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
use std::{
convert::TryInto,
error,
fmt,
result,
str::FromStr,
sync::atomic::{AtomicUsize, Ordering},
time::SystemTime,
};
use chrono::Utc;
use hex::{self, FromHexError};
use lazy_static::lazy_static;
use rand::{Rng, thread_rng};
const TIMESTAMP_SIZE: usize = 4;
const PROCESS_ID_SIZE: usize = 5;
const COUNTER_SIZE: usize = 3;
const TIMESTAMP_OFFSET: usize = 0;
const PROCESS_ID_OFFSET: usize = TIMESTAMP_OFFSET + TIMESTAMP_SIZE;
const COUNTER_OFFSET: usize = PROCESS_ID_OFFSET + PROCESS_ID_SIZE;
const MAX_U24: usize = 0xFF_FFFF;
lazy_static! {
static ref OID_COUNTER: AtomicUsize = AtomicUsize::new(thread_rng().gen_range(0, MAX_U24 + 1));
}
#[derive(Debug)]
#[non_exhaustive]
pub enum Error {
ArgumentError { message: String },
FromHexError(FromHexError),
}
impl From<FromHexError> for Error {
fn from(err: FromHexError) -> Error {
Error::FromHexError(err)
}
}
pub type Result<T> = result::Result<T, Error>;
impl fmt::Display for Error {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
match *self {
Error::ArgumentError { ref message } => message.fmt(fmt),
Error::FromHexError(ref inner) => inner.fmt(fmt),
}
}
}
impl error::Error for Error {
fn cause(&self) -> Option<&dyn error::Error> {
match *self {
Error::ArgumentError { .. } => None,
Error::FromHexError(ref inner) => Some(inner),
}
}
}
#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash)]
pub struct ObjectId {
id: [u8; 12],
}
impl Default for ObjectId {
fn default() -> Self {
Self::new()
}
}
impl FromStr for ObjectId {
type Err = Error;
fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
Self::with_string(s)
}
}
impl ObjectId {
pub fn new() -> ObjectId {
let timestamp = ObjectId::gen_timestamp();
let process_id = ObjectId::gen_process_id();
let counter = ObjectId::gen_count();
let mut buf: [u8; 12] = [0; 12];
buf[TIMESTAMP_OFFSET..(TIMESTAMP_SIZE + TIMESTAMP_OFFSET)]
.clone_from_slice(×tamp[..TIMESTAMP_SIZE]);
buf[PROCESS_ID_OFFSET..(PROCESS_ID_SIZE + PROCESS_ID_OFFSET)]
.clone_from_slice(&process_id[..PROCESS_ID_SIZE]);
buf[COUNTER_OFFSET..(COUNTER_SIZE + COUNTER_OFFSET)]
.clone_from_slice(&counter[..COUNTER_SIZE]);
ObjectId::with_bytes(buf)
}
pub fn with_bytes(bytes: [u8; 12]) -> ObjectId {
ObjectId { id: bytes }
}
pub fn with_string(s: &str) -> Result<ObjectId> {
let bytes: Vec<u8> = hex::decode(s.as_bytes())?;
if bytes.len() != 12 {
Err(Error::ArgumentError {
message: "Provided string must be a 12-byte hexadecimal string.".to_owned(),
})
} else {
let mut byte_array: [u8; 12] = [0; 12];
byte_array[..].copy_from_slice(&bytes[..]);
Ok(ObjectId::with_bytes(byte_array))
}
}
pub fn timestamp(&self) -> chrono::DateTime<Utc> {
let mut buf = [0; 4];
buf.copy_from_slice(&self.id[0..4]);
let seconds_since_epoch = u32::from_be_bytes(buf);
let naive_datetime = chrono::NaiveDateTime::from_timestamp(seconds_since_epoch as i64, 0);
let timestamp: chrono::DateTime<Utc> = chrono::DateTime::from_utc(naive_datetime, Utc);
timestamp
}
pub fn bytes(&self) -> [u8; 12] {
self.id
}
pub fn to_hex(&self) -> String {
hex::encode(self.id)
}
fn gen_timestamp() -> [u8; 4] {
let timestamp: u32 = SystemTime::now()
.duration_since(SystemTime::UNIX_EPOCH)
.expect("system clock is before 1970")
.as_secs()
.try_into()
.unwrap();
timestamp.to_be_bytes()
}
fn gen_process_id() -> [u8; 5] {
lazy_static! {
static ref BUF: [u8; 5] = {
let rng = thread_rng().gen_range(0, MAX_U24) as u32;
let mut buf: [u8; 5] = [0; 5];
buf[0..4].copy_from_slice(&rng.to_be_bytes());
buf
};
}
*BUF
}
fn gen_count() -> [u8; 3] {
let u_counter = OID_COUNTER.fetch_add(1, Ordering::SeqCst);
let u = u_counter % (MAX_U24 + 1);
let u_int = u as u64;
let buf = u_int.to_be_bytes();
let buf_u24: [u8; 3] = [buf[5], buf[6], buf[7]];
buf_u24
}
}
impl fmt::Display for ObjectId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str(&self.to_hex())
}
}
impl fmt::Debug for ObjectId {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str(&format!("ObjectId({})", self.to_hex()))
}
}
#[cfg(test)]
mod test {
use chrono::{offset::TimeZone, Utc};
#[test]
fn test_new() {
println!("objectId:{}",super::ObjectId::new().to_string());
println!("objectId:{}",super::ObjectId::new().to_string());
println!("objectId:{}",super::ObjectId::new().to_string());
println!("objectId:{}",super::ObjectId::new().to_string());
}
#[test]
fn test_display() {
let id = super::ObjectId::with_string("53e37d08776f724e42000000").unwrap();
assert_eq!(format!("{}", id), "53e37d08776f724e42000000")
}
#[test]
fn test_debug() {
let id = super::ObjectId::with_string("53e37d08776f724e42000000").unwrap();
assert_eq!(format!("{:?}", id), "ObjectId(53e37d08776f724e42000000)")
}
#[test]
fn test_timestamp() {
let id = super::ObjectId::with_string("000000000000000000000000").unwrap();
assert_eq!(Utc.ymd(1970, 1, 1).and_hms(0, 0, 0), id.timestamp());
let id = super::ObjectId::with_string("7FFFFFFF0000000000000000").unwrap();
assert_eq!(Utc.ymd(2038, 1, 19).and_hms(3, 14, 7), id.timestamp());
let id = super::ObjectId::with_string("800000000000000000000000").unwrap();
assert_eq!(Utc.ymd(2038, 1, 19).and_hms(3, 14, 8), id.timestamp());
let id = super::ObjectId::with_string("FFFFFFFF0000000000000000").unwrap();
assert_eq!(Utc.ymd(2106, 2, 7).and_hms(6, 28, 15), id.timestamp());
}
}