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| 1 | +// Copyright 2025 The go-ethereum Authors |
| 2 | +// This file is part of the go-ethereum library. |
| 3 | +// |
| 4 | +// The go-ethereum library is free software: you can redistribute it and/or modify |
| 5 | +// it under the terms of the GNU Lesser General Public License as published by |
| 6 | +// the Free Software Foundation, either version 3 of the License, or |
| 7 | +// (at your option) any later version. |
| 8 | +// |
| 9 | +// The go-ethereum library is distributed in the hope that it will be useful, |
| 10 | +// but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 11 | +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 12 | +// GNU Lesser General Public License for more details. |
| 13 | +// |
| 14 | +// You should have received a copy of the GNU Lesser General Public License |
| 15 | +// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. |
| 16 | + |
| 17 | +package filtermaps |
| 18 | + |
| 19 | +import ( |
| 20 | + "github.com/ethereum/go-ethereum/common" |
| 21 | + "github.com/ethereum/go-ethereum/core/types" |
| 22 | + "github.com/ethereum/go-ethereum/log" |
| 23 | +) |
| 24 | + |
| 25 | +// blockchain represents the underlying blockchain of ChainView. |
| 26 | +type blockchain interface { |
| 27 | + GetHeader(hash common.Hash, number uint64) *types.Header |
| 28 | + GetCanonicalHash(number uint64) common.Hash |
| 29 | + GetReceiptsByHash(hash common.Hash) types.Receipts |
| 30 | +} |
| 31 | + |
| 32 | +// ChainView represents an immutable view of a chain with a block id and a set |
| 33 | +// of receipts associated to each block number and a block hash associated with |
| 34 | +// all block numbers except the head block. This is because in the future |
| 35 | +// ChainView might represent a view where the head block is currently being |
| 36 | +// created. Block id is a unique identifier that can also be calculated for the |
| 37 | +// head block. |
| 38 | +// Note that the view's head does not have to be the current canonical head |
| 39 | +// of the underlying blockchain, it should only possess the block headers |
| 40 | +// and receipts up until the expected chain view head. |
| 41 | +type ChainView struct { |
| 42 | + chain blockchain |
| 43 | + headNumber uint64 |
| 44 | + hashes []common.Hash // block hashes starting backwards from headNumber until first canonical hash |
| 45 | +} |
| 46 | + |
| 47 | +// NewChainView creates a new ChainView. |
| 48 | +func NewChainView(chain blockchain, number uint64, hash common.Hash) *ChainView { |
| 49 | + cv := &ChainView{ |
| 50 | + chain: chain, |
| 51 | + headNumber: number, |
| 52 | + hashes: []common.Hash{hash}, |
| 53 | + } |
| 54 | + cv.extendNonCanonical() |
| 55 | + return cv |
| 56 | +} |
| 57 | + |
| 58 | +// getBlockHash returns the block hash belonging to the given block number. |
| 59 | +// Note that the hash of the head block is not returned because ChainView might |
| 60 | +// represent a view where the head block is currently being created. |
| 61 | +func (cv *ChainView) getBlockHash(number uint64) common.Hash { |
| 62 | + if number >= cv.headNumber { |
| 63 | + panic("invalid block number") |
| 64 | + } |
| 65 | + return cv.blockHash(number) |
| 66 | +} |
| 67 | + |
| 68 | +// getBlockId returns the unique block id belonging to the given block number. |
| 69 | +// Note that it is currently equal to the block hash. In the future it might |
| 70 | +// be a different id for future blocks if the log index root becomes part of |
| 71 | +// consensus and therefore rendering the index with the new head will happen |
| 72 | +// before the hash of that new head is available. |
| 73 | +func (cv *ChainView) getBlockId(number uint64) common.Hash { |
| 74 | + if number > cv.headNumber { |
| 75 | + panic("invalid block number") |
| 76 | + } |
| 77 | + return cv.blockHash(number) |
| 78 | +} |
| 79 | + |
| 80 | +// getReceipts returns the set of receipts belonging to the block at the given |
| 81 | +// block number. |
| 82 | +func (cv *ChainView) getReceipts(number uint64) types.Receipts { |
| 83 | + if number > cv.headNumber { |
| 84 | + panic("invalid block number") |
| 85 | + } |
| 86 | + return cv.chain.GetReceiptsByHash(cv.blockHash(number)) |
| 87 | +} |
| 88 | + |
| 89 | +// limitedView returns a new chain view that is a truncated version of the parent view. |
| 90 | +func (cv *ChainView) limitedView(newHead uint64) *ChainView { |
| 91 | + if newHead >= cv.headNumber { |
| 92 | + return cv |
| 93 | + } |
| 94 | + return NewChainView(cv.chain, newHead, cv.blockHash(newHead)) |
| 95 | +} |
| 96 | + |
| 97 | +// equalViews returns true if the two chain views are equivalent. |
| 98 | +func equalViews(cv1, cv2 *ChainView) bool { |
| 99 | + if cv1 == nil || cv2 == nil { |
| 100 | + return false |
| 101 | + } |
| 102 | + return cv1.headNumber == cv2.headNumber && cv1.getBlockId(cv1.headNumber) == cv2.getBlockId(cv2.headNumber) |
| 103 | +} |
| 104 | + |
| 105 | +// matchViews returns true if the two chain views are equivalent up until the |
| 106 | +// specified block number. If the specified number is higher than one of the |
| 107 | +// heads then false is returned. |
| 108 | +func matchViews(cv1, cv2 *ChainView, number uint64) bool { |
| 109 | + if cv1 == nil || cv2 == nil { |
| 110 | + return false |
| 111 | + } |
| 112 | + if cv1.headNumber < number || cv2.headNumber < number { |
| 113 | + return false |
| 114 | + } |
| 115 | + if number == cv1.headNumber || number == cv2.headNumber { |
| 116 | + return cv1.getBlockId(number) == cv2.getBlockId(number) |
| 117 | + } |
| 118 | + return cv1.getBlockHash(number) == cv2.getBlockHash(number) |
| 119 | +} |
| 120 | + |
| 121 | +// extendNonCanonical checks whether the previously known reverse list of head |
| 122 | +// hashes still ends with one that is canonical on the underlying blockchain. |
| 123 | +// If necessary then it traverses further back on the header chain and adds |
| 124 | +// more hashes to the list. |
| 125 | +func (cv *ChainView) extendNonCanonical() bool { |
| 126 | + for { |
| 127 | + hash, number := cv.hashes[len(cv.hashes)-1], cv.headNumber-uint64(len(cv.hashes)-1) |
| 128 | + if cv.chain.GetCanonicalHash(number) == hash { |
| 129 | + return true |
| 130 | + } |
| 131 | + if number == 0 { |
| 132 | + log.Error("Unknown genesis block hash found") |
| 133 | + return false |
| 134 | + } |
| 135 | + header := cv.chain.GetHeader(hash, number) |
| 136 | + if header == nil { |
| 137 | + log.Error("Header not found", "number", number, "hash", hash) |
| 138 | + return false |
| 139 | + } |
| 140 | + cv.hashes = append(cv.hashes, header.ParentHash) |
| 141 | + } |
| 142 | +} |
| 143 | + |
| 144 | +// blockHash returns the given block hash without doing the head number check. |
| 145 | +func (cv *ChainView) blockHash(number uint64) common.Hash { |
| 146 | + if number+uint64(len(cv.hashes)) <= cv.headNumber { |
| 147 | + hash := cv.chain.GetCanonicalHash(number) |
| 148 | + if !cv.extendNonCanonical() { |
| 149 | + return common.Hash{} |
| 150 | + } |
| 151 | + if number+uint64(len(cv.hashes)) <= cv.headNumber { |
| 152 | + return hash |
| 153 | + } |
| 154 | + } |
| 155 | + return cv.hashes[cv.headNumber-number] |
| 156 | +} |
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