The name findLatestKnownCheckpoint is confusing and doesn't really convey
the fact the purpose of the function is to the find the checkpoint prior
to the current known block.
Therefore, rename the function to findPreviousCheckpoint for clarity.
Also, update some comments to follow suit.
This commit adds an additional check to the block acceptance rules which
prevents new blocks that fork the main chain before the previous known
good checkpoint. This prevents storage of new, otherwise valid, blocks
from building off of old blocks which are likely at a much easier
difficulty and therefore could be used to waste cache and disk space.
Note this is slightly different than the other existing check which
prevents blocks with a timestamp before the timestamp of the latest known
good checkpoint since that check effectively prevents old side chain
blocks that already existed (per the claimed timestamp).
ok drahn@
This commit modifies local variables that are used for more convenient
access to a block's header to use pointers. This avoids copying the
header multiple times.
It is not necessary to do all of the transaction validation on
blocks if they have been confirmed to be in the block chain leading
up to the final checkpoint in a given blockschain.
This algorithm fetches block headers from the peer, then once it has
established the full blockchain connection, it requests blocks.
Any blocks before the final checkpoint pass true for fastAdd on
btcchain operation, which causes it to do less valiation on the block.
Rather than defining CheckBlockSanity as a member of a BlockChain
instance, define it at the root level so it is truly context free as
intended. In order to make it context free, the proof of work limit is
now a required parameter.
This commit modifies the main processing loop for orphan dependencies
(orphans that are processed due to their parents showing up) to use an
index based for loop over range. Since the Go range statement does not
reevaluate on every iteration, it was previously possible under certain
circumstances for the slice to be changed out from under the range
statement while processing the orphan blocks.
This commit modifies the code to choose sane defaults for the backing
arrays for slices that involve a lot of appends such block locators, hash
processing, and needed transactions. This is an optimization to avoid
the overhead of growing the backing arrays and copying the data multiple
times in the most common case. This also prevents a leak in Go GC which
will likely ultimatley be fixed, but the efficiecy gains alone are worth
the change.
Rather than sending the root of the an orphan chain when sending an orphan
notification, send the hash of the orphan block itself. The caller can
then call the GetOrphanRoot function with the hash to get the root of the
orphan chain as needed. This is being changed since it's cleaner and more
detministic sending the hash for the orphan block that was just processed
rather than sending a possibly different hash depending on whether there
is an orphan chain or not.
This commit exposes GetOrphanRoot to callers. It also modifies the code
to allow the function to be called in a concurrent safe manner. This
allows the information to be safely obtained from multiple goroutines.
This commit modifies the code to use params based on the active network
which paves the way for supporting the special rules and different genesis
blocks used by the test networks.
