Implement rudimentary reference counting for sqfs_object_t

Implement grab/drop functions to increase/decrease reference count
and destroy the object if the count drops to 0.

Make sure that all objects that maintain internal references actually
grab that reference, duplicate it in the copy function, drop it in
the destroy handler.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

3 files changed, 6 insertions, 4 deletions

diff --git a/lib/io/compress/ostream_compressor.c b/lib/io/compress/ostream_compressor.c
index f63a3d2..a5f16d5 100644
--- a/lib/io/compress/ostream_compressor.c
+++ b/lib/io/compress/ostream_compressor.c
@@ -56,7 +56,7 @@ static void comp_destroy(sqfs_object_t *obj)
 	ostream_comp_t *comp = (ostream_comp_t *)obj;
 
 	comp->cleanup(comp);
-	sqfs_destroy(comp->wrapped);
+	sqfs_drop(comp->wrapped);
 	free(comp);
 }
 
@@ -95,7 +95,7 @@ ostream_t *ostream_compressor_create(ostream_t *strm, int comp_id)
 
 	sqfs_object_init(comp, comp_destroy, NULL);
 
-	comp->wrapped = strm;
+	comp->wrapped = sqfs_grab(strm);
 	comp->inbuf_used = 0;
 
 	base = (ostream_t *)comp;
diff --git a/lib/io/uncompress/istream_compressor.c b/lib/io/uncompress/istream_compressor.c
index 1c73e3a..d4e1aea 100644
--- a/lib/io/uncompress/istream_compressor.c
+++ b/lib/io/uncompress/istream_compressor.c
@@ -18,7 +18,7 @@ static void comp_destroy(sqfs_object_t *obj)
 	istream_comp_t *comp = (istream_comp_t *)obj;
 
 	comp->cleanup(comp);
-	sqfs_destroy(comp->wrapped);
+	sqfs_drop(comp->wrapped);
 	free(comp);
 }
 
@@ -57,7 +57,7 @@ istream_t *istream_compressor_create(istream_t *strm, int comp_id)
 
 	sqfs_object_init(comp, comp_destroy, NULL);
 
-	comp->wrapped = strm;
+	comp->wrapped = sqfs_grab(strm);
 
 	base = (istream_t *)comp;
 	base->get_filename = comp_get_filename;
diff --git a/lib/io/unix/ostream.c b/lib/io/unix/ostream.c
index 6ed18e6..5ef2af2 100644
--- a/lib/io/unix/ostream.c
+++ b/lib/io/unix/ostream.c
@@ -163,6 +163,8 @@ ostream_t *ostream_open_stdout(void)
 	strm->append = file_append;
 	strm->flush = file_flush;
 	strm->get_filename = file_get_filename;
+
+	sqfs_object_init(file, file_destroy, NULL);
 	return strm;
 fail:
 	perror("creating file wrapper for stdout");