blockchain/chainquery.go

@@ -0,0 +1,123 @@
+package blockchain
+
+import (
+	"sort"
+	"strings"
+
+	btcutil "github.com/lbryio/lbcutil"
+)
+
+type ChainTip struct { // duplicate of btcjson.GetChainTipsResult to avoid circular reference
+	Height    int64
+	Hash      string
+	BranchLen int64
+	Status    string
+}
+
+// nodeHeightSorter implements sort.Interface to allow a slice of nodes to
+// be sorted by height in ascending order.
+type nodeHeightSorter []ChainTip
+
+// Len returns the number of nodes in the slice.  It is part of the
+// sort.Interface implementation.
+func (s nodeHeightSorter) Len() int {
+	return len(s)
+}
+
+// Swap swaps the nodes at the passed indices.  It is part of the
+// sort.Interface implementation.
+func (s nodeHeightSorter) Swap(i, j int) {
+	s[i], s[j] = s[j], s[i]
+}
+
+// Less returns whether the node with index i should sort before the node with
+// index j.  It is part of the sort.Interface implementation.
+func (s nodeHeightSorter) Less(i, j int) bool {
+	// To ensure stable order when the heights are the same, fall back to
+	// sorting based on hash.
+	if s[i].Height == s[j].Height {
+		return strings.Compare(s[i].Hash, s[j].Hash) < 0
+	}
+	return s[i].Height < s[j].Height
+}
+
+// ChainTips returns information, in JSON-RPC format, about all the currently
+// known chain tips in the block index.
+func (b *BlockChain) ChainTips() []ChainTip {
+	// we need our current tip
+	// we also need all of our orphans that aren't in the prevOrphans
+	var results []ChainTip
+
+	tip := b.bestChain.Tip()
+	results = append(results, ChainTip{
+		Height:    int64(tip.height),
+		Hash:      tip.hash.String(),
+		BranchLen: 0,
+		Status:    "active",
+	})
+
+	b.orphanLock.RLock()
+	defer b.orphanLock.RUnlock()
+
+	notInBestChain := func(block *btcutil.Block) bool {
+		node := b.bestChain.NodeByHeight(block.Height())
+		if node == nil {
+			return false
+		}
+		return node.hash.IsEqual(block.Hash())
+	}
+
+	for hash, orphan := range b.orphans {
+		if len(b.prevOrphans[hash]) > 0 {
+			continue
+		}
+		fork := orphan.block
+		for fork != nil && notInBestChain(fork) {
+			fork = b.orphans[*fork.Hash()].block
+		}
+
+		result := ChainTip{
+			Height:    int64(orphan.block.Height()),
+			Hash:      hash.String(),
+			BranchLen: int64(orphan.block.Height() - fork.Height()),
+		}
+
+		// Determine the status of the chain tip.
+		//
+		// active:
+		//   The current best chain tip.
+		//
+		// invalid:
+		//   The block or one of its ancestors is invalid.
+		//
+		// headers-only:
+		//   The block or one of its ancestors does not have the full block data
+		//   available which also means the block can't be validated or
+		//   connected.
+		//
+		// valid-fork:
+		//   The block is fully validated which implies it was probably part of
+		//   main chain at one point and was reorganized.
+		//
+		// valid-headers:
+		//   The full block data is available and the header is valid, but the
+		//   block was never validated which implies it was probably never part
+		//   of the main chain.
+		tipStatus := b.index.LookupNode(&hash).status
+		if tipStatus.KnownInvalid() {
+			result.Status = "invalid"
+		} else if !tipStatus.HaveData() {
+			result.Status = "headers-only"
+		} else if tipStatus.KnownValid() {
+			result.Status = "valid-fork"
+		} else {
+			result.Status = "valid-headers"
+		}
+
+		results = append(results, result)
+	}
+
+	// Generate the results sorted by descending height.
+	sort.Sort(sort.Reverse(nodeHeightSorter(results)))
+	return results
+}

btcjson/chainsvrresults.go

@@ -325,6 +325,14 @@ type GetMempoolEntryResult struct {
 	Depends         []string    `json:"depends"`
 }
 
+// GetChainTipsResult models the data returns from the getchaintips command.
+type GetChainTipsResult struct {
+	Height    int64  `json:"height"`
+	Hash      string `json:"hash"`
+	BranchLen int64  `json:"branchlen"`
+	Status    string `json:"status"`
+}
+
 // GetMempoolInfoResult models the data returned from the getmempoolinfo
 // command.
 type GetMempoolInfoResult struct {

rpcserver.go

@@ -147,6 +147,7 @@ var rpcHandlersBeforeInit = map[string]commandHandler{
 	"getblockcount":          handleGetBlockCount,
 	"getblockhash":           handleGetBlockHash,
 	"getblockheader":         handleGetBlockHeader,
+	"getchaintips":           handleGetChainTips,
 	"getblocktemplate":       handleGetBlockTemplate,
 	"getcfilter":             handleGetCFilter,
 	"getcfilterheader":       handleGetCFilterHeader,
@@ -1471,6 +1472,16 @@ func handleGetBlockHeader(s *rpcServer, cmd interface{}, closeChan <-chan struct
 	return blockHeaderReply, nil
 }
 
+// handleGetChainTips implements the getchaintips command.
+func handleGetChainTips(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
+	tips := s.cfg.Chain.ChainTips()
+	results := make([]btcjson.GetChainTipsResult, 0, len(tips))
+	for _, tip := range tips {
+		results = append(results, btcjson.GetChainTipsResult(tip))
+	}
+	return results, nil
+}
+
 // encodeTemplateID encodes the passed details into an ID that can be used to
 // uniquely identify a block template.
 func encodeTemplateID(prevHash *chainhash.Hash, lastGenerated time.Time) string {

rpcserverhelp.go

@@ -353,6 +353,22 @@ var helpDescsEnUS = map[string]string{
 	"getblocktemplate--condition2": "mode=proposal, accepted",
 	"getblocktemplate--result1":    "An error string which represents why the proposal was rejected or nothing if accepted",
 
+	// GetChainTips help.
+	"getchaintips--synopsis": "Returns information about all known chain tips the in the block tree.\n\n" +
+		"The statuses in the result have the following meanings:\n" +
+		"active: The current best chain tip.\n" +
+		"invalid: The block or one of its ancestors is invalid.\n" +
+		"headers-only: The block or one of its ancestors does not have the full block data available which also means the block can't be validated or connected.\n" +
+		"valid-fork: The block is fully validated which implies it was probably part of the main chain at one point and was reorganized.\n" +
+		"valid-headers: The full block data is available and the header is valid, but the block was never validated which implies it was probably never part of the main chain.",
+
+	// GetChainTipsResult help.
+	"getchaintipsresult-height":    "The height of the chain tip",
+	"getchaintipsresult-hash":      "The block hash of the chain tip",
+	"getchaintipsresult-branchlen": "The length of the branch that connects the tip to the main chain (0 for the main chain tip)",
+	"getchaintipsresult-status":    "The status of the chain (active, invalid, headers-only, valid-fork, valid-headers)",
+	"getchaintipsresults--result0": "test",
+
 	// GetCFilterCmd help.
 	"getcfilter--synopsis":  "Returns a block's committed filter given its hash.",
 	"getcfilter-filtertype": "The type of filter to return (0=regular)",
@@ -837,6 +853,7 @@ var rpcResultTypes = map[string][]interface{}{
 	"getblockchaininfo":      {(*btcjson.GetBlockChainInfoResult)(nil)},
 	"getcfilter":             {(*string)(nil)},
 	"getcfilterheader":       {(*string)(nil)},
+	"getchaintips":           {(*[]btcjson.GetChainTipsResult)(nil)},
 	"getconnectioncount":     {(*int32)(nil)},
 	"getcurrentnet":          {(*uint32)(nil)},
 	"getdifficulty":          {(*float64)(nil)},