forest-filecoin 0.33.5

// Copyright 2019-2026 ChainSafe Systems
// SPDX-License-Identifier: Apache-2.0, MIT

use super::{
    Error,
    index::{ChainIndex, ResolveNullTipset},
    tipset_tracker::TipsetTracker,
};
use crate::networks::{ChainConfig, Height};
use crate::prelude::*;
use crate::rpc::{
    chain::ChainGetTipSetFinalityStatus,
    eth::{eth_tx_from_signed_eth_message, types::EthHash},
};
use crate::shim::clock::ChainEpoch;
use crate::shim::{executor::Receipt, message::Message, version::NetworkVersion};
use crate::state_manager::ExecutedTipset;
use crate::utils::db::{BlockstoreExt, CborStoreExt};
use crate::{
    blocks::{CachingBlockHeader, Tipset, TipsetKey, TxMeta},
    db::{DbImpl, HeaviestTipsetKeyProvider},
    message::{ChainMessage, SignedMessage},
};
use crate::{db::EthMappingsStoreExt, rpc::chain::PathChange};
use crate::{fil_cns, utils::cache::SizeTrackingCache};
use crate::{
    interpreter::{BlockMessages, VMTrace},
    rpc::chain::PathChanges,
};
use ahash::HashMap;
use fil_actors_shared::fvm_ipld_amt::Amtv0 as Amt;
use fvm_ipld_encoding::CborStore;
use nonzero_ext::nonzero;
use parking_lot::RwLock;
use serde::{Serialize, de::DeserializeOwned};
use std::{
    num::NonZeroUsize,
    sync::atomic::{self, AtomicI64},
};
use tokio::sync::broadcast;
use tracing::{debug, error, trace, warn};

// A cap on the size of the future_sink
const SINK_CAP: usize = 200;

// Assume a tipset has 5 blocks on average, we cache 1-day-worth of validated blocks. (5 * 2 * 60 * 24 = 14400)
const VALIDATED_BLOCKS_CACHE_SIZE: NonZeroUsize = nonzero!(14400usize);

/// Disambiguate the type to signify that we are expecting a delta and not an actual epoch/height
/// while maintaining the same type.
pub type ChainEpochDelta = ChainEpoch;

/// `Enum` for `pubsub` channel that defines message type variant and data
/// contained in message type.
pub type HeadChange = PathChange<Tipset>;

pub type HeadChanges = PathChanges<Tipset>;

/// Stores chain data such as heaviest tipset and cached tipset info at each
/// epoch. This structure is thread-safe, and all caches are wrapped in a mutex
/// to allow a consistent `ChainStore` to be shared across tasks.
pub struct ChainStore {
    /// Publisher for head change events
    head_changes_tx: broadcast::Sender<HeadChanges>,

    /// Heaviest tipset cache
    heaviest_tipset: Arc<RwLock<Tipset>>,

    /// F3 finalized tipset cache
    f3_finalized_tipset: Arc<RwLock<Option<Tipset>>>,

    /// EC calculator finalized epoch cache
    ec_calculator_finalized_epoch: Arc<AtomicI64>,

    /// Used as a cache for tipset `lookbacks`.
    chain_index: ChainIndex,

    /// Tracks blocks for the purpose of forming tipsets.
    tipset_tracker: TipsetTracker<DbImpl>,

    genesis_block_header: Arc<CachingBlockHeader>,

    /// validated blocks
    pub(crate) validated_blocks: SizeTrackingCache<CidWrapper, ()>,

    /// Needed by the Ethereum mapping.
    chain_config: Arc<ChainConfig>,

    /// Cache for messages in tipsets, keyed by tipset key.
    messages_in_tipset_cache: MessagesInTipsetCache,
}

impl ShallowClone for ChainStore {
    fn shallow_clone(&self) -> Self {
        Self {
            head_changes_tx: self.head_changes_tx.clone(),
            heaviest_tipset: self.heaviest_tipset.shallow_clone(),
            f3_finalized_tipset: self.f3_finalized_tipset.shallow_clone(),
            ec_calculator_finalized_epoch: self.ec_calculator_finalized_epoch.shallow_clone(),
            chain_index: self.chain_index.shallow_clone(),
            tipset_tracker: self.tipset_tracker.shallow_clone(),
            genesis_block_header: self.genesis_block_header.shallow_clone(),
            validated_blocks: self.validated_blocks.shallow_clone(),
            chain_config: self.chain_config.shallow_clone(),
            messages_in_tipset_cache: self.messages_in_tipset_cache.shallow_clone(),
        }
    }
}

impl ChainStore {
    pub fn new(
        db: impl Into<DbImpl>,
        chain_config: Arc<ChainConfig>,
        genesis_block_header: CachingBlockHeader,
    ) -> anyhow::Result<Self> {
        let db = db.into();
        let (publisher, _) = broadcast::channel(SINK_CAP);
        let head = if let Some(head_tsk) = db
            .heaviest_tipset_key()
            .context("failed to load head tipset key")?
        {
            Tipset::load_required(&db, &head_tsk)
                .with_context(|| format!("failed to load head tipset with key {head_tsk}"))?
        } else {
            Tipset::from(&genesis_block_header)
        };
        let heaviest_tipset = Arc::new(RwLock::new(head.shallow_clone()));
        let f3_finalized_tipset: Arc<RwLock<Option<Tipset>>> = Default::default();
        let chain_index = ChainIndex::new(db.shallow_clone());
        let ec_calculator_finalized_epoch = Arc::new(AtomicI64::new(
            ChainGetTipSetFinalityStatus::get_ec_finality_epoch(&chain_index, &chain_config, &head),
        ));
        let chain_index = chain_index.with_is_tipset_finalized(Arc::new({
            let f3_finalized_tipset = f3_finalized_tipset.shallow_clone();
            let ec_calculator_finalized_epoch = ec_calculator_finalized_epoch.shallow_clone();
            move |ts| {
                let finalized = f3_finalized_tipset
                    .read()
                    .as_ref()
                    .map(|ts| ts.epoch())
                    .unwrap_or_default()
                    .max(ec_calculator_finalized_epoch.load(atomic::Ordering::Acquire));
                ts.epoch() <= finalized
            }
        }));
        Ok(Self {
            head_changes_tx: publisher,
            chain_index,
            tipset_tracker: TipsetTracker::new(db, chain_config.clone()),
            heaviest_tipset,
            f3_finalized_tipset,
            ec_calculator_finalized_epoch,
            genesis_block_header: genesis_block_header.into(),
            validated_blocks: SizeTrackingCache::new_with_metrics(
                "validated_blocks",
                VALIDATED_BLOCKS_CACHE_SIZE,
            ),
            chain_config,
            messages_in_tipset_cache: Default::default(),
        })
    }

    /// Sets F3 finalized tipset
    pub fn set_f3_finalized_tipset(&self, ts: Tipset) {
        self.f3_finalized_tipset.write().replace(ts);
    }

    /// Gets F3 finalized tipset
    pub fn f3_finalized_tipset(&self) -> Option<Tipset> {
        self.f3_finalized_tipset.read().clone()
    }

    /// Gets the EC calculator finalized epoch
    pub fn ec_calculator_finalized_epoch(&self) -> ChainEpoch {
        self.ec_calculator_finalized_epoch
            .load(atomic::Ordering::Acquire)
    }

    /// Cache for messages in tipsets, keyed by tipset key.
    pub fn messages_in_tipset_cache(&self) -> &MessagesInTipsetCache {
        &self.messages_in_tipset_cache
    }

    /// Sets heaviest tipset
    pub fn set_heaviest_tipset(&self, head: Tipset) -> Result<(), Error> {
        head.key().save(self.db())?;
        self.db().set_heaviest_tipset_key(head.key())?;
        let old_head = std::mem::replace(&mut *self.heaviest_tipset.write(), head.shallow_clone());
        self.ec_calculator_finalized_epoch.store(
            ChainGetTipSetFinalityStatus::get_ec_finality_epoch(
                self.chain_index(),
                self.chain_config(),
                &head,
            ),
            atomic::Ordering::Release,
        );
        if crate::utils::broadcast::has_subscribers(&self.head_changes_tx) {
            let changes = match crate::rpc::chain::chain_get_path(self, old_head.key(), head.key())
            {
                Ok(changes) => changes,
                Err(e) => {
                    // Do not warn when the old head is genesis
                    if old_head.epoch() > 0 {
                        error!("failed to get chain path changes: {e:#}");
                    }
                    // Fallback to single apply
                    PathChanges {
                        applies: vec![head],
                        reverts: vec![],
                    }
                }
            };
            if self.head_changes_tx.send(changes).is_err() {
                debug!("did not publish changes, no active receivers");
            }
        }

        Ok(())
    }

    /// Adds a block header to the tipset tracker, which tracks valid headers.
    pub fn add_to_tipset_tracker(&self, header: &CachingBlockHeader) {
        self.tipset_tracker.add(header);
    }

    /// Writes tipset block headers to data store and updates heaviest tipset
    /// with other compatible tracked headers.
    pub fn put_tipset(&self, ts: &Tipset) -> Result<(), Error> {
        persist_objects(self.db(), ts.block_headers().iter())?;

        // Expand tipset to include other compatible blocks at the epoch.
        let expanded = self.expand_tipset(ts.min_ticket_block().clone())?;
        self.update_heaviest(expanded)?;
        Ok(())
    }

    /// Reads the `TipsetKey` from the blockstore for `EthAPI` queries.
    pub fn get_required_tipset_key(&self, hash: &EthHash) -> Result<TipsetKey, Error> {
        Ok(TipsetKey::load(self.db(), &hash.to_cid())?)
    }

    /// Writes with timestamp the `Hash` to `Cid` mapping to the blockstore for `EthAPI` queries.
    pub fn put_mapping(&self, k: EthHash, v: Cid, timestamp: u64) -> Result<(), Error> {
        self.db().write_obj(&k, &(v, timestamp))?;
        Ok(())
    }

    /// Reads the `Cid` from the blockstore for `EthAPI` queries.
    pub fn get_mapping(&self, hash: &EthHash) -> Result<Option<Cid>, Error> {
        Ok(self.db().read_obj::<(Cid, u64)>(hash)?.map(|(cid, _)| cid))
    }

    /// Expands tipset to tipset with all other headers in the same epoch using
    /// the tipset tracker.
    fn expand_tipset(&self, header: CachingBlockHeader) -> Result<Tipset, Error> {
        self.tipset_tracker.expand(header)
    }

    pub fn genesis_block_header(&self) -> &CachingBlockHeader {
        &self.genesis_block_header
    }

    /// Returns the currently tracked heaviest tipset.
    pub fn heaviest_tipset(&self) -> Tipset {
        self.heaviest_tipset.read().clone()
    }

    /// Returns the genesis tipset.
    pub fn genesis_tipset(&self) -> Tipset {
        Tipset::from(self.genesis_block_header())
    }

    /// Subscribes head changes.
    pub fn subscribe_head_changes(&self) -> broadcast::Receiver<HeadChanges> {
        self.head_changes_tx.subscribe()
    }

    /// Returns a borrowed key-value store instance.
    pub fn db(&self) -> &DbImpl {
        self.chain_index().db()
    }

    /// Returns an owned key-value store instance.
    pub fn db_owned(&self) -> DbImpl {
        self.chain_index().db_owned()
    }

    /// Returns the chain index
    pub fn chain_index(&self) -> &ChainIndex {
        &self.chain_index
    }

    /// Returns the chain configuration
    pub fn chain_config(&self) -> &Arc<ChainConfig> {
        &self.chain_config
    }

    /// Lotus often treats an empty [`TipsetKey`] as shorthand for "the heaviest tipset".
    /// You may opt-in to that behavior by calling this method with [`None`].
    ///
    /// This calls fails if the tipset is missing or invalid.
    #[tracing::instrument(skip_all)]
    pub fn load_required_tipset_or_heaviest<'a>(
        &self,
        maybe_key: impl Into<Option<&'a TipsetKey>>,
    ) -> Result<Tipset, Error> {
        match maybe_key.into() {
            Some(key) => self.chain_index.load_required_tipset(key),
            None => Ok(self.heaviest_tipset()),
        }
    }

    /// Returns [`None`] when `ts` has no known child on the current heaviest chain
    /// (e.g. `ts` is the chain head). Blockstore errors are returned as [`Err`].
    pub fn load_child_tipset(&self, ts: &Tipset) -> Result<Option<Tipset>, Error> {
        let head = self.heaviest_tipset();
        if head.parents() == ts.key() {
            Ok(Some(head))
        } else if head.epoch() > ts.epoch() {
            match self.chain_index().tipset_by_height(
                ts.epoch() + 1,
                head,
                ResolveNullTipset::TakeNewer,
            )? {
                Some(maybe_child) if maybe_child.parents() == ts.key() => Ok(Some(maybe_child)),
                _ => Ok(None),
            }
        } else {
            Ok(None)
        }
    }

    /// Determines if provided tipset is heavier than existing known heaviest
    /// tipset
    fn update_heaviest(&self, ts: Tipset) -> Result<(), Error> {
        // Calculate heaviest weight before matching to avoid deadlock with mutex
        let heaviest_weight = fil_cns::weight(self.db(), &self.heaviest_tipset())?;

        let new_weight = fil_cns::weight(self.db(), &ts)?;
        let curr_weight = heaviest_weight;

        if new_weight > curr_weight {
            self.set_heaviest_tipset(ts)?;
        }
        Ok(())
    }

    /// Checks metadata file if block has already been validated.
    pub fn is_block_validated(&self, cid: &Cid) -> bool {
        let validated = self.validated_blocks.get(cid).is_some();
        if validated {
            trace!("Block {cid} was previously validated");
        }
        validated
    }

    /// Marks block as validated in the metadata file.
    pub fn mark_block_as_validated(&self, cid: &Cid) {
        self.validated_blocks.insert((*cid).into(), ());
    }

    pub fn unmark_block_as_validated(&self, cid: &Cid) {
        self.validated_blocks.remove(cid);
    }

    /// Retrieves ordered valid messages from a `Tipset`. This will only include
    /// messages that will be passed through the VM.
    pub fn messages_for_tipset(&self, ts: &Tipset) -> Result<Arc<Vec<ChainMessage>>, Error> {
        Ok(self
            .messages_in_tipset_cache()
            .get_or_insert_with(ts.key(), || {
                let bmsgs = BlockMessages::for_tipset(self.db(), ts)?;
                anyhow::Ok(
                    bmsgs
                        .into_iter()
                        .flat_map(|bm| bm.messages)
                        .collect_vec()
                        .into(),
                )
            })?)
    }

    /// Gets look-back tipset (and state-root of that tipset) for block
    /// validations.
    ///
    /// The look-back tipset for a round is the tipset with epoch `round -
    /// chain_finality`. [Chain
    /// finality](https://docs.filecoin.io/reference/general/glossary/#finality)
    /// is usually 900. The `heaviest_tipset` is a reference point in the
    /// blockchain. It must be a child of the look-back tipset.
    pub fn get_lookback_tipset_for_round(
        chain_index: &ChainIndex,
        chain_config: &Arc<ChainConfig>,
        heaviest_tipset: &Tipset,
        round: ChainEpoch,
    ) -> Result<(Tipset, Cid), Error> {
        let version = chain_config.network_version(round);
        let lb = if version <= NetworkVersion::V3 {
            ChainEpoch::from(10)
        } else {
            chain_config.policy.chain_finality
        };
        let lbr = (round - lb).max(0);

        // More null blocks than lookback
        if lbr >= heaviest_tipset.epoch() {
            // This situation is extremely rare so it's fine to compute the
            // state-root without caching.
            let genesis_timestamp = heaviest_tipset.genesis(chain_index.db())?.timestamp;
            let beacon = Arc::new(chain_config.get_beacon_schedule(genesis_timestamp));
            let ExecutedTipset { state_root, .. } = crate::state_manager::apply_block_messages(
                genesis_timestamp,
                chain_index.shallow_clone(),
                chain_config.shallow_clone(),
                beacon,
                // Using shared WASM engine here as creating new WASM engines is expensive
                // (takes seconds to minutes). It's only acceptable here because this situation is
                // so rare (may happen in dev-networks, doesn't happen in calibnet or mainnet.)
                &crate::shim::machine::GLOBAL_MULTI_ENGINE,
                heaviest_tipset.clone(),
                crate::state_manager::NO_CALLBACK,
                VMTrace::NotTraced,
            )
            .map_err(|e| Error::Other(e.to_string()))?;
            return Ok((heaviest_tipset.clone(), state_root));
        }

        let next_ts = chain_index
            .load_required_tipset_by_height(
                lbr + 1,
                heaviest_tipset.clone(),
                ResolveNullTipset::TakeNewer,
            )
            .map_err(|e| Error::Other(format!("Could not get tipset by height {e:?}")))?;
        if lbr > next_ts.epoch() {
            return Err(Error::Other(format!(
                "failed to find non-null tipset {:?} {} which is known to exist, found {:?} {}",
                heaviest_tipset.key(),
                heaviest_tipset.epoch(),
                next_ts.key(),
                next_ts.epoch()
            )));
        }
        let lbts = chain_index
            .load_required_tipset(next_ts.parents())
            .map_err(|e| Error::Other(format!("Could not get tipset from keys {e:?}")))?;
        Ok((lbts, *next_ts.parent_state()))
    }

    /// Filter [`SignedMessage`]'s to keep only the most recent ones, then write corresponding entries to the Ethereum mapping.
    pub fn process_signed_messages(&self, messages: &[(SignedMessage, u64)]) -> anyhow::Result<()> {
        let eth_txs: Vec<(EthHash, Cid, u64, usize)> = messages
            .iter()
            .enumerate()
            .filter_map(|(i, (smsg, timestamp))| {
                if let Ok((_, tx)) =
                    eth_tx_from_signed_eth_message(smsg, self.chain_config.eth_chain_id)
                {
                    if let Ok(hash) = tx.eth_hash() {
                        // newest messages are the ones with lowest index
                        Some((hash.into(), smsg.cid(), *timestamp, i))
                    } else {
                        None
                    }
                } else {
                    None
                }
            })
            .collect();
        let filtered = filter_lowest_index(eth_txs);
        let num_entries = filtered.len();

        // write back
        for (k, v, timestamp) in filtered.into_iter() {
            tracing::trace!("Insert mapping {} => {}", k, v);
            self.put_mapping(k, v, timestamp)?;
        }
        tracing::trace!("Wrote {} entries in Ethereum mapping", num_entries);
        Ok(())
    }

    pub fn headers_delegated_messages<'a>(
        &self,
        headers: impl Iterator<Item = &'a CachingBlockHeader>,
    ) -> anyhow::Result<Vec<(SignedMessage, u64)>> {
        let mut delegated_messages = vec![];

        // Hygge is the start of Ethereum support in the FVM (through the FEVM actor).
        // Before this height, no notion of an Ethereum-like API existed.
        let filtered_headers =
            headers.filter(|bh| bh.epoch >= self.chain_config.epoch(Height::Hygge));

        for bh in filtered_headers {
            if let Ok((_, secp_cids)) = block_messages(self.db(), bh) {
                let mut messages: Vec<_> = secp_cids
                    .into_iter()
                    .filter(|msg| msg.is_delegated())
                    .map(|m| (m, bh.timestamp))
                    .collect();
                delegated_messages.append(&mut messages);
            }
        }

        Ok(delegated_messages)
    }
}

fn filter_lowest_index(values: Vec<(EthHash, Cid, u64, usize)>) -> Vec<(EthHash, Cid, u64)> {
    let map: HashMap<EthHash, (Cid, u64, usize)> = values.into_iter().fold(
        HashMap::default(),
        |mut acc, (hash, cid, timestamp, index)| {
            acc.entry(hash)
                .and_modify(|&mut (_, _, ref mut min_index)| {
                    if index < *min_index {
                        *min_index = index;
                    }
                })
                .or_insert((cid, timestamp, index));
            acc
        },
    );

    map.into_iter()
        .map(|(hash, (cid, timestamp, _))| (hash, cid, timestamp))
        .collect()
}

/// Returns a Tuple of BLS messages of type `UnsignedMessage` and SECP messages
/// of type `SignedMessage`
pub fn block_messages<DB>(
    db: &DB,
    bh: &CachingBlockHeader,
) -> Result<(Vec<Message>, Vec<SignedMessage>), Error>
where
    DB: Blockstore,
{
    let (bls_cids, secpk_cids) = read_msg_cids(db, bh)?;

    let bls_msgs: Vec<Message> = messages_from_cids(db, &bls_cids)?;
    let secp_msgs: Vec<SignedMessage> = messages_from_cids(db, &secpk_cids)?;

    Ok((bls_msgs, secp_msgs))
}

/// Returns a tuple of `UnsignedMessage` and `SignedMessages` from their CID
pub fn block_messages_from_cids<DB>(
    db: &DB,
    bls_cids: &[Cid],
    secp_cids: &[Cid],
) -> Result<(Vec<Message>, Vec<SignedMessage>), Error>
where
    DB: Blockstore,
{
    let bls_msgs: Vec<Message> = messages_from_cids(db, bls_cids)?;
    let secp_msgs: Vec<SignedMessage> = messages_from_cids(db, secp_cids)?;

    Ok((bls_msgs, secp_msgs))
}

/// Returns a tuple of CIDs for both unsigned and signed messages
pub fn read_msg_cids<DB>(
    db: &DB,
    block_header: &CachingBlockHeader,
) -> Result<(Vec<Cid>, Vec<Cid>), Error>
where
    DB: Blockstore,
{
    let msg_cid = &block_header.messages;
    if let Some(roots) = db.get_cbor::<TxMeta>(msg_cid)? {
        let bls_cids = read_amt_cids(db, &roots.bls_message_root)?;
        let secpk_cids = read_amt_cids(db, &roots.secp_message_root)?;
        Ok((bls_cids, secpk_cids))
    } else {
        Err(Error::UndefinedKey(format!(
            "no msg root with cid {msg_cid} at epoch {} in block {}",
            block_header.epoch,
            block_header.cid(),
        )))
    }
}

/// Persists slice of `serializable` objects to `blockstore`.
pub fn persist_objects<'a, DB, C>(
    db: &DB,
    headers: impl Iterator<Item = &'a C>,
) -> Result<(), Error>
where
    DB: Blockstore,
    C: 'a + Serialize,
{
    for chunk in &headers.chunks(256) {
        db.bulk_put(chunk, DB::default_code())?;
    }
    Ok(())
}

/// Returns a vector of CIDs from provided root CID
fn read_amt_cids<DB>(db: &DB, root: &Cid) -> Result<Vec<Cid>, Error>
where
    DB: Blockstore,
{
    let amt = Amt::<Cid, _>::load(root, db)?;

    let mut cids = Vec::with_capacity(amt.count() as usize);
    amt.for_each_cacheless(|_, c| {
        cids.push(*c);
        Ok(())
    })?;

    Ok(cids)
}

/// Attempts to de-serialize to unsigned message or signed message and then
/// returns it as a [`ChainMessage`].
pub fn get_chain_message<DB>(db: &DB, key: &Cid) -> Result<ChainMessage, Error>
where
    DB: Blockstore,
{
    db.get_cbor(key)?
        .ok_or_else(|| Error::UndefinedKey(key.to_string()))
}

/// A cache structure mapping tipset keys to messages. The regular [`messages_for_tipset`], based
/// on performance measurements, is resource-intensive and can be a bottleneck for certain
/// use-cases. This cache is intended to be used with a complementary function;
/// [`messages_for_tipset_with_cache`].
#[derive(derive_more::Deref)]
pub struct MessagesInTipsetCache(SizeTrackingCache<TipsetKey, Arc<Vec<ChainMessage>>>);

impl MessagesInTipsetCache {
    pub fn new(capacity: NonZeroUsize) -> Self {
        Self(SizeTrackingCache::new_with_metrics(
            "msg_in_tipset",
            capacity,
        ))
    }

    /// Reads the intended cache size for this process from the environment or uses the default.
    fn read_cache_size() -> NonZeroUsize {
        // Arbitrary number, can be adjusted
        const DEFAULT: NonZeroUsize = nonzero!(1024usize);
        std::env::var("FOREST_MESSAGES_IN_TIPSET_CACHE_SIZE")
            .ok()
            .and_then(|s| s.parse().ok())
            .unwrap_or(DEFAULT)
    }
}

impl Default for MessagesInTipsetCache {
    fn default() -> Self {
        Self::new(Self::read_cache_size())
    }
}

impl ShallowClone for MessagesInTipsetCache {
    fn shallow_clone(&self) -> Self {
        Self(self.deref().shallow_clone())
    }
}

/// Returns messages from key-value store based on a slice of [`Cid`]s.
pub fn messages_from_cids<DB, T>(db: &DB, keys: &[Cid]) -> Result<Vec<T>, Error>
where
    DB: Blockstore,
    T: DeserializeOwned,
{
    keys.iter().map(|k| message_from_cid(db, k)).collect()
}

/// Returns message from key-value store based on a [`Cid`].
pub fn message_from_cid<DB, T>(db: &DB, key: &Cid) -> Result<T, Error>
where
    DB: Blockstore,
    T: DeserializeOwned,
{
    db.get_cbor(key)?
        .ok_or_else(|| Error::UndefinedKey(key.to_string()))
}

/// Returns parent message receipt given `block_header` and message index.
pub fn get_parent_receipt(
    db: &impl Blockstore,
    block_header: &CachingBlockHeader,
    i: usize,
) -> Result<Option<Receipt>, Error> {
    Ok(Receipt::get_receipt(
        db,
        &block_header.message_receipts,
        i as u64,
    )?)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::utils::multihash::prelude::*;
    use crate::{blocks::RawBlockHeader, shim::address::Address};
    use fvm_ipld_encoding::DAG_CBOR;

    #[test]
    fn genesis_test() {
        let db = Arc::new(crate::db::MemoryDB::default());
        let chain_config = Arc::new(ChainConfig::default());

        let gen_block = CachingBlockHeader::new(RawBlockHeader {
            miner_address: Address::new_id(0),
            state_root: Cid::new_v1(DAG_CBOR, MultihashCode::Identity.digest(&[])),
            epoch: 1,
            weight: 2u32.into(),
            messages: Cid::new_v1(DAG_CBOR, MultihashCode::Identity.digest(&[])),
            message_receipts: Cid::new_v1(DAG_CBOR, MultihashCode::Identity.digest(&[])),
            ..Default::default()
        });
        let cs = ChainStore::new(db, chain_config, gen_block.clone()).unwrap();

        assert_eq!(cs.genesis_block_header(), &gen_block);
    }

    #[test]
    fn block_validation_cache_basic() {
        let db = DbImpl::from(Arc::new(crate::db::MemoryDB::default()));
        let chain_config = Arc::new(ChainConfig::default());
        let gen_block = CachingBlockHeader::new(RawBlockHeader {
            miner_address: Address::new_id(0),
            ..Default::default()
        });

        let cs = ChainStore::new(db, chain_config, gen_block).unwrap();

        let cid = Cid::new_v1(DAG_CBOR, MultihashCode::Blake2b256.digest(&[1, 2, 3]));
        assert!(!cs.is_block_validated(&cid));

        cs.mark_block_as_validated(&cid);
        assert!(cs.is_block_validated(&cid));
    }

    #[test]
    fn test_messages_in_tipset_cache() {
        let cache = MessagesInTipsetCache::new(nonzero!(2_usize));
        let key1 = TipsetKey::from(nunny::vec![Cid::new_v1(
            DAG_CBOR,
            MultihashCode::Blake2b256.digest(&[1])
        )]);
        assert!(cache.get(&key1).is_none());

        let msgs = Arc::new(vec![Message::default().into()]);
        cache.insert(key1.clone(), msgs.clone());
        assert_eq!(&msgs, &cache.get(&key1).unwrap());

        let inserter_executed: std::sync::atomic::AtomicBool =
            std::sync::atomic::AtomicBool::new(false);
        let key_inserter = || {
            inserter_executed.store(true, std::sync::atomic::Ordering::Relaxed);
            anyhow::Ok(msgs.clone())
        };

        assert_eq!(
            &msgs,
            &cache.get_or_insert_with(&key1, key_inserter).unwrap()
        );
        assert!(!inserter_executed.load(std::sync::atomic::Ordering::Relaxed));

        let key2 = TipsetKey::from(nunny::vec![Cid::new_v1(
            DAG_CBOR,
            MultihashCode::Blake2b256.digest(&[2])
        )]);

        assert!(cache.get(&key2).is_none());
        assert_eq!(
            &msgs,
            &cache.get_or_insert_with(&key2, key_inserter).unwrap()
        );
        assert!(inserter_executed.load(std::sync::atomic::Ordering::Relaxed));
    }
}