optimise & simplify node propagation in joinResult

Instead of copying unmatched nodes at the end, and matched nodes when
we encounter them, copy *all* nodes at the beginning.

render/container.go

@@ -71,7 +71,7 @@ func (c connectionJoin) Render(rpt report.Report) Nodes {
 			}
 		}
 	}
-	ret := newJoinResults()
+	ret := newJoinResults(inputNodes.Nodes)
 
 	// Now look at all the endpoints and see which map to IP nodes
 	for _, m := range endpoints.Nodes {
@@ -99,7 +99,6 @@ func (c connectionJoin) Render(rpt report.Report) Nodes {
 			})
 		}
 	}
-	ret.copyUnmatched(inputNodes)
 	return ret.result(endpoints)
 }
 

render/host.go

@@ -26,7 +26,7 @@ var HostRenderer = MakeReduce(
 // not have enough info to do that, and the resulting graph must be
 // merged with a host graph to get that info.
 func nodes2Hosts(nodes Nodes) Nodes {
-	ret := newJoinResults()
+	ret := newJoinResults(nil)
 
 	for _, n := range nodes.Nodes {
 		if n.Topology == Pseudo {
@@ -51,7 +51,7 @@ func (e endpoints2Hosts) Render(rpt report.Report) Nodes {
 	local := LocalNetworks(rpt)
 	hosts := SelectHost.Render(rpt)
 	endpoints := SelectEndpoint.Render(rpt)
-	ret := newJoinResults()
+	ret := newJoinResults(hosts.Nodes)
 
 	for _, n := range endpoints.Nodes {
 		// Nodes without a hostid are treated as pseudo nodes
@@ -72,6 +72,5 @@ func (e endpoints2Hosts) Render(rpt report.Report) Nodes {
 			})
 		}
 	}
-	ret.copyUnmatched(hosts)
 	return ret.result(endpoints)
 }

render/process.go

@@ -86,7 +86,7 @@ func (e endpoints2Processes) Render(rpt report.Report) Nodes {
 	local := LocalNetworks(rpt)
 	processes := SelectProcess.Render(rpt)
 	endpoints := SelectEndpoint.Render(rpt)
-	ret := newJoinResults()
+	ret := newJoinResults(processes.Nodes)
 
 	for _, n := range endpoints.Nodes {
 		// Nodes without a hostid are treated as pseudo nodes
@@ -115,7 +115,6 @@ func (e endpoints2Processes) Render(rpt report.Report) Nodes {
 			})
 		}
 	}
-	ret.copyUnmatched(processes)
 	return ret.result(endpoints)
 }
 
@@ -148,7 +147,7 @@ func hasMoreThanOneConnection(n report.Node, endpoints report.Nodes) bool {
 
 // processes2Names maps process Nodes to Nodes for each process name.
 func processes2Names(processes Nodes) Nodes {
-	ret := newJoinResults()
+	ret := newJoinResults(nil)
 
 	for _, n := range processes.Nodes {
 		if n.Topology == Pseudo {

render/render.go

@@ -166,8 +166,12 @@ type joinResults struct {
 	mapped map[string]string // input node ID -> output node ID
 }
 
-func newJoinResults() joinResults {
-	return joinResults{nodes: make(report.Nodes), mapped: map[string]string{}}
+func newJoinResults(inputNodes report.Nodes) joinResults {
+	nodes := make(report.Nodes, len(inputNodes))
+	for id, n := range inputNodes {
+		nodes[id] = n
+	}
+	return joinResults{nodes: nodes, mapped: map[string]string{}}
 }
 
 // Add m as a child of the node at id, creating a new result node if
@@ -207,14 +211,6 @@ func (ret *joinResults) passThrough(n report.Node) {
 	ret.mapped[n.ID] = n.ID
 }
 
-func (ret *joinResults) copyUnmatched(input Nodes) {
-	for _, n := range input.Nodes {
-		if _, found := ret.nodes[n.ID]; !found {
-			ret.nodes[n.ID] = n
-		}
-	}
-}
-
 // Rewrite Adjacency of nodes in ret mapped from original nodes in
 // input, and return the result.
 func (ret *joinResults) result(input Nodes) Nodes {