Index combined diff sensitivity

internal/engine/diff_sensitivity.go

@@ -0,0 +1,48 @@
+package engine
+
+type diffSensitivity struct {
+	prefixes pathPrefixIndex
+	pointers []string
+}
+
+func newDiffSensitivity(left, right map[string]bool) *diffSensitivity {
+	sensitivity := &diffSensitivity{}
+	seen := make(map[string]struct{}, len(left)+len(right))
+	for _, classifications := range []map[string]bool{left, right} {
+		for pointer, classified := range classifications {
+			if !classified {
+				continue
+			}
+			if _, found := seen[pointer]; found {
+				continue
+			}
+			seen[pointer] = struct{}{}
+			id := len(sensitivity.pointers)
+			sensitivity.pointers = append(sensitivity.pointers, pointer)
+			sensitivity.prefixes.insert(pointer, id)
+		}
+	}
+	return sensitivity
+}
+
+func (sensitivity *diffSensitivity) isSensitiveAtOrAbove(pointer string) bool {
+	if sensitivity == nil {
+		return false
+	}
+	found := false
+	sensitivity.prefixes.visitAncestors(pointer, func(int) { found = true })
+	return found
+}
+
+func (sensitivity *diffSensitivity) hasStrictDescendant(pointer string) bool {
+	if sensitivity == nil {
+		return false
+	}
+	found := false
+	sensitivity.prefixes.visitDescendants(pointer, func(id int) {
+		if sensitivity.pointers[id] != pointer {
+			found = true
+		}
+	})
+	return found
+}