api/v2: Duplicate merkle branch definition

This removes the dependency on the main module's merkle package.

The JSON marshaling of the merkle branch is disgusting but this would need to
be cleaned up in a v3 API if anyone attempts this.

Part of a larger change to make actually make the api/v2 submodule actually
go-gettable.  It is completely busted at the moment, due to importing the main
module's merkle package without a require on the main module.

api/v2/go.mod

@@ -1,3 +1,3 @@
 module github.com/decred/dcrtime/api/v2
 
-go 1.13
+go 1.17

api/v2/v2.go

@@ -5,10 +5,9 @@
 package v2
 
 import (
+	"crypto/sha256"
 	"fmt"
 	"regexp"
-
-	"github.com/decred/dcrtime/merkle"
 )
 
 type ResultT int
@@ -217,15 +216,23 @@ type VerifyBatchReply struct {
 	Timestamps []VerifyTimestamp `json:"timestamps"`
 }
 
+// MerkleBranch shares the same struct definition as merkle.Branch.
+// This has known horrible JSON marshaling in /v2.
+type MerkleBranch struct {
+	NumLeaves uint32              // Nuber of leaves
+	Hashes    [][sha256.Size]byte // Merkle branch
+	Flags     []byte              // Bitmap of merkle tree
+}
+
 // ChainInformation is returned by the server on a verify digest request.
 // It contains the merkle path of that digest.
 type ChainInformation struct {
-	ChainTimestamp   int64         `json:"chaintimestamp"`
-	Confirmations    *int32        `json:"confirmations,omitempty"` // Using a pointer because we don't want to omit 0
-	MinConfirmations int32         `json:"minconfirmations,omitempty"`
-	Transaction      string        `json:"transaction"`
-	MerkleRoot       string        `json:"merkleroot"`
-	MerklePath       merkle.Branch `json:"merklepath"`
+	ChainTimestamp   int64        `json:"chaintimestamp"`
+	Confirmations    *int32       `json:"confirmations,omitempty"` // Using a pointer because we don't want to omit 0
+	MinConfirmations int32        `json:"minconfirmations,omitempty"`
+	Transaction      string       `json:"transaction"`
+	MerkleRoot       string       `json:"merkleroot"`
+	MerklePath       MerkleBranch `json:"merklepath"`
 }
 
 // CollectionInformation is returned by the server on a verify timestamp

cmd/dcrtime/dcrtime.go

@@ -410,7 +410,7 @@ func verifyDigests(vd []v2.VerifyDigest) {
 		}
 
 		// Verify merkle path.
-		root, err := merkle.VerifyAuthPath(&d.ChainInformation.MerklePath)
+		root, err := merkle.VerifyAuthPath((*merkle.Branch)(&d.ChainInformation.MerklePath))
 		if err != nil {
 			if err != merkle.ErrEmpty {
 				fmt.Printf("%v invalid auth path %v\n",

cmd/dcrtime_checker/dcrtime_checker.go

@@ -55,7 +55,7 @@ func verifyV2(digest string, fProof *os.File) error {
 	}
 
 	// Verify merkle path.
-	root, err := merkle.VerifyAuthPath(&v.ChainInformation.MerklePath)
+	root, err := merkle.VerifyAuthPath((*merkle.Branch)(&v.ChainInformation.MerklePath))
 	if err != nil {
 		if err != merkle.ErrEmpty {
 			return fmt.Errorf("%v invalid auth path %v",

dcrtimed/dcrtimed.go

@@ -927,7 +927,7 @@ func (d *DcrtimeStore) verifyBatchV2(w http.ResponseWriter, r *http.Request) {
 				ChainTimestamp:   dr.AnchoredTimestamp,
 				Transaction:      dr.Tx.String(),
 				MerkleRoot:       hex.EncodeToString(dr.MerkleRoot[:]),
-				MerklePath:       dr.MerklePath,
+				MerklePath:       v2.MerkleBranch(dr.MerklePath),
 			},
 			Result: -1,
 		}
@@ -1182,7 +1182,7 @@ func (d *DcrtimeStore) verifyV2(w http.ResponseWriter, r *http.Request) {
 				ChainTimestamp:   dr.AnchoredTimestamp,
 				Transaction:      dr.Tx.String(),
 				MerkleRoot:       hex.EncodeToString(dr.MerkleRoot[:]),
-				MerklePath:       dr.MerklePath,
+				MerklePath:       v2.MerkleBranch(dr.MerklePath),
 			},
 			Result: -1,
 		}
@@ -1283,7 +1283,7 @@ func (d *DcrtimeStore) lastDigestsV2(w http.ResponseWriter, r *http.Request) {
 				MinConfirmations: vr.MinConfirmations,
 				Transaction:      vr.Tx.String(),
 				MerkleRoot:       hex.EncodeToString(vr.MerkleRoot[:]),
-				MerklePath:       vr.MerklePath,
+				MerklePath:       v2.MerkleBranch(vr.MerklePath),
 			},
 			Result: -1,
 		}