Support dependency wait

Connor1996 commented 4 years ago

Is your feature request related to a problem? Please describe.

Make fail-point support dependencies (one fail-point wait for another before proceed) we can refer to the implementation of rocksdb syncpoint https://github.com/facebook/rocksdb/blob/e9e0101ca46f00e8a456e69912a913d907be56fc/test_util/sync_point.h

Describe the solution you'd like

Support writting like this fail::cfg("point_A", "wait(point_B)")

wait indicates pause on point_A until point_B is passed.
wait_local indicates point_A is enabled when point_A and point_B are processed on same thread. And it will also pause on point_A until point_B is passed.

Additional context

part of #https://github.com/tikv/rust-rocksdb/issues/361

yiwu-arbug commented 4 years ago

What's use case of wait_local?

Connor1996 commented 4 years ago

No use case for now @yiwu-arbug

BusyJay commented 4 years ago

I think with #50, this can be implemented on the application side easily.

tikv / fail-rs