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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2022-04-09 23:20:09 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2022-04-09 23:26:13 +0200
commit020698f3a92195eb371e806a0b3ed0649565046f (patch)
treece27b06f5c30f8cd68879083bbf4dabdb9caf12b /lib/sqfs/dir_reader/dcache.c
parent94c3fdc66b9aa8130b20a644f399fc021d0a823c (diff)
Add support for '.' and '..' entries in sqfs_dir_reader_t
Two flags are added to the dir reader API, one for the create function that the dir reader should report those entries and one to the open function to suppress that if it was enabled. To implement the feature, a mapping of visited directory inodes is maintained internally, that mapps inode numbers to inode references. When opening a directory, state is maintained to generate the fake entries for '.' and '..'. Since all the other functions are based on the open/read/rewind API, no alterations need to be made. The tree scan function is modified, to use the suppress flag, so it does not accidentally catch those entries. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
Diffstat (limited to 'lib/sqfs/dir_reader/dcache.c')
-rw-r--r--lib/sqfs/dir_reader/dcache.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/lib/sqfs/dir_reader/dcache.c b/lib/sqfs/dir_reader/dcache.c
new file mode 100644
index 0000000..47fbf73
--- /dev/null
+++ b/lib/sqfs/dir_reader/dcache.c
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: LGPL-3.0-or-later */
+/*
+ * dcache.c
+ *
+ * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
+ */
+#define SQFS_BUILDING_DLL
+#include "internal.h"
+
+static int dcache_key_compare(const void *ctx, const void *l, const void *r)
+{
+ sqfs_u32 lhs = *((const sqfs_u32 *)l), rhs = *((const sqfs_u32 *)r);
+ (void)ctx;
+
+ return lhs < rhs ? -1 : (lhs > rhs ? 1 : 0);
+}
+
+int sqfs_dir_reader_dcache_init(sqfs_dir_reader_t *rd, sqfs_u32 flags)
+{
+ if (!(flags & SQFS_DIR_READER_DOT_ENTRIES))
+ return 0;
+
+ return rbtree_init(&rd->dcache, sizeof(sqfs_u32), sizeof(sqfs_u64),
+ dcache_key_compare);
+}
+
+int sqfs_dir_reader_dcache_init_copy(sqfs_dir_reader_t *copy,
+ const sqfs_dir_reader_t *rd)
+{
+ if (!(rd->flags & SQFS_DIR_READER_DOT_ENTRIES))
+ return 0;
+
+ return rbtree_copy(&rd->dcache, &copy->dcache);
+}
+
+void sqfs_dir_reader_dcache_cleanup(sqfs_dir_reader_t *rd)
+{
+ if (!(rd->flags & SQFS_DIR_READER_DOT_ENTRIES))
+ return;
+
+ rbtree_cleanup(&rd->dcache);
+}
+
+int sqfs_dir_reader_dcache_add(sqfs_dir_reader_t *rd,
+ sqfs_u32 inode, sqfs_u64 ref)
+{
+ rbtree_node_t *node;
+
+ if (!(rd->flags & SQFS_DIR_READER_DOT_ENTRIES))
+ return 0;
+
+ node = rbtree_lookup(&rd->dcache, &inode);
+ if (node != NULL)
+ return 0;
+
+ return rbtree_insert(&rd->dcache, &inode, &ref);
+}
+
+int sqfs_dir_reader_dcache_find(sqfs_dir_reader_t *rd,
+ sqfs_u32 inode, sqfs_u64 *ref)
+{
+ rbtree_node_t *node;
+
+ if (!(rd->flags & SQFS_DIR_READER_DOT_ENTRIES))
+ return SQFS_ERROR_NO_ENTRY;
+
+ node = rbtree_lookup(&rd->dcache, &inode);
+ if (node == NULL)
+ return SQFS_ERROR_NO_ENTRY;
+
+ *ref = *((sqfs_u64 *)rbtree_node_value(node));
+ return 0;
+}