update dependencies (#6267)

Signed-off-by: hongming <coder.scala@gmail.com>

vendor/github.com/open-policy-agent/opa/topdown/cache.go

@@ -9,6 +9,29 @@ import (
 	"github.com/open-policy-agent/opa/util"
 )
 
+// VirtualCache defines the interface for a cache that stores the results of
+// evaluated virtual documents (rules).
+// The cache is a stack of frames, where each frame is a mapping from references
+// to values.
+type VirtualCache interface {
+	// Push pushes a new, empty frame of value mappings onto the stack.
+	Push()
+
+	// Pop pops the top frame of value mappings from the stack, removing all associated entries.
+	Pop()
+
+	// Get returns the value associated with the given reference. The second return value
+	// indicates whether the reference has a recorded 'undefined' result.
+	Get(ref ast.Ref) (*ast.Term, bool)
+
+	// Put associates the given reference with the given value. If the value is nil, the reference
+	// is marked as having an 'undefined' result.
+	Put(ref ast.Ref, value *ast.Term)
+
+	// Keys returns the set of keys that have been cached for the active frame.
+	Keys() []ast.Ref
+}
+
 type virtualCache struct {
 	stack []*virtualCacheElem
 }
@@ -19,7 +42,7 @@ type virtualCacheElem struct {
 	undefined bool
 }
 
-func newVirtualCache() *virtualCache {
+func NewVirtualCache() VirtualCache {
 	cache := &virtualCache{}
 	cache.Push()
 	return cache
@@ -77,6 +100,26 @@ func (c *virtualCache) Put(ref ast.Ref, value *ast.Term) {
 	}
 }
 
+func (c *virtualCache) Keys() []ast.Ref {
+	node := c.stack[len(c.stack)-1]
+	return keysRecursive(nil, node)
+}
+
+func keysRecursive(root ast.Ref, node *virtualCacheElem) []ast.Ref {
+	var keys []ast.Ref
+	node.children.Iter(func(k, v util.T) bool {
+		ref := root.Append(k.(*ast.Term))
+		if v.(*virtualCacheElem).value != nil {
+			keys = append(keys, ref)
+		}
+		if v.(*virtualCacheElem).children.Len() > 0 {
+			keys = append(keys, keysRecursive(ref, v.(*virtualCacheElem))...)
+		}
+		return false
+	})
+	return keys
+}
+
 func newVirtualCacheElem() *virtualCacheElem {
 	return &virtualCacheElem{children: newVirtualCacheHashMap()}
 }