+static bool fetch_internaldate_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_RECEIVED_DATE;
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       "\"01-Jan-1970 00:00:00 +0000\"",
+			       fetch_internaldate, NULL);
+	return TRUE;
+}
+
+static int fetch_modseq(struct imap_fetch_context *ctx, struct mail *mail,
+			void *context ATTR_UNUSED)
+{
+	uint64_t modseq;
+
+	modseq = mail_get_modseq(mail);
+	if (ctx->client->highest_fetch_modseq < modseq)
+		ctx->client->highest_fetch_modseq = modseq;
+	str_printfa(ctx->state.cur_str, "MODSEQ (%"PRIu64") ", modseq);
+	return 1;
+}
+
+bool imap_fetch_modseq_init(struct imap_fetch_init_context *ctx)
+{
+	if (ctx->fetch_ctx->client->nonpermanent_modseqs) {
+		ctx->error = "FETCH MODSEQ can't be used with non-permanent modseqs";
+		return FALSE;
+	}
+	client_enable(ctx->fetch_ctx->client, imap_feature_condstore);
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       NULL, fetch_modseq, NULL);
+	return TRUE;
+}
+
+static int fetch_uid(struct imap_fetch_context *ctx, struct mail *mail,
+		     void *context ATTR_UNUSED)
+{
+	str_printfa(ctx->state.cur_str, "UID %u ", mail->uid);
+	return 1;
+}
+
+bool imap_fetch_uid_init(struct imap_fetch_init_context *ctx)
+{
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       NULL, fetch_uid, NULL);
+	return TRUE;
+}
+
+static int imap_fetch_savedate(struct imap_fetch_context *ctx, struct mail *mail,
+			       void *context ATTR_UNUSED)
+{
+	time_t date;
+	int ret;
+
+	ret = mail_get_save_date(mail, &date);
+	if (ret < 0)
+		return -1;
+
+	if (ret == 0)
+		str_append(ctx->state.cur_str, "SAVEDATE NIL ");
+	else {
+		str_printfa(ctx->state.cur_str, "SAVEDATE \"%s\" ",
+			    imap_to_datetime(date));
+	}
+	return 1;
+}
+
+static bool imap_fetch_savedate_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_SAVE_DATE;
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       "NIL", imap_fetch_savedate, NULL);
+	return TRUE;
+}
+
+static int fetch_guid(struct imap_fetch_context *ctx, struct mail *mail,
+		      void *context ATTR_UNUSED)
+{
+	const char *value;
+
+	if (mail_get_special(mail, MAIL_FETCH_GUID, &value) < 0)
+		return -1;
+
+	str_append(ctx->state.cur_str, "X-GUID ");
+	imap_append_astring(ctx->state.cur_str, value);
+	str_append_c(ctx->state.cur_str, ' ');
+	return 1;
+}
+
+static bool fetch_guid_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_GUID;
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       "", fetch_guid, NULL);
+	return TRUE;
+}
+
+static int fetch_x_mailbox(struct imap_fetch_context *ctx, struct mail *mail,
+			   void *context ATTR_UNUSED)
+{
+	const char *name;
+	string_t *mutf7_name;
+
+	if (mail_get_special(mail, MAIL_FETCH_MAILBOX_NAME, &name) < 0) {
+		/* This can happen with virtual mailbox if the backend mail
+		   is expunged. */
+		return -1;
+	}
+
+	mutf7_name = t_str_new(strlen(name)*2);
+	if (imap_utf8_to_utf7(name, mutf7_name) < 0)
+		i_panic("FETCH: Mailbox name not UTF-8: %s", name);
+
+	str_append(ctx->state.cur_str, "X-MAILBOX ");
+	imap_append_astring(ctx->state.cur_str, str_c(mutf7_name));
+	str_append_c(ctx->state.cur_str, ' ');
+	return 1;
+}
+
+static bool fetch_x_mailbox_init(struct imap_fetch_init_context *ctx)
+{
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       NULL, fetch_x_mailbox, NULL);
+	return TRUE;
+}
+
+static int fetch_x_real_uid(struct imap_fetch_context *ctx, struct mail *mail,
+			    void *context ATTR_UNUSED)
+{
+	struct mail *real_mail;
+
+	if (mail_get_backend_mail(mail, &real_mail) < 0)
+		return -1;
+	str_printfa(ctx->state.cur_str, "X-REAL-UID %u ", real_mail->uid);
+	return 1;
+}
+
+static bool fetch_x_real_uid_init(struct imap_fetch_init_context *ctx)
+{
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       NULL, fetch_x_real_uid, NULL);
+	return TRUE;
+}
+
+static int fetch_x_savedate(struct imap_fetch_context *ctx, struct mail *mail,
+			    void *context ATTR_UNUSED)
+{
+	time_t date;
+
+	if (mail_get_save_date(mail, &date) < 0)
+		return -1;
+
+	str_printfa(ctx->state.cur_str, "X-SAVEDATE \"%s\" ",
+		    imap_to_datetime(date));
+	return 1;
+}
+
+static bool fetch_x_savedate_init(struct imap_fetch_init_context *ctx)
+{
+	ctx->fetch_ctx->fetch_data |= MAIL_FETCH_SAVE_DATE;
+	imap_fetch_add_handler(ctx, IMAP_FETCH_HANDLER_FLAG_BUFFERED,
+			       "\"01-Jan-1970 00:00:00 +0000\"",
+			       fetch_x_savedate, NULL);
+	return TRUE;
+}
+
+static const struct imap_fetch_handler
+imap_fetch_default_handlers[] = {
+	{ "BINARY", imap_fetch_binary_init },
+	{ "BODY", fetch_body_init },
+	{ "BODYSTRUCTURE", fetch_bodystructure_init },
+	{ "ENVELOPE", fetch_envelope_init },
+	{ "FLAGS", imap_fetch_flags_init },
+	{ "INTERNALDATE", fetch_internaldate_init },
+	{ "MODSEQ", imap_fetch_modseq_init },
+	{ "PREVIEW", imap_fetch_preview_init },
+	{ "RFC822", imap_fetch_rfc822_init },
+	{ "SNIPPET", imap_fetch_snippet_init },
+	{ "UID", imap_fetch_uid_init },
+	{ "SAVEDATE", imap_fetch_savedate_init },
+	{ "X-GUID", fetch_guid_init },
+	{ "X-MAILBOX", fetch_x_mailbox_init },
+	{ "X-REAL-UID", fetch_x_real_uid_init },
+	{ "X-SAVEDATE", fetch_x_savedate_init }
+};
+
+void imap_fetch_handlers_init(void)
+{
+	i_array_init(&fetch_handlers, 32);
+	imap_fetch_handlers_register(imap_fetch_default_handlers,
+				     N_ELEMENTS(imap_fetch_default_handlers));
+}
+
+void imap_fetch_handlers_deinit(void)
+{
+	array_free(&fetch_handlers);
+}