New API function isoburn_prepare_blind_grow() for -as mkisofs -multi

libisoburn/data_source.c

@@ -85,6 +85,19 @@ int ds_read_block(IsoDataSource *src, uint32_t lba, uint8_t *buffer)
 
  icd = (struct isoburn_cached_drive *) src->data;
  d = (struct burn_drive*) icd->drive;
+
+ if(d == NULL) {
+   /* This would happen if libisoburn saw output data in the fifo and
+      performed early drive release and afterwards libisofs still tries
+      to read data.
+      That would constitute a bad conceptual problem in libisoburn.
+   */
+   isoburn_msgs_submit(NULL, 0x00060000,
+     "Programming error: Drive released while libisofs still attempts to read",
+     0, "FATAL", 0);
+   return ISO_ASSERT_FAILURE;
+ }
+
  tiles = (struct isoburn_cache_tile *) icd->tiles;
 
  aligned_lba= lba & ~(Libisoburn_tile_blockS - 1);
@@ -189,6 +202,19 @@ static void ds_free_data(IsoDataSource *src)
  src->data= NULL;
 }
 
+
+int isoburn_data_source_shutdown(IsoDataSource *src, int flag)
+{
+ struct isoburn_cached_drive *icd;
+
+ if(src==NULL)
+   return(0);
+ icd= (struct isoburn_cached_drive *) src->data;
+ icd->drive= NULL;
+ return(1);
+}
+
+
 IsoDataSource *isoburn_data_source_new(struct burn_drive *d)
 {
  IsoDataSource *ret;