make driver_t::prepare_load_box() return the final options

... and make 'opts' private to the drivers.

src/driver.h

@@ -93,7 +93,6 @@ typedef struct store {
 	message_t *msgs; /* own */
 	int uidvalidity;
 	int uidnext; /* from SELECT responses */
-	uint opts; /* maybe preset? */
 	/* note that the following do _not_ reflect stats from msgs, but mailbox totals */
 	int count; /* # of messages */
 	int recent; /* # of recent messages - don't trust this beyond the initial read */
@@ -196,8 +195,8 @@ struct driver {
 
 	/* Invoked before load_box(), this informs the driver which operations (OP_*)
 	 * will be performed on the mailbox. The driver may extend the set by implicitly
-	 * needed or available operations. */
-	void (*prepare_load_box)( store_t *ctx, int opts );
+	 * needed or available operations. Returns this possibly extended set. */
+	int (*prepare_load_box)( store_t *ctx, int opts );
 
 	/* Load the message attributes needed to perform the requested operations.
 	 * Consider only messages with UIDs between minuid and maxuid (inclusive)

src/drv_imap.c

@@ -100,6 +100,7 @@ struct imap_store {
 	const char *prefix;
 	const char *name;
 	int ref_count;
+	uint opts;
 	enum { SST_BAD, SST_HALF, SST_GOOD } state;
 	/* trash folder's existence is not confirmed yet */
 	enum { TrashUnknown, TrashChecking, TrashKnown } trashnc;
@@ -2436,10 +2437,13 @@ imap_finish_delete_box( store_t *gctx ATTR_UNUSED )
 
 /******************* imap_load_box *******************/
 
-static void
+static int
 imap_prepare_load_box( store_t *gctx, int opts )
 {
-	gctx->opts = opts;
+	imap_store_t *ctx = (imap_store_t *)gctx;
+
+	ctx->opts = opts;
+	return opts;
 }
 
 enum { WantSize = 1, WantTuids = 2, WantMsgids = 4 };
@@ -2495,7 +2499,7 @@ imap_load_box( store_t *gctx, int minuid, int maxuid, int newuid, int seenuid, i
 				if (i != j)
 					bl += sprintf( buf + bl, ":%d", excs.data[i] );
 			}
-			imap_submit_load( ctx, buf, shifted_bit( ctx->gen.opts, OPEN_OLD_IDS, WantMsgids ), sts );
+			imap_submit_load( ctx, buf, shifted_bit( ctx->opts, OPEN_OLD_IDS, WantMsgids ), sts );
 		}
 		if (maxuid == INT_MAX)
 			maxuid = ctx->gen.uidnext - 1;
@@ -2505,12 +2509,12 @@ imap_load_box( store_t *gctx, int minuid, int maxuid, int newuid, int seenuid, i
 			ranges[0].last = maxuid;
 			ranges[0].flags = 0;
 			int nranges = 1;
-			if (ctx->gen.opts & (OPEN_OLD_SIZE | OPEN_NEW_SIZE))
-				imap_set_range( ranges, &nranges, shifted_bit( ctx->gen.opts, OPEN_OLD_SIZE, WantSize),
-				                                  shifted_bit( ctx->gen.opts, OPEN_NEW_SIZE, WantSize), seenuid );
-			if (ctx->gen.opts & OPEN_FIND)
+			if (ctx->opts & (OPEN_OLD_SIZE | OPEN_NEW_SIZE))
+				imap_set_range( ranges, &nranges, shifted_bit( ctx->opts, OPEN_OLD_SIZE, WantSize),
+				                                  shifted_bit( ctx->opts, OPEN_NEW_SIZE, WantSize), seenuid );
+			if (ctx->opts & OPEN_FIND)
 				imap_set_range( ranges, &nranges, 0, WantTuids, newuid - 1 );
-			if (ctx->gen.opts & OPEN_OLD_IDS)
+			if (ctx->opts & OPEN_OLD_IDS)
 				imap_set_range( ranges, &nranges, WantMsgids, 0, seenuid );
 			for (int r = 0; r < nranges; r++) {
 				sprintf( buf, "%d:%d", ranges[r].first, ranges[r].last );
@@ -2527,7 +2531,7 @@ imap_submit_load( imap_store_t *ctx, const char *buf, int flags, imap_cmd_refcou
 {
 	imap_exec( ctx, imap_refcounted_new_cmd( sts ), imap_refcounted_done_box,
 	           "UID FETCH %s (UID%s%s%s%s%s%s%s)", buf,
-	           (ctx->gen.opts & OPEN_FLAGS) ? " FLAGS" : "",
+	           (ctx->opts & OPEN_FLAGS) ? " FLAGS" : "",
 	           (flags & WantSize) ? " RFC822.SIZE" : "",
 	           (flags & (WantTuids | WantMsgids)) ? " BODY.PEEK[HEADER.FIELDS (" : "",
 	           (flags & WantTuids) ? "X-TUID" : "",

src/drv_maildir.c

@@ -69,6 +69,7 @@ typedef struct {
 
 typedef struct {
 	store_t gen;
+	uint opts;
 	int uvfd, uvok, nuid, is_inbox, fresh[3];
 	int minuid, maxuid, newuid, seenuid;
 	int_array_t excs;
@@ -1116,9 +1117,9 @@ maildir_scan( maildir_store_t *ctx, msg_t_array_alloc_t *msglist )
 				free( entry->base );
 				entry->base = nfstrndup( buf + bl + 4, fnl );
 			}
-			int want_size = (uid > ctx->seenuid) ? (ctx->gen.opts & OPEN_NEW_SIZE) : (ctx->gen.opts & OPEN_OLD_SIZE);
-			int want_tuid = ((ctx->gen.opts & OPEN_FIND) && uid >= ctx->newuid);
-			int want_msgid = ((ctx->gen.opts & OPEN_OLD_IDS) && uid <= ctx->seenuid);
+			int want_size = (uid > ctx->seenuid) ? (ctx->opts & OPEN_NEW_SIZE) : (ctx->opts & OPEN_OLD_SIZE);
+			int want_tuid = ((ctx->opts & OPEN_FIND) && uid >= ctx->newuid);
+			int want_msgid = ((ctx->opts & OPEN_OLD_IDS) && uid <= ctx->seenuid);
 			if (!want_size && !want_tuid && !want_msgid)
 				continue;
 			if (!fnl)
@@ -1201,7 +1202,7 @@ maildir_init_msg( maildir_store_t *ctx, maildir_message_t *msg, msg_t *entry )
 	memcpy( msg->gen.tuid, entry->tuid, TUIDL );
 	if (entry->recent)
 		msg->gen.status |= M_RECENT;
-	if (ctx->gen.opts & OPEN_FLAGS) {
+	if (ctx->opts & OPEN_FLAGS) {
 		msg->gen.status |= M_FLAGS;
 		msg->gen.flags = maildir_parse_flags( ((maildir_store_conf_t *)ctx->gen.conf)->info_prefix, msg->base );
 	} else
@@ -1383,14 +1384,17 @@ maildir_finish_delete_box( store_t *gctx )
 	return DRV_OK;
 }
 
-static void
+static int
 maildir_prepare_load_box( store_t *gctx, int opts )
 {
+	maildir_store_t *ctx = (maildir_store_t *)gctx;
+
 	if (opts & OPEN_SETFLAGS)
 		opts |= OPEN_OLD;
 	if (opts & OPEN_EXPUNGE)
 		opts |= OPEN_OLD|OPEN_NEW|OPEN_FLAGS;
-	gctx->opts = opts;
+	ctx->opts = opts;
+	return opts;
 }
 
 static void

src/sync.c

@@ -153,7 +153,7 @@ typedef struct {
 	const char *orig_name[2];
 	message_t *new_msgs[2];
 	int_array_alloc_t trashed_msgs[2];
-	int state[2], ref_count, nsrecs, ret, lfd, existing, replayed;
+	int state[2], opts[2], ref_count, nsrecs, ret, lfd, existing, replayed;
 	int new_pending[2], flags_pending[2], trash_pending[2];
 	int maxuid[2]; /* highest UID that was already propagated */
 	int newmaxuid[2]; /* highest UID that is currently being propagated */
@@ -1258,11 +1258,11 @@ box_opened2( sync_vars_t *svars, int t )
 					assert( !"sync record with stray TUID" );
 			}
 		}
-	svars->drv[M]->prepare_load_box( ctx[M], opts[M] );
-	svars->drv[S]->prepare_load_box( ctx[S], opts[S] );
+	svars->opts[M] = svars->drv[M]->prepare_load_box( ctx[M], opts[M] );
+	svars->opts[S] = svars->drv[S]->prepare_load_box( ctx[S], opts[S] );
 
 	ARRAY_INIT( &mexcs );
-	if (svars->ctx[M]->opts & OPEN_OLD) {
+	if (svars->opts[M] & OPEN_OLD) {
 		if (chan->max_messages) {
 			/* When messages have been expired on the slave, the master fetch is split into
 			 * two ranges: The bulk fetch which corresponds with the most recent messages, and an
@@ -1275,7 +1275,7 @@ box_opened2( sync_vars_t *svars, int t )
 				if (srec->status & S_DEAD)
 					continue;
 				if (srec->uid[M] > 0 && srec->uid[S] > 0 && minwuid > srec->uid[M] &&
-				    (!(svars->ctx[M]->opts & OPEN_NEW) || svars->maxuid[M] >= srec->uid[M])) {
+				    (!(svars->opts[M] & OPEN_NEW) || svars->maxuid[M] >= srec->uid[M])) {
 					/* The pair is alive, but outside the bulk range. */
 					*int_array_append( &mexcs ) = srec->uid[M];
 				}
@@ -1294,7 +1294,7 @@ box_opened2( sync_vars_t *svars, int t )
 	sync_ref( svars );
 	load_box( svars, M, minwuid, mexcs.array );
 	if (!check_cancel( svars ))
-		load_box( svars, S, (ctx[S]->opts & OPEN_OLD) ? 1 : INT_MAX, (int_array_t){ 0, 0 } );
+		load_box( svars, S, (svars->opts[S] & OPEN_OLD) ? 1 : INT_MAX, (int_array_t){ 0, 0 } );
 	sync_deref( svars );
 }
 
@@ -1315,15 +1315,15 @@ load_box( sync_vars_t *svars, int t, int minwuid, int_array_t mexcs )
 {
 	int maxwuid, seenuid;
 
-	if (svars->ctx[t]->opts & OPEN_NEW) {
+	if (svars->opts[t] & OPEN_NEW) {
 		if (minwuid > svars->maxuid[t] + 1)
 			minwuid = svars->maxuid[t] + 1;
 		maxwuid = INT_MAX;
-		if (svars->ctx[t]->opts & (OPEN_OLD_IDS|OPEN_OLD_SIZE))
+		if (svars->opts[t] & (OPEN_OLD_IDS|OPEN_OLD_SIZE))
 			seenuid = get_seenuid( svars, t );
 		else
 			seenuid = 0;
-	} else if (svars->ctx[t]->opts & OPEN_OLD) {
+	} else if (svars->opts[t] & OPEN_OLD) {
 		maxwuid = seenuid = get_seenuid( svars, t );
 	} else
 		maxwuid = seenuid = 0;
@@ -1482,8 +1482,8 @@ box_loaded( int sts, void *aux )
 			continue;
 		debug( "pair (%d,%d)\n", srec->uid[M], srec->uid[S] );
 		// no[] means that a message is known to be not there.
-		no[M] = !srec->msg[M] && (svars->ctx[M]->opts & OPEN_OLD);
-		no[S] = !srec->msg[S] && (svars->ctx[S]->opts & OPEN_OLD);
+		no[M] = !srec->msg[M] && (svars->opts[M] & OPEN_OLD);
+		no[S] = !srec->msg[S] && (svars->opts[S] & OPEN_OLD);
 		if (no[M] && no[S]) {
 			// It does not matter whether one side was already known to be missing
 			// (never stored [skipped or failed] or expunged [possibly expired]) -