On 05/17/2017 07:44 PM, Stefan Beller wrote:
> On Wed, May 17, 2017 at 5:05 AM, Michael Haggerty <mhag...@alum.mit.edu> 
> wrote:
>> Break the function `ref_transaction_commit()` into two functions,
>> `ref_transaction_prepare()` and `ref_transaction_finish()`, with a
>> third function, `ref_transaction_abort()`, that can be used to abort
>> the transaction. Break up the `ref_store` methods similarly.
>> This split will make it easier to implement compound reference stores,
>> where a transaction might have to span multiple underlying stores. In
>> that case, we would first want to "prepare" the sub-transactions in
>> each of the reference stores. If any of the "prepare" steps fails, we
>> would "abort" all of the sub-transactions. Only if all of the
>> "prepare" steps succeed would we "finish" each of them.
> [...]

Thanks for your comments. While I was incorporating them, I realized
that other parts of the documentation needed updates, too. And while I
was fixing that, I noticed that the interface was unnecessarily
complicated. The old version required either `commit` or `prepare`
followed by `finish`. But there is no reason that the public API has to
expose `finish`. So instead, let's call `prepare` an optional step that
is allowed to precede `commit`, and make `commit` smart enough to call
`prepare` if it hasn't been called already, and then call `finish`.

Furthermore, let's make it possible to call `abort` when the transaction
is in OPEN as well as PREPARED state rather than requiring `free` in
OPEN state and `abort` in PREPARED state.

I will make these changes and revamp the docs for v2.


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