make the basic demo work

1 files changed, 234 insertions, 0 deletions

diff --git a/consensus/dummy/consensus.go b/consensus/dummy/consensus.go
new file mode 100644
index 0000000..a496262
--- /dev/null
+++ b/consensus/dummy/consensus.go
@@ -0,0 +1,234 @@
+package dummy
+
+import (
+    "fmt"
+    "time"
+    "errors"
+    "runtime"
+    "math/big"
+    "golang.org/x/crypto/sha3"
+
+    "github.com/ethereum/go-ethereum/consensus"
+    "github.com/ethereum/go-ethereum/core/types"
+    "github.com/ethereum/go-ethereum/core/state"
+    "github.com/ethereum/go-ethereum/params"
+    "github.com/ethereum/go-ethereum/common"
+    "github.com/ethereum/go-ethereum/rlp"
+    "github.com/ethereum/go-ethereum/rpc"
+)
+
+type DummyEngine struct {
+}
+
+var (
+    allowedFutureBlockTime    = 15 * time.Second  // Max time from current time allowed for blocks, before they're considered future blocks
+)
+
+var (
+    errZeroBlockTime     = errors.New("timestamp equals parent's")
+)
+
+// modified from consensus.go
+func (self *DummyEngine) verifyHeader(chain consensus.ChainReader, header, parent *types.Header, uncle bool, seal bool) error {
+    // Ensure that the header's extra-data section is of a reasonable size
+    if uint64(len(header.Extra)) > params.MaximumExtraDataSize {
+        return fmt.Errorf("extra-data too long: %d > %d", len(header.Extra), params.MaximumExtraDataSize)
+    }
+    // Verify the header's timestamp
+    if !uncle {
+        if header.Time > uint64(time.Now().Add(allowedFutureBlockTime).Unix()) {
+            return consensus.ErrFutureBlock
+        }
+    }
+    if header.Time <= parent.Time {
+        return errZeroBlockTime
+    }
+    // Verify that the gas limit is <= 2^63-1
+    cap := uint64(0x7fffffffffffffff)
+    if header.GasLimit > cap {
+        return fmt.Errorf("invalid gasLimit: have %v, max %v", header.GasLimit, cap)
+    }
+    // Verify that the gasUsed is <= gasLimit
+    if header.GasUsed > header.GasLimit {
+        return fmt.Errorf("invalid gasUsed: have %d, gasLimit %d", header.GasUsed, header.GasLimit)
+    }
+
+    // Verify that the gas limit remains within allowed bounds
+    diff := int64(parent.GasLimit) - int64(header.GasLimit)
+    if diff < 0 {
+        diff *= -1
+    }
+    limit := parent.GasLimit / params.GasLimitBoundDivisor
+
+    if uint64(diff) >= limit || header.GasLimit < params.MinGasLimit {
+        return fmt.Errorf("invalid gas limit: have %d, want %d += %d", header.GasLimit, parent.GasLimit, limit)
+    }
+    // Verify that the block number is parent's +1
+    if diff := new(big.Int).Sub(header.Number, parent.Number); diff.Cmp(big.NewInt(1)) != 0 {
+        return consensus.ErrInvalidNumber
+    }
+    // Verify the engine specific seal securing the block
+    if seal {
+        if err := self.VerifySeal(chain, header); err != nil {
+            return err
+        }
+    }
+    return nil
+}
+
+func (self *DummyEngine) verifyHeaderWorker(chain consensus.ChainReader, headers []*types.Header, seals []bool, index int) error {
+    var parent *types.Header
+    if index == 0 {
+        parent = chain.GetHeader(headers[0].ParentHash, headers[0].Number.Uint64()-1)
+    } else if headers[index-1].Hash() == headers[index].ParentHash {
+        parent = headers[index-1]
+    }
+    if parent == nil {
+        return consensus.ErrUnknownAncestor
+    }
+    if chain.GetHeader(headers[index].Hash(), headers[index].Number.Uint64()) != nil {
+        return nil // known block
+    }
+    return self.verifyHeader(chain, headers[index], parent, false, seals[index])
+}
+
+func (self *DummyEngine) Author(header *types.Header) (common.Address, error) {
+    addr := common.Address{}
+    return addr, nil
+}
+
+func (self *DummyEngine) VerifyHeader(chain consensus.ChainReader, header *types.Header, seal bool) error {
+    // Short circuit if the header is known, or it's parent not
+    number := header.Number.Uint64()
+    if chain.GetHeader(header.Hash(), number) != nil {
+        return nil
+    }
+    parent := chain.GetHeader(header.ParentHash, number-1)
+    if parent == nil {
+        return consensus.ErrUnknownAncestor
+    }
+    // Sanity checks passed, do a proper verification
+    return self.verifyHeader(chain, header, parent, false, seal)
+}
+
+func (self *DummyEngine) VerifyHeaders(chain consensus.ChainReader, headers []*types.Header, seals []bool) (chan<- struct{}, <-chan error) {
+    // Spawn as many workers as allowed threads
+    workers := runtime.GOMAXPROCS(0)
+    if len(headers) < workers {
+        workers = len(headers)
+    }
+
+    // Create a task channel and spawn the verifiers
+    var (
+        inputs = make(chan int)
+        done   = make(chan int, workers)
+        errors = make([]error, len(headers))
+        abort  = make(chan struct{})
+    )
+    for i := 0; i < workers; i++ {
+        go func() {
+            for index := range inputs {
+                errors[index] = self.verifyHeaderWorker(chain, headers, seals, index)
+                done <- index
+            }
+        }()
+    }
+
+    errorsOut := make(chan error, len(headers))
+    go func() {
+        defer close(inputs)
+        var (
+            in, out = 0, 0
+            checked = make([]bool, len(headers))
+            inputs  = inputs
+        )
+        for {
+            select {
+            case inputs <- in:
+                if in++; in == len(headers) {
+                    // Reached end of headers. Stop sending to workers.
+                    inputs = nil
+                }
+            case index := <-done:
+                for checked[index] = true; checked[out]; out++ {
+                    errorsOut <- errors[out]
+                    if out == len(headers)-1 {
+                        return
+                    }
+                }
+            case <-abort:
+                return
+            }
+        }
+    }()
+    return abort, errorsOut
+}
+
+func (self *DummyEngine) VerifyUncles(chain consensus.ChainReader, block *types.Block) error {
+    return nil
+}
+
+func (self *DummyEngine) VerifySeal(chain consensus.ChainReader, header *types.Header) error {
+    return nil
+}
+
+func (self *DummyEngine) Prepare(chain consensus.ChainReader, header *types.Header) error {
+    header.Difficulty = big.NewInt(0)
+    return nil
+}
+
+func (self *DummyEngine) Finalize(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction,
+uncles []*types.Header) {
+    // commit the final state root
+    header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
+}
+
+func (self *DummyEngine) FinalizeAndAssemble(chain consensus.ChainReader, header *types.Header, state *state.StateDB, txs []*types.Transaction,
+uncles []*types.Header, receipts []*types.Receipt) (*types.Block, error) {
+    // commit the final state root
+    header.Root = state.IntermediateRoot(chain.Config().IsEIP158(header.Number))
+
+    // Header seems complete, assemble into a block and return
+    return types.NewBlock(header, txs, uncles, receipts), nil
+}
+
+func (self *DummyEngine) Seal(chain consensus.ChainReader, block *types.Block, results chan<- *types.Block, stop <-chan struct{}) error {
+    time.Sleep(1000 * time.Millisecond)
+    fmt.Printf("sealed %s\n", block.ParentHash().String())
+    results <- block
+    return nil
+}
+
+func (self *DummyEngine) SealHash(header *types.Header) (hash common.Hash) {
+    hasher := sha3.NewLegacyKeccak256()
+
+    rlp.Encode(hasher, []interface{}{
+        header.ParentHash,
+        header.UncleHash,
+        header.Coinbase,
+        header.Root,
+        header.TxHash,
+        header.ReceiptHash,
+        header.Bloom,
+        header.Difficulty,
+        header.Number,
+        header.GasLimit,
+        header.GasUsed,
+        header.Time,
+        header.Extra,
+    })
+    hasher.Sum(hash[:0])
+    return hash
+}
+
+func (self *DummyEngine) CalcDifficulty(chain consensus.ChainReader, time uint64, parent *types.Header) *big.Int {
+    return big.NewInt(0)
+}
+
+func (self *DummyEngine) APIs(chain consensus.ChainReader) []rpc.API {
+    return nil
+}
+
+func (self *DummyEngine) Close() error {
+    return nil
+}