forked from open-policy-agent/opa
/
input.go
74 lines (61 loc) · 1.69 KB
/
input.go
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// 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 (
"fmt"
"github.com/open-policy-agent/opa/ast"
)
var errConflictingDoc = fmt.Errorf("conflicting documents")
var errBadPath = fmt.Errorf("bad document path")
func mergeTermWithValues(exist *ast.Term, pairs [][2]*ast.Term) (*ast.Term, error) {
var result *ast.Term
if exist != nil {
result = exist.Copy()
}
for _, pair := range pairs {
if err := ast.IsValidImportPath(pair[0].Value); err != nil {
return nil, errBadPath
}
target := pair[0].Value.(ast.Ref)
if len(target) == 1 {
result = pair[1]
} else 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++ {
if child := node.Get(target[i]); child == nil {
obj, ok := node.Value.(ast.Object)
if !ok {
return nil, errConflictingDoc
}
obj.Insert(target[i], ast.NewTerm(makeTree(target[i+1:], pair[1])))
done = true
} else {
node = child
}
}
if !done {
obj, ok := node.Value.(ast.Object)
if !ok {
return nil, errConflictingDoc
}
obj.Insert(target[len(target)-1], pair[1])
}
}
}
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
}