[Trivial] add comment about setting peer as HB peer.

jnewbery · jnewbery · commit dd5b0114cf90 · 2017-01-20T15:05:12.000-05:00
This adds a comment to the new logic for setting HB peers based
on block validation (and aligns the code below to reflect the comment).
It's not obvious why we're checking mapBlocksInFlight. Add a comment to
explain.
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
@@ -865,7 +865,15 @@ void PeerLogicValidation::BlockChecked(const CBlock& block, const CValidationSta
                 Misbehaving(it->second.first, nDoS);
         }
     }
-    else if (state.IsValid() && !IsInitialBlockDownload() && mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
+    // Check that:
+    // 1. The block is valid
+    // 2. We're not in initial block download
+    // 3. This is currently the best block we're aware of. We haven't updated
+    //    the tip yet so we have no way to check this directly here. Instead we
+    //    just check that there are currently no other blocks in flight.
+    else if (state.IsValid() &&
+             !IsInitialBlockDownload() &&
+             mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
         if (it != mapBlockSource.end()) {
             MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, *connman);
         }

Original file line number	Diff line number	Diff line change
`@@ -865,7 +865,15 @@ void PeerLogicValidation::BlockChecked(const CBlock& block, const CValidationSta`
`865`	`865`	`Misbehaving(it->second.first, nDoS);`
`866`	`866`	`}`
`867`	`867`	`}`
`868`		`- else if (state.IsValid() && !IsInitialBlockDownload() && mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {`
	`868`	`+ // Check that:`
	`869`	`+ // 1. The block is valid`
	`870`	`+ // 2. We're not in initial block download`
	`871`	`+ // 3. This is currently the best block we're aware of. We haven't updated`
	`872`	`+ // the tip yet so we have no way to check this directly here. Instead we`
	`873`	`+ // just check that there are currently no other blocks in flight.`
	`874`	`+ else if (state.IsValid() &&`
	`875`	`+ !IsInitialBlockDownload() &&`
	`876`	`+ mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {`
`869`	`877`	`if (it != mapBlockSource.end()) {`
`870`	`878`	`MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, *connman);`
`871`	`879`	`}`