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extern crate chrono;
#[macro_use]
extern crate lazy_static;
extern crate rand;
extern crate uuid;
use std::fmt;
use std::fs::File;
use std::io::Read;
use chrono::Utc;
use rand::Rand;
use uuid::{Uuid, UuidV1Context};
#[derive(Debug)]
pub struct OrderedUuid(Uuid);
struct Config {
ctx: UuidV1Context,
node: Uuid,
}
lazy_static! {
static ref CONFIG: Config = {
let ctx = {
let mut rng = rand::thread_rng();
UuidV1Context::rand(&mut rng)
};
let node = {
let mut machine_id = None;
if let Ok(mut file) = File::open("/etc/machine-id") {
let mut contents = String::new();
if file.read_to_string(&mut contents).is_ok() {
if let Ok(id) = Uuid::parse_str(contents.trim()) {
machine_id = Some(id);
}
}
}
match machine_id {
Some(id) => id,
None => Uuid::new_v4(),
}
};
Config { ctx, node }
};
}
pub trait Uuid1 {
fn v1() -> Uuid;
fn ordered(&self) -> Option<OrderedUuid>;
}
impl Uuid1 for Uuid {
fn v1() -> Uuid {
let ctx = &CONFIG.ctx;
let node = &CONFIG.node.as_bytes()[..6];
let now = Utc::now();
let seconds = now.timestamp() as u64;
let nsecs = now.timestamp_subsec_nanos();
Uuid::new_v1(ctx, seconds, nsecs, node).unwrap()
}
fn ordered(&self) -> Option<OrderedUuid> {
if self.get_version_num() == 1 {
let ordered: [u8; 16] = {
let bytes = self.as_bytes();
unsafe {[
*bytes.get_unchecked(6),
*bytes.get_unchecked(7),
*bytes.get_unchecked(4),
*bytes.get_unchecked(5),
*bytes.get_unchecked(0),
*bytes.get_unchecked(1),
*bytes.get_unchecked(2),
*bytes.get_unchecked(3),
*bytes.get_unchecked(8),
*bytes.get_unchecked(9),
*bytes.get_unchecked(10),
*bytes.get_unchecked(11),
*bytes.get_unchecked(12),
*bytes.get_unchecked(13),
*bytes.get_unchecked(14),
*bytes.get_unchecked(15),
]}
};
let uuid = Uuid::from_bytes(&ordered).unwrap();
return Some(OrderedUuid(uuid));
}
None
}
}
impl fmt::Display for OrderedUuid {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", self.0)
}
}
#[cfg(test)]
mod tests {
use Uuid1;
use uuid::Uuid;
#[test]
fn ordered_uuid_is_some() {
let uuid = Uuid::v1();
assert!(uuid.ordered().is_some());
}
}