nimbus-eth1/nimbus/utils/header.nim

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# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import eth/[common, rlp], ../constants, strformat, times, ../validation
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export BlockHeader
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proc hasUncles*(header: BlockHeader): bool = header.ommersHash != EMPTY_UNCLE_HASH
proc `$`*(header: BlockHeader): string =
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result = &"BlockHeader(timestamp: {header.timestamp} difficulty: {header.difficulty} blockNumber: {header.blockNumber} gasLimit: {header.gasLimit})"
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proc gasLimitBounds*(parent: BlockHeader): (GasInt, GasInt) =
## Compute the boundaries for the block gas limit based on the parent block.
let
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boundaryRange = parent.gasLimit div GAS_LIMIT_ADJUSTMENT_FACTOR
upperBound = parent.gasLimit + boundaryRange
lowerBound = max(GAS_LIMIT_MINIMUM, parent.gasLimit - boundaryRange)
return (lowerBound, upperBound)
#[
proc validate_gaslimit(header: BlockHeader):
let parent_header = getBlockHeaderByHash(header.parent_hash)
low_bound, high_bound = compute_gas_limit_bounds(parent_header)
if header.gas_limit < low_bound:
raise ValidationError(
"The gas limit on block {0} is too low: {1}. It must be at least {2}".format(
encode_hex(header.hash), header.gas_limit, low_bound))
elif header.gas_limit > high_bound:
raise ValidationError(
"The gas limit on block {0} is too high: {1}. It must be at most {2}".format(
encode_hex(header.hash), header.gas_limit, high_bound))
]#
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proc computeGasLimit*(parent: BlockHeader, gasLimitFloor: GasInt): GasInt =
#[
For each block:
- decrease by 1/1024th of the gas limit from the previous block
- increase by 50% of the total gas used by the previous block
If the value is less than the given `gas_limit_floor`:
- increase the gas limit by 1/1024th of the gas limit from the previous block.
If the value is less than the GAS_LIMIT_MINIMUM:
- use the GAS_LIMIT_MINIMUM as the new gas limit.
]#
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if gasLimitFloor < GAS_LIMIT_MINIMUM:
raise newException(ValueError,
&"""
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The `gasLimitFloor` value must be greater than the GAS_LIMIT_MINIMUM.
Got {gasLimitFloor}. Must be greater than {GAS_LIMIT_MINIMUM}
"""
)
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let decay = parent.gasLimit div GAS_LIMIT_EMA_DENOMINATOR
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var usageIncrease: GasInt
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if parent.gasUsed > 0:
usageIncrease = (
parent.gas_used * GAS_LIMIT_USAGE_ADJUSTMENT_NUMERATOR
) div GAS_LIMIT_USAGE_ADJUSTMENT_DENOMINATOR div GAS_LIMIT_EMA_DENOMINATOR
let gasLimit = max(
GAS_LIMIT_MINIMUM,
parent.gasLimit - decay + usage_increase
)
if gas_limit < GAS_LIMIT_MINIMUM:
return GAS_LIMIT_MINIMUM
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elif gas_limit < gasLimitFloor:
return parent.gas_limit + decay
else:
return gas_limit
proc generateHeaderFromParentHeader*(
computeDifficultyFn: proc(parentHeader: BlockHeader, timestamp: int): int,
parent: BlockHeader,
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coinbase: EthAddress,
timestamp: int = -1,
extraData: string = ""): BlockHeader =
# TODO: validateGt(timestamp, parent.timestamp)
result = BlockHeader(
timestamp: max(getTime(), parent.timestamp + 1.milliseconds), # Note: Py-evm uses +1 second, not ms
blockNumber: (parent.blockNumber + 1),
# TODO: difficulty: parent.computeDifficulty(parent.timestamp),
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gasLimit: computeGasLimit(parent, gasLimitFloor = GENESIS_GAS_LIMIT),
stateRoot: parent.stateRoot,
coinbase: coinbase,
# TODO: data: extraData,
)