ceph-csi/vendor/github.com/google/cel-go/common/debug/debug.go

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// Copyright 2018 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 debug provides tools to print a parsed expression graph and
// adorn each expression element with additional metadata.
package debug
import (
"bytes"
"fmt"
"strconv"
"strings"
"github.com/google/cel-go/common/ast"
"github.com/google/cel-go/common/types"
"github.com/google/cel-go/common/types/ref"
)
// Adorner returns debug metadata that will be tacked on to the string
// representation of an expression.
type Adorner interface {
// GetMetadata for the input context.
GetMetadata(ctx any) string
}
// Writer manages writing expressions to an internal string.
type Writer interface {
fmt.Stringer
// Buffer pushes an expression into an internal queue of expressions to
// write to a string.
Buffer(e ast.Expr)
}
type emptyDebugAdorner struct {
}
var emptyAdorner Adorner = &emptyDebugAdorner{}
func (a *emptyDebugAdorner) GetMetadata(e any) string {
return ""
}
// ToDebugString gives the unadorned string representation of the Expr.
func ToDebugString(e ast.Expr) string {
return ToAdornedDebugString(e, emptyAdorner)
}
// ToAdornedDebugString gives the adorned string representation of the Expr.
func ToAdornedDebugString(e ast.Expr, adorner Adorner) string {
w := newDebugWriter(adorner)
w.Buffer(e)
return w.String()
}
// debugWriter is used to print out pretty-printed debug strings.
type debugWriter struct {
adorner Adorner
buffer bytes.Buffer
indent int
lineStart bool
}
func newDebugWriter(a Adorner) *debugWriter {
return &debugWriter{
adorner: a,
indent: 0,
lineStart: true,
}
}
func (w *debugWriter) Buffer(e ast.Expr) {
if e == nil {
return
}
switch e.Kind() {
case ast.LiteralKind:
w.append(formatLiteral(e.AsLiteral()))
case ast.IdentKind:
w.append(e.AsIdent())
case ast.SelectKind:
w.appendSelect(e.AsSelect())
case ast.CallKind:
w.appendCall(e.AsCall())
case ast.ListKind:
w.appendList(e.AsList())
case ast.MapKind:
w.appendMap(e.AsMap())
case ast.StructKind:
w.appendStruct(e.AsStruct())
case ast.ComprehensionKind:
w.appendComprehension(e.AsComprehension())
}
w.adorn(e)
}
func (w *debugWriter) appendSelect(sel ast.SelectExpr) {
w.Buffer(sel.Operand())
w.append(".")
w.append(sel.FieldName())
if sel.IsTestOnly() {
w.append("~test-only~")
}
}
func (w *debugWriter) appendCall(call ast.CallExpr) {
if call.IsMemberFunction() {
w.Buffer(call.Target())
w.append(".")
}
w.append(call.FunctionName())
w.append("(")
if len(call.Args()) > 0 {
w.addIndent()
w.appendLine()
for i, arg := range call.Args() {
if i > 0 {
w.append(",")
w.appendLine()
}
w.Buffer(arg)
}
w.removeIndent()
w.appendLine()
}
w.append(")")
}
func (w *debugWriter) appendList(list ast.ListExpr) {
w.append("[")
if len(list.Elements()) > 0 {
w.appendLine()
w.addIndent()
for i, elem := range list.Elements() {
if i > 0 {
w.append(",")
w.appendLine()
}
w.Buffer(elem)
}
w.removeIndent()
w.appendLine()
}
w.append("]")
}
func (w *debugWriter) appendStruct(obj ast.StructExpr) {
w.append(obj.TypeName())
w.append("{")
if len(obj.Fields()) > 0 {
w.appendLine()
w.addIndent()
for i, f := range obj.Fields() {
field := f.AsStructField()
if i > 0 {
w.append(",")
w.appendLine()
}
if field.IsOptional() {
w.append("?")
}
w.append(field.Name())
w.append(":")
w.Buffer(field.Value())
w.adorn(f)
}
w.removeIndent()
w.appendLine()
}
w.append("}")
}
func (w *debugWriter) appendMap(m ast.MapExpr) {
w.append("{")
if m.Size() > 0 {
w.appendLine()
w.addIndent()
for i, e := range m.Entries() {
entry := e.AsMapEntry()
if i > 0 {
w.append(",")
w.appendLine()
}
if entry.IsOptional() {
w.append("?")
}
w.Buffer(entry.Key())
w.append(":")
w.Buffer(entry.Value())
w.adorn(e)
}
w.removeIndent()
w.appendLine()
}
w.append("}")
}
func (w *debugWriter) appendComprehension(comprehension ast.ComprehensionExpr) {
w.append("__comprehension__(")
w.addIndent()
w.appendLine()
w.append("// Variable")
w.appendLine()
w.append(comprehension.IterVar())
w.append(",")
w.appendLine()
w.append("// Target")
w.appendLine()
w.Buffer(comprehension.IterRange())
w.append(",")
w.appendLine()
w.append("// Accumulator")
w.appendLine()
w.append(comprehension.AccuVar())
w.append(",")
w.appendLine()
w.append("// Init")
w.appendLine()
w.Buffer(comprehension.AccuInit())
w.append(",")
w.appendLine()
w.append("// LoopCondition")
w.appendLine()
w.Buffer(comprehension.LoopCondition())
w.append(",")
w.appendLine()
w.append("// LoopStep")
w.appendLine()
w.Buffer(comprehension.LoopStep())
w.append(",")
w.appendLine()
w.append("// Result")
w.appendLine()
w.Buffer(comprehension.Result())
w.append(")")
w.removeIndent()
}
func formatLiteral(c ref.Val) string {
switch v := c.(type) {
case types.Bool:
return fmt.Sprintf("%t", v)
case types.Bytes:
return fmt.Sprintf("b\"%s\"", string(v))
case types.Double:
return fmt.Sprintf("%v", float64(v))
case types.Int:
return fmt.Sprintf("%d", int64(v))
case types.String:
return strconv.Quote(string(v))
case types.Uint:
return fmt.Sprintf("%du", uint64(v))
case types.Null:
return "null"
default:
panic("Unknown constant type")
}
}
func (w *debugWriter) append(s string) {
w.doIndent()
w.buffer.WriteString(s)
}
func (w *debugWriter) appendFormat(f string, args ...any) {
w.append(fmt.Sprintf(f, args...))
}
func (w *debugWriter) doIndent() {
if w.lineStart {
w.lineStart = false
w.buffer.WriteString(strings.Repeat(" ", w.indent))
}
}
func (w *debugWriter) adorn(e any) {
w.append(w.adorner.GetMetadata(e))
}
func (w *debugWriter) appendLine() {
w.buffer.WriteString("\n")
w.lineStart = true
}
func (w *debugWriter) addIndent() {
w.indent++
}
func (w *debugWriter) removeIndent() {
w.indent--
if w.indent < 0 {
panic("negative indent")
}
}
func (w *debugWriter) String() string {
return w.buffer.String()
}