Initial QSfera import

Server/vendor/github.com/open-policy-agent/opa/v1/topdown/input.go

@@ -0,0 +1,100 @@
+// Copyright 2016 The OPA Authors.  All rights reserved.
+// Use of this source code is governed by an Apache2
+// license that can be found in the LICENSE file.
+
+package topdown
+
+import (
+	"errors"
+
+	"github.com/open-policy-agent/opa/v1/ast"
+)
+
+var errBadPath = errors.New("bad document path")
+
+func mergeTermWithValues(exist *ast.Term, pairs [][2]*ast.Term) (*ast.Term, error) {
+
+	var result *ast.Term
+	var init bool
+
+	for i, pair := range pairs {
+
+		if err := ast.IsValidImportPath(pair[0].Value); err != nil {
+			return nil, errBadPath
+		}
+
+		target := pair[0].Value.(ast.Ref)
+
+		// Copy the value if subsequent pairs in the slice would modify it.
+		for j := i + 1; j < len(pairs); j++ {
+			other := pairs[j][0].Value.(ast.Ref)
+			if len(other) > len(target) && other.HasPrefix(target) {
+				pair[1] = pair[1].Copy()
+				break
+			}
+		}
+
+		if len(target) == 1 {
+			result = pair[1]
+			init = true
+		} else {
+			if !init {
+				result = exist.Copy()
+				init = true
+			}
+			if result == nil {
+				result = ast.NewTerm(makeTree(target[1:], pair[1]))
+			} else {
+				node := result
+				done := false
+				for i := 1; i < len(target)-1 && !done; i++ {
+					obj, ok := node.Value.(ast.Object)
+					if !ok {
+						result = ast.NewTerm(makeTree(target[i:], pair[1]))
+						done = true
+						continue
+					}
+					if child := obj.Get(target[i]); !isObject(child) {
+						obj.Insert(target[i], ast.NewTerm(makeTree(target[i+1:], pair[1])))
+						done = true
+					} else { // child is object
+						node = child
+					}
+				}
+				if !done {
+					if obj, ok := node.Value.(ast.Object); ok {
+						obj.Insert(target[len(target)-1], pair[1])
+					} else {
+						result = ast.NewTerm(makeTree(target[len(target)-1:], pair[1]))
+					}
+				}
+			}
+		}
+	}
+
+	if !init {
+		result = exist
+	}
+
+	return result, nil
+}
+
+// makeTree returns an object that represents a document where the value v is
+// the leaf and elements in k represent intermediate objects.
+func makeTree(k ast.Ref, v *ast.Term) ast.Object {
+	var obj ast.Object
+	for i := len(k) - 1; i >= 1; i-- {
+		obj = ast.NewObject(ast.Item(k[i], v))
+		v = &ast.Term{Value: obj}
+	}
+	obj = ast.NewObject(ast.Item(k[0], v))
+	return obj
+}
+
+func isObject(x *ast.Term) bool {
+	if x == nil {
+		return false
+	}
+	_, ok := x.Value.(ast.Object)
+	return ok
+}