Initial QSfera import

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

@@ -0,0 +1,97 @@
+// Copyright 2021 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"
+	"io"
+	"strings"
+
+	"github.com/open-policy-agent/opa/v1/ast"
+	"github.com/open-policy-agent/opa/v1/topdown/builtins"
+	"github.com/open-policy-agent/opa/v1/topdown/print"
+)
+
+func NewPrintHook(w io.Writer) print.Hook {
+	return printHook{w: w}
+}
+
+type printHook struct {
+	w io.Writer
+}
+
+func (h printHook) Print(_ print.Context, msg string) error {
+	_, err := fmt.Fprintln(h.w, msg)
+	return err
+}
+
+func builtinPrint(bctx BuiltinContext, operands []*ast.Term, iter func(*ast.Term) error) error {
+	if bctx.PrintHook == nil {
+		return iter(nil)
+	}
+
+	arr, err := builtins.ArrayOperand(operands[0].Value, 1)
+	if err != nil {
+		return err
+	}
+
+	buf := make([]string, arr.Len())
+
+	err = builtinPrintCrossProductOperands(bctx.Location, buf, arr, 0, func(buf []string) error {
+		pctx := print.Context{
+			Context:  bctx.Context,
+			Location: bctx.Location,
+		}
+		return bctx.PrintHook.Print(pctx, strings.Join(buf, " "))
+	})
+	if err != nil {
+		return err
+	}
+
+	return iter(nil)
+}
+
+func builtinPrintCrossProductOperands(loc *ast.Location, buf []string, operands *ast.Array, i int, f func([]string) error) error {
+	if i >= operands.Len() {
+		return f(buf)
+	}
+
+	operand := operands.Elem(i)
+
+	// We allow primitives ...
+	switch x := operand.Value.(type) {
+	case ast.String:
+		buf[i] = string(x)
+		return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
+	case ast.Number, ast.Boolean, ast.Null:
+		buf[i] = x.String()
+		return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
+	}
+
+	// ... but all other operand types must be sets.
+	xs, ok := operand.Value.(ast.Set)
+	if !ok {
+		return Halt{Err: internalErr(loc, "illegal argument type: "+ast.ValueName(operand.Value))}
+	}
+
+	if xs.Len() == 0 {
+		buf[i] = "<undefined>"
+		return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
+	}
+
+	return xs.Iter(func(x *ast.Term) error {
+		switch v := x.Value.(type) {
+		case ast.String:
+			buf[i] = string(v)
+		default:
+			buf[i] = v.String()
+		}
+		return builtinPrintCrossProductOperands(loc, buf, operands, i+1, f)
+	})
+}
+
+func init() {
+	RegisterBuiltinFunc(ast.InternalPrint.Name, builtinPrint)
+}