path: root/light/odr_util.go

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package light

import (
    "bytes"
    "context"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core"
    "github.com/ethereum/go-ethereum/core/types"
    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/rlp"
)

var sha3_nil = crypto.Keccak256Hash(nil)

func GetHeaderByNumber(ctx context.Context, odr OdrBackend, number uint64) (*types.Header, error) {
    db := odr.Database()
    hash := core.GetCanonicalHash(db, number)
    if (hash != common.Hash{}) {
        // if there is a canonical hash, there is a header too
        header := core.GetHeader(db, hash, number)
        if header == nil {
            panic("Canonical hash present but header not found")
        }
        return header, nil
    }

    var (
        chtCount, sectionHeadNum uint64
        sectionHead              common.Hash
    )
    if odr.ChtIndexer() != nil {
        chtCount, sectionHeadNum, sectionHead = odr.ChtIndexer().Sections()
        canonicalHash := core.GetCanonicalHash(db, sectionHeadNum)
        // if the CHT was injected as a trusted checkpoint, we have no canonical hash yet so we accept zero hash too
        for chtCount > 0 && canonicalHash != sectionHead && canonicalHash != (common.Hash{}) {
            chtCount--
            if chtCount > 0 {
                sectionHeadNum = chtCount*CHTFrequencyClient - 1
                sectionHead = odr.ChtIndexer().SectionHead(chtCount - 1)
                canonicalHash = core.GetCanonicalHash(db, sectionHeadNum)
            }
        }
    }
    if number >= chtCount*CHTFrequencyClient {
        return nil, ErrNoTrustedCht
    }
    r := &ChtRequest{ChtRoot: GetChtRoot(db, chtCount-1, sectionHead), ChtNum: chtCount - 1, BlockNum: number}
    if err := odr.Retrieve(ctx, r); err != nil {
        return nil, err
    }
    return r.Header, nil
}

func GetCanonicalHash(ctx context.Context, odr OdrBackend, number uint64) (common.Hash, error) {
    hash := core.GetCanonicalHash(odr.Database(), number)
    if (hash != common.Hash{}) {
        return hash, nil
    }
    header, err := GetHeaderByNumber(ctx, odr, number)
    if header != nil {
        return header.Hash(), nil
    }
    return common.Hash{}, err
}

// GetBodyRLP retrieves the block body (transactions and uncles) in RLP encoding.
func GetBodyRLP(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (rlp.RawValue, error) {
    if data := core.GetBodyRLP(odr.Database(), hash, number); data != nil {
        return data, nil
    }
    r := &BlockRequest{Hash: hash, Number: number}
    if err := odr.Retrieve(ctx, r); err != nil {
        return nil, err
    } else {
        return r.Rlp, nil
    }
}

// GetBody retrieves the block body (transactons, uncles) corresponding to the
// hash.
func GetBody(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Body, error) {
    data, err := GetBodyRLP(ctx, odr, hash, number)
    if err != nil {
        return nil, err
    }
    body := new(types.Body)
    if err := rlp.Decode(bytes.NewReader(data), body); err != nil {
        return nil, err
    }
    return body, nil
}

// GetBlock retrieves an entire block corresponding to the hash, assembling it
// back from the stored header and body.
func GetBlock(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (*types.Block, error) {
    // Retrieve the block header and body contents
    header := core.GetHeader(odr.Database(), hash, number)
    if header == nil {
        return nil, ErrNoHeader
    }
    body, err := GetBody(ctx, odr, hash, number)
    if err != nil {
        return nil, err
    }
    // Reassemble the block and return
    return types.NewBlockWithHeader(header).WithBody(body.Transactions, body.Uncles), nil
}

// GetBlockReceipts retrieves the receipts generated by the transactions included
// in a block given by its hash.
func GetBlockReceipts(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) (types.Receipts, error) {
    // Retrieve the potentially incomplete receipts from disk or network
    receipts := core.GetBlockReceipts(odr.Database(), hash, number)
    if receipts == nil {
        r := &ReceiptsRequest{Hash: hash, Number: number}
        if err := odr.Retrieve(ctx, r); err != nil {
            return nil, err
        }
        receipts = r.Receipts
    }
    // If the receipts are incomplete, fill the derived fields
    if len(receipts) > 0 && receipts[0].TxHash == (common.Hash{}) {
        block, err := GetBlock(ctx, odr, hash, number)
        if err != nil {
            return nil, err
        }
        genesis := core.GetCanonicalHash(odr.Database(), 0)
        config, _ := core.GetChainConfig(odr.Database(), genesis)

        core.SetReceiptsData(config, block, receipts)
        core.WriteBlockReceipts(odr.Database(), hash, number, receipts)
    }
    return receipts, nil
}

// GetBlockLogs retrieves the logs generated by the transactions included in a
// block given by its hash.
func GetBlockLogs(ctx context.Context, odr OdrBackend, hash common.Hash, number uint64) ([][]*types.Log, error) {
    // Retrieve the potentially incomplete receipts from disk or network
    receipts := core.GetBlockReceipts(odr.Database(), hash, number)
    if receipts == nil {
        r := &ReceiptsRequest{Hash: hash, Number: number}
        if err := odr.Retrieve(ctx, r); err != nil {
            return nil, err
        }
        receipts = r.Receipts
    }
    // Return the logs without deriving any computed fields on the receipts
    logs := make([][]*types.Log, len(receipts))
    for i, receipt := range receipts {
        logs[i] = receipt.Logs
    }
    return logs, nil
}

// GetBloomBits retrieves a batch of compressed bloomBits vectors belonging to the given bit index and section indexes
func GetBloomBits(ctx context.Context, odr OdrBackend, bitIdx uint, sectionIdxList []uint64) ([][]byte, error) {
    db := odr.Database()
    result := make([][]byte, len(sectionIdxList))
    var (
        reqList []uint64
        reqIdx  []int
    )

    var (
        bloomTrieCount, sectionHeadNum uint64
        sectionHead                    common.Hash
    )
    if odr.BloomTrieIndexer() != nil {
        bloomTrieCount, sectionHeadNum, sectionHead = odr.BloomTrieIndexer().Sections()
        canonicalHash := core.GetCanonicalHash(db, sectionHeadNum)
        // if the BloomTrie was injected as a trusted checkpoint, we have no canonical hash yet so we accept zero hash too
        for bloomTrieCount > 0 && canonicalHash != sectionHead && canonicalHash != (common.Hash{}) {
            bloomTrieCount--
            if bloomTrieCount > 0 {
                sectionHeadNum = bloomTrieCount*BloomTrieFrequency - 1
                sectionHead = odr.BloomTrieIndexer().SectionHead(bloomTrieCount - 1)
                canonicalHash = core.GetCanonicalHash(db, sectionHeadNum)
            }
        }
    }

    for i, sectionIdx := range sectionIdxList {
        sectionHead := core.GetCanonicalHash(db, (sectionIdx+1)*BloomTrieFrequency-1)
        // if we don't have the canonical hash stored for this section head number, we'll still look for
        // an entry with a zero sectionHead (we store it with zero section head too if we don't know it
        // at the time of the retrieval)
        bloomBits, err := core.GetBloomBits(db, bitIdx, sectionIdx, sectionHead)
        if err == nil {
            result[i] = bloomBits
        } else {
            if sectionIdx >= bloomTrieCount {
                return nil, ErrNoTrustedBloomTrie
            }
            reqList = append(reqList, sectionIdx)
            reqIdx = append(reqIdx, i)
        }
    }
    if reqList == nil {
        return result, nil
    }

    r := &BloomRequest{BloomTrieRoot: GetBloomTrieRoot(db, bloomTrieCount-1, sectionHead), BloomTrieNum: bloomTrieCount - 1, BitIdx: bitIdx, SectionIdxList: reqList}
    if err := odr.Retrieve(ctx, r); err != nil {
        return nil, err
    } else {
        for i, idx := range reqIdx {
            result[idx] = r.BloomBits[i]
        }
        return result, nil
    }
}