Improve RDB type correctness

It's possible large objects could be larger than 'int', so let's
upgrade all size counters to ssize_t.

This also fixes rdbSaveObject serialized bytes calculation.
Since entire serializations of data structures can be large,
so we don't want to limit their calculated size to a 32 bit signed max.

This commit increases object size calculation and
cascades the change back up to serializedlength printing.

Before:
127.0.0.1:6379> debug object hihihi
... encoding:quicklist serializedlength:-2147483559 ...

After:
127.0.0.1:6379> debug object hihihi
... encoding:quicklist serializedlength:2147483737 ...

1 files changed, 2 insertions, 3 deletions

diff --git a/src/rdb.h b/src/rdb.h
index 6319f5d02..a72607b71 100644
--- a/src/rdb.h
+++ b/src/rdb.h
@@ -109,9 +109,8 @@ int rdbSaveBackground(char *filename);
 int rdbSaveToSlavesSockets(void);
 void rdbRemoveTempFile(pid_t childpid);
 int rdbSave(char *filename);
-int rdbSaveObject(rio *rdb, robj *o);
-off_t rdbSavedObjectLen(robj *o);
-off_t rdbSavedObjectPages(robj *o);
+ssize_t rdbSaveObject(rio *rdb, robj *o);
+size_t rdbSavedObjectLen(robj *o);
 robj *rdbLoadObject(int type, rio *rdb);
 void backgroundSaveDoneHandler(int exitcode, int bysignal);
 int rdbSaveKeyValuePair(rio *rdb, robj *key, robj *val, long long expiretime, long long now);