core/rawdb: remove dead code and restore useful test

core/rawdb/accessors_chain.go

@@ -827,33 +827,6 @@ func WriteBadBlock(db ethdb.KeyValueStore, block *types.Block) {
 	}
 }
 
-// FindCommonAncestor returns the last common ancestor of two block headers
-func FindCommonAncestor(db ethdb.Reader, a, b *types.Header) *types.Header {
-	for bn := b.Number.Uint64(); a.Number.Uint64() > bn; {
-		a = ReadHeader(db, a.ParentHash, a.Number.Uint64()-1)
-		if a == nil {
-			return nil
-		}
-	}
-	for an := a.Number.Uint64(); an < b.Number.Uint64(); {
-		b = ReadHeader(db, b.ParentHash, b.Number.Uint64()-1)
-		if b == nil {
-			return nil
-		}
-	}
-	for a.Hash() != b.Hash() {
-		a = ReadHeader(db, a.ParentHash, a.Number.Uint64()-1)
-		if a == nil {
-			return nil
-		}
-		b = ReadHeader(db, b.ParentHash, b.Number.Uint64()-1)
-		if b == nil {
-			return nil
-		}
-	}
-	return a
-}
-
 // ReadHeadHeader returns the current canonical head header.
 func ReadHeadHeader(db ethdb.Reader) *types.Header {
 	headHeaderHash := ReadHeadHeaderHash(db)

core/rawdb/accessors_chain_test.go

@@ -508,6 +508,35 @@ func TestWriteAncientHeaderChain(t *testing.T) {
 	}
 }
 
+func TestHashesInRange(t *testing.T) {
+	mkHeader := func(number, seq int) *types.Header {
+		h := types.Header{
+			Difficulty: new(big.Int),
+			Number:     big.NewInt(int64(number)),
+			GasLimit:   uint64(seq),
+		}
+		return &h
+	}
+	db := NewMemoryDatabase()
+	// For each number, write N versions of that particular number
+	total := 0
+	for i := 0; i < 15; i++ {
+		for ii := 0; ii < i; ii++ {
+			WriteHeader(db, mkHeader(i, ii))
+			total++
+		}
+	}
+	if have, want := len(ReadAllHashes(db, 10)), 10; have != want {
+		t.Fatalf("Wrong number of hashes read, want %d, got %d", want, have)
+	}
+	if have, want := len(ReadAllHashes(db, 16)), 0; have != want {
+		t.Fatalf("Wrong number of hashes read, want %d, got %d", want, have)
+	}
+	if have, want := len(ReadAllHashes(db, 1)), 1; have != want {
+		t.Fatalf("Wrong number of hashes read, want %d, got %d", want, have)
+	}
+}
+
 // This measures the write speed of the WriteAncientBlocks operation.
 func BenchmarkWriteAncientBlocks(b *testing.B) {
 	// Open freezer database.