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authormo khan <mo@mokhan.ca>2025-07-22 17:35:49 -0600
committermo khan <mo@mokhan.ca>2025-07-22 17:35:49 -0600
commit20ef0d92694465ac86b550df139e8366a0a2b4fa (patch)
tree3f14589e1ce6eb9306a3af31c3a1f9e1af5ed637 /vendor/github.com/authzed/cel-go/parser/unparser.go
parent44e0d272c040cdc53a98b9f1dc58ae7da67752e6 (diff)
feat: connect to spicedb
Diffstat (limited to 'vendor/github.com/authzed/cel-go/parser/unparser.go')
-rw-r--r--vendor/github.com/authzed/cel-go/parser/unparser.go629
1 files changed, 629 insertions, 0 deletions
diff --git a/vendor/github.com/authzed/cel-go/parser/unparser.go b/vendor/github.com/authzed/cel-go/parser/unparser.go
new file mode 100644
index 0000000..f0afa28
--- /dev/null
+++ b/vendor/github.com/authzed/cel-go/parser/unparser.go
@@ -0,0 +1,629 @@
+// Copyright 2019 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package parser
+
+import (
+ "errors"
+ "fmt"
+ "strconv"
+ "strings"
+
+ "github.com/authzed/cel-go/common/ast"
+ "github.com/authzed/cel-go/common/operators"
+ "github.com/authzed/cel-go/common/types"
+)
+
+// Unparse takes an input expression and source position information and generates a human-readable
+// expression.
+//
+// Note, unparsing an AST will often generate the same expression as was originally parsed, but some
+// formatting may be lost in translation, notably:
+//
+// - All quoted literals are doubled quoted.
+// - Byte literals are represented as octal escapes (same as Google SQL).
+// - Floating point values are converted to the small number of digits needed to represent the value.
+// - Spacing around punctuation marks may be lost.
+// - Parentheses will only be applied when they affect operator precedence.
+//
+// This function optionally takes in one or more UnparserOption to alter the unparsing behavior, such as
+// performing word wrapping on expressions.
+func Unparse(expr ast.Expr, info *ast.SourceInfo, opts ...UnparserOption) (string, error) {
+ unparserOpts := &unparserOption{
+ wrapOnColumn: defaultWrapOnColumn,
+ wrapAfterColumnLimit: defaultWrapAfterColumnLimit,
+ operatorsToWrapOn: defaultOperatorsToWrapOn,
+ }
+
+ var err error
+ for _, opt := range opts {
+ unparserOpts, err = opt(unparserOpts)
+ if err != nil {
+ return "", err
+ }
+ }
+
+ un := &unparser{
+ info: info,
+ options: unparserOpts,
+ }
+ err = un.visit(expr)
+ if err != nil {
+ return "", err
+ }
+ return un.str.String(), nil
+}
+
+// unparser visits an expression to reconstruct a human-readable string from an AST.
+type unparser struct {
+ str strings.Builder
+ info *ast.SourceInfo
+ options *unparserOption
+ lastWrappedIndex int
+}
+
+func (un *unparser) visit(expr ast.Expr) error {
+ if expr == nil {
+ return errors.New("unsupported expression")
+ }
+ visited, err := un.visitMaybeMacroCall(expr)
+ if visited || err != nil {
+ return err
+ }
+ switch expr.Kind() {
+ case ast.CallKind:
+ return un.visitCall(expr)
+ case ast.LiteralKind:
+ return un.visitConst(expr)
+ case ast.IdentKind:
+ return un.visitIdent(expr)
+ case ast.ListKind:
+ return un.visitList(expr)
+ case ast.MapKind:
+ return un.visitStructMap(expr)
+ case ast.SelectKind:
+ return un.visitSelect(expr)
+ case ast.StructKind:
+ return un.visitStructMsg(expr)
+ default:
+ return fmt.Errorf("unsupported expression: %v", expr)
+ }
+}
+
+func (un *unparser) visitCall(expr ast.Expr) error {
+ c := expr.AsCall()
+ fun := c.FunctionName()
+ switch fun {
+ // ternary operator
+ case operators.Conditional:
+ return un.visitCallConditional(expr)
+ // optional select operator
+ case operators.OptSelect:
+ return un.visitOptSelect(expr)
+ // index operator
+ case operators.Index:
+ return un.visitCallIndex(expr)
+ // optional index operator
+ case operators.OptIndex:
+ return un.visitCallOptIndex(expr)
+ // unary operators
+ case operators.LogicalNot, operators.Negate:
+ return un.visitCallUnary(expr)
+ // binary operators
+ case operators.Add,
+ operators.Divide,
+ operators.Equals,
+ operators.Greater,
+ operators.GreaterEquals,
+ operators.In,
+ operators.Less,
+ operators.LessEquals,
+ operators.LogicalAnd,
+ operators.LogicalOr,
+ operators.Modulo,
+ operators.Multiply,
+ operators.NotEquals,
+ operators.OldIn,
+ operators.Subtract:
+ return un.visitCallBinary(expr)
+ // standard function calls.
+ default:
+ return un.visitCallFunc(expr)
+ }
+}
+
+func (un *unparser) visitCallBinary(expr ast.Expr) error {
+ c := expr.AsCall()
+ fun := c.FunctionName()
+ args := c.Args()
+ lhs := args[0]
+ // add parens if the current operator is lower precedence than the lhs expr operator.
+ lhsParen := isComplexOperatorWithRespectTo(fun, lhs)
+ rhs := args[1]
+ // add parens if the current operator is lower precedence than the rhs expr operator,
+ // or the same precedence and the operator is left recursive.
+ rhsParen := isComplexOperatorWithRespectTo(fun, rhs)
+ if !rhsParen && isLeftRecursive(fun) {
+ rhsParen = isSamePrecedence(fun, rhs)
+ }
+ err := un.visitMaybeNested(lhs, lhsParen)
+ if err != nil {
+ return err
+ }
+ unmangled, found := operators.FindReverseBinaryOperator(fun)
+ if !found {
+ return fmt.Errorf("cannot unmangle operator: %s", fun)
+ }
+
+ un.writeOperatorWithWrapping(fun, unmangled)
+ return un.visitMaybeNested(rhs, rhsParen)
+}
+
+func (un *unparser) visitCallConditional(expr ast.Expr) error {
+ c := expr.AsCall()
+ args := c.Args()
+ // add parens if operand is a conditional itself.
+ nested := isSamePrecedence(operators.Conditional, args[0]) ||
+ isComplexOperator(args[0])
+ err := un.visitMaybeNested(args[0], nested)
+ if err != nil {
+ return err
+ }
+ un.writeOperatorWithWrapping(operators.Conditional, "?")
+
+ // add parens if operand is a conditional itself.
+ nested = isSamePrecedence(operators.Conditional, args[1]) ||
+ isComplexOperator(args[1])
+ err = un.visitMaybeNested(args[1], nested)
+ if err != nil {
+ return err
+ }
+
+ un.str.WriteString(" : ")
+ // add parens if operand is a conditional itself.
+ nested = isSamePrecedence(operators.Conditional, args[2]) ||
+ isComplexOperator(args[2])
+
+ return un.visitMaybeNested(args[2], nested)
+}
+
+func (un *unparser) visitCallFunc(expr ast.Expr) error {
+ c := expr.AsCall()
+ fun := c.FunctionName()
+ args := c.Args()
+ if c.IsMemberFunction() {
+ nested := isBinaryOrTernaryOperator(c.Target())
+ err := un.visitMaybeNested(c.Target(), nested)
+ if err != nil {
+ return err
+ }
+ un.str.WriteString(".")
+ }
+ un.str.WriteString(fun)
+ un.str.WriteString("(")
+ for i, arg := range args {
+ err := un.visit(arg)
+ if err != nil {
+ return err
+ }
+ if i < len(args)-1 {
+ un.str.WriteString(", ")
+ }
+ }
+ un.str.WriteString(")")
+ return nil
+}
+
+func (un *unparser) visitCallIndex(expr ast.Expr) error {
+ return un.visitCallIndexInternal(expr, "[")
+}
+
+func (un *unparser) visitCallOptIndex(expr ast.Expr) error {
+ return un.visitCallIndexInternal(expr, "[?")
+}
+
+func (un *unparser) visitCallIndexInternal(expr ast.Expr, op string) error {
+ c := expr.AsCall()
+ args := c.Args()
+ nested := isBinaryOrTernaryOperator(args[0])
+ err := un.visitMaybeNested(args[0], nested)
+ if err != nil {
+ return err
+ }
+ un.str.WriteString(op)
+ err = un.visit(args[1])
+ if err != nil {
+ return err
+ }
+ un.str.WriteString("]")
+ return nil
+}
+
+func (un *unparser) visitCallUnary(expr ast.Expr) error {
+ c := expr.AsCall()
+ fun := c.FunctionName()
+ args := c.Args()
+ unmangled, found := operators.FindReverse(fun)
+ if !found {
+ return fmt.Errorf("cannot unmangle operator: %s", fun)
+ }
+ un.str.WriteString(unmangled)
+ nested := isComplexOperator(args[0])
+ return un.visitMaybeNested(args[0], nested)
+}
+
+func (un *unparser) visitConst(expr ast.Expr) error {
+ val := expr.AsLiteral()
+ switch val := val.(type) {
+ case types.Bool:
+ un.str.WriteString(strconv.FormatBool(bool(val)))
+ case types.Bytes:
+ // bytes constants are surrounded with b"<bytes>"
+ un.str.WriteString(`b"`)
+ un.str.WriteString(bytesToOctets([]byte(val)))
+ un.str.WriteString(`"`)
+ case types.Double:
+ // represent the float using the minimum required digits
+ d := strconv.FormatFloat(float64(val), 'g', -1, 64)
+ un.str.WriteString(d)
+ if !strings.Contains(d, ".") {
+ un.str.WriteString(".0")
+ }
+ case types.Int:
+ i := strconv.FormatInt(int64(val), 10)
+ un.str.WriteString(i)
+ case types.Null:
+ un.str.WriteString("null")
+ case types.String:
+ // strings will be double quoted with quotes escaped.
+ un.str.WriteString(strconv.Quote(string(val)))
+ case types.Uint:
+ // uint literals have a 'u' suffix.
+ ui := strconv.FormatUint(uint64(val), 10)
+ un.str.WriteString(ui)
+ un.str.WriteString("u")
+ default:
+ return fmt.Errorf("unsupported constant: %v", expr)
+ }
+ return nil
+}
+
+func (un *unparser) visitIdent(expr ast.Expr) error {
+ un.str.WriteString(expr.AsIdent())
+ return nil
+}
+
+func (un *unparser) visitList(expr ast.Expr) error {
+ l := expr.AsList()
+ elems := l.Elements()
+ optIndices := make(map[int]bool, len(elems))
+ for _, idx := range l.OptionalIndices() {
+ optIndices[int(idx)] = true
+ }
+ un.str.WriteString("[")
+ for i, elem := range elems {
+ if optIndices[i] {
+ un.str.WriteString("?")
+ }
+ err := un.visit(elem)
+ if err != nil {
+ return err
+ }
+ if i < len(elems)-1 {
+ un.str.WriteString(", ")
+ }
+ }
+ un.str.WriteString("]")
+ return nil
+}
+
+func (un *unparser) visitOptSelect(expr ast.Expr) error {
+ c := expr.AsCall()
+ args := c.Args()
+ operand := args[0]
+ field := args[1].AsLiteral().(types.String)
+ return un.visitSelectInternal(operand, false, ".?", string(field))
+}
+
+func (un *unparser) visitSelect(expr ast.Expr) error {
+ sel := expr.AsSelect()
+ return un.visitSelectInternal(sel.Operand(), sel.IsTestOnly(), ".", sel.FieldName())
+}
+
+func (un *unparser) visitSelectInternal(operand ast.Expr, testOnly bool, op string, field string) error {
+ // handle the case when the select expression was generated by the has() macro.
+ if testOnly {
+ un.str.WriteString("has(")
+ }
+ nested := !testOnly && isBinaryOrTernaryOperator(operand)
+ err := un.visitMaybeNested(operand, nested)
+ if err != nil {
+ return err
+ }
+ un.str.WriteString(op)
+ un.str.WriteString(field)
+ if testOnly {
+ un.str.WriteString(")")
+ }
+ return nil
+}
+
+func (un *unparser) visitStructMsg(expr ast.Expr) error {
+ m := expr.AsStruct()
+ fields := m.Fields()
+ un.str.WriteString(m.TypeName())
+ un.str.WriteString("{")
+ for i, f := range fields {
+ field := f.AsStructField()
+ f := field.Name()
+ if field.IsOptional() {
+ un.str.WriteString("?")
+ }
+ un.str.WriteString(f)
+ un.str.WriteString(": ")
+ v := field.Value()
+ err := un.visit(v)
+ if err != nil {
+ return err
+ }
+ if i < len(fields)-1 {
+ un.str.WriteString(", ")
+ }
+ }
+ un.str.WriteString("}")
+ return nil
+}
+
+func (un *unparser) visitStructMap(expr ast.Expr) error {
+ m := expr.AsMap()
+ entries := m.Entries()
+ un.str.WriteString("{")
+ for i, e := range entries {
+ entry := e.AsMapEntry()
+ k := entry.Key()
+ if entry.IsOptional() {
+ un.str.WriteString("?")
+ }
+ err := un.visit(k)
+ if err != nil {
+ return err
+ }
+ un.str.WriteString(": ")
+ v := entry.Value()
+ err = un.visit(v)
+ if err != nil {
+ return err
+ }
+ if i < len(entries)-1 {
+ un.str.WriteString(", ")
+ }
+ }
+ un.str.WriteString("}")
+ return nil
+}
+
+func (un *unparser) visitMaybeMacroCall(expr ast.Expr) (bool, error) {
+ call, found := un.info.GetMacroCall(expr.ID())
+ if !found {
+ return false, nil
+ }
+ return true, un.visit(call)
+}
+
+func (un *unparser) visitMaybeNested(expr ast.Expr, nested bool) error {
+ if nested {
+ un.str.WriteString("(")
+ }
+ err := un.visit(expr)
+ if err != nil {
+ return err
+ }
+ if nested {
+ un.str.WriteString(")")
+ }
+ return nil
+}
+
+// isLeftRecursive indicates whether the parser resolves the call in a left-recursive manner as
+// this can have an effect of how parentheses affect the order of operations in the AST.
+func isLeftRecursive(op string) bool {
+ return op != operators.LogicalAnd && op != operators.LogicalOr
+}
+
+// isSamePrecedence indicates whether the precedence of the input operator is the same as the
+// precedence of the (possible) operation represented in the input Expr.
+//
+// If the expr is not a Call, the result is false.
+func isSamePrecedence(op string, expr ast.Expr) bool {
+ if expr.Kind() != ast.CallKind {
+ return false
+ }
+ c := expr.AsCall()
+ other := c.FunctionName()
+ return operators.Precedence(op) == operators.Precedence(other)
+}
+
+// isLowerPrecedence indicates whether the precedence of the input operator is lower precedence
+// than the (possible) operation represented in the input Expr.
+//
+// If the expr is not a Call, the result is false.
+func isLowerPrecedence(op string, expr ast.Expr) bool {
+ c := expr.AsCall()
+ other := c.FunctionName()
+ return operators.Precedence(op) < operators.Precedence(other)
+}
+
+// Indicates whether the expr is a complex operator, i.e., a call expression
+// with 2 or more arguments.
+func isComplexOperator(expr ast.Expr) bool {
+ if expr.Kind() == ast.CallKind && len(expr.AsCall().Args()) >= 2 {
+ return true
+ }
+ return false
+}
+
+// Indicates whether it is a complex operation compared to another.
+// expr is *not* considered complex if it is not a call expression or has
+// less than two arguments, or if it has a higher precedence than op.
+func isComplexOperatorWithRespectTo(op string, expr ast.Expr) bool {
+ if expr.Kind() != ast.CallKind || len(expr.AsCall().Args()) < 2 {
+ return false
+ }
+ return isLowerPrecedence(op, expr)
+}
+
+// Indicate whether this is a binary or ternary operator.
+func isBinaryOrTernaryOperator(expr ast.Expr) bool {
+ if expr.Kind() != ast.CallKind || len(expr.AsCall().Args()) < 2 {
+ return false
+ }
+ _, isBinaryOp := operators.FindReverseBinaryOperator(expr.AsCall().FunctionName())
+ return isBinaryOp || isSamePrecedence(operators.Conditional, expr)
+}
+
+// bytesToOctets converts byte sequences to a string using a three digit octal encoded value
+// per byte.
+func bytesToOctets(byteVal []byte) string {
+ var b strings.Builder
+ for _, c := range byteVal {
+ fmt.Fprintf(&b, "\\%03o", c)
+ }
+ return b.String()
+}
+
+// writeOperatorWithWrapping outputs the operator and inserts a newline for operators configured
+// in the unparser options.
+func (un *unparser) writeOperatorWithWrapping(fun string, unmangled string) bool {
+ _, wrapOperatorExists := un.options.operatorsToWrapOn[fun]
+ lineLength := un.str.Len() - un.lastWrappedIndex + len(fun)
+
+ if wrapOperatorExists && lineLength >= un.options.wrapOnColumn {
+ un.lastWrappedIndex = un.str.Len()
+ // wrapAfterColumnLimit flag dictates whether the newline is placed
+ // before or after the operator
+ if un.options.wrapAfterColumnLimit {
+ // Input: a && b
+ // Output: a &&\nb
+ un.str.WriteString(" ")
+ un.str.WriteString(unmangled)
+ un.str.WriteString("\n")
+ } else {
+ // Input: a && b
+ // Output: a\n&& b
+ un.str.WriteString("\n")
+ un.str.WriteString(unmangled)
+ un.str.WriteString(" ")
+ }
+ return true
+ }
+ un.str.WriteString(" ")
+ un.str.WriteString(unmangled)
+ un.str.WriteString(" ")
+ return false
+}
+
+// Defined defaults for the unparser options
+var (
+ defaultWrapOnColumn = 80
+ defaultWrapAfterColumnLimit = true
+ defaultOperatorsToWrapOn = map[string]bool{
+ operators.LogicalAnd: true,
+ operators.LogicalOr: true,
+ }
+)
+
+// UnparserOption is a functional option for configuring the output formatting
+// of the Unparse function.
+type UnparserOption func(*unparserOption) (*unparserOption, error)
+
+// Internal representation of the UnparserOption type
+type unparserOption struct {
+ wrapOnColumn int
+ operatorsToWrapOn map[string]bool
+ wrapAfterColumnLimit bool
+}
+
+// WrapOnColumn wraps the output expression when its string length exceeds a specified limit
+// for operators set by WrapOnOperators function or by default, "&&" and "||" will be wrapped.
+//
+// Example usage:
+//
+// Unparse(expr, sourceInfo, WrapOnColumn(40), WrapOnOperators(Operators.LogicalAnd))
+//
+// This will insert a newline immediately after the logical AND operator for the below example input:
+//
+// Input:
+// 'my-principal-group' in request.auth.claims && request.auth.claims.iat > now - duration('5m')
+//
+// Output:
+// 'my-principal-group' in request.auth.claims &&
+// request.auth.claims.iat > now - duration('5m')
+func WrapOnColumn(col int) UnparserOption {
+ return func(opt *unparserOption) (*unparserOption, error) {
+ if col < 1 {
+ return nil, fmt.Errorf("Invalid unparser option. Wrap column value must be greater than or equal to 1. Got %v instead", col)
+ }
+ opt.wrapOnColumn = col
+ return opt, nil
+ }
+}
+
+// WrapOnOperators specifies which operators to perform word wrapping on an output expression when its string length
+// exceeds the column limit set by WrapOnColumn function.
+//
+// Word wrapping is supported on non-unary symbolic operators. Refer to operators.go for the full list
+//
+// This will replace any previously supplied operators instead of merging them.
+func WrapOnOperators(symbols ...string) UnparserOption {
+ return func(opt *unparserOption) (*unparserOption, error) {
+ opt.operatorsToWrapOn = make(map[string]bool)
+ for _, symbol := range symbols {
+ _, found := operators.FindReverse(symbol)
+ if !found {
+ return nil, fmt.Errorf("Invalid unparser option. Unsupported operator: %s", symbol)
+ }
+ arity := operators.Arity(symbol)
+ if arity < 2 {
+ return nil, fmt.Errorf("Invalid unparser option. Unary operators are unsupported: %s", symbol)
+ }
+
+ opt.operatorsToWrapOn[symbol] = true
+ }
+
+ return opt, nil
+ }
+}
+
+// WrapAfterColumnLimit dictates whether to insert a newline before or after the specified operator
+// when word wrapping is performed.
+//
+// Example usage:
+//
+// Unparse(expr, sourceInfo, WrapOnColumn(40), WrapOnOperators(Operators.LogicalAnd), WrapAfterColumnLimit(false))
+//
+// This will insert a newline immediately before the logical AND operator for the below example input, ensuring
+// that the length of a line never exceeds the specified column limit:
+//
+// Input:
+// 'my-principal-group' in request.auth.claims && request.auth.claims.iat > now - duration('5m')
+//
+// Output:
+// 'my-principal-group' in request.auth.claims
+// && request.auth.claims.iat > now - duration('5m')
+func WrapAfterColumnLimit(wrapAfter bool) UnparserOption {
+ return func(opt *unparserOption) (*unparserOption, error) {
+ opt.wrapAfterColumnLimit = wrapAfter
+ return opt, nil
+ }
+}