tdb: increase readability of read_record_on_left()

by using early returns and better variable names,
and reducing indentation.

Signed-off-by: Michael Adam <obnox@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>

diff --git a/lib/tdb/common/freelist.c b/lib/tdb/common/freelist.c
index e6f7db511f65d38a01a9c8cac2ef31c9daa407e3..4a48c3d67040ca2fe06a8141834b589d28ab475d 100644 (file)
--- a/lib/tdb/common/freelist.c
+++ b/lib/tdb/common/freelist.c
@@ -101,45 +101,59 @@ static int update_tailer(struct tdb_context *tdb, tdb_off_t offset,
  * Read the record directly on the left.
  * Fail if there is no record on the left.
  */
-static int read_record_on_left(struct tdb_context *tdb, tdb_off_t offset,
+static int read_record_on_left(struct tdb_context *tdb, tdb_off_t rec_ptr,
                               tdb_off_t *left_p,
                               struct tdb_record *left_r)
 {
-       tdb_off_t left = offset - sizeof(tdb_off_t);
-       struct tdb_record l;
-       tdb_off_t leftsize;
+       tdb_off_t left_ptr;
+       tdb_off_t left_size;
+       struct tdb_record left_rec;
+       int ret;
 
-       if (offset - sizeof(tdb_off_t) > TDB_DATA_START(tdb->hash_size)) {
+       left_ptr = rec_ptr - sizeof(tdb_off_t);
 
-               /* Read in tailer and jump back to header */
-               if (tdb_ofs_read(tdb, left, &leftsize) == -1) {
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: left offset read failed at %u\n", left));
-                       return -1;
-               }
+       if (left_ptr <= TDB_DATA_START(tdb->hash_size)) {
+               /* no record on the left */
+               return -1;
+       }
 
-               /* it could be uninitialised data */
-               if (leftsize == 0 || leftsize == TDB_PAD_U32) {
-                       return -1;
-               }
+       /* Read in tailer and jump back to header */
+       ret = tdb_ofs_read(tdb, left_ptr, &left_size);
+       if (ret == -1) {
+               TDB_LOG((tdb, TDB_DEBUG_FATAL,
+                       "tdb_free: left offset read failed at %u\n", left_ptr));
+               return -1;
+       }
 
-               left = offset - leftsize;
+       /* it could be uninitialised data */
+       if (left_size == 0 || left_size == TDB_PAD_U32) {
+               return -1;
+       }
 
-               if (leftsize > offset ||
-                   left < TDB_DATA_START(tdb->hash_size)) {
-                       return -1;
-               }
+       if (left_size > rec_ptr) {
+               return -1;
+       }
 
-               /* Now read in the left record */
-               if (tdb->methods->tdb_read(tdb, left, &l, sizeof(l), DOCONV()) == -1) {
-                       TDB_LOG((tdb, TDB_DEBUG_FATAL, "tdb_free: left read failed at %u (%u)\n", left, leftsize));
-                       return -1;
-               }
+       left_ptr = rec_ptr - left_size;
+
+       if (left_ptr < TDB_DATA_START(tdb->hash_size)) {
+               return -1;
+       }
 
-               *left_p = left;
-               *left_r = l;
+       /* Now read in the left record */
+       ret = tdb->methods->tdb_read(tdb, left_ptr, &left_rec,
+                                    sizeof(left_rec), DOCONV());
+       if (ret == -1) {
+               TDB_LOG((tdb, TDB_DEBUG_FATAL,
+                        "tdb_free: left read failed at %u (%u)\n",
+                        left_ptr, left_size));
+               return -1;
        }
 
-       return -1;
+       *left_p = left_ptr;
+       *left_r = left_rec;
+
+       return 0;
 }
 
 /* Add an element into the freelist. Merge adjacent records if