From 3e62f7b75462c77f712a575e1d14a2a16aa109bb Mon Sep 17 00:00:00 2001
From: Bryan Boreham <bjboreham@gmail.com>
Date: Sat, 11 Nov 2017 11:49:25 +0000
Subject: [PATCH] Rewrite MapProcess2Name to process all nodes in one pass

This is more efficient as there are typically many fewer names than
processes.
---
 render/process.go | 41 ++++++++++++++++++-----------------------
 render/render.go  |  7 +++++++
 2 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/render/process.go b/render/process.go
index eacf95f91..b69586e21 100644
--- a/render/process.go
+++ b/render/process.go
@@ -74,12 +74,7 @@ var ProcessWithContainerNameRenderer = processWithContainerNameRenderer{ProcessR
 // name graph by munging the progess graph.
 //
 // not memoised
-var ProcessNameRenderer = ConditionalRenderer(renderProcesses,
-	MakeMap(
-		MapProcess2Name,
-		ProcessRenderer,
-	),
-)
+var ProcessNameRenderer = CustomRenderer{RenderFunc: processes2Names, Renderer: ProcessRenderer}
 
 // endpoints2Processes joins the endpoint topology to the process
 // topology, matching on hostID and pid.
@@ -132,23 +127,23 @@ func (e endpoints2Processes) Render(rpt report.Report) Nodes {
 	return ret.result()
 }
 
-// MapProcess2Name maps process Nodes to Nodes
-// for each process name.
-//
-// This mapper is unlike the other foo2bar mappers as the intention
-// is not to join the information with another topology.
-func MapProcess2Name(n report.Node, _ report.Networks) report.Nodes {
-	if n.Topology == Pseudo {
-		return report.Nodes{n.ID: n}
-	}
+// processes2Names maps process Nodes to Nodes for each process name.
+func processes2Names(processes Nodes) Nodes {
+	ret := newJoinResults()
 
-	name, timestamp, ok := n.Latest.LookupEntry(process.Name)
-	if !ok {
-		return report.Nodes{}
+	for _, n := range processes.Nodes {
+		if n.Topology == Pseudo {
+			ret.passThrough(n)
+		} else {
+			name, timestamp, ok := n.Latest.LookupEntry(process.Name)
+			if ok {
+				ret.addChildAndChildren(n, name, func(id string) report.Node {
+					return report.MakeNode(id).WithTopology(MakeGroupNodeTopology(n.Topology, process.Name)).
+						WithLatest(process.Name, timestamp, name)
+				})
+			}
+		}
 	}
-
-	node := NewDerivedNode(name, n).WithTopology(MakeGroupNodeTopology(n.Topology, process.Name))
-	node.Latest = node.Latest.Set(process.Name, timestamp, name)
-	node.Counters = node.Counters.Add(n.Topology, 1)
-	return report.Nodes{name: node}
+	ret.fixupAdjacencies(processes)
+	return ret.result()
 }
diff --git a/render/render.go b/render/render.go
index b67e84e64..4b3d9e0fe 100644
--- a/render/render.go
+++ b/render/render.go
@@ -188,6 +188,13 @@ func (ret *joinResults) addChildAndChildren(m report.Node, id string, create fun
 	ret.mapped[m.ID] = id
 }
 
+// Add a copy of n straight into the results
+func (ret *joinResults) passThrough(n report.Node) {
+	n.Adjacency = nil // fixupAdjacencies assumes all nodes start with blank lists
+	ret.nodes[n.ID] = n
+	ret.mapped[n.ID] = n.ID
+}
+
 // Rewrite Adjacency for new nodes in ret for original nodes in input
 func (ret *joinResults) fixupAdjacencies(input Nodes) {
 	for _, n := range input.Nodes {