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use std::io::Write;
use std::time::{Duration, SystemTime, UNIX_EPOCH};
use deserialize::{self, FromSql};
use pg::Pg;
use serialize::{self, Output, ToSql};
use sql_types;
fn pg_epoch() -> SystemTime {
let thirty_years = Duration::from_secs(946_684_800);
UNIX_EPOCH + thirty_years
}
impl ToSql<sql_types::Timestamp, Pg> for SystemTime {
fn to_sql<W: Write>(&self, out: &mut Output<W, Pg>) -> serialize::Result {
let (before_epoch, duration) = match self.duration_since(pg_epoch()) {
Ok(duration) => (false, duration),
Err(time_err) => (true, time_err.duration()),
};
let time_since_epoch = if before_epoch {
-(duration_to_usecs(duration) as i64)
} else {
duration_to_usecs(duration) as i64
};
ToSql::<sql_types::BigInt, Pg>::to_sql(&time_since_epoch, out)
}
}
impl FromSql<sql_types::Timestamp, Pg> for SystemTime {
fn from_sql(bytes: Option<&[u8]>) -> deserialize::Result<Self> {
let usecs_passed = <i64 as FromSql<sql_types::BigInt, Pg>>::from_sql(bytes)?;
let before_epoch = usecs_passed < 0;
let time_passed = usecs_to_duration(usecs_passed.abs() as u64);
if before_epoch {
Ok(pg_epoch() - time_passed)
} else {
Ok(pg_epoch() + time_passed)
}
}
}
const USEC_PER_SEC: u64 = 1_000_000;
const NANO_PER_USEC: u32 = 1_000;
fn usecs_to_duration(usecs_passed: u64) -> Duration {
let usecs_passed = usecs_passed;
let seconds = usecs_passed / USEC_PER_SEC;
let subsecond_usecs = usecs_passed % USEC_PER_SEC;
let subseconds = subsecond_usecs as u32 * NANO_PER_USEC;
Duration::new(seconds, subseconds)
}
fn duration_to_usecs(duration: Duration) -> u64 {
let seconds = duration.as_secs() * USEC_PER_SEC;
let subseconds = duration.subsec_micros();
seconds + u64::from(subseconds)
}
#[cfg(test)]
mod tests {
extern crate dotenv;
use self::dotenv::dotenv;
use std::time::{Duration, SystemTime, UNIX_EPOCH};
use dsl::{now, sql};
use prelude::*;
use select;
use sql_types::Timestamp;
fn connection() -> PgConnection {
dotenv().ok();
let connection_url = ::std::env::var("PG_DATABASE_URL")
.or_else(|_| ::std::env::var("DATABASE_URL"))
.expect("DATABASE_URL must be set in order to run tests");
PgConnection::establish(&connection_url).unwrap()
}
#[test]
fn unix_epoch_encodes_correctly() {
let connection = connection();
let query = select(sql::<Timestamp>("'1970-01-01'").eq(UNIX_EPOCH));
assert!(query.get_result::<bool>(&connection).unwrap());
}
#[test]
fn unix_epoch_decodes_correctly() {
let connection = connection();
let epoch_from_sql = select(sql::<Timestamp>("'1970-01-01'::timestamp"))
.get_result::<SystemTime>(&connection);
assert_eq!(Ok(UNIX_EPOCH), epoch_from_sql);
}
#[test]
fn times_relative_to_now_encode_correctly() {
let connection = connection();
let time = SystemTime::now() + Duration::from_secs(60);
let query = select(now.at_time_zone("utc").lt(time));
assert!(query.get_result::<bool>(&connection).unwrap());
let time = SystemTime::now() - Duration::from_secs(60);
let query = select(now.at_time_zone("utc").gt(time));
assert!(query.get_result::<bool>(&connection).unwrap());
}
}