Module transaction

Transactions are the only way make changes to the ref store in order to increase the chance of consistency in a multi-threaded environment.

Transactions currently allow to…

• create or update reference
• delete references

The following guarantees are made:

• transactions are prepared which is when other writers are prevented from changing them
  • errors during preparations will cause a perfect rollback
• prepared transactions are committed to finalize the change
  • errors when committing while leave the ref store in an inconsistent, but operational state.

Structs

• LogChange
  A change to the reflog.
• RefEdit
  A reference that is to be changed

Enums

• Change
  A description of an edit to perform.
• PreviousValue
  The desired value of an updated value
• RefLog
  The way to deal with the Reflog in deletions.

Traits

• RefEditsExt
  An extension trait to perform commonly used operations on edits across different ref stores.