95 lines
2.3 KiB
Go
95 lines
2.3 KiB
Go
// Copyright 2016 The OPA Authors. All rights reserved.
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// Use of this source code is governed by an Apache2
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// license that can be found in the LICENSE file.
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package topdown
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import (
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"github.com/open-policy-agent/opa/ast"
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"github.com/open-policy-agent/opa/topdown/builtins"
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)
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// Deprecated in v0.4.2 in favour of minus/infix "-" operation.
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func builtinSetDiff(_ BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
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s1, err := builtins.SetOperand(operands[0].Value, 1)
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if err != nil {
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return err
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}
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s2, err := builtins.SetOperand(operands[1].Value, 2)
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if err != nil {
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return err
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}
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return iter(ast.NewTerm(s1.Diff(s2)))
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}
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// builtinSetIntersection returns the intersection of the given input sets
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func builtinSetIntersection(_ BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
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inputSet, err := builtins.SetOperand(operands[0].Value, 1)
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if err != nil {
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return err
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}
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// empty input set
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if inputSet.Len() == 0 {
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return iter(ast.NewTerm(ast.NewSet()))
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}
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var result ast.Set
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err = inputSet.Iter(func(x *ast.Term) error {
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n, err := builtins.SetOperand(x.Value, 1)
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if err != nil {
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return err
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}
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if result == nil {
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result = n
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} else {
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result = result.Intersect(n)
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}
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return nil
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})
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if err != nil {
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return err
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}
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return iter(ast.NewTerm(result))
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}
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// builtinSetUnion returns the union of the given input sets
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func builtinSetUnion(_ BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
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// The set union logic here is duplicated and manually inlined on
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// purpose. By lifting this logic up a level, and not doing pairwise
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// set unions, we avoid a number of heap allocations. This improves
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// performance dramatically over the naive approach.
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result := ast.NewSet()
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inputSet, err := builtins.SetOperand(operands[0].Value, 1)
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if err != nil {
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return err
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}
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err = inputSet.Iter(func(x *ast.Term) error {
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item, err := builtins.SetOperand(x.Value, 1)
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if err != nil {
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return err
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}
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item.Foreach(result.Add)
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return nil
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})
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if err != nil {
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return err
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}
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return iter(ast.NewTerm(result))
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}
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func init() {
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RegisterBuiltinFunc(ast.SetDiff.Name, builtinSetDiff)
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RegisterBuiltinFunc(ast.Intersection.Name, builtinSetIntersection)
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RegisterBuiltinFunc(ast.Union.Name, builtinSetUnion)
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}
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