89 lines
2.4 KiB
Go
89 lines
2.4 KiB
Go
package eth
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import (
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"context"
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"errors"
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"fmt"
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"math/big"
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"github.com/vulcanize/vulcanizedb/pkg/datastore/postgres"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/rlp"
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"github.com/ethereum/go-ethereum/rpc"
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"github.com/hashicorp/golang-lru"
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"github.com/vulcanize/vulcanizedb/pkg/ipfs"
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"github.com/vulcanize/vulcanizedb/pkg/super_node"
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)
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var (
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errPendingBlockNumber = errors.New("pending block number not supported")
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)
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type Backend struct {
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retriever super_node.CIDRetriever
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fetcher ipfs.IPLDFetcher
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db *postgres.DB
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headerCache *lru.Cache // Cache for the most recent block headers
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tdCache *lru.Cache // Cache for the most recent block total difficulties
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numberCache *lru.Cache // Cache for the most recent block numbers
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}
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func NewEthBackend(r super_node.CIDRetriever, f ipfs.IPLDFetcher) *Backend {
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return &Backend{
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retriever: r,
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fetcher: f,
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db: r.Database(),
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}
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}
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func (b *Backend) HeaderByNumber(ctx context.Context, blockNumber rpc.BlockNumber) (*types.Header, error) {
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number := blockNumber.Int64()
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var err error
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if blockNumber == rpc.LatestBlockNumber {
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number, err = b.retriever.RetrieveLastBlockNumber()
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if err != nil {
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return nil, err
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}
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}
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if blockNumber == rpc.PendingBlockNumber {
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return nil, errPendingBlockNumber
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}
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// Retrieve the CIDs for headers at this height
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tx, err := b.db.Beginx()
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if err != nil {
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return nil, err
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}
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headerCids, err := b.retriever.RetrieveHeaderCIDs(tx, number)
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if err != nil {
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return nil, err
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}
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if err := tx.Commit(); err != nil {
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return nil, err
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}
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// If there are none, throw an error
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if len(headerCids) < 1 {
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return nil, fmt.Errorf("header at block %d is not available", number)
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}
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// Fetch the header IPLDs for those CIDs
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headerIPLDs, err := b.fetcher.FetchHeaders(headerCids)
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if err != nil {
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return nil, err
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}
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// Decode the first header at this block height and return it
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// We throw an error in FetchHeaders() if the number of headers does not match the number of CIDs and we already
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// confirmed the number of CIDs is greater than 0 so there is no need to bound check the slice before accessing
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header := new(types.Header)
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if err := rlp.DecodeBytes(headerIPLDs[0].RawData(), header); err != nil {
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return nil, err
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}
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return header, nil
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}
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func (b *Backend) GetTd(blockHash common.Hash) *big.Int {
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panic("implement me")
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}
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