fix line ending conversion logic

imap may very well store messages with LF line endings. only RFC2822
requires CRLF.
consequently, preserve the line endings as much as possible unless the
mailbox format does not support it (this would be the case for unix mbox
- i actually have no idea about maildir).

src/drv_maildir.c

@@ -1250,7 +1250,7 @@ maildir_parse_store( conffile_t *cfg, store_conf_t **storep, int *err )
 }
 
 struct driver maildir_driver = {
-	0,
+	0, /* XXX DRV_CRLF? */
 	maildir_parse_store,
 	maildir_cleanup_drv,
 	maildir_open_store,

src/isync.h

@@ -174,6 +174,11 @@ typedef struct {
 
 /* All memory belongs to the driver's user. */
 
+/*
+   This flag says that the driver CAN store messages with CRLFs,
+   not that it must. The lack of it OTOH implies that it CANNOT,
+   and as CRLF is the canonical format, we convert.
+*/
 #define DRV_CRLF        1
 
 #define TUIDL 12

src/sync.c

@@ -211,7 +211,7 @@ msg_fetched( int sts, void *aux )
 	copy_vars_t *vars = (copy_vars_t *)aux;
 	SVARS(vars->aux)
 	char *fmap, *buf;
-	int i, len, extra, cra, crd, scr, tcr, crds;
+	int i, len, extra, scr, tcr, lcrs, crs, lines;
 	int start, sbreak = 0, ebreak = 0;
 	char c;
 
@@ -224,29 +224,24 @@ msg_fetched( int sts, void *aux )
 		if (vars->srec || scr != tcr) {
 			fmap = vars->data.data;
 			len = vars->data.len;
-			cra = crd = 0;
-			if (scr > tcr)
-				crd = -1;
-			else if (scr < tcr)
-				cra = 1;
-			extra = 0, i = 0;
+			extra = lines = crs = i = 0;
 			if (vars->srec) {
-				extra += 8 + TUIDL + 1 + tcr;
 			  nloop:
 				start = i;
-				crds = 0;
+				lcrs = 0;
 				while (i < len) {
 					c = fmap[i++];
 					if (c == '\r')
-						crds += crd;
+						lcrs++;
 					else if (c == '\n') {
 						if (!memcmp( fmap + start, "X-TUID: ", 8 )) {
-							extra -= (ebreak = i) - (sbreak = start);
+							extra = (sbreak = start) - (ebreak = i);
 							goto oke;
 						}
-						extra += cra + crds;
-						if (i - 1 - scr == start) {
-							sbreak = ebreak = i - 1 - scr;
+						lines++;
+						crs += lcrs;
+						if (i - lcrs - 1 == start) {
+							sbreak = ebreak = start;
 							goto oke;
 						}
 						goto nloop;
@@ -257,54 +252,66 @@ msg_fetched( int sts, void *aux )
 				      vars->msg->uid, str_ms[1-t] );
 				free( fmap );
 				return vars->cb( SYNC_NOGOOD, 0, vars );
+			  oke:
+				extra += 8 + TUIDL + 1 + (tcr && crs);
 			}
-		  oke:
-			if (cra || crd)
+			if (tcr != scr) {
 				for (; i < len; i++) {
 					c = fmap[i];
 					if (c == '\r')
-						extra += crd;
+						crs++;
 					else if (c == '\n')
-						extra += cra;
+						lines++;
 				}
+				extra -= crs;
+				if (tcr)
+					extra += lines;
+			}
 
 			vars->data.len = len + extra;
 			buf = vars->data.data = nfmalloc( vars->data.len );
 			i = 0;
 			if (vars->srec) {
-				if (cra) {
-					for (; i < sbreak; i++) {
-						if (fmap[i] == '\n')
-							*buf++ = '\r';
-						*buf++ = fmap[i];
+				if (tcr != scr) {
+					if (tcr) {
+						for (; i < sbreak; i++)
+							if ((c = fmap[i]) != '\r') {
+								if (c == '\n')
+									*buf++ = '\r';
+								*buf++ = c;
+							}
+					} else {
+						for (; i < sbreak; i++)
+							if ((c = fmap[i]) != '\r')
+								*buf++ = c;
 					}
-				} else if (crd) {
-					for (; i < sbreak; i++)
-						if (fmap[i] != '\r')
-							*buf++ = fmap[i];
 				} else {
 					memcpy( buf, fmap, sbreak );
 					buf += sbreak;
 				}
+
 				memcpy( buf, "X-TUID: ", 8 );
 				buf += 8;
 				memcpy( buf, vars->srec->tuid, TUIDL );
 				buf += TUIDL;
-				if (tcr)
+				if (tcr && crs)
 					*buf++ = '\r';
 				*buf++ = '\n';
 				i = ebreak;
 			}
-			if (cra) {
-				for (; i < len; i++) {
-					if (fmap[i] == '\n')
-						*buf++ = '\r';
-					*buf++ = fmap[i];
+			if (tcr != scr) {
+				if (tcr) {
+					for (; i < len; i++)
+						if ((c = fmap[i]) != '\r') {
+							if (c == '\n')
+								*buf++ = '\r';
+							*buf++ = c;
+						}
+				} else {
+					for (; i < len; i++)
+						if ((c = fmap[i]) != '\r')
+							*buf++ = c;
 				}
-			} else if (crd) {
-				for (; i < len; i++)
-					if (fmap[i] != '\r')
-						*buf++ = fmap[i];
 			} else
 				memcpy( buf, fmap + i, len - i );