split OPEN_PAIRED from OPEN_OLD, and rename OPEN_OLD_IDS accordingly

this emphasizes the non-complementarity to OPEN_NEW.
the "real" OPEN_OLD is currently used only for trashing.

src/driver.h

@@ -82,16 +82,17 @@ static_assert_bits(F, message_t, flags);
 static_assert_bits(M, message_t, status);
 
 // For driver_t->prepare_load_box(), which may amend the passed flags.
-// The drivers don't use the first two, but may set them if loading the
+// The drivers don't use the first three, but may set them if loading the
 // particular range is required to handle some other flag; note that these
 // ranges may overlap.
 BIT_ENUM(
-	OPEN_OLD,         // Paired messages *in* this store.
+	OPEN_PAIRED,      // Paired messages *in* this store.
+	OPEN_OLD,         // Messages that should be already propagated *from* this store.
 	OPEN_NEW,         // Messages (possibly) not yet propagated *from* this store.
 	OPEN_FIND,
 	OPEN_FLAGS,       // Note that fetch_msg() gets the flags regardless.
 	OPEN_NEW_SIZE,
-	OPEN_OLD_IDS,
+	OPEN_PAIRED_IDS,
 	OPEN_APPEND,
 	OPEN_SETFLAGS,
 	OPEN_EXPUNGE,
@@ -235,7 +236,7 @@ struct driver {
 	 * and those named in the excs array (smaller than minuid).
 	 * The driver takes ownership of the excs array.
 	 * Messages starting with finduid need to have the TUID populated when OPEN_FIND is set.
-	 * Messages up to pairuid need to have the Message-Id populated when OPEN_OLD_IDS is set.
+	 * Messages up to pairuid need to have the Message-Id populated when OPEN_PAIRED_IDS is set.
 	 * Messages up to newuid need to have the size populated when OPEN_OLD_SIZE is set;
 	 * likewise messages above newuid when OPEN_NEW_SIZE is set.
 	 * The returned message list remains owned by the driver. */

src/drv_imap.c

@@ -2885,7 +2885,7 @@ imap_load_box( store_t *gctx, uint minuid, uint maxuid, uint finduid, uint pairu
 				if (i != j)
 					bl += sprintf( buf + bl, ":%u", excs.data[i] );
 			}
-			imap_submit_load( ctx, buf, shifted_bit( ctx->opts, OPEN_OLD_IDS, WantMsgids ), sts );
+			imap_submit_load( ctx, buf, shifted_bit( ctx->opts, OPEN_PAIRED_IDS, WantMsgids ), sts );
 		}
 		if (maxuid == UINT_MAX)
 			maxuid = ctx->uidnext - 1;
@@ -2899,7 +2899,7 @@ imap_load_box( store_t *gctx, uint minuid, uint maxuid, uint finduid, uint pairu
 				imap_set_range( ranges, &nranges, 0, WantSize, newuid );
 			if (ctx->opts & OPEN_FIND)
 				imap_set_range( ranges, &nranges, 0, WantTuids, finduid - 1 );
-			if (ctx->opts & OPEN_OLD_IDS)
+			if (ctx->opts & OPEN_PAIRED_IDS)
 				imap_set_range( ranges, &nranges, WantMsgids, 0, pairuid );
 			for (uint r = 0; r < nranges; r++) {
 				sprintf( buf, "%u:%u", ranges[r].first, ranges[r].last );

src/drv_maildir.c

@@ -1113,7 +1113,7 @@ maildir_scan( maildir_store_t *ctx, msg_t_array_alloc_t *msglist )
 			}
 			int want_size = ((ctx->opts & OPEN_NEW_SIZE) && uid > ctx->newuid);
 			int want_tuid = ((ctx->opts & OPEN_FIND) && uid >= ctx->finduid);
-			int want_msgid = ((ctx->opts & OPEN_OLD_IDS) && uid <= ctx->pairuid);
+			int want_msgid = ((ctx->opts & OPEN_PAIRED_IDS) && uid <= ctx->pairuid);
 			if (!want_size && !want_tuid && !want_msgid)
 				continue;
 			if (!fnl)
@@ -1401,9 +1401,9 @@ maildir_prepare_load_box( store_t *gctx, uint opts )
 	maildir_store_t *ctx = (maildir_store_t *)gctx;
 
 	if (opts & OPEN_SETFLAGS)
-		opts |= OPEN_OLD;
+		opts |= OPEN_PAIRED;
 	if (opts & OPEN_EXPUNGE)
-		opts |= OPEN_OLD|OPEN_NEW|OPEN_FLAGS;
+		opts |= OPEN_PAIRED | OPEN_OLD | OPEN_NEW | OPEN_FLAGS;
 	ctx->opts = opts;
 	return opts;
 }

src/sync.c

@@ -741,7 +741,7 @@ box_opened2( sync_vars_t *svars, int t )
 
 	opts[F] = opts[N] = 0;
 	if (fails)
-		opts[F] = opts[N] = OPEN_OLD|OPEN_OLD_IDS;
+		opts[F] = opts[N] = OPEN_PAIRED | OPEN_PAIRED_IDS;
 	for (t = 0; t < 2; t++) {
 		if (any_purges[t]) {
 			debug( "resuming %d %s purge(s)\n", any_purges[t], str_fn[t] );
@@ -754,7 +754,7 @@ box_opened2( sync_vars_t *svars, int t )
 		}
 		if (chan->ops[t] & (OP_GONE | OP_FLAGS)) {
 			opts[t] |= OPEN_SETFLAGS;
-			opts[t^1] |= OPEN_OLD;
+			opts[t^1] |= OPEN_PAIRED;
 			if (chan->ops[t] & OP_FLAGS)
 				opts[t^1] |= OPEN_FLAGS;
 		}
@@ -773,8 +773,8 @@ box_opened2( sync_vars_t *svars, int t )
 			if ((chan->ops[t] & OP_UPGRADE) || any_upgrades[t]) {
 				debug( "resuming %s of %d upgrade(s)\n", str_hl[t], any_upgrades[t] );
 				if (chan->ops[t] & OP_UPGRADE)
-					opts[t] |= OPEN_OLD | OPEN_FLAGS | OPEN_SETFLAGS;
+					opts[t] |= OPEN_PAIRED | OPEN_FLAGS | OPEN_SETFLAGS;
-				opts[t^1] |= OPEN_OLD;
+				opts[t^1] |= OPEN_PAIRED;
 			}
 			if ((chan->ops[t] | chan->ops[t^1]) & OP_EXPUNGE)  // Don't propagate doomed msgs
 				opts[t^1] |= OPEN_FLAGS;
@@ -798,9 +798,9 @@ box_opened2( sync_vars_t *svars, int t )
 	if ((chan->ops[N] & (OP_NEW | OP_UPGRADE | OP_FLAGS)) && chan->max_messages)
 		svars->any_expiring = 1;
 	if (svars->any_expiring) {
-		opts[N] |= OPEN_OLD | OPEN_FLAGS;
+		opts[N] |= OPEN_PAIRED | OPEN_FLAGS;
 		if (any_dummies[N])
-			opts[F] |= OPEN_OLD | OPEN_FLAGS;
+			opts[F] |= OPEN_PAIRED | OPEN_FLAGS;
 		else if (chan->ops[N] & (OP_NEW | OP_UPGRADE))
 			opts[F] |= OPEN_FLAGS;
 	}
@@ -808,7 +808,7 @@ box_opened2( sync_vars_t *svars, int t )
 	svars->opts[N] = svars->drv[N]->prepare_load_box( ctx[N], opts[N] );
 
 	ARRAY_INIT( &mexcs );
-	if ((svars->opts[F] & OPEN_OLD) && chan->max_messages) {
+	if ((svars->opts[F] & OPEN_PAIRED) && !(svars->opts[F] & OPEN_OLD) && chan->max_messages) {
 		/* When messages have been expired on the near side, the far side fetch is split into
 		 * two ranges: The bulk fetch which corresponds with the most recent messages, and an
 		 * exception list of messages which would have been expired if they weren't important. */
@@ -859,13 +859,29 @@ load_box( sync_vars_t *svars, int t, uint minwuid, uint_array_t mexcs )
 	uint maxwuid = 0, pairuid = UINT_MAX;
 
 	if (svars->opts[t] & OPEN_NEW) {
-		if (!(svars->opts[t] & OPEN_OLD) || (minwuid > svars->maxuid[t] + 1))
+		if (svars->opts[t] & OPEN_OLD) {
+			svars->opts[t] |= OPEN_PAIRED;
+			minwuid = 1;
+		} else if (!(svars->opts[t] & OPEN_PAIRED) || (minwuid > svars->maxuid[t] + 1)) {
 			minwuid = svars->maxuid[t] + 1;
+		}
 		maxwuid = UINT_MAX;
-		if (svars->opts[t] & OPEN_OLD_IDS)  // Implies OPEN_OLD
+		if (svars->opts[t] & OPEN_PAIRED_IDS)  // Implies OPEN_PAIRED
 			pairuid = get_seenuid( svars, t );
-	} else if (svars->opts[t] & OPEN_OLD) {
+	} else if (svars->opts[t] & (OPEN_PAIRED | OPEN_OLD)) {
-		maxwuid = get_seenuid( svars, t );
+		uint seenuid = get_seenuid( svars, t );
+		if (svars->opts[t] & OPEN_OLD) {
+			minwuid = 1;
+			maxwuid = svars->maxuid[t];
+			if (maxwuid < seenuid) {
+				if (svars->opts[t] & OPEN_PAIRED)
+					maxwuid = seenuid;
+			} else {
+				svars->opts[t] |= OPEN_PAIRED;
+			}
+		} else {  // OPEN_PAIRED
+			maxwuid = seenuid;
+		}
 	} else {
 		minwuid = UINT_MAX;
 	}
@@ -1030,8 +1046,8 @@ box_loaded( int sts, message_t *msgs, int total_msgs, int recent_msgs, void *aux
 		debug( "pair (%u,%u)\n", srec->uid[F], srec->uid[N] );
 		assert( !srec->tuid[0] );
 		// no[] means that a message is known to be not there.
-		no[F] = !srec->msg[F] && (svars->opts[F] & OPEN_OLD);
+		no[F] = !srec->msg[F] && (svars->opts[F] & OPEN_PAIRED);
-		no[N] = !srec->msg[N] && (svars->opts[N] & OPEN_OLD);
+		no[N] = !srec->msg[N] && (svars->opts[N] & OPEN_PAIRED);
 		if (no[F] && no[N]) {
 			// It does not matter whether one side was already known to be missing
 			// (never stored [skipped or failed] or expunged [possibly expired]) -