Golang pow.PoW類代碼示例

// verifyNonces starts a concurrent nonce verification, returning a quit channel
// to abort the operations and a results channel to retrieve the async checks.
func verifyNonces(checker pow.PoW, items []pow.Block) (chan<- struct{}, <-chan nonceCheckResult) {
	// Spawn as many workers as allowed threads
	workers := runtime.GOMAXPROCS(0)
	if len(items) < workers {
		workers = len(items)
	}
	// Create a task channel and spawn the verifiers
	tasks := make(chan int, workers)
	results := make(chan nonceCheckResult, len(items)) // Buffered to make sure all workers stop
	for i := 0; i < workers; i++ {
		go func() {
			for index := range tasks {
				results <- nonceCheckResult{index: index, valid: checker.Verify(items[index])}
			}
		}()
	}
	// Feed item indices to the workers until done or aborted
	abort := make(chan struct{})
	go func() {
		defer close(tasks)

		for i := range items {
			select {
			case tasks <- i:
				continue
			case <-abort:
				return
			}
		}
	}()
	return abort, results
}

// block verifies nonces of the given blocks in parallel and returns
// an error if one of the blocks nonce verifications failed.
func verifyNonces(pow pow.PoW, blocks []*types.Block, quit <-chan struct{}, done chan<- nonceResult) {
	// Spawn a few workers. They listen for blocks on the in channel
	// and send results on done. The workers will exit in the
	// background when in is closed.
	var (
		in       = make(chan int)
		nworkers = runtime.GOMAXPROCS(0)
	)
	defer close(in)
	if len(blocks) < nworkers {
		nworkers = len(blocks)
	}
	for i := 0; i < nworkers; i++ {
		go func() {
			for i := range in {
				done <- nonceResult{i: i, valid: pow.Verify(blocks[i])}
			}
		}()
	}
	// Feed block indices to the workers.
	for i := range blocks {
		select {
		case in <- i:
			continue
		case <-quit:
			return
		}
	}
}

// See YP section 4.3.4. "Block Header Validity"
// Validates a block. Returns an error if the block is invalid.
func ValidateHeader(pow pow.PoW, block *types.Header, parent *types.Block, checkPow, uncle bool) error {
	if big.NewInt(int64(len(block.Extra))).Cmp(params.MaximumExtraDataSize) == 1 {
		return fmt.Errorf("Block extra data too long (%d)", len(block.Extra))
	}

	if uncle {
		if block.Time.Cmp(common.MaxBig) == 1 {
			return BlockTSTooBigErr
		}
	} else {
		if block.Time.Cmp(big.NewInt(time.Now().Unix())) == 1 {
			return BlockFutureErr
		}
	}
	if block.Time.Cmp(parent.Time()) != 1 {
		return BlockEqualTSErr
	}

	expd := CalcDifficulty(block.Time.Uint64(), parent.Time().Uint64(), parent.Number(), parent.Difficulty())
	if expd.Cmp(block.Difficulty) != 0 {
		return fmt.Errorf("Difficulty check failed for block %v, %v", block.Difficulty, expd)
	}

	var a, b *big.Int
	a = parent.GasLimit()
	a = a.Sub(a, block.GasLimit)
	a.Abs(a)
	b = parent.GasLimit()
	b = b.Div(b, params.GasLimitBoundDivisor)
	if !(a.Cmp(b) < 0) || (block.GasLimit.Cmp(params.MinGasLimit) == -1) {
		return fmt.Errorf("GasLimit check failed for block %v (%v > %v)", block.GasLimit, a, b)
	}

	num := parent.Number()
	num.Sub(block.Number, num)
	if num.Cmp(big.NewInt(1)) != 0 {
		return BlockNumberErr
	}

	if checkPow {
		// Verify the nonce of the block. Return an error if it's not valid
		if !pow.Verify(types.NewBlockWithHeader(block)) {
			return ValidationError("Block's nonce is invalid (= %x)", block.Nonce)
		}
	}

	return nil
}

// Validates a header. Returns an error if the header is invalid.
//
// See YP section 4.3.4. "Block Header Validity"
func ValidateHeader(config *ChainConfig, pow pow.PoW, header *types.Header, parent *types.Header, checkPow, uncle bool) error {
	if big.NewInt(int64(len(header.Extra))).Cmp(params.MaximumExtraDataSize) == 1 {
		return fmt.Errorf("Header extra data too long (%d)", len(header.Extra))
	}

	if uncle {
		if header.Time.Cmp(common.MaxBig) == 1 {
			return BlockTSTooBigErr
		}
	} else {
		if header.Time.Cmp(big.NewInt(time.Now().Unix())) == 1 {
			return BlockFutureErr
		}
	}
	if header.Time.Cmp(parent.Time) != 1 {
		return BlockEqualTSErr
	}

	expd := CalcDifficulty(config, header.Time.Uint64(), parent.Time.Uint64(), parent.Number, parent.Difficulty)
	if expd.Cmp(header.Difficulty) != 0 {
		return fmt.Errorf("Difficulty check failed for header %v, %v", header.Difficulty, expd)
	}

	a := new(big.Int).Set(parent.GasLimit)
	a = a.Sub(a, header.GasLimit)
	a.Abs(a)
	b := new(big.Int).Set(parent.GasLimit)
	b = b.Div(b, params.GasLimitBoundDivisor)
	if !(a.Cmp(b) < 0) || (header.GasLimit.Cmp(params.MinGasLimit) == -1) {
		return fmt.Errorf("GasLimit check failed for header %v (%v > %v)", header.GasLimit, a, b)
	}

	num := new(big.Int).Set(parent.Number)
	num.Sub(header.Number, num)
	if num.Cmp(big.NewInt(1)) != 0 {
		return BlockNumberErr
	}

	if checkPow {
		// Verify the nonce of the header. Return an error if it's not valid
		if !pow.Verify(types.NewBlockWithHeader(header)) {
			return &BlockNonceErr{header.Number, header.Hash(), header.Nonce.Uint64()}
		}
	}
	// If all checks passed, validate the extra-data field for hard forks
	return ValidateDAOHeaderExtraData(config, header)
}

// See YP section 4.3.4. "Block Header Validity"
// Validates a block. Returns an error if the block is invalid.
func ValidateHeader(pow pow.PoW, block, parent *types.Header, checkPow bool) error {
	if big.NewInt(int64(len(block.Extra))).Cmp(params.MaximumExtraDataSize) == 1 {
		return fmt.Errorf("Block extra data too long (%d)", len(block.Extra))
	}

	expd := CalcDifficulty(block, parent)
	if expd.Cmp(block.Difficulty) != 0 {
		return fmt.Errorf("Difficulty check failed for block %v, %v", block.Difficulty, expd)
	}

	a := new(big.Int).Sub(block.GasLimit, parent.GasLimit)
	a.Abs(a)
	b := new(big.Int).Div(parent.GasLimit, params.GasLimitBoundDivisor)
	if !(a.Cmp(b) < 0) || (block.GasLimit.Cmp(params.MinGasLimit) == -1) {
		return fmt.Errorf("GasLimit check failed for block %v (%v > %v)", block.GasLimit, a, b)
	}

	if int64(block.Time) > time.Now().Unix() {
		return BlockFutureErr
	}

	if new(big.Int).Sub(block.Number, parent.Number).Cmp(big.NewInt(1)) != 0 {
		return BlockNumberErr
	}

	if block.Time <= parent.Time {
		return BlockEqualTSErr //ValidationError("Block timestamp equal or less than previous block (%v - %v)", block.Time, parent.Time)
	}

	if checkPow {
		// Verify the nonce of the block. Return an error if it's not valid
		if !pow.Verify(types.NewBlockWithHeader(block)) {
			return ValidationError("Block's nonce is invalid (= %x)", block.Nonce)
		}
	}

	return nil
}