This avoids a naming conflict with a p2p class BlockHeader.
Notice that the block data structures are mostly still private API, they
are in the utils dir but headers are not installed, nobody has needed
them so far.
People all over the Internet, including on the BCH spec, seem confused
about these enum values. They think they are opcodes.
So lets be clear and rename them to the thing they are. Placeholders or
a return-code.
The CAmount name is not helpful as its just an int64_t and not a
class, like the name implies. There were a handful of places where
it was passed in as const-ref, as a good example of this actually
creating sub-par code.
Move the MutableTransactionSignatureChecker class out of the header and
thereby remove the need to include transaction.h in the header.
This checker was never used in any app, just in the unit tests.
This also fixes includes around.
Summary:
CMerkleBlock::CMerkleBlock called IsRelevantAndUpdate() on each transaction
in order, which (due to the outpoint-adding feature) assumes a topological
order of transactions in order to work correctly. If an outpoint of
interest were created later in a block than when gets spent, then it would
be added into the bloom filter too late, and thus that spending transaction
would get missed.
This changes CMerkleBlock::CMerkleBlock to scan all outputs first, then
make a second loop to scan all inputs. This requires breaking up the
IsRelevantAndUpdate() function into two parts. The original
IsRelevantAndUpdate() functionality remains fully intact however, as it
gets called from mempool-related code (mempool has topological order) and
tests.
Note that vMatchedTxn.push_back is moved into the second loop so that index
i keeps ascending order, in case that is somehow relevant. (the tests at
least do check this)
A two-loop construction like this will very slightly increase the false
positive rate.
Originally by: Mark Lundeberg
To make sure that a pair of really large transactions being used
to create a DSP doesn't cause a blocking thread, this runs a
benchmark on a pair of transactions with 300 inputs each, causing
45k comparisons to be made.
On my laptop this results in 0.6 msecs for this creation of the DSP.
* API docs
* Fix possible race condition in addOrphan()
* Reject proofs that violate simple constraints
* clear up possible confusing API (first/double spender getters).
This is part of the protocol upgrade for 2020-05-15, and in general it
seems to go the direction of "we did this before, lets do this again".
The spec is clear enough, but there is still a lack of questioning and
testing. The problem this attempts to fix has been neutered for years[1].
The spec states:
> The essential idea of SigChecks is to perform counting solely in the
> spending transaction, and count actual executed signature check
> operations.
This, however nobel and logical, ignores that the
check-for-being-too-costly just pulled in a UTXO lookup and the loading
of the output script from the historical chain.
The goal that we protect against CPU over-use may be reached, but the
price is a total system slowdown. You can have multiple CPUs, but the
bus to permanent storage has one, max 2 parallel pipes.
To ensure theHub stays the number one scalable node, I didn't blindly
follow the spec, while making sure that the Hub is correctly going to
follow/reject consensus violations of newly mined blocks.
As a result the implementation in Flowee the Hub:
* does not check sigcheck-counts on historical blocks (more than 1000
blocks in the past).
This may increase the risk of chain-splits ever so slightly, but the cost
of disk-IO would be too high.
* No longer stores the value in the mempool, nor uses it for the
CPU-miner.
* Ties the sigcheck-limits to the user-set block-size-accept-limit.
This is contrary to the spec which mistakenly thinks that BCH has a
max block-size in the consensus rules. The effect is the same, though.
* The per-intput standardness suggestion is not implemented because
standardness checks don't currently fetch the previous outputs and
that would be too expensive to add.
* Standardness rules for the whole transaction are moved to the
mempool-acceptance logic instead. The cost would be too great
otherwise, similar to the previous point.
Again, the effect is the same as likely intented.
---
1) since the intro of the CachingTransactionSignatureChecker
It was only called twice, and in very close proximity. The class didn't
add anything.
This improves readability and with the new state its easier to write
too.
Merkle-block and merkle-tree classes and methods are pretty much stand-
alone and can be moved with no efforts.
Also move the relevent unit test to qtestlib.
tomFlowee
TomZ