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>

2 files changed, 13 insertions, 13 deletions

diff --git a/lib/sqfs/dir_reader/dir_reader.c b/lib/sqfs/dir_reader/dir_reader.c
index 38700df..d70f729 100644
--- a/lib/sqfs/dir_reader/dir_reader.c
+++ b/lib/sqfs/dir_reader/dir_reader.c
@@ -67,8 +67,8 @@ static void dir_reader_destroy(sqfs_object_t *obj)
 	if (rd->flags & SQFS_DIR_READER_DOT_ENTRIES)
 		rbtree_cleanup(&rd->dcache);
 
-	sqfs_destroy(rd->meta_inode);
-	sqfs_destroy(rd->meta_dir);
+	sqfs_drop(rd->meta_inode);
+	sqfs_drop(rd->meta_dir);
 	free(rd);
 }
 
@@ -97,7 +97,7 @@ static sqfs_object_t *dir_reader_copy(const sqfs_object_t *obj)
 
 	return (sqfs_object_t *)copy;
 fail_mdir:
-	sqfs_destroy(copy->meta_inode);
+	sqfs_drop(copy->meta_inode);
 fail_mino:
 	if (copy->flags & SQFS_DIR_READER_DOT_ENTRIES)
 		rbtree_cleanup(&copy->dcache);
@@ -152,12 +152,12 @@ sqfs_dir_reader_t *sqfs_dir_reader_create(const sqfs_super_t *super,
 	if (rd->meta_dir == NULL)
 		goto fail_mdir;
 
-	rd->super = super;
+	rd->super = *super;
 	rd->flags = flags;
 	rd->state = DIR_STATE_NONE;
 	return rd;
 fail_mdir:
-	sqfs_destroy(rd->meta_inode);
+	sqfs_drop(rd->meta_inode);
 fail_mino:
 	if (flags & SQFS_DIR_READER_DOT_ENTRIES)
 		rbtree_cleanup(&rd->dcache);
@@ -176,7 +176,7 @@ int sqfs_dir_reader_open_dir(sqfs_dir_reader_t *rd,
 	if (flags & (~SQFS_DIR_OPEN_ALL_FLAGS))
 		return SQFS_ERROR_UNSUPPORTED;
 
-	ret = sqfs_readdir_state_init(&rd->it, rd->super, inode);
+	ret = sqfs_readdir_state_init(&rd->it, &rd->super, inode);
 	if (ret)
 		return ret;
 
@@ -191,7 +191,7 @@ int sqfs_dir_reader_open_dir(sqfs_dir_reader_t *rd,
 		if (dcache_find(rd, inode->base.inode_number, &rd->cur_ref))
 			return SQFS_ERROR_NO_ENTRY;
 
-		if (rd->cur_ref == rd->super->root_inode_ref) {
+		if (rd->cur_ref == rd->super.root_inode_ref) {
 			rd->parent_ref = rd->cur_ref;
 		} else if (dcache_find(rd, parent, &rd->parent_ref)) {
 			return SQFS_ERROR_NO_ENTRY;
@@ -291,7 +291,7 @@ int sqfs_dir_reader_get_inode(sqfs_dir_reader_t *rd,
 {
 	int ret;
 
-	ret = sqfs_meta_reader_read_inode(rd->meta_inode, rd->super,
+	ret = sqfs_meta_reader_read_inode(rd->meta_inode, &rd->super,
 					  rd->ent_ref >> 16,
 					  rd->ent_ref & 0x0FFFF, inode);
 	if (ret != 0)
@@ -303,16 +303,16 @@ int sqfs_dir_reader_get_inode(sqfs_dir_reader_t *rd,
 int sqfs_dir_reader_get_root_inode(sqfs_dir_reader_t *rd,
 				   sqfs_inode_generic_t **inode)
 {
-	sqfs_u64 block_start = rd->super->root_inode_ref >> 16;
-	sqfs_u16 offset = rd->super->root_inode_ref & 0xFFFF;
+	sqfs_u64 block_start = rd->super.root_inode_ref >> 16;
+	sqfs_u16 offset = rd->super.root_inode_ref & 0xFFFF;
 	int ret;
 
-	ret = sqfs_meta_reader_read_inode(rd->meta_inode, rd->super,
+	ret = sqfs_meta_reader_read_inode(rd->meta_inode, &rd->super,
 					  block_start, offset, inode);
 	if (ret != 0)
 		return ret;
 
-	return dcache_add(rd, *inode, rd->super->root_inode_ref);
+	return dcache_add(rd, *inode, rd->super.root_inode_ref);
 }
 
 int sqfs_dir_reader_find_by_path(sqfs_dir_reader_t *rd,
diff --git a/lib/sqfs/dir_reader/internal.h b/lib/sqfs/dir_reader/internal.h
index 7275cd2..471d197 100644
--- a/lib/sqfs/dir_reader/internal.h
+++ b/lib/sqfs/dir_reader/internal.h
@@ -35,7 +35,7 @@ struct sqfs_dir_reader_t {
 
 	sqfs_meta_reader_t *meta_dir;
 	sqfs_meta_reader_t *meta_inode;
-	const sqfs_super_t *super;
+	sqfs_super_t super;
 
 	sqfs_readdir_state_t it;