59 lines
1.1 KiB
Go
59 lines
1.1 KiB
Go
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// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package jsondb provides a trivial "database": a Go object saved to
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// disk as JSON.
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package jsondb
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import (
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"encoding/json"
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"errors"
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"io/fs"
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"os"
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"tailscale.com/atomicfile"
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)
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// DB is a database backed by a JSON file.
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type DB[T any] struct {
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// Data is the contents of the database.
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Data *T
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path string
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}
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// Open opens the database at path, creating it with a zero value if
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// necessary.
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func Open[T any](path string) (*DB[T], error) {
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bs, err := os.ReadFile(path)
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if errors.Is(err, fs.ErrNotExist) {
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return &DB[T]{
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Data: new(T),
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path: path,
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}, nil
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} else if err != nil {
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return nil, err
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}
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var val T
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if err := json.Unmarshal(bs, &val); err != nil {
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return nil, err
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}
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return &DB[T]{
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Data: &val,
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path: path,
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}, nil
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}
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// Save writes db.Data back to disk.
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func (db *DB[T]) Save() error {
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bs, err := json.Marshal(db.Data)
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if err != nil {
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return err
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}
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return atomicfile.WriteFile(db.path, bs, 0600)
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}
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