def buildMutation()

in s2core/src/main/scala/org/apache/s2graph/core/S2Edge.scala [642:689]
38 lines of code
13 McCabe index (conditional complexity)

  def buildMutation(snapshotEdgeOpt: Option[S2EdgeLike],
                    requestEdge: S2EdgeLike,
                    newVersion: Long,
                    oldPropsWithTs: Map[LabelMeta, InnerValLikeWithTs],
                    newPropsWithTs: Map[LabelMeta, InnerValLikeWithTs]): EdgeMutate = {

    if (oldPropsWithTs == newPropsWithTs) {
      // all requests should be dropped. so empty mutation.
      EdgeMutate(edgesToDelete = Nil, edgesToInsert = Nil, newSnapshotEdge = None)
    } else {
      val withOutDeletedAt = newPropsWithTs.filter(kv => kv._1 != LabelMeta.lastDeletedAtSeq)
      val newOp = snapshotEdgeOpt match {
        case None => requestEdge.getOp()
        case Some(old) =>
          val oldMaxTs = old.getPropsWithTs().asScala.map(_._2.ts).max
          if (oldMaxTs > requestEdge.ts) old.getOp()
          else requestEdge.getOp()
      }

      val newSnapshotEdge = requestEdge.copyOp(newOp).copyVersion(newVersion).copyEdgeWithState(newPropsWithTs)

      val newSnapshotEdgeOpt = Option(newSnapshotEdge.toSnapshotEdge)
      // delete request must always update snapshot.
      if (withOutDeletedAt == oldPropsWithTs && newPropsWithTs.contains(LabelMeta.lastDeletedAt)) {
        // no mutation on indexEdges. only snapshotEdge should be updated to record lastDeletedAt.
        EdgeMutate(edgesToDelete = Nil, edgesToInsert = Nil, newSnapshotEdge = newSnapshotEdgeOpt)
      } else {
        val edgesToDelete = snapshotEdgeOpt match {
          case Some(snapshotEdge) if snapshotEdge.getOp() != GraphUtil.operations("delete") =>
            snapshotEdge.copyOp(GraphUtil.defaultOpByte)
              .relatedEdges.flatMap { relEdge => relEdge.edgesWithIndexValid }
          case _ => Nil
        }

        val edgesToInsert =
          if (newPropsWithTs.isEmpty || allPropsDeleted(newPropsWithTs)) Nil
          else {
            val newEdge = requestEdge.copyOp(GraphUtil.defaultOpByte).copyVersion(newVersion).copyEdgeWithState(S2Edge.EmptyState)
            newPropsWithTs.foreach { case (k, v) => newEdge.propertyInner(k.name, v.innerVal.value, v.ts) }

            newEdge.relatedEdges.flatMap { relEdge => relEdge.edgesWithIndexValid }
          }


        EdgeMutate(edgesToDelete = edgesToDelete, edgesToInsert = edgesToInsert, newSnapshotEdge = newSnapshotEdgeOpt)
      }
    }
  }