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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package lowmemjson
import (
"git.lukeshu.com/go/lowmemjson/internal/jsonparse"
)
type reEncodeIndent struct {
out reEncoderModule
// String to use to indent.
//
// Newlines are emitted *between* top-level values; a newline
// is not emitted after the *last* top-level value.
Indent string
// String to put before indents.
Prefix string
// state
lastNonSpace jsonparse.RuneType
lastNonSpaceNonEOF jsonparse.RuneType
curIndent int
}
var _ reEncoderModule = (*reEncodeIndent)(nil)
func (enc *reEncodeIndent) PopWriteBarrier() {
enc.lastNonSpace = enc.lastNonSpaceNonEOF
enc.out.PopWriteBarrier()
}
func (enc *reEncodeIndent) HandleRune(c rune, t jsonparse.RuneType, escape BackslashEscapeMode, stackSize int) error {
// emit newlines between top-level values
if enc.lastNonSpace == jsonparse.RuneTypeEOF && t != jsonparse.RuneTypeSpace {
if err := enc.out.HandleRune('\n', jsonparse.RuneTypeSpace, 0, 0); err != nil {
return err
}
}
// indent
switch t {
case jsonparse.RuneTypeSpace:
// let us manage whitespace, don't pass it through
return nil
case jsonparse.RuneTypeObjectEnd, jsonparse.RuneTypeArrayEnd:
enc.curIndent--
switch enc.lastNonSpace {
case jsonparse.RuneTypeObjectBeg, jsonparse.RuneTypeArrayBeg:
// collapse
default:
if err := enc.emitNlIndent(stackSize + 1); err != nil {
return err
}
}
default:
switch enc.lastNonSpace {
case jsonparse.RuneTypeObjectBeg, jsonparse.RuneTypeObjectComma, jsonparse.RuneTypeArrayBeg, jsonparse.RuneTypeArrayComma:
if err := enc.emitNlIndent(stackSize); err != nil {
return err
}
case jsonparse.RuneTypeObjectColon:
if err := enc.out.HandleRune(' ', jsonparse.RuneTypeSpace, 0, stackSize); err != nil {
return err
}
}
switch t {
case jsonparse.RuneTypeObjectBeg, jsonparse.RuneTypeArrayBeg:
enc.curIndent++
}
}
if t != jsonparse.RuneTypeSpace {
enc.lastNonSpace = t
if t != jsonparse.RuneTypeEOF {
enc.lastNonSpaceNonEOF = t
}
}
return enc.out.HandleRune(c, t, escape, stackSize)
}
func (enc *reEncodeIndent) emitNlIndent(stackSize int) error {
if err := enc.out.HandleRune('\n', jsonparse.RuneTypeSpace, 0, stackSize); err != nil {
return err
}
for _, c := range enc.Prefix {
if err := enc.out.HandleRune(c, jsonparse.RuneTypeSpace, 0, stackSize); err != nil {
return err
}
}
for i := 0; i < enc.curIndent; i++ {
for _, c := range enc.Indent {
if err := enc.out.HandleRune(c, jsonparse.RuneTypeSpace, 0, stackSize); err != nil {
return err
}
}
}
return nil
}
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