This udpates the blockchain module to use the lastest module major
versions.
While here, it also corrects a few typos and updates some test function
names to more accurately reflect their purpose.
The updated direct dependencies are as follows:
- github.com/decred/dcrd/blockchain/stake/v2@v2.0.1
- github.com/decred/dcrd/chaincfg/v2@v2.2.0
- github.com/decred/dcrd/database/v2@v2.0.0
- github.com/decred/dcrd/dcrutil/v2@v2.0.0
- github.com/decred/dcrd/txscript/v2@v2.0.0
This updates blockchain to make use of the coinbase check function in
the standalone module.
It also deprecates the related exported functions in the blockchain
module so they can be removed in the next major version and rewrites
them in terms of the standalone module in the mean time.
The changes to reverse the utxoset semantics also had the side effect of
correcting the behavior for sequence locks when inside of a block to the
expected behavior instead of the actual current consensus behavior.
In order to avoid that, this modifies the blockchain consensus rules to
properly preserve the old incorrect behavior of sequence locks within
blocks and also updates the mempool to to reject transactions
accordingly thus providing parity between the two.
The behavior needs to be corrected, but since it constitutes a change to
the consensus rules, a vote will be necessary.
This refactors and simplifies the code in blockchain to use the new more
efficient chain views.
An overview of the logic changes are as follows:
- Remove inMainChain from block nodes since that can now be efficiently
determined by using the chain view
- Track the best chain via a chain view instead of a single block node
- Use the tip of the best chain view everywhere bestNode was used
- Update chain view tip instead of updating best node
- Remove height map and associated lock in favor of chain view
- Use chain view NodeByHeight everywhere height map was used
- Change reorg logic to use more efficient chain view fork finding logic
- Change block locator code over to use more efficient chain view logic
- Remove now unused block-index-based block locator code
- Move BlockLocator definition to chain.go
- Move BlockLocatorFromHash and LatestBlockLocator to chain.go
- Update both to use more efficient chain view logic
- Rework several functions to use chain view for main chain detection
- fetchMainChainBlockByNode
- BlockByHeight
- MainChainHasBlock
- findPreviousCheckpoint
- IsCheckpointCandidate
This reworks the block index code such that it loads all of the headers
in the main chain at startup and constructs the full block index
accordingly.
Since the full index from the current best tip all the way back to the
genesis block is now guaranteed to be in memory, this also removes all
code related to dynamically loading the nodes and updates some of the
logic to take advantage of the fact traversing the block index can no
longer potentially fail. There are also many more optimizations and
simplifications that can be made in the future as a result of this.
Due to removing all of the extra overhead of tracking the dynamic state,
and ensuring the block node structs are aligned to eliminate extra
padding, the end result of a fully populated block index now takes quite
a bit less memory than the previous dynamically loaded version.
It also speeds up the initial startup process by roughly 2x since it is
faster to bulk load the nodes in order as opposed to dynamically loading
only the nodes near the tip in backwards order.
For example, here is some startup timing information before and after
this commit on a node that contains roughly 238,000 blocks:
7200 RPM HDD:
-------------
Startup time before this commit: ~7.71s
Startup time after this commit: ~3.47s
SSD:
----
Startup time before this commit: ~6.34s
Startup time after this commit: ~3.51s
Some additional benefits are:
- Since every block node is in memory, the code which reconstructs
headers from block nodes means that all headers can always be served
from memory which will be important since the network will be moving
to header-based semantics
- Several of the error paths can be removed since they are no longer
necessary
- It is no longer expensive to calculate CSV sequence locks or median
times of blocks way in the past
- It is much less expensive to calculate the initial states for the
various intervals such as the stake and voter version
- It will be possible to create much more efficient iteration and
simplified views of the overall index
An overview of the logic changes are as follows:
- Move AncestorNode from blockIndex to blockNode and greatly simplify
since it no longer has to deal with the possibility of dynamically
loading nodes and related failures
- Replace nodeAtHeightFromTopNode from BlockChain with RelativeAncestor
on blockNode and define it in terms of AncestorNode
- Move CalcPastMedianTime from blockIndex to blockNode and remove no
longer necessary test for nil
- Remove findNode and replace all of its uses with direct queries of the
block index
- Remove blockExists and replace all of its uses with direct queries of
the block index
- Remove all functions and fields related to dynamically loading nodes
- children and parentHash fields from blockNode
- depNodes from blockIndex
- loadBlockNode from blockIndex
- PrevNodeFromBlock from blockIndex
- {p,P}revNodeFromNode from blockIndex
- RemoveNode
- Replace all instances of iterating backwards through nodes to directly
access the parent now that nodes don't potentially need to be
dynamically loaded
- Introduce a lookupNode function on blockIndex which allows the
initialization code to locklessly query the index
- No longer take the chain lock when only access to the block index,
which has its own lock, is needed
- Removed the error paths from several functions that can no longer fail
- getReorganizeNodes
- findPrevTestNetDifficulty
- sumPurchasedTickets
- findStakeVersionPriorNode
- Removed all error paths related to node iteration that can no longer
fail
- Modify FetchUtxoView to return an empty view for the genesis block
This replaces the ErrDoubleSpend and ErrMissingTx error codes with a
single error code named ErrMissingTxOut and updates the relevant errors
and expected test results accordingly.
Once upon a time, the code relied on a transaction index, so it was able
to definitively differentiate between a transaction output that
legitimately did not exist and one that had already been spent.
However, since the code now uses a pruned utxoset, it is no longer
possible to reliably differentiate since once all outputs of a
transaction are spent, it is removed from the utxoset completely.
Consequently, a missing transaction could be either because the
transaction never existed or because it is fully spent.
Also, while here, consistently use the LookupEntry function on the
UtxoView instead of directly accessing the internal map as intended.
This refactors the block index logic into a separate struct and
introduces an individual lock for it so it can be queried independent of
the chain lock.
It also modifies the `newBlockNode` function to accept nil for the
ticket spend information parameter and updates all of the test code that
doesn't require it to use nil.
This modifies the IsSStx, IsSSGen, and IsSSRtx functions to only return
a bool and introduces CheckSStx, CheckSSGen, and CheckSSRtx to return
the actual error as needed by consensus.
This is being done because "is" functions are much nicer to use when
they don't return an error and the callers that use them almost never
care why they aren't of the type, they just want to determine if they
are. In the few cases where the caller does care, they can use of the
new check functions.
While here, also update the comments to call out what the more common
names for the transaction types are and to add comments to the test
functions for consistency.
Finally, it updates all callers in the repo accordingly.
This merge commit adds the following code from the
github.com/decred/dcrutil package into a new
github.com/decred/dcrd/dcrutil package:
* Address handling
* Amount type
* AppDataDir func
* bitflags functions
* Block wrapper type
* Hash160 func
* Tx wrapper type
* WIF type
as well as all tests for this code.
The old github.com/decred/dcrutil/hdkeychain package has also been
merged and moved to github.com/decred/dcrd/dcrutil/hdkeychain.
dcrd packages have been updated to use the new packages and the dep
files have been updated for this change.
This repurposes the sequence number of version 2 transaction inputs to
provide consensus-enforced relative lock-time semantics so that a
transaction can require inputs to have a specified relative age before
they are allowed to be included in a block. Each relative time lock can
either specify a relative number of seconds (with a granularity of 512
seconds and a maximum value of 33,553,920) or a specific number of
blocks (max 65535).
The number of seconds is calculated relative to the past median time of
the block before the one that contains the referenced output. This is
done because, due to other changes that will also be included in the
same agenda vote, said time will become the earliest possible time the
block that contains the referenced output could have been (technically
it will be one second after that, but that complexity is ignored since
there is already a granularity involved anyways).
It is also possible to disable the behavior by setting bit 31 of the
sequence number (which all transactions currently do by default since
they are set to the max).
In order for the transaction to be permitted to the mempool, relayed,
considered for inclusion into block templates, and allowed into a block,
the specified relative time locks for all of its inputs must be
satisfied.
This only implements the required logic and tests to enforce the new
behavior. Code to enforce the new behavior when considering candidate
transactions for acceptance to the mempool, relaying, and inclusion into
block templates will be added in a separate commit.
A consensus vote is required in order to reject blocks which contain
transactions that violate the new rules at a consensus level. Code to
selectively enable consensus enforcement based on the result of an
agenda vote will be added in a separate commit.
In order to accomplish this new behavior, the concept of a sequence lock
is introduced which allows the minimum possible time and height at which
a transaction can be included into a block to be calculated from all
inputs with non-disabled relative time locks, and functions to calculate
and evaluate the sequence lock are added.
The following is an overview of the changes:
- Introduce a new struct named SequenceLock to represent the previously
described sequence lock
- Define new constants related to sequence numbers named
SequenceLockTimeDisabled, SequenceLockTimeIsSeconds,
SequenceLockTimeMask, and SequenceLockTimeGranularity
- Add a new function named calcSequenceLock to calculate the sequence
lock for a given transaction
- Add a new function named SequenceLockActive to determine if a given
sequence lock is satisfied for a given block height and past median
time
- Add a convenience function named LockTimeToSequence which can be used
to convert a relative lock time to a sequence number
- Add a comprehensive set of tests for all of the new funcs
