Update Carnot-Specs

content/roadmap/consensus/candidates/carnot/Carnot-Specs

@@ -49,53 +49,58 @@ Utilities:
      download(view): Download missing block for the view.
      getMaxViewQC(qcs): returns the qc with the highest view number.
      memberOfLeafCommittee(): returns true if a node is in the leaf committee of the committee overlay
-     memberOfInternalComExceptRoot(): returns true if a node is member of internal committees within the committee tree overlay
+     memberOfInternalComExceptRoot(): returns true if a node is member of internal committees within the committee tree overlay except root committee
-     childcommittee(nodeIndx): returns true if the node id in the nodeIndx is member internal node (but not root) of the overlay
+     childcommittee (signer): returns true if the node id (signer) in the nodeIndx is member of the child committee 
      supermajority(votes): returns if the number of distinctive signers of votes for a block is is equal to the threshold or returns if the qourum size has reached.
      morethanSsupermajority(votes): returns if the number of distinctive signers of votes for a block is is more than the threshold
 
 #Core Functions of the Carnot consensus:
 
         Func safeBlock(block){
+		 # this check makes sure block is not old and the previous leader did not fail
 	        if block.QC != Null{
 		        return block.view >= curView and block.view == block.qc.block.view + 1
                 }
-	        if block.aggQC != Null{
+		# this meails previous leader/leaders have failed. But still we need to check if the block is not old and the block extends from a valid ancestor.
+	        if block.aggQC != Null{ 
 		        return block.view >= curView and extends(block, block.aggQC.highQC.block)
 
                 }
         }
 	
-	Func tryToCommitGrandParent(block){
+	# Commit a grand parent if the grandparent and the parent have been added during two consecutive views.
+	Func tryToCommitGrandParent(block){ 
 	          parentBlock = block.qc.block
 		  grandparentBlock = parentBlock.qc.block
 		  return parentBlock.view = grandparentBlock.view+1
 
 	}
 
-
+	#Update the latest certification (qc) and view number 
         Func update_higQC(qc, aggQC){
-		if qc != Null{ # Happy case
+		# Happy case
+		if qc != Null{ 
 			if qc.block.view > highQC.block.view{
 				highQC = qc
 				}
 			if qc.block.view > curView { 	# download blocks from missing views
 				while curView++ <= qc.block.view {
 				download(curView) 
+				reset()
 				}
 			}
-			#reset()
+		}
-			}
 
-		if aggQC != Null { # Unhappy case
+		 # Unhappy case
+		if aggQC != Null {
 			if aggQC.highQC.block.view != highQC.block.view{
 				highQC = aggQC.highQC # release the lock and adopt the global lock 
 				if aggQC.highQC.block.view > curView { # download the blocks of the missed views
 					while curView++ <=  aggQC.highQC.view {
 						download(curView) 
+						reset()
 					}
 				}
-			#reset()
    
         		}
 	}
@@ -106,16 +111,21 @@ Utilities:
         Func receive(block){
 		if block.hash is known OR block.view <= latestCommittedBlock.view {return}
 		if block.parent missing{ download(block.parent)}
+		#Previous leader did not fail and its proposal was certified
 		if block.qc != Null 
 			{if block.qc.block.view <= latestCommittedBlock.view {return}}
+	
+		# Previous leader failed
 		if block.aggQC! = Null
 			{ 
 			block.aggQC.highQC = getMaxViewQC (block.agg_qc.qcs)
+			# Since verification of signatures  is not included in this psuedocode, it is worth mentioning that here verification of block.aggQC.highQC
+			# along with the block.aggQC.signature is suffice. No need to verify each qc inside block.aggQC
 			if block.aggQC.highQC.view <= latestCommittedBlock.view {return}
 			}
 		
 		if safeBlock(block){
-		update_higQC(block.qc, block.aggQC)
+			update_higQC(block.qc, block.aggQC)
 			if memberOfLeafCommittee(){ send(vote, parentCommittee)
 			reset()
 			tryToCommitGrandParent(block)
@@ -135,7 +145,7 @@ Utilities:
 		if vote.block missing {download(vote.block)}
 		if vote.block.view < curView - 1{ return}
 		if memberOfInternalComExceptRoot(nodeIndx) {
-			if childcommittee(vote.signer) { collection[vote.block].append(vote)}
+			if childcommittee (vote.signer) { collection[vote.block].append(vote)}
 			if supermajority(collection[vote.block]){
 			send(vote, parentCommittee)
 			curView++