This commit introduces two new functions to the btcdb.Db interface named
FetchBlockHeightBySha and FetchBlockHeaderBySha.
The FetchBlockHeightBySha function is useful since previously it was only
possible to get the height of block by fetching the entire block with
FetchBlockBySha and pulling the height out of the returned btcutil.Block.
The FetchBlockHeaderBySha function will ultimately make it much more
efficient to fetch block headers. Currently, due to the database design
in the ldb backend, the entire block has to be loaded anyways, so the only
current benefit is to avoid the deserialize on all of the transactions.
However, ultimately btcdb will gain a more efficient backend which can
also avoid reading all of the extra transaction data altogether.
FetchTxBySha changes what it returns, it can now return a TxListReply and
and error if none are found.
FetchTxByShaList is renamed to FetchUnSpentTxByShaList to indicate that
it will (likey/eventually) only return Tx that have some unspent TxOuts.
Tx which are fully spent may not be (reliably) looked up using this API.
improved error handling
Fix testing, no point in running tests multiple times
Fix error when no blocks in database, reopen would misreport NewstSha() return
This code is still prototype at this time.
It appears to function correctly but something
consumes more memory than is considered reasonable
for the dataset comprised of the full bitcoind chain.
Not recommened for use at this time.
