Use std::string more often, and factor out Commit.
Use std::string more often, and factor out Commit.

nandub/ldid,songchenwen/ldid,tpoechtrager/ldid,nandub/ldid,tpoechtrager/ldid,nandub/ldid,songchenwen/ldid,songchenwen/ldid,tpoechtrager/ldid