Курнат Андрей
98 lines
2.2 KiB
Go
98 lines
2.2 KiB
Go
// Copyright 2021 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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"fmt"
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"io"
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"strings"
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"github.com/open-policy-agent/opa/v1/ast"
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"github.com/open-policy-agent/opa/v1/topdown/builtins"
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"github.com/open-policy-agent/opa/v1/topdown/print"
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)
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func NewPrintHook(w io.Writer) print.Hook {
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return printHook{w: w}
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}
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type printHook struct {
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w io.Writer
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}
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func (h printHook) Print(_ print.Context, msg string) error {
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_, err := fmt.Fprintln(h.w, msg)
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return err
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}
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func builtinPrint(bctx BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
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if bctx.PrintHook == nil {
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return iter(nil)
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}
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arr, err := builtins.ArrayOperand(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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buf := make([]string, arr.Len())
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err = builtinPrintCrossProductOperands(bctx.Location, buf, arr, 0, func(buf []string) error {
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pctx := print.Context{
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Context: bctx.Context,
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Location: bctx.Location,
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}
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return bctx.PrintHook.Print(pctx, strings.Join(buf, " "))
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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(nil)
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}
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func builtinPrintCrossProductOperands(loc *ast.Location, buf []string, operands *ast.Array, i int, f func([]string) error) error {
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if i >= operands.Len() {
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return f(buf)
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}
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operand := operands.Elem(i)
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// We allow primitives ...
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switch x := operand.Value.(type) {
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case ast.String:
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buf[i] = string(x)
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return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
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case ast.Number, ast.Boolean, ast.Null:
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buf[i] = x.String()
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return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
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}
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// ... but all other operand types must be sets.
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xs, ok := operand.Value.(ast.Set)
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if !ok {
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return Halt{Err: internalErr(loc, "illegal argument type: "+ast.ValueName(operand.Value))}
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}
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if xs.Len() == 0 {
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buf[i] = "<undefined>"
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return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
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}
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return xs.Iter(func(x *ast.Term) error {
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switch v := x.Value.(type) {
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case ast.String:
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buf[i] = string(v)
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default:
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buf[i] = v.String()
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}
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return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
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})
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}
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func init() {
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RegisterBuiltinFunc(ast.InternalPrint.Name, builtinPrint)
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}
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