1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/*
* Copyright (c) 2023 Vaughn Nugent
*
* Library: CMNext
* Package: Content.Publishing.Blog.Admin
* File: JsonRecordDb.cs
*
* CMNext is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* CMNext is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
using System;
using System.IO;
using System.Linq;
using System.Text.Json;
using System.Collections.Generic;
using VNLib.Utils.IO;
using VNLib.Utils.Extensions;
namespace Content.Publishing.Blog.Admin.Model
{
/// <summary>
/// A json backed record database
/// </summary>
/// <typeparam name="T">The record type</typeparam>
internal class JsonRecordDb<T> : IRecordDb<T> where T : IRecord
{
private static readonly Version CurrentVersion = new (0, 1, 0);
private DateTimeOffset _lastModified;
private Version? _version;
/*
* Records in the list are only ever read from, any changes are made by
* creating a new list and re-ordering it.
*
* We dont need any synchronization in this case
*/
private IReadOnlyList<T> _records;
public JsonRecordDb()
{
_lastModified = DateTimeOffset.UnixEpoch;
_records = new List<T>();
}
///<inheritdoc/>
public T? GetRecord(string id)
{
return _records.SingleOrDefault(r => r.Id!.Equals(id, StringComparison.OrdinalIgnoreCase));
}
///<inheritdoc/>
public IEnumerable<T> GetRecords()
{
return _records;
}
///<inheritdoc/>
public void RemoveRecord(string id)
{
_ = id ?? throw new ArgumentNullException(nameof(id));
//Create new list without the record and re-order
_records = _records.Where(r => !id.Equals(r.Id, StringComparison.OrdinalIgnoreCase))
.OrderByDescending(static r => r.Date)
.ToList();
}
///<inheritdoc/>
public void SetRecord(T record)
{
_ = record?.Id ?? throw new ArgumentNullException(nameof(record));
//Remove record if it already exists
RemoveRecord(record.Id);
//Add the record and re-order
_records = _records.Append(record)
.OrderByDescending(static r => r.Date)
.ToList();
//Update last modified time
_lastModified = DateTimeOffset.UtcNow;
}
///<inheritdoc/>
public void Load(Stream stream)
{
if (stream.Length == 0)
{
//Set defaults
_lastModified = DateTimeOffset.UnixEpoch;
_records = new List<T>();
}
else
{
//Read stream into a doc
using JsonDocument doc = JsonDocument.Parse(stream);
//Read the last modified time
_lastModified = DateTimeOffset.FromUnixTimeSeconds(doc.RootElement.GetProperty("last_modified").GetInt64());
//Try to read the version
if (doc.RootElement.TryGetProperty("version", out JsonElement versionEl))
{
_ = Version.TryParse(versionEl.GetString(), out _version);
}
if (doc.RootElement.TryGetProperty("records", out JsonElement el))
{
//Read the records array
_records = el.Deserialize<List<T>>() ?? new List<T>();
}
else
{
//Set defaults
_records = new List<T>();
}
}
}
///<inheritdoc/>
public void Store(Stream stream)
{
using Utf8JsonWriter writer = new(stream);
writer.WriteStartObject();
//Write last modified time
writer.WriteNumber("last_modified", _lastModified.ToUnixTimeSeconds());
//Set version if not already set
_version ??= CurrentVersion;
//Write version
writer.WriteString("version", _version.ToString());
//Write the records array
writer.WritePropertyName("records");
JsonSerializer.Serialize(writer, _records, VNLib.Plugins.Essentials.Statics.SR_OPTIONS);
writer.WriteEndObject();
}
/// <summary>
/// Create a new <see cref="JsonRecordDb{T}"/> of a given type
/// </summary>
/// <returns>The new record store</returns>
public static JsonRecordDb<T> Create()
{
return new JsonRecordDb<T>();
}
}
}
|