Merge pull request #93 from ApexTheory/84-batch-merkle-proof

Batch Merkle Proof - override equals for matcher array equality

Author: kushti

src/main/scala/scorex/crypto/authds/merkle/BatchMerkleProof.scala

@@ -5,6 +5,7 @@ import scorex.crypto.authds.merkle.MerkleTree.InternalNodePrefix
 import scorex.crypto.hash.{CryptographicHash, Digest}
 import scorex.util.ScorexEncoding
 
+import java.util
 import scala.language.postfixOps
 
   /**
@@ -90,6 +91,31 @@ case class BatchMerkleProof[D <: Digest](indices: Seq[(Int, Digest)], proofs: Se
     }
 
     val e = indices sortBy(_._1)
-    loop(indices.map(_._1), e, proofs).head.sameElements(expectedRootHash)
+    loop(indices.map(_._1), e, proofs) match {
+      case root: Seq[Digest] if root.size == 1 => root.head.sameElements(expectedRootHash)
+      case _ => false
+    }
   }
+
+    override def equals(obj: Any): Boolean = obj match {
+      case that: BatchMerkleProof[D] =>
+        if (this.indices.size != that.indices.size ||
+          this.proofs.size != that.proofs.size) {
+          return false
+        }
+        for (i <- this.indices.indices) {
+          if (this.indices.apply(i)._1 != that.indices.apply(i)._1 ||
+            !util.Arrays.equals(this.indices.apply(i)._2, that.indices.apply(i)._2)) {
+            return false
+          }
+        }
+        for (i <- this.proofs.indices) {
+          if (this.proofs.apply(i)._2 != that.proofs.apply(i)._2 ||
+            !util.Arrays.equals(this.proofs.apply(i)._1, that.proofs.apply(i)._1)) {
+            return false
+          }
+        }
+        true
+      case _ => false
+    }
 }

src/main/scala/scorex/crypto/authds/merkle/MerkleTree.scala

@@ -95,7 +95,7 @@ case class MerkleTree[D <: Digest](topNode: Node[D],
       m
     }
 
-    if (indices.forall(index => index >= 0 && index < length)) {
+    if (indices.nonEmpty && indices.forall(index => index >= 0 && index < length)) {
       val hashes: Seq[Digest] = elementsHashIndex.toSeq.sortBy(_._2).map(_._1.toArray.asInstanceOf[Digest])
       val normalized_indices = indices.distinct.sorted
       val multiproof = loop(normalized_indices, hashes)

src/test/scala/scorex/crypto/authds/merkle/MerkleTreeSpecification.scala

@@ -82,6 +82,12 @@ class MerkleTreeSpecification extends AnyPropSpec with ScalaCheckDrivenPropertyC
     tree.proofByIndices(Seq(2,10)) shouldBe None
   }
 
+  property("Empty Batch proof generation should be None") {
+    val d = (0 until 10).map(_ => LeafData @@ scorex.utils.Random.randomBytes(LeafSize))
+    val tree = MerkleTree(d)
+    tree.proofByIndices(Seq.empty[Int]) shouldBe None
+  }
+
   property("Tree creation from 0 elements") {
     val tree = MerkleTree(Seq.empty)(hf)
     tree.rootHash shouldEqual Array.fill(hf.DigestSize)(0: Byte)