Golang BlockHeader.ID方法代碼示例

// validateHeader does some early, low computation verification on the header
// to determine if the block should be downloaded. Callers should not assume
// that validation will happen in a particular order.
func (cs *ConsensusSet) validateHeader(tx dbTx, h types.BlockHeader) error {
	// Check if the block is a DoS block - a known invalid block that is expensive
	// to validate.
	id := h.ID()
	_, exists := cs.dosBlocks[id]
	if exists {
		return errDoSBlock
	}

	// Check if the block is already known.
	blockMap := tx.Bucket(BlockMap)
	if blockMap == nil {
		return errNoBlockMap
	}
	if blockMap.Get(id[:]) != nil {
		return modules.ErrBlockKnown
	}

	// Check for the parent.
	parentID := h.ParentID
	parentBytes := blockMap.Get(parentID[:])
	if parentBytes == nil {
		return errOrphan
	}
	var parent processedBlock
	err := cs.marshaler.Unmarshal(parentBytes, &parent)
	if err != nil {
		return err
	}

	// Check that the target of the new block is sufficient.
	if !checkHeaderTarget(h, parent.ChildTarget) {
		return modules.ErrBlockUnsolved
	}

	// TODO: check if the block is a non extending block once headers-first
	// downloads are implemented.

	// Check that the timestamp is not too far in the past to be acceptable.
	minTimestamp := cs.blockRuleHelper.minimumValidChildTimestamp(blockMap, &parent)
	if minTimestamp > h.Timestamp {
		return errEarlyTimestamp
	}

	// Check if the block is in the extreme future. We make a distinction between
	// future and extreme future because there is an assumption that by the time
	// the extreme future arrives, this block will no longer be a part of the
	// longest fork because it will have been ignored by all of the miners.
	if h.Timestamp > types.CurrentTimestamp()+types.ExtremeFutureThreshold {
		return errExtremeFutureTimestamp
	}

	// We do not check if the header is in the near future here, because we want
	// to get the corresponding block as soon as possible, even if the block is in
	// the near future.

	return nil
}

// TestCheckHeaderTarget probes the checkHeaderTarget function and checks that
// the result matches the result of checkTarget.
func TestCheckHeaderTarget(t *testing.T) {
	var b types.Block
	var h types.BlockHeader

	tests := []struct {
		target   types.Target
		expected bool
		msg      string
	}{
		{types.RootDepth, true, "checkHeaderTarget failed for a low target"},
		{types.Target{}, false, "checkHeaderTarget passed for a high target"},
		{types.Target(h.ID()), true, "checkHeaderTarget failed for a same target"},
	}
	for _, tt := range tests {
		if checkHeaderTarget(h, tt.target) != tt.expected {
			t.Error(tt.msg)
		}
		if checkHeaderTarget(h, tt.target) != checkTarget(b, tt.target) {
			t.Errorf("checkHeaderTarget and checkTarget do not match for target %v", tt.target)
		}
	}
}

// threadedRPCRelayHeader is an RPC that accepts a block header from a peer.
func (cs *ConsensusSet) threadedRPCRelayHeader(conn modules.PeerConn) error {
	err := cs.tg.Add()
	if err != nil {
		return err
	}
	wg := new(sync.WaitGroup)
	defer func() {
		go func() {
			wg.Wait()
			cs.tg.Done()
		}()
	}()

	// Decode the block header from the connection.
	var h types.BlockHeader
	err = encoding.ReadObject(conn, &h, types.BlockHeaderSize)
	if err != nil {
		return err
	}

	// Start verification inside of a bolt View tx.
	cs.mu.RLock()
	err = cs.db.View(func(tx *bolt.Tx) error {
		// Do some relatively inexpensive checks to validate the header
		return cs.validateHeader(boltTxWrapper{tx}, h)
	})
	cs.mu.RUnlock()
	if err == errOrphan {
		// If the header is an orphan, try to find the parents. Call needs to
		// be made in a separate goroutine as execution requires calling an
		// exported gateway method - threadedRPCRelayHeader was likely called
		// from an exported gateway function.
		//
		// NOTE: In general this is bad design. Rather than recycling other
		// calls, the whole protocol should have been kept in a single RPC.
		// Because it is not, we have to do weird threading to prevent
		// deadlocks, and we also have to be concerned every time the code in
		// managedReceiveBlocks is adjusted.
		wg.Add(1)
		go func() {
			err := cs.gateway.RPC(conn.RPCAddr(), "SendBlocks", cs.managedReceiveBlocks)
			if err != nil {
				cs.log.Debugln("WARN: failed to get parents of orphan header:", err)
			}
			wg.Done()
		}()
		return nil
	} else if err != nil {
		return err
	}

	// If the header is valid and extends the heaviest chain, fetch the
	// corresponding block. Call needs to be made in a separate goroutine
	// because an exported call to the gateway is used, which is a deadlock
	// risk given that rpcRelayHeader is called from the gateway.
	//
	// NOTE: In general this is bad design. Rather than recycling other calls,
	// the whole protocol should have been kept in a single RPC. Because it is
	// not, we have to do weird threading to prevent deadlocks, and we also
	// have to be concerned every time the code in managedReceiveBlock is
	// adjusted.
	wg.Add(1)
	go func() {
		err = cs.gateway.RPC(conn.RPCAddr(), "SendBlk", cs.managedReceiveBlock(h.ID()))
		if err != nil {
			cs.log.Debugln("WARN: failed to get header's corresponding block:", err)
		}
		wg.Done()
	}()
	return nil
}

// checkHeaderTarget returns true if the header's ID meets the given target.
func checkHeaderTarget(h types.BlockHeader, target types.Target) bool {
	blockHash := h.ID()
	return bytes.Compare(target[:], blockHash[:]) >= 0
}