An ActionSet doesn't need to walk the graph.

Resolutions map back to the root, but actions do not. An iteration
works just fine.

Simplify TargetNodeSet so that it is directly iterable.

Bug: 261787132

Test: m droid dist compliance_dumpgraph compliance_dumpresolutions \
        compliance_sbom compliance_listshare compliance_rtrace \
        compliance_checkshare xmlnotice textnotice htmlnotice \
        compliancenotice_shippedlibs compliancenotice_bom

Test: m compliance_checkshare cts && \
        out/host/linux-x86/bin/compliance_checkshare out/host/linux-x86/gen/META/lic_intermediates/out/host/linux-x86/cts/android-cts.zip.meta_lic

Change-Id: Ic5a2d809b5a9a47b5d85f61e3a4a790dbe8f5fd2
diff --git a/tools/compliance/graph.go b/tools/compliance/graph.go
index 80a2f47..fac1d05 100644
--- a/tools/compliance/graph.go
+++ b/tools/compliance/graph.go
@@ -459,36 +459,25 @@
 }
 
 // TargetNodeSet describes a set of distinct nodes in a license graph.
-type TargetNodeSet struct {
-	nodes map[*TargetNode]struct{}
-}
+type TargetNodeSet map[*TargetNode]struct{}
 
 // Contains returns true when `target` is an element of the set.
-func (ts *TargetNodeSet) Contains(target *TargetNode) bool {
-	_, isPresent := ts.nodes[target]
+func (ts TargetNodeSet) Contains(target *TargetNode) bool {
+	_, isPresent := ts[target]
 	return isPresent
 }
 
-// AsList returns the list of target nodes in the set. (unordered)
-func (ts *TargetNodeSet) AsList() TargetNodeList {
-	result := make(TargetNodeList, 0, len(ts.nodes))
-	for tn := range ts.nodes {
-		result = append(result, tn)
-	}
-	return result
-}
-
 // Names returns the array of target node namess in the set. (unordered)
-func (ts *TargetNodeSet) Names() []string {
-	result := make([]string, 0, len(ts.nodes))
-	for tn := range ts.nodes {
+func (ts TargetNodeSet) Names() []string {
+	result := make([]string, 0, len(ts))
+	for tn := range ts {
 		result = append(result, tn.name)
 	}
 	return result
 }
 
 // String returns a human-readable string representation of the set.
-func (ts *TargetNodeSet) String() string {
+func (ts TargetNodeSet) String() string {
 	return fmt.Sprintf("{%s}", strings.Join(ts.Names(), ", "))
 }
 
diff --git a/tools/compliance/noticeindex.go b/tools/compliance/noticeindex.go
index dbfede6..c91a8df 100644
--- a/tools/compliance/noticeindex.go
+++ b/tools/compliance/noticeindex.go
@@ -42,7 +42,7 @@
 	// rs identifies the set of resolutions upon which the index is based.
 	rs ResolutionSet
 	// shipped identifies the set of target nodes shipped directly or as derivative works.
-	shipped *TargetNodeSet
+	shipped TargetNodeSet
 	// rootFS locates the root of the file system from which to read the files.
 	rootFS fs.FS
 	// hash maps license text filenames to content hashes
diff --git a/tools/compliance/policy_shipped.go b/tools/compliance/policy_shipped.go
index 75c8399..b21a95a 100644
--- a/tools/compliance/policy_shipped.go
+++ b/tools/compliance/policy_shipped.go
@@ -16,15 +16,15 @@
 
 // ShippedNodes returns the set of nodes in a license graph where the target or
 // a derivative work gets distributed. (caches result)
-func ShippedNodes(lg *LicenseGraph) *TargetNodeSet {
+func ShippedNodes(lg *LicenseGraph) TargetNodeSet {
 	lg.mu.Lock()
 	shipped := lg.shippedNodes
 	lg.mu.Unlock()
 	if shipped != nil {
-		return shipped
+		return *shipped
 	}
 
-	tset := make(map[*TargetNode]struct{})
+	tset := make(TargetNodeSet)
 
 	WalkTopDown(NoEdgeContext{}, lg, func(lg *LicenseGraph, tn *TargetNode, path TargetEdgePath) bool {
 		if _, alreadyWalked := tset[tn]; alreadyWalked {
@@ -39,7 +39,7 @@
 		return true
 	})
 
-	shipped = &TargetNodeSet{tset}
+	shipped = &tset
 
 	lg.mu.Lock()
 	if lg.shippedNodes == nil {
@@ -50,5 +50,5 @@
 	}
 	lg.mu.Unlock()
 
-	return shipped
+	return *shipped
 }
diff --git a/tools/compliance/policy_walk.go b/tools/compliance/policy_walk.go
index beb6d53..e6b94ab 100644
--- a/tools/compliance/policy_walk.go
+++ b/tools/compliance/policy_walk.go
@@ -247,40 +247,16 @@
 // WalkActionsForCondition performs a top-down walk of the LicenseGraph
 // resolving all distributed works for `conditions`.
 func WalkActionsForCondition(lg *LicenseGraph, conditions LicenseConditionSet) ActionSet {
-	shipped := ShippedNodes(lg)
-
-	// cmap identifies previously walked target/condition pairs.
-	cmap := make(map[resolutionKey]struct{})
-
 	// amap maps 'actsOn' targets to the applicable conditions
 	//
 	// amap is the resulting ActionSet
 	amap := make(ActionSet)
-	WalkTopDown(ApplicableConditionsContext{conditions}, lg, func(lg *LicenseGraph, tn *TargetNode, path TargetEdgePath) bool {
-		universe := conditions
-		if len(path) > 0 {
-			universe = path[len(path)-1].ctx.(LicenseConditionSet)
+
+	for tn := range ShippedNodes(lg) {
+		if cs := conditions.Intersection(tn.resolution); !cs.IsEmpty() {
+			amap[tn] = cs
 		}
-		if universe.IsEmpty() {
-			return false
-		}
-		key := resolutionKey{tn, universe}
-		if _, ok := cmap[key]; ok {
-			return false
-		}
-		if !shipped.Contains(tn) {
-			return false
-		}
-		cs := universe.Intersection(tn.resolution)
-		if !cs.IsEmpty() {
-			if _, ok := amap[tn]; ok {
-				amap[tn] = cs
-			} else {
-				amap[tn] = amap[tn].Union(cs)
-			}
-		}
-		return true
-	})
+	}
 
 	return amap
 }