github.com/rajeev159/opa@v0.45.0/topdown/input.go (about) 1 // Copyright 2016 The OPA Authors. All rights reserved. 2 // Use of this source code is governed by an Apache2 3 // license that can be found in the LICENSE file. 4 5 package topdown 6 7 import ( 8 "fmt" 9 10 "github.com/open-policy-agent/opa/ast" 11 ) 12 13 var errBadPath = fmt.Errorf("bad document path") 14 15 func mergeTermWithValues(exist *ast.Term, pairs [][2]*ast.Term) (*ast.Term, error) { 16 17 var result *ast.Term 18 var init bool 19 20 for i, pair := range pairs { 21 22 if err := ast.IsValidImportPath(pair[0].Value); err != nil { 23 return nil, errBadPath 24 } 25 26 target := pair[0].Value.(ast.Ref) 27 28 // Copy the value if subsequent pairs in the slice would modify it. 29 for j := i + 1; j < len(pairs); j++ { 30 other := pairs[j][0].Value.(ast.Ref) 31 if len(other) > len(target) && other.HasPrefix(target) { 32 pair[1] = pair[1].Copy() 33 break 34 } 35 } 36 37 if len(target) == 1 { 38 result = pair[1] 39 init = true 40 } else { 41 if !init { 42 result = exist.Copy() 43 init = true 44 } 45 if result == nil { 46 result = ast.NewTerm(makeTree(target[1:], pair[1])) 47 } else { 48 node := result 49 done := false 50 for i := 1; i < len(target)-1 && !done; i++ { 51 obj, ok := node.Value.(ast.Object) 52 if !ok { 53 result = ast.NewTerm(makeTree(target[i:], pair[1])) 54 done = true 55 continue 56 } 57 if child := obj.Get(target[i]); !isObject(child) { 58 obj.Insert(target[i], ast.NewTerm(makeTree(target[i+1:], pair[1]))) 59 done = true 60 } else { // child is object 61 node = child 62 } 63 } 64 if !done { 65 if obj, ok := node.Value.(ast.Object); ok { 66 obj.Insert(target[len(target)-1], pair[1]) 67 } else { 68 result = ast.NewTerm(makeTree(target[len(target)-1:], pair[1])) 69 } 70 } 71 } 72 } 73 } 74 75 if !init { 76 result = exist 77 } 78 79 return result, nil 80 } 81 82 // makeTree returns an object that represents a document where the value v is 83 // the leaf and elements in k represent intermediate objects. 84 func makeTree(k ast.Ref, v *ast.Term) ast.Object { 85 var obj ast.Object 86 for i := len(k) - 1; i >= 1; i-- { 87 obj = ast.NewObject(ast.Item(k[i], v)) 88 v = &ast.Term{Value: obj} 89 } 90 obj = ast.NewObject(ast.Item(k[0], v)) 91 return obj 92 } 93 94 func isObject(x *ast.Term) bool { 95 if x == nil { 96 return false 97 } 98 _, ok := x.Value.(ast.Object) 99 return ok 100 }