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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
use std::collections::HashMap;
use crate::command::Command;
use crate::parser;
use std::io::prelude::*;
use crate::utils::fs_utils::{file_clear, open_or_create_file};
type MemdbInner = HashMap<String, Vec<u8>>;
#[derive(Debug, Clone, PartialEq, Default)]
pub struct Memdb {
inner: MemdbInner,
}
impl Memdb {
pub fn new() -> Memdb {
Memdb {
inner: HashMap::new(),
}
}
pub fn restore(
db_file_path: &str,
log_file_path: &str,
) -> Result<Memdb, Box<dyn std::error::Error>> {
let mut db_file = open_or_create_file(db_file_path)?;
let mut contents = String::new();
db_file.read_to_string(&mut contents)?;
let mut db = Memdb::deserialize(contents.as_bytes())?;
let mut log_file = open_or_create_file(log_file_path)?;
let mut logs = String::new();
log_file.read_to_string(&mut logs)?;
logs.lines().for_each(|log| {
let _ = db.exec(log);
});
file_clear(log_file_path)?;
Ok(db)
}
/// # Example
/// ```
/// use tyozo::Memdb;
/// let mut db = Memdb::new();
///
/// let result = db.exec("set hoge value");
/// assert_eq!(result, Ok(String::from("OK")));
///
/// let result = db.exec("get hoge");
/// assert_eq!(result, Ok(String::from("value")));
///
/// db.exec("set fuga value").unwrap();
/// let result = db.exec("del hoge fuga");
/// assert_eq!(result, Ok(String::from("2")));
///
/// let result = db.exec("setnx hoge value");
/// assert!(result.is_ok());
///
/// let result = db.exec("setnx hoge value");
/// assert!(result.is_err());
/// ```
pub fn exec<S: Into<String>>(&mut self, input: S) -> Result<String, String> {
let command = parser::parse(input)?;
self.exec_command(command)
}
pub fn exec_command(&mut self, command: Command) -> Result<String, String> {
match command {
Command::Set { key, value } => {
self.set(key, value);
Ok(String::from("OK"))
}
Command::SetNX { key, value } => {
self.setnx(key, value)?;
Ok(String::from("OK"))
}
Command::Get { key } => match self.get(key) {
None => Ok(String::from("None")),
Some(v) => Ok(String::from_utf8(v).unwrap()),
},
Command::Del { keys } => {
let result = self.del(keys);
Ok(format!("{}", result))
}
Command::Multi => todo!(),
Command::Exec => todo!(),
Command::Abort => todo!(),
_ => unreachable!(),
}
}
/// # Example
/// ```
/// use tyozo::Memdb;
/// let mut memdb = Memdb::new();
///
/// memdb.set("key", "value");
/// assert_eq!(memdb.inner().get("key"), Some(&b"value".to_vec()));
///
/// // value is override
/// memdb.set("key", "next value");
/// assert_eq!(memdb.inner().get("key"), Some(&b"next value".to_vec()));
/// ```
pub fn set(&mut self, key: impl AsRef<str>, value: impl AsRef<[u8]>) {
self.inner
.insert(key.as_ref().to_owned(), value.as_ref().to_owned());
}
/// # Example
/// ```
/// use tyozo::Memdb;
/// let mut memdb = Memdb::new();
/// let result = memdb.setnx("key", "value");
/// assert!(result.is_ok());
/// assert_eq!(memdb.inner().get("key"), Some(&b"value".to_vec()));
/// // value is not override
/// let result = memdb.setnx("key", "next value");
/// assert!(result.is_err());
/// assert_eq!(memdb.inner().get("key"), Some(&b"value".to_vec()));
/// ```
pub fn setnx(&mut self, key: impl AsRef<str>, value: impl AsRef<[u8]>) -> Result<(), String> {
if self.get(&key).is_some() {
return Err(String::from("ERR key is already exists"));
}
self.inner
.insert(key.as_ref().to_owned(), value.as_ref().to_owned());
Ok(())
}
/// # Exmaple
/// ```
/// use tyozo::Memdb;
/// let mut memdb = Memdb::new();
///
/// memdb.set("key", "value");
///
/// assert_eq!(memdb.get("key"), Some(b"value".to_vec()));
///
/// assert_eq!(memdb.get("not setted key"), None);
/// ```
pub fn get(&self, key: impl AsRef<str>) -> Option<Vec<u8>> {
self.inner.get(&key.as_ref().to_owned()).cloned()
}
/// # Exmaple
/// ```
/// use tyozo::Memdb;
/// let mut memdb = Memdb::new();
/// memdb.set("key", "value");
///
/// let delete_count = memdb.del(vec!["key", "key2"]);
///
/// assert_eq!(delete_count, 1);
/// assert_eq!(memdb.get("key"), None);
///
/// let delete_count = memdb.del(vec!["key"]);
/// assert_eq!(delete_count, 0);
/// ```
pub fn del(&mut self, keys: Vec<impl AsRef<str>>) -> usize {
keys.into_iter()
.map(|key| self.inner.remove(&key.as_ref().to_owned()))
.filter(|v| v.is_some())
.count()
}
pub fn inner(&self) -> &MemdbInner {
&self.inner
}
/// # Example
/// ```
/// use tyozo::Memdb;
///
/// let mut memdb = Memdb::new();
/// memdb.set("k", "v");
///
/// let serialized = memdb.serialize();
///
/// assert_eq!(serialized, vec![0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 107, 118]);
/// ```
pub fn serialize(&self) -> Vec<u8> {
self.inner.iter().fold(vec![], |mut buf, (key, value)| {
let key_length_bytes = key.len().to_be_bytes();
let value_length_bytes = value.len().to_be_bytes();
buf.extend_from_slice(&key_length_bytes);
buf.extend_from_slice(&value_length_bytes);
buf.extend_from_slice(&key.as_bytes());
buf.extend_from_slice(&value);
buf
})
}
/// # Example
/// ```
/// use tyozo::Memdb;
///
/// let input = &vec![0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 107, 118, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 118, 107];
///
/// let mut deserialized = Memdb::deserialize(input).unwrap();
///
/// let result = deserialized.exec("get k");
/// assert_eq!(result, Ok(String::from("v")));
///
/// let result = deserialized.exec("get v");
/// assert_eq!(result, Ok(String::from("k")));
/// ```
pub fn deserialize(input: &[u8]) -> Result<Memdb, String> {
let mut position = 0usize;
let mut inner = HashMap::new();
while input.len() > position {
position += Memdb::deserialize_paier(&mut inner, &input[position..])?;
}
Ok(Memdb { inner })
}
fn deserialize_paier(inner: &mut MemdbInner, input: &[u8]) -> Result<usize, String> {
let key_position = 8;
let key_length = match input.get(0..key_position) {
None => return Err(String::from("ERR invalid database format")),
Some(bytes) => usize::from_be_bytes([
// FIXME 絶対なにかいい方法がある！！
bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7],
]),
};
let value_position = key_position + 8;
let value_length = match input.get(key_position..value_position) {
None => return Err(String::from("ERR invalid database format")),
Some(bytes) => usize::from_be_bytes([
bytes[0], bytes[1], bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7],
]),
};
let key_position = value_position + value_length;
// TODO add error handle
let key =
String::from_utf8(input.get(value_position..key_position).unwrap().to_vec()).unwrap();
// TODO add error handle
let value_position = key_position + key_length;
let value = input.get(key_position..value_position).unwrap().to_vec();
inner.insert(key, value);
Ok(value_position)
}
}