+ if (lock.l_type == F_UNLCK) {
+ return 0;
+ }
+ return 1;
+}
+
+/* --------------- */
+int ad_testlock(struct adouble *ad, int eid, const off_t off)
+{
+ struct ad_fd *adf;
+ off_t lock_offset;
+
+ lock_offset = off;
+ if (eid == ADEID_DFORK) {
+ adf = &ad->ad_data_fork;
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ lock_offset = df2off(off);
+ }
+ }
+ else { /* rfork */
+ if (ad_meta_fileno(ad) == -1) {
+ /* there's no resource fork. return no lock */
+ return 0;
+ }
+ adf = ad->ad_md;
+ lock_offset = hf2off(off);
+ }
+ return testlock(adf, lock_offset, 1);
+}
+
+/* -------------------------
+ return if a file is open by another process.
+ Optimized for the common case:
+ - there's no locks held by another process (clients)
+ - or we already know the answer and don't need to test.
+*/
+u_int16_t ad_openforks(struct adouble *ad, u_int16_t attrbits)
+{
+ u_int16_t ret = 0;
+ struct ad_fd *adf;
+ off_t off;
+
+ if (!(attrbits & (ATTRBIT_DOPEN | ATTRBIT_ROPEN))) {
+ off_t len;
+ /* XXX know the locks layout:
+ AD_FILELOCK_OPEN_WR is first
+ and use it for merging requests
+ */
+ if (ad_meta_fileno(ad) != -1) {
+ /* there's a resource fork test the four bytes for
+ * data RW/RD and fork RW/RD locks in one request
+ */
+ adf = ad->ad_md;
+ off = LOCK_DATA_WR;
+ len = 4;
+ }
+ else {
+ /* no resource fork, only data RD/RW may exist */
+ adf = &ad->ad_data_fork;
+ off = AD_FILELOCK_OPEN_WR;
+ len = 2;
+ }
+ if (!testlock(adf, off, len))
+ return ret;
+ }
+ /* either there's a lock or we already know one
+ fork is open
+ */
+ if (!(attrbits & ATTRBIT_DOPEN)) {
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ off = LOCK_DATA_WR;
+ }
+ else {
+ adf = &ad->ad_data_fork;
+ off = AD_FILELOCK_OPEN_WR;
+ }
+ ret = testlock(adf, off, 2) > 0? ATTRBIT_DOPEN : 0;
+ }
+
+ if (!(attrbits & ATTRBIT_ROPEN)) {
+ if (ad_meta_fileno(ad) != -1) {
+ adf = ad->ad_md;
+ off = LOCK_RSRC_WR;
+ ret |= testlock(adf, off, 2) > 0? ATTRBIT_ROPEN : 0;
+ }
+ }
+
+ return ret;