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// Copyright (C) 2022-2023 Luke Shumaker <lukeshu@lukeshu.com>
//
// SPDX-License-Identifier: GPL-2.0-or-later
package main
import (
"bufio"
"context"
"io"
"os"
"git.lukeshu.com/go/lowmemjson"
"github.com/datawire/dlib/dlog"
"git.lukeshu.com/btrfs-progs-ng/lib/streamio"
)
func readJSONFile[T any](ctx context.Context, filename string) (T, error) {
fh, err := os.Open(filename)
if err != nil {
var zero T
return zero, err
}
buf, err := streamio.NewRuneScanner(dlog.WithField(ctx, "btrfs.read-json-file", filename), fh)
defer func() {
_ = buf.Close()
}()
if err != nil {
var zero T
return zero, err
}
var ret T
if err := lowmemjson.NewDecoder(buf).DecodeThenEOF(&ret); err != nil {
var zero T
return zero, err
}
return ret, nil
}
func writeJSONFile(w io.Writer, obj any, cfg lowmemjson.ReEncoderConfig) (err error) {
buffer := bufio.NewWriter(w)
defer func() {
if _err := buffer.Flush(); err == nil && _err != nil {
err = _err
}
}()
return lowmemjson.NewEncoder(lowmemjson.NewReEncoder(buffer, cfg)).Encode(obj)
}
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