github.com/mister-meeseeks/go-ethereum@v1.9.7/contracts/checkpointoracle/oracle.go (about)

     1  // Copyright 2019 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 checkpointoracle is a an on-chain light client checkpoint oracle.
    18  package checkpointoracle
    19  
    20  //go:generate abigen --sol contract/oracle.sol --pkg contract --out contract/oracle.go
    21  
    22  import (
    23  	"errors"
    24  	"math/big"
    25  
    26  	"github.com/ethereum/go-ethereum/accounts/abi/bind"
    27  	"github.com/ethereum/go-ethereum/common"
    28  	"github.com/ethereum/go-ethereum/contracts/checkpointoracle/contract"
    29  	"github.com/ethereum/go-ethereum/core/types"
    30  )
    31  
    32  // CheckpointOracle is a Go wrapper around an on-chain light client checkpoint oracle.
    33  type CheckpointOracle struct {
    34  	contract *contract.CheckpointOracle
    35  }
    36  
    37  // NewCheckpointOracle binds checkpoint contract and returns a registrar instance.
    38  func NewCheckpointOracle(contractAddr common.Address, backend bind.ContractBackend) (*CheckpointOracle, error) {
    39  	c, err := contract.NewCheckpointOracle(contractAddr, backend)
    40  	if err != nil {
    41  		return nil, err
    42  	}
    43  	return &CheckpointOracle{contract: c}, nil
    44  }
    45  
    46  // Contract returns the underlying contract instance.
    47  func (oracle *CheckpointOracle) Contract() *contract.CheckpointOracle {
    48  	return oracle.contract
    49  }
    50  
    51  // LookupCheckpointEvents searches checkpoint event for specific section in the
    52  // given log batches.
    53  func (oracle *CheckpointOracle) LookupCheckpointEvents(blockLogs [][]*types.Log, section uint64, hash common.Hash) []*contract.CheckpointOracleNewCheckpointVote {
    54  	var votes []*contract.CheckpointOracleNewCheckpointVote
    55  
    56  	for _, logs := range blockLogs {
    57  		for _, log := range logs {
    58  			event, err := oracle.contract.ParseNewCheckpointVote(*log)
    59  			if err != nil {
    60  				continue
    61  			}
    62  			if event.Index == section && common.Hash(event.CheckpointHash) == hash {
    63  				votes = append(votes, event)
    64  			}
    65  		}
    66  	}
    67  	return votes
    68  }
    69  
    70  // RegisterCheckpoint registers the checkpoint with a batch of associated signatures
    71  // that are collected off-chain and sorted by lexicographical order.
    72  //
    73  // Notably all signatures given should be transformed to "ethereum style" which transforms
    74  // v from 0/1 to 27/28 according to the yellow paper.
    75  func (oracle *CheckpointOracle) RegisterCheckpoint(opts *bind.TransactOpts, index uint64, hash []byte, rnum *big.Int, rhash [32]byte, sigs [][]byte) (*types.Transaction, error) {
    76  	var (
    77  		r [][32]byte
    78  		s [][32]byte
    79  		v []uint8
    80  	)
    81  	for i := 0; i < len(sigs); i++ {
    82  		if len(sigs[i]) != 65 {
    83  			return nil, errors.New("invalid signature")
    84  		}
    85  		r = append(r, common.BytesToHash(sigs[i][:32]))
    86  		s = append(s, common.BytesToHash(sigs[i][32:64]))
    87  		v = append(v, sigs[i][64])
    88  	}
    89  	return oracle.contract.SetCheckpoint(opts, rnum, rhash, common.BytesToHash(hash), index, v, r, s)
    90  }