tree ff20741bccfd92e97dfd80a94dda96096c8f8b4d
parent 6bf4e9080d1903140d6dac239d1ddbad82a4c852
author Sergey Rogulenko <rogulenko@google.com> 1438646007 -0700
committer Sergey Rogulenko <rogulenko@google.com> 1438646009 -0700

internal storage engine: improve compile-time typing

This change does to internal storage engine API changes.

First, renaming Snapshot.Close() -> Snapshot.Abort().
Before this change, the Store interface implemented the
Snapshot interface, now it doesn't.

Second, adding the SnapshotOrTranscation interface.
Only Snapshot and Transaction implement this interface.
Transaction doesn't implement Snapshot.

Third, the StoreReadWriter becomes private. The StoreReadWriter
was replaced by the Transaction. This was done because in lots
of places the StoreReadWriter was checked to be the Transaction
at runtime.

This change also updates the code to the new API and removes
extra runtime type checking.

MultiPart: 1/2

Change-Id: Ic213cc0479a6cd8604bc62c29edaf7adb95b260e