alloy_consensus/block/

header.rs

use crate::{
    block::{HeaderInfo, HeaderRoots},
    constants::{EMPTY_OMMER_ROOT_HASH, EMPTY_ROOT_HASH},
    Block, BlockBody,
};
use alloc::vec::Vec;
use alloy_eips::{
    eip1559::{calc_next_block_base_fee, BaseFeeParams},
    eip1898::BlockWithParent,
    eip7840::BlobParams,
    merge::ALLOWED_FUTURE_BLOCK_TIME_SECONDS,
    BlockNumHash,
};
use alloy_primitives::{
    keccak256, Address, BlockNumber, Bloom, Bytes, Sealable, Sealed, B256, B64, U256,
};
use alloy_rlp::{length_of_length, BufMut, Decodable, Encodable};

/// Ethereum Block header
#[derive(Clone, Debug, PartialEq, Eq, Hash)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
#[cfg_attr(feature = "serde", serde(rename_all = "camelCase"))]
#[cfg_attr(feature = "borsh", derive(borsh::BorshSerialize, borsh::BorshDeserialize))]
pub struct Header {
    /// The Keccak 256-bit hash of the parent
    /// block’s header, in its entirety; formally Hp.
    pub parent_hash: B256,
    /// The Keccak 256-bit hash of the ommers list portion of this block; formally Ho.
    #[cfg_attr(feature = "serde", serde(rename = "sha3Uncles", alias = "ommersHash"))]
    pub ommers_hash: B256,
    /// The 160-bit address to which all fees collected from the successful mining of this block
    /// be transferred; formally Hc.
    #[cfg_attr(feature = "serde", serde(rename = "miner", alias = "beneficiary"))]
    pub beneficiary: Address,
    /// The Keccak 256-bit hash of the root node of the state trie, after all transactions are
    /// executed and finalisations applied; formally Hr.
    pub state_root: B256,
    /// The Keccak 256-bit hash of the root node of the trie structure populated with each
    /// transaction in the transactions list portion of the block; formally Ht.
    pub transactions_root: B256,
    /// The Keccak 256-bit hash of the root node of the trie structure populated with the receipts
    /// of each transaction in the transactions list portion of the block; formally He.
    pub receipts_root: B256,
    /// The Bloom filter composed from indexable information (logger address and log topics)
    /// contained in each log entry from the receipt of each transaction in the transactions list;
    /// formally Hb.
    pub logs_bloom: Bloom,
    /// A scalar value corresponding to the difficulty level of this block. This can be calculated
    /// from the previous block’s difficulty level and the timestamp; formally Hd.
    pub difficulty: U256,
    /// A scalar value equal to the number of ancestor blocks. The genesis block has a number of
    /// zero; formally Hi.
    #[cfg_attr(feature = "serde", serde(with = "alloy_serde::quantity"))]
    pub number: BlockNumber,
    /// A scalar value equal to the current limit of gas expenditure per block; formally Hl.
    #[cfg_attr(feature = "serde", serde(with = "alloy_serde::quantity"))]
    pub gas_limit: u64,
    /// A scalar value equal to the total gas used in transactions in this block; formally Hg.
    #[cfg_attr(feature = "serde", serde(with = "alloy_serde::quantity"))]
    pub gas_used: u64,
    /// A scalar value equal to the reasonable output of Unix’s time() at this block’s inception;
    /// formally Hs.
    #[cfg_attr(feature = "serde", serde(with = "alloy_serde::quantity"))]
    pub timestamp: u64,
    /// An arbitrary byte array containing data relevant to this block. This must be 32 bytes or
    /// fewer; formally Hx.
    pub extra_data: Bytes,
    /// A 256-bit hash which, combined with the
    /// nonce, proves that a sufficient amount of computation has been carried out on this block;
    /// formally Hm.
    pub mix_hash: B256,
    /// A 64-bit value which, combined with the mixhash, proves that a sufficient amount of
    /// computation has been carried out on this block; formally Hn.
    pub nonce: B64,
    /// A scalar representing EIP1559 base fee which can move up or down each block according
    /// to a formula which is a function of gas used in parent block and gas target
    /// (block gas limit divided by elasticity multiplier) of parent block.
    /// The algorithm results in the base fee per gas increasing when blocks are
    /// above the gas target, and decreasing when blocks are below the gas target. The base fee per
    /// gas is burned.
    #[cfg_attr(
        feature = "serde",
        serde(
            default,
            with = "alloy_serde::quantity::opt",
            skip_serializing_if = "Option::is_none"
        )
    )]
    pub base_fee_per_gas: Option<u64>,
    /// The Keccak 256-bit hash of the withdrawals list portion of this block.
    /// <https://eips.ethereum.org/EIPS/eip-4895>
    #[cfg_attr(feature = "serde", serde(default, skip_serializing_if = "Option::is_none"))]
    pub withdrawals_root: Option<B256>,
    /// The total amount of blob gas consumed by the transactions within the block, added in
    /// EIP-4844.
    #[cfg_attr(
        feature = "serde",
        serde(
            default,
            with = "alloy_serde::quantity::opt",
            skip_serializing_if = "Option::is_none"
        )
    )]
    pub blob_gas_used: Option<u64>,
    /// A running total of blob gas consumed in excess of the target, prior to the block. Blocks
    /// with above-target blob gas consumption increase this value, blocks with below-target blob
    /// gas consumption decrease it (bounded at 0). This was added in EIP-4844.
    #[cfg_attr(
        feature = "serde",
        serde(
            default,
            with = "alloy_serde::quantity::opt",
            skip_serializing_if = "Option::is_none"
        )
    )]
    pub excess_blob_gas: Option<u64>,
    /// The hash of the parent beacon block's root is included in execution blocks, as proposed by
    /// EIP-4788.
    ///
    /// This enables trust-minimized access to consensus state, supporting staking pools, bridges,
    /// and more.
    ///
    /// The beacon roots contract handles root storage, enhancing Ethereum's functionalities.
    #[cfg_attr(feature = "serde", serde(default, skip_serializing_if = "Option::is_none"))]
    pub parent_beacon_block_root: Option<B256>,
    /// The Keccak 256-bit hash of the an RLP encoded list with each
    /// [EIP-7685] request in the block body.
    ///
    /// [EIP-7685]: https://eips.ethereum.org/EIPS/eip-7685
    #[cfg_attr(feature = "serde", serde(default, skip_serializing_if = "Option::is_none"))]
    pub requests_hash: Option<B256>,
}

impl AsRef<Self> for Header {
    fn as_ref(&self) -> &Self {
        self
    }
}

impl Default for Header {
    fn default() -> Self {
        Self {
            parent_hash: Default::default(),
            ommers_hash: EMPTY_OMMER_ROOT_HASH,
            beneficiary: Default::default(),
            state_root: EMPTY_ROOT_HASH,
            transactions_root: EMPTY_ROOT_HASH,
            receipts_root: EMPTY_ROOT_HASH,
            logs_bloom: Default::default(),
            difficulty: Default::default(),
            number: 0,
            gas_limit: 0,
            gas_used: 0,
            timestamp: 0,
            extra_data: Default::default(),
            mix_hash: Default::default(),
            nonce: B64::ZERO,
            base_fee_per_gas: None,
            withdrawals_root: None,
            blob_gas_used: None,
            excess_blob_gas: None,
            parent_beacon_block_root: None,
            requests_hash: None,
        }
    }
}

impl Sealable for Header {
    fn hash_slow(&self) -> B256 {
        Self::hash_slow(self)
    }
}

impl Header {
    /// Create a [`Block`] from the body and its header.
    pub const fn into_block<T>(self, body: BlockBody<T>) -> Block<T> {
        body.into_block(self)
    }

    /// Heavy function that will calculate hash of data and will *not* save the change to metadata.
    ///
    /// Use [`Header::seal_slow`] and unlock if you need the hash to be persistent.
    pub fn hash_slow(&self) -> B256 {
        let mut out = Vec::<u8>::new();
        self.encode(&mut out);
        keccak256(&out)
    }

    /// Decodes the RLP-encoded header and computes the hash from the raw RLP bytes.
    ///
    /// This is more efficient than decoding and then re-encoding to compute the hash,
    /// as it reuses the original RLP bytes for hashing.
    pub fn decode_sealed(buf: &mut &[u8]) -> alloy_rlp::Result<Sealed<Self>> {
        let start = *buf;
        let header = Self::decode(buf)?;
        let hash = keccak256(&start[..start.len() - buf.len()]);
        Ok(header.seal_unchecked(hash))
    }

    /// Check if the ommers hash equals to empty hash list.
    pub fn ommers_hash_is_empty(&self) -> bool {
        self.ommers_hash == EMPTY_OMMER_ROOT_HASH
    }

    /// Check if the transaction root equals to empty root.
    pub fn transaction_root_is_empty(&self) -> bool {
        self.transactions_root == EMPTY_ROOT_HASH
    }

    /// Returns the blob fee for _this_ block according to the EIP-4844 spec.
    ///
    /// Returns `None` if `excess_blob_gas` is None
    pub fn blob_fee(&self, blob_params: BlobParams) -> Option<u128> {
        Some(blob_params.calc_blob_fee(self.excess_blob_gas?))
    }

    /// Returns the blob fee for the next block according to the EIP-4844 spec.
    ///
    /// Returns `None` if `excess_blob_gas` is None.
    ///
    /// See also [Self::next_block_excess_blob_gas]
    pub fn next_block_blob_fee(&self, blob_params: BlobParams) -> Option<u128> {
        Some(blob_params.calc_blob_fee(self.next_block_excess_blob_gas(blob_params)?))
    }

    /// Calculate base fee for next block according to the EIP-1559 spec.
    ///
    /// Returns a `None` if no base fee is set, no EIP-1559 support
    pub fn next_block_base_fee(&self, base_fee_params: BaseFeeParams) -> Option<u64> {
        Some(calc_next_block_base_fee(
            self.gas_used,
            self.gas_limit,
            self.base_fee_per_gas?,
            base_fee_params,
        ))
    }

    /// Calculate excess blob gas for the next block according to the EIP-4844
    /// spec.
    ///
    /// Returns `None` if `excess_blob_gas`, `blob_gas_used`, or `base_fee_per_gas` is not set.
    pub fn next_block_excess_blob_gas(&self, blob_params: BlobParams) -> Option<u64> {
        Some(blob_params.next_block_excess_blob_gas_osaka(
            self.excess_blob_gas?,
            self.blob_gas_used?,
            self.base_fee_per_gas?,
        ))
    }

    /// Calculate a heuristic for the in-memory size of the [Header].
    #[inline]
    pub fn size(&self) -> usize {
        size_of::<Self>() + self.extra_data.len()
    }

    fn header_payload_length(&self) -> usize {
        let mut length = 0;
        length += self.parent_hash.length();
        length += self.ommers_hash.length();
        length += self.beneficiary.length();
        length += self.state_root.length();
        length += self.transactions_root.length();
        length += self.receipts_root.length();
        length += self.logs_bloom.length();
        length += self.difficulty.length();
        length += U256::from(self.number).length();
        length += U256::from(self.gas_limit).length();
        length += U256::from(self.gas_used).length();
        length += self.timestamp.length();
        length += self.extra_data.length();
        length += self.mix_hash.length();
        length += self.nonce.length();

        if let Some(base_fee) = self.base_fee_per_gas {
            // Adding base fee length if it exists.
            length += U256::from(base_fee).length();
        }

        if let Some(root) = self.withdrawals_root {
            // Adding withdrawals_root length if it exists.
            length += root.length();
        }

        if let Some(blob_gas_used) = self.blob_gas_used {
            // Adding blob_gas_used length if it exists.
            length += U256::from(blob_gas_used).length();
        }

        if let Some(excess_blob_gas) = self.excess_blob_gas {
            // Adding excess_blob_gas length if it exists.
            length += U256::from(excess_blob_gas).length();
        }

        if let Some(parent_beacon_block_root) = self.parent_beacon_block_root {
            length += parent_beacon_block_root.length();
        }

        if let Some(requests_hash) = self.requests_hash {
            length += requests_hash.length();
        }

        length
    }

    /// Returns the parent block's number and hash
    ///
    /// Note: for the genesis block the parent number is 0 and the parent hash is the zero hash.
    pub const fn parent_num_hash(&self) -> BlockNumHash {
        BlockNumHash { number: self.number.saturating_sub(1), hash: self.parent_hash }
    }

    /// Returns the block's number and hash.
    ///
    /// Note: this hashes the header.
    pub fn num_hash_slow(&self) -> BlockNumHash {
        BlockNumHash { number: self.number, hash: self.hash_slow() }
    }

    /// Returns the block's number and hash with the parent hash.
    ///
    /// Note: this hashes the header.
    pub fn num_hash_with_parent_slow(&self) -> BlockWithParent {
        BlockWithParent::new(self.parent_hash, self.num_hash_slow())
    }

    /// Seal the header with a known hash.
    ///
    /// WARNING: This method does not perform validation whether the hash is correct.
    #[inline]
    pub const fn seal(self, hash: B256) -> Sealed<Self> {
        Sealed::new_unchecked(self, hash)
    }

    /// True if the shanghai hardfork is active.
    ///
    /// This function checks that the withdrawals root field is present.
    pub const fn shanghai_active(&self) -> bool {
        self.withdrawals_root.is_some()
    }

    /// True if the Cancun hardfork is active.
    ///
    /// This function checks that the blob gas used field is present.
    pub const fn cancun_active(&self) -> bool {
        self.blob_gas_used.is_some()
    }

    /// True if the Prague hardfork is active.
    ///
    /// This function checks that the requests hash is present.
    pub const fn prague_active(&self) -> bool {
        self.requests_hash.is_some()
    }
}

impl Encodable for Header {
    fn encode(&self, out: &mut dyn BufMut) {
        let list_header =
            alloy_rlp::Header { list: true, payload_length: self.header_payload_length() };
        list_header.encode(out);
        self.parent_hash.encode(out);
        self.ommers_hash.encode(out);
        self.beneficiary.encode(out);
        self.state_root.encode(out);
        self.transactions_root.encode(out);
        self.receipts_root.encode(out);
        self.logs_bloom.encode(out);
        self.difficulty.encode(out);
        U256::from(self.number).encode(out);
        U256::from(self.gas_limit).encode(out);
        U256::from(self.gas_used).encode(out);
        self.timestamp.encode(out);
        self.extra_data.encode(out);
        self.mix_hash.encode(out);
        self.nonce.encode(out);

        // Encode all the fork specific fields
        if let Some(ref base_fee) = self.base_fee_per_gas {
            U256::from(*base_fee).encode(out);
        }

        if let Some(ref root) = self.withdrawals_root {
            root.encode(out);
        }

        if let Some(ref blob_gas_used) = self.blob_gas_used {
            U256::from(*blob_gas_used).encode(out);
        }

        if let Some(ref excess_blob_gas) = self.excess_blob_gas {
            U256::from(*excess_blob_gas).encode(out);
        }

        if let Some(ref parent_beacon_block_root) = self.parent_beacon_block_root {
            parent_beacon_block_root.encode(out);
        }

        if let Some(ref requests_hash) = self.requests_hash {
            requests_hash.encode(out);
        }
    }

    fn length(&self) -> usize {
        let mut length = 0;
        length += self.header_payload_length();
        length += length_of_length(length);
        length
    }
}

impl Decodable for Header {
    fn decode(buf: &mut &[u8]) -> alloy_rlp::Result<Self> {
        let rlp_head = alloy_rlp::Header::decode(buf)?;
        if !rlp_head.list {
            return Err(alloy_rlp::Error::UnexpectedString);
        }
        let started_len = buf.len();
        let mut this = Self {
            parent_hash: Decodable::decode(buf)?,
            ommers_hash: Decodable::decode(buf)?,
            beneficiary: Decodable::decode(buf)?,
            state_root: Decodable::decode(buf)?,
            transactions_root: Decodable::decode(buf)?,
            receipts_root: Decodable::decode(buf)?,
            logs_bloom: Decodable::decode(buf)?,
            difficulty: Decodable::decode(buf)?,
            number: u64::decode(buf)?,
            gas_limit: u64::decode(buf)?,
            gas_used: u64::decode(buf)?,
            timestamp: Decodable::decode(buf)?,
            extra_data: Decodable::decode(buf)?,
            mix_hash: Decodable::decode(buf)?,
            nonce: B64::decode(buf)?,
            base_fee_per_gas: None,
            withdrawals_root: None,
            blob_gas_used: None,
            excess_blob_gas: None,
            parent_beacon_block_root: None,
            requests_hash: None,
        };
        if started_len - buf.len() < rlp_head.payload_length {
            this.base_fee_per_gas = Some(u64::decode(buf)?);
        }

        // Withdrawals root for post-shanghai headers
        if started_len - buf.len() < rlp_head.payload_length {
            this.withdrawals_root = Some(Decodable::decode(buf)?);
        }

        // Blob gas used and excess blob gas for post-cancun headers
        if started_len - buf.len() < rlp_head.payload_length {
            this.blob_gas_used = Some(u64::decode(buf)?);
        }

        if started_len - buf.len() < rlp_head.payload_length {
            this.excess_blob_gas = Some(u64::decode(buf)?);
        }

        // Decode parent beacon block root.
        if started_len - buf.len() < rlp_head.payload_length {
            this.parent_beacon_block_root = Some(B256::decode(buf)?);
        }

        // Decode requests hash.
        if started_len - buf.len() < rlp_head.payload_length {
            this.requests_hash = Some(B256::decode(buf)?);
        }

        let consumed = started_len - buf.len();
        if consumed != rlp_head.payload_length {
            return Err(alloy_rlp::Error::ListLengthMismatch {
                expected: rlp_head.payload_length,
                got: consumed,
            });
        }
        Ok(this)
    }
}

#[cfg(any(test, feature = "arbitrary"))]
impl<'a> arbitrary::Arbitrary<'a> for Header {
    fn arbitrary(u: &mut arbitrary::Unstructured<'a>) -> arbitrary::Result<Self> {
        let is_prague = u.arbitrary::<bool>()?;
        let is_cancun = is_prague || u.arbitrary::<bool>()?;
        let is_shanghai = is_cancun || u.arbitrary::<bool>()?;
        let is_london = is_shanghai || u.arbitrary::<bool>()?;

        Ok(Self {
            parent_hash: u.arbitrary()?,
            ommers_hash: u.arbitrary()?,
            beneficiary: u.arbitrary()?,
            state_root: u.arbitrary()?,
            transactions_root: u.arbitrary()?,
            receipts_root: u.arbitrary()?,
            logs_bloom: u.arbitrary()?,
            difficulty: u.arbitrary()?,
            number: u.arbitrary()?,
            gas_limit: u.arbitrary()?,
            gas_used: u.arbitrary()?,
            timestamp: u.arbitrary()?,
            extra_data: u.arbitrary()?,
            mix_hash: u.arbitrary()?,
            nonce: u.arbitrary()?,
            base_fee_per_gas: if is_london { Some(u.arbitrary()?) } else { None },
            withdrawals_root: if is_shanghai { Some(u.arbitrary()?) } else { None },
            blob_gas_used: if is_cancun { Some(u.arbitrary()?) } else { None },
            excess_blob_gas: if is_cancun { Some(u.arbitrary()?) } else { None },
            parent_beacon_block_root: if is_cancun { Some(u.arbitrary()?) } else { None },
            requests_hash: if is_prague { Some(u.arbitrary()?) } else { None },
        })
    }
}

/// Trait for extracting specific Ethereum block data from a header
#[auto_impl::auto_impl(&, Arc)]
pub trait BlockHeader {
    /// Extracts essential information into one container type.
    fn header_info(&self) -> HeaderInfo {
        HeaderInfo {
            number: self.number(),
            beneficiary: self.beneficiary(),
            timestamp: self.timestamp(),
            gas_limit: self.gas_limit(),
            base_fee_per_gas: self.base_fee_per_gas(),
            excess_blob_gas: self.excess_blob_gas(),
            blob_gas_used: self.blob_gas_used(),
            difficulty: self.difficulty(),
            mix_hash: self.mix_hash(),
        }
    }

    /// Returns all roots contained in the header.
    fn header_roots(&self) -> HeaderRoots {
        HeaderRoots {
            state_root: self.state_root(),
            transactions_root: self.transactions_root(),
            receipts_root: self.receipts_root(),
            withdrawals_root: self.withdrawals_root(),
            parent_beacon_block_root: self.parent_beacon_block_root(),
            logs_bloom: self.logs_bloom(),
        }
    }

    /// Retrieves the parent hash of the block
    fn parent_hash(&self) -> B256;

    /// Retrieves the ommers hash of the block
    fn ommers_hash(&self) -> B256;

    /// Retrieves the beneficiary (miner) of the block
    fn beneficiary(&self) -> Address;

    /// Retrieves the state root hash of the block
    fn state_root(&self) -> B256;

    /// Retrieves the transactions root hash of the block
    fn transactions_root(&self) -> B256;

    /// Retrieves the receipts root hash of the block
    fn receipts_root(&self) -> B256;

    /// Retrieves the withdrawals root hash of the block, if available
    fn withdrawals_root(&self) -> Option<B256>;

    /// Retrieves the logs bloom filter of the block
    fn logs_bloom(&self) -> Bloom;

    /// Retrieves the difficulty of the block
    fn difficulty(&self) -> U256;

    /// Retrieves the block number
    fn number(&self) -> BlockNumber;

    /// Retrieves the gas limit of the block
    fn gas_limit(&self) -> u64;

    /// Retrieves the gas used by the block
    fn gas_used(&self) -> u64;

    /// Retrieves the timestamp of the block
    fn timestamp(&self) -> u64;

    /// Retrieves the mix hash of the block, if available
    fn mix_hash(&self) -> Option<B256>;

    /// Retrieves the nonce of the block, if available
    fn nonce(&self) -> Option<B64>;

    /// Retrieves the base fee per gas of the block, if available
    fn base_fee_per_gas(&self) -> Option<u64>;

    /// Retrieves the blob gas used by the block, if available
    fn blob_gas_used(&self) -> Option<u64>;

    /// Retrieves the excess blob gas of the block, if available
    fn excess_blob_gas(&self) -> Option<u64>;

    /// Retrieves the parent beacon block root of the block, if available
    fn parent_beacon_block_root(&self) -> Option<B256>;

    /// Retrieves the requests hash of the block, if available
    fn requests_hash(&self) -> Option<B256>;

    /// Retrieves the block's extra data field
    fn extra_data(&self) -> &Bytes;

    /// Returns the blob fee for _this_ block according to the EIP-4844 spec.
    ///
    /// Returns `None` if `excess_blob_gas` is None
    fn blob_fee(&self, blob_params: BlobParams) -> Option<u128> {
        Some(blob_params.calc_blob_fee(self.excess_blob_gas()?))
    }

    /// Calculate excess blob gas for the next block according to the EIP-4844
    /// spec.
    ///
    /// Returns a `None` if no excess blob gas is set, no EIP-4844 support
    fn next_block_excess_blob_gas(&self, blob_params: BlobParams) -> Option<u64> {
        Some(blob_params.next_block_excess_blob_gas_osaka(
            self.excess_blob_gas()?,
            self.blob_gas_used()?,
            self.base_fee_per_gas()?,
        ))
    }

    /// Convenience function for [`Self::next_block_excess_blob_gas`] with an optional
    /// [`BlobParams`] argument.
    ///
    /// Returns `None` if the `blob_params` are `None`.
    fn maybe_next_block_excess_blob_gas(&self, blob_params: Option<BlobParams>) -> Option<u64> {
        self.next_block_excess_blob_gas(blob_params?)
    }

    /// Returns the blob fee for the next block according to the EIP-4844 spec.
    ///
    /// Returns `None` if `excess_blob_gas` is None.
    ///
    /// See also [BlockHeader::next_block_excess_blob_gas]
    fn next_block_blob_fee(&self, blob_params: BlobParams) -> Option<u128> {
        Some(blob_params.calc_blob_fee(self.next_block_excess_blob_gas(blob_params)?))
    }

    /// Convenience function for [`Self::next_block_blob_fee`] with an optional [`BlobParams`]
    /// argument.
    ///
    /// Returns `None` if the `blob_params` are `None`.
    fn maybe_next_block_blob_fee(&self, blob_params: Option<BlobParams>) -> Option<u128> {
        self.next_block_blob_fee(blob_params?)
    }

    /// Calculate base fee for next block according to the EIP-1559 spec.
    ///
    /// Returns a `None` if no base fee is set, no EIP-1559 support
    fn next_block_base_fee(&self, base_fee_params: BaseFeeParams) -> Option<u64> {
        Some(calc_next_block_base_fee(
            self.gas_used(),
            self.gas_limit(),
            self.base_fee_per_gas()?,
            base_fee_params,
        ))
    }

    /// Returns the parent block's number and hash
    ///
    /// Note: for the genesis block the parent number is 0 and the parent hash is the zero hash.
    fn parent_num_hash(&self) -> BlockNumHash {
        BlockNumHash { number: self.number().saturating_sub(1), hash: self.parent_hash() }
    }

    /// Checks if the header is considered empty - has no transactions, no ommers or withdrawals
    fn is_empty(&self) -> bool {
        let txs_and_ommers_empty = self.transactions_root() == EMPTY_ROOT_HASH
            && self.ommers_hash() == EMPTY_OMMER_ROOT_HASH;
        self.withdrawals_root().map_or(txs_and_ommers_empty, |withdrawals_root| {
            txs_and_ommers_empty && withdrawals_root == EMPTY_ROOT_HASH
        })
    }

    /// Checks if the block's difficulty is set to zero, indicating a Proof-of-Stake header.
    ///
    /// This function is linked to EIP-3675, proposing the consensus upgrade to Proof-of-Stake:
    /// [EIP-3675](https://eips.ethereum.org/EIPS/eip-3675#replacing-difficulty-with-0)
    ///
    /// Verifies whether, as per the EIP, the block's difficulty is updated to zero,
    /// signifying the transition to a Proof-of-Stake mechanism.
    ///
    /// Returns `true` if the block's difficulty matches the constant zero set by the EIP.
    fn is_zero_difficulty(&self) -> bool {
        self.difficulty().is_zero()
    }

    /// Checks if the block's timestamp is in the future based on the present timestamp.
    ///
    /// Clock can drift but this can be consensus issue.
    ///
    /// Note: This check is relevant only pre-merge.
    fn exceeds_allowed_future_timestamp(&self, present_timestamp: u64) -> bool {
        self.timestamp() > present_timestamp + ALLOWED_FUTURE_BLOCK_TIME_SECONDS
    }

    /// Checks if the nonce exists, and if it exists, if it's zero.
    ///
    /// If the nonce is `None`, then this returns `false`.
    fn is_nonce_zero(&self) -> bool {
        self.nonce().is_some_and(|nonce| nonce.is_zero())
    }
}

impl BlockHeader for Header {
    fn parent_hash(&self) -> B256 {
        self.parent_hash
    }

    fn ommers_hash(&self) -> B256 {
        self.ommers_hash
    }

    fn beneficiary(&self) -> Address {
        self.beneficiary
    }

    fn state_root(&self) -> B256 {
        self.state_root
    }

    fn transactions_root(&self) -> B256 {
        self.transactions_root
    }

    fn receipts_root(&self) -> B256 {
        self.receipts_root
    }

    fn withdrawals_root(&self) -> Option<B256> {
        self.withdrawals_root
    }

    fn logs_bloom(&self) -> Bloom {
        self.logs_bloom
    }

    fn difficulty(&self) -> U256 {
        self.difficulty
    }

    fn number(&self) -> BlockNumber {
        self.number
    }

    fn gas_limit(&self) -> u64 {
        self.gas_limit
    }

    fn gas_used(&self) -> u64 {
        self.gas_used
    }

    fn timestamp(&self) -> u64 {
        self.timestamp
    }

    fn mix_hash(&self) -> Option<B256> {
        Some(self.mix_hash)
    }

    fn nonce(&self) -> Option<B64> {
        Some(self.nonce)
    }

    fn base_fee_per_gas(&self) -> Option<u64> {
        self.base_fee_per_gas
    }

    fn blob_gas_used(&self) -> Option<u64> {
        self.blob_gas_used
    }

    fn excess_blob_gas(&self) -> Option<u64> {
        self.excess_blob_gas
    }

    fn parent_beacon_block_root(&self) -> Option<B256> {
        self.parent_beacon_block_root
    }

    fn requests_hash(&self) -> Option<B256> {
        self.requests_hash
    }

    fn extra_data(&self) -> &Bytes {
        &self.extra_data
    }
}

#[cfg(feature = "serde")]
impl<T: BlockHeader> BlockHeader for alloy_serde::WithOtherFields<T> {
    fn parent_hash(&self) -> B256 {
        self.inner.parent_hash()
    }

    fn ommers_hash(&self) -> B256 {
        self.inner.ommers_hash()
    }

    fn beneficiary(&self) -> Address {
        self.inner.beneficiary()
    }

    fn state_root(&self) -> B256 {
        self.inner.state_root()
    }

    fn transactions_root(&self) -> B256 {
        self.inner.transactions_root()
    }

    fn receipts_root(&self) -> B256 {
        self.inner.receipts_root()
    }

    fn withdrawals_root(&self) -> Option<B256> {
        self.inner.withdrawals_root()
    }

    fn logs_bloom(&self) -> Bloom {
        self.inner.logs_bloom()
    }

    fn difficulty(&self) -> U256 {
        self.inner.difficulty()
    }

    fn number(&self) -> u64 {
        self.inner.number()
    }

    fn gas_limit(&self) -> u64 {
        self.inner.gas_limit()
    }

    fn gas_used(&self) -> u64 {
        self.inner.gas_used()
    }

    fn timestamp(&self) -> u64 {
        self.inner.timestamp()
    }

    fn mix_hash(&self) -> Option<B256> {
        self.inner.mix_hash()
    }

    fn nonce(&self) -> Option<B64> {
        self.inner.nonce()
    }

    fn base_fee_per_gas(&self) -> Option<u64> {
        self.inner.base_fee_per_gas()
    }

    fn blob_gas_used(&self) -> Option<u64> {
        self.inner.blob_gas_used()
    }

    fn excess_blob_gas(&self) -> Option<u64> {
        self.inner.excess_blob_gas()
    }

    fn parent_beacon_block_root(&self) -> Option<B256> {
        self.inner.parent_beacon_block_root()
    }

    fn requests_hash(&self) -> Option<B256> {
        self.inner.requests_hash()
    }

    fn extra_data(&self) -> &Bytes {
        self.inner.extra_data()
    }

    fn is_empty(&self) -> bool {
        self.inner.is_empty()
    }
}

/// Bincode-compatible [`Header`] serde implementation.
#[cfg(all(feature = "serde", feature = "serde-bincode-compat"))]
pub(crate) mod serde_bincode_compat {
    use alloc::borrow::Cow;
    use alloy_primitives::{Address, BlockNumber, Bloom, Bytes, B256, B64, U256};
    use serde::{Deserialize, Deserializer, Serialize, Serializer};
    use serde_with::{DeserializeAs, SerializeAs};

    /// Bincode-compatible [`super::Header`] serde implementation.
    ///
    /// Intended to use with the [`serde_with::serde_as`] macro in the following way:
    /// ```rust
    /// use alloy_consensus::{serde_bincode_compat, Header};
    /// use serde::{Deserialize, Serialize};
    /// use serde_with::serde_as;
    ///
    /// #[serde_as]
    /// #[derive(Serialize, Deserialize)]
    /// struct Data {
    ///     #[serde_as(as = "serde_bincode_compat::Header")]
    ///     header: Header,
    /// }
    /// ```
    #[derive(Debug, Serialize, Deserialize)]
    pub struct Header<'a> {
        parent_hash: B256,
        ommers_hash: B256,
        beneficiary: Address,
        state_root: B256,
        transactions_root: B256,
        receipts_root: B256,
        #[serde(default)]
        withdrawals_root: Option<B256>,
        logs_bloom: Bloom,
        difficulty: U256,
        number: BlockNumber,
        gas_limit: u64,
        gas_used: u64,
        timestamp: u64,
        mix_hash: B256,
        nonce: B64,
        #[serde(default)]
        base_fee_per_gas: Option<u64>,
        #[serde(default)]
        blob_gas_used: Option<u64>,
        #[serde(default)]
        excess_blob_gas: Option<u64>,
        #[serde(default)]
        parent_beacon_block_root: Option<B256>,
        #[serde(default)]
        requests_hash: Option<B256>,
        extra_data: Cow<'a, Bytes>,
    }

    impl<'a> From<&'a super::Header> for Header<'a> {
        fn from(value: &'a super::Header) -> Self {
            Self {
                parent_hash: value.parent_hash,
                ommers_hash: value.ommers_hash,
                beneficiary: value.beneficiary,
                state_root: value.state_root,
                transactions_root: value.transactions_root,
                receipts_root: value.receipts_root,
                withdrawals_root: value.withdrawals_root,
                logs_bloom: value.logs_bloom,
                difficulty: value.difficulty,
                number: value.number,
                gas_limit: value.gas_limit,
                gas_used: value.gas_used,
                timestamp: value.timestamp,
                mix_hash: value.mix_hash,
                nonce: value.nonce,
                base_fee_per_gas: value.base_fee_per_gas,
                blob_gas_used: value.blob_gas_used,
                excess_blob_gas: value.excess_blob_gas,
                parent_beacon_block_root: value.parent_beacon_block_root,
                requests_hash: value.requests_hash,
                extra_data: Cow::Borrowed(&value.extra_data),
            }
        }
    }

    impl<'a> From<Header<'a>> for super::Header {
        fn from(value: Header<'a>) -> Self {
            Self {
                parent_hash: value.parent_hash,
                ommers_hash: value.ommers_hash,
                beneficiary: value.beneficiary,
                state_root: value.state_root,
                transactions_root: value.transactions_root,
                receipts_root: value.receipts_root,
                withdrawals_root: value.withdrawals_root,
                logs_bloom: value.logs_bloom,
                difficulty: value.difficulty,
                number: value.number,
                gas_limit: value.gas_limit,
                gas_used: value.gas_used,
                timestamp: value.timestamp,
                mix_hash: value.mix_hash,
                nonce: value.nonce,
                base_fee_per_gas: value.base_fee_per_gas,
                blob_gas_used: value.blob_gas_used,
                excess_blob_gas: value.excess_blob_gas,
                parent_beacon_block_root: value.parent_beacon_block_root,
                requests_hash: value.requests_hash,
                extra_data: value.extra_data.into_owned(),
            }
        }
    }

    impl SerializeAs<super::Header> for Header<'_> {
        fn serialize_as<S>(source: &super::Header, serializer: S) -> Result<S::Ok, S::Error>
        where
            S: Serializer,
        {
            Header::from(source).serialize(serializer)
        }
    }

    impl<'de> DeserializeAs<'de, super::Header> for Header<'de> {
        fn deserialize_as<D>(deserializer: D) -> Result<super::Header, D::Error>
        where
            D: Deserializer<'de>,
        {
            Header::deserialize(deserializer).map(Into::into)
        }
    }

    #[cfg(test)]
    mod tests {
        use super::super::{serde_bincode_compat, Header};
        use arbitrary::Arbitrary;
        use bincode::config;
        use rand::Rng;
        use serde::{Deserialize, Serialize};
        use serde_with::serde_as;

        #[test]
        fn test_header_bincode_roundtrip() {
            #[serde_as]
            #[derive(Debug, PartialEq, Eq, Serialize, Deserialize)]
            struct Data {
                #[serde_as(as = "serde_bincode_compat::Header")]
                header: Header,
            }

            let mut bytes = [0u8; 1024];
            rand::thread_rng().fill(bytes.as_mut_slice());
            let data = Data {
                header: Header::arbitrary(&mut arbitrary::Unstructured::new(&bytes)).unwrap(),
            };

            let encoded = bincode::serde::encode_to_vec(&data, config::legacy()).unwrap();
            let (decoded, _) =
                bincode::serde::decode_from_slice::<Data, _>(&encoded, config::legacy()).unwrap();
            assert_eq!(decoded, data);
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use alloy_primitives::{b256, hex};

    #[test]
    fn decode_header_rlp() {
        // ronin header
        let raw = hex!("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");
        let header = Header::decode(&mut raw.as_slice()).unwrap();
        assert_eq!(
            header.hash_slow(),
            b256!("0x4f05e4392969fc82e41f6d6a8cea379323b0b2d3ddf7def1a33eec03883e3a33")
        );
    }
}

#[cfg(all(test, feature = "serde"))]
mod serde_tests {
    use super::*;
    use alloy_primitives::b256;

    #[test]
    fn test_header_serde_json_roundtrip() {
        let raw = r#"{"parentHash":"0x0000000000000000000000000000000000000000000000000000000000000000","sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","miner":"0x0000000000000000000000000000000000000000","stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","transactionsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","receiptsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","difficulty":"0x0","number":"0x0","gasLimit":"0x0","gasUsed":"0x0","timestamp":"0x0","extraData":"0x","mixHash":"0x0000000000000000000000000000000000000000000000000000000000000000","nonce":"0x0000000000000000","baseFeePerGas":"0x1","withdrawalsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"}"#;
        let header = Header {
            base_fee_per_gas: Some(1),
            withdrawals_root: Some(EMPTY_ROOT_HASH),
            ..Default::default()
        };

        let encoded = serde_json::to_string(&header).unwrap();
        assert_eq!(encoded, raw);

        let decoded: Header = serde_json::from_str(&encoded).unwrap();
        assert_eq!(decoded, header);

        // Create a vector to store the encoded RLP
        let mut encoded_rlp = Vec::new();

        // Encode the header data
        decoded.encode(&mut encoded_rlp);

        // Decode the RLP data
        let decoded_rlp = Header::decode(&mut encoded_rlp.as_slice()).unwrap();

        // Check that the decoded RLP data matches the original header data
        assert_eq!(decoded_rlp, decoded);
    }

    #[test]
    fn serde_rlp_prague() {
        // Note: Some fields are renamed from eth_getHeaderByHash
        let raw = r#"{"baseFeePerGas":"0x7","blobGasUsed":"0x20000","difficulty":"0x0","excessBlobGas":"0x40000","extraData":"0xd883010e0c846765746888676f312e32332e32856c696e7578","gasLimit":"0x1c9c380","gasUsed":"0x5208","hash":"0x661da523f3e44725f3a1cee38183d35424155a05674609a9f6ed81243adf9e26","logsBloom":"0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000","miner":"0xf97e180c050e5ab072211ad2c213eb5aee4df134","mixHash":"0xe6d9c084dd36560520d5776a5387a82fb44793c9cd1b69afb61d53af29ee64b0","nonce":"0x0000000000000000","number":"0x315","parentBeaconBlockRoot":"0xd0bdb48ab45028568e66c8ddd600ac4c2a52522714bbfbf00ea6d20ba40f3ae2","parentHash":"0x60f1563d2c572116091a4b91421d8d972118e39604d23455d841f9431cea4b6a","receiptsRoot":"0xeaa8c40899a61ae59615cf9985f5e2194f8fd2b57d273be63bde6733e89b12ab","requestsHash":"0x6036c41849da9c076ed79654d434017387a88fb833c2856b32e18218b3341c5f","sha3Uncles":"0x1dcc4de8dec75d7aab85b567b6ccd41ad312451b948a7413f0a142fd40d49347","stateRoot":"0x8101d88f2761eb9849634740f92fe09735551ad5a4d5e9da9bcae1ef4726a475","timestamp":"0x6712ba6e","transactionsRoot":"0xf543eb3d405d2d6320344d348b06703ff1abeef71288181a24061e53f89bb5ef","withdrawalsRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421"}
"#;
        let header = serde_json::from_str::<Header>(raw).unwrap();
        let hash = header.hash_slow();
        assert_eq!(hash, b256!("661da523f3e44725f3a1cee38183d35424155a05674609a9f6ed81243adf9e26"));
        let mut v = Vec::new();
        header.encode(&mut v);
        let decoded = Header::decode(&mut v.as_slice()).unwrap();
        assert_eq!(decoded, header);
    }
}