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Only implement the offset_from_ methods on Local
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@pitdicker
pitdicker committed May 18, 2023
1 parent 7c7bc85 commit 6d82f95
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Showing 5 changed files with 82 additions and 344 deletions.
87 changes: 15 additions & 72 deletions src/offset/local/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,13 +8,11 @@ use rkyv::{Archive, Deserialize, Serialize};

use super::fixed::FixedOffset;
use super::{LocalResult, TimeZone};
use crate::naive::{NaiveDate, NaiveDateTime};
use crate::naive::{NaiveDate, NaiveDateTime, NaiveTime};
#[allow(deprecated)]
use crate::Date;
use crate::{DateTime, Utc};

// we don't want `stub.rs` when the target_os is not wasi or emscripten
// as we use js-sys to get the date instead
#[cfg(all(
not(unix),
not(windows),
Expand All @@ -35,6 +33,14 @@ mod inner;
#[path = "windows.rs"]
mod inner;

#[cfg(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
))]
#[path = "wasmbind.rs"]
mod inner;

#[cfg(unix)]
mod tz_info;

Expand Down Expand Up @@ -103,87 +109,24 @@ impl TimeZone for Local {
Local
}

// they are easier to define in terms of the finished date and time unlike other offsets
#[allow(deprecated)]
fn offset_from_local_date(&self, local: &NaiveDate) -> LocalResult<FixedOffset> {
self.from_local_date(local).map(|date| *date.offset())
// Get the offset at local midnight.
self.offset_from_local_datetime(&local.and_time(NaiveTime::MIN))
}

fn offset_from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<FixedOffset> {
self.from_local_datetime(local).map(|datetime| *datetime.offset())
inner::offset_from_local_datetime(local)
}

#[allow(deprecated)]
fn offset_from_utc_date(&self, utc: &NaiveDate) -> FixedOffset {
*self.from_utc_date(utc).offset()
// Get the offset at midnight.
self.offset_from_utc_datetime(&utc.and_time(NaiveTime::MIN))
}

fn offset_from_utc_datetime(&self, utc: &NaiveDateTime) -> FixedOffset {
*self.from_utc_datetime(utc).offset()
}

// override them for avoiding redundant works
#[allow(deprecated)]
fn from_local_date(&self, local: &NaiveDate) -> LocalResult<Date<Local>> {
// this sounds very strange, but required for keeping `TimeZone::ymd` sane.
// in the other words, we use the offset at the local midnight
// but keep the actual date unaltered (much like `FixedOffset`).
let midnight = self.from_local_datetime(&local.and_hms_opt(0, 0, 0).unwrap());
midnight.map(|datetime| Date::from_utc(*local, *datetime.offset()))
}

#[cfg(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
))]
fn from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<DateTime<Local>> {
let mut local = local.clone();
// Get the offset from the js runtime
let offset =
FixedOffset::west_opt((js_sys::Date::new_0().get_timezone_offset() as i32) * 60)
.unwrap();
local -= crate::Duration::seconds(offset.local_minus_utc() as i64);
LocalResult::Single(DateTime::from_utc(local, offset))
}

#[cfg(not(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
)))]
fn from_local_datetime(&self, local: &NaiveDateTime) -> LocalResult<DateTime<Local>> {
inner::naive_to_local(local, true)
}

#[allow(deprecated)]
fn from_utc_date(&self, utc: &NaiveDate) -> Date<Local> {
let midnight = self.from_utc_datetime(&utc.and_hms_opt(0, 0, 0).unwrap());
Date::from_utc(*utc, *midnight.offset())
}

#[cfg(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
))]
fn from_utc_datetime(&self, utc: &NaiveDateTime) -> DateTime<Local> {
// Get the offset from the js runtime
let offset =
FixedOffset::west_opt((js_sys::Date::new_0().get_timezone_offset() as i32) * 60)
.unwrap();
DateTime::from_utc(*utc, offset)
}

#[cfg(not(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
)))]
fn from_utc_datetime(&self, utc: &NaiveDateTime) -> DateTime<Local> {
// this is OK to unwrap as getting local time from a UTC
// timestamp is never ambiguous
inner::naive_to_local(utc, false).unwrap()
inner::offset_from_utc_datetime(utc).unwrap()
}
}

Expand Down
216 changes: 5 additions & 211 deletions src/offset/local/stub.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,218 +8,12 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use std::time::{SystemTime, UNIX_EPOCH};
use crate::{FixedOffset, LocalResult, NaiveDateTime};

use super::{FixedOffset, Local};
use crate::{DateTime, Datelike, LocalResult, NaiveDate, NaiveDateTime, NaiveTime, Timelike};

/// Converts a local `NaiveDateTime` to the `time::Timespec`.
#[cfg(not(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
)))]
pub(super) fn naive_to_local(d: &NaiveDateTime, local: bool) -> LocalResult<DateTime<Local>> {
let tm = Tm {
tm_sec: d.second() as i32,
tm_min: d.minute() as i32,
tm_hour: d.hour() as i32,
tm_mday: d.day() as i32,
tm_mon: d.month0() as i32, // yes, C is that strange...
tm_year: d.year() - 1900, // this doesn't underflow, we know that d is `NaiveDateTime`.
tm_wday: 0, // to_local ignores this
tm_yday: 0, // and this
tm_isdst: -1,
// This seems pretty fake?
tm_utcoff: if local { 1 } else { 0 },
// do not set this, OS APIs are heavily inconsistent in terms of leap second handling
tm_nsec: 0,
};

let spec = Timespec {
sec: match local {
false => utc_tm_to_time(&tm),
true => local_tm_to_time(&tm),
},
nsec: tm.tm_nsec,
};

// Adjust for leap seconds
let mut tm = spec.local();
assert_eq!(tm.tm_nsec, 0);
tm.tm_nsec = d.nanosecond() as i32;

LocalResult::Single(tm_to_datetime(tm))
}

/// Converts a `time::Tm` struct into the timezone-aware `DateTime`.
/// This assumes that `time` is working correctly, i.e. any error is fatal.
#[cfg(not(all(
target_arch = "wasm32",
feature = "wasmbind",
not(any(target_os = "emscripten", target_os = "wasi"))
)))]
fn tm_to_datetime(mut tm: Tm) -> DateTime<Local> {
if tm.tm_sec >= 60 {
tm.tm_nsec += (tm.tm_sec - 59) * 1_000_000_000;
tm.tm_sec = 59;
}

let date = NaiveDate::from_yo(tm.tm_year + 1900, tm.tm_yday as u32 + 1);
let time = NaiveTime::from_hms_nano(
tm.tm_hour as u32,
tm.tm_min as u32,
tm.tm_sec as u32,
tm.tm_nsec as u32,
);

let offset = FixedOffset::east_opt(tm.tm_utcoff).unwrap();
DateTime::from_utc(date.and_time(time) - offset, offset)
}

/// A record specifying a time value in seconds and nanoseconds, where
/// nanoseconds represent the offset from the given second.
///
/// For example a timespec of 1.2 seconds after the beginning of the epoch would
/// be represented as {sec: 1, nsec: 200000000}.
struct Timespec {
sec: i64,
nsec: i32,
}

impl Timespec {
/// Converts this timespec into the system's local time.
fn local(self) -> Tm {
let mut tm = Tm {
tm_sec: 0,
tm_min: 0,
tm_hour: 0,
tm_mday: 0,
tm_mon: 0,
tm_year: 0,
tm_wday: 0,
tm_yday: 0,
tm_isdst: 0,
tm_utcoff: 0,
tm_nsec: 0,
};
time_to_local_tm(self.sec, &mut tm);
tm.tm_nsec = self.nsec;
tm
}
}

/// Holds a calendar date and time broken down into its components (year, month,
/// day, and so on), also called a broken-down time value.
// FIXME: use c_int instead of i32?
#[repr(C)]
pub(super) struct Tm {
/// Seconds after the minute - [0, 60]
tm_sec: i32,

/// Minutes after the hour - [0, 59]
tm_min: i32,

/// Hours after midnight - [0, 23]
tm_hour: i32,

/// Day of the month - [1, 31]
tm_mday: i32,

/// Months since January - [0, 11]
tm_mon: i32,

/// Years since 1900
tm_year: i32,

/// Days since Sunday - [0, 6]. 0 = Sunday, 1 = Monday, ..., 6 = Saturday.
tm_wday: i32,

/// Days since January 1 - [0, 365]
tm_yday: i32,

/// Daylight Saving Time flag.
///
/// This value is positive if Daylight Saving Time is in effect, zero if
/// Daylight Saving Time is not in effect, and negative if this information
/// is not available.
tm_isdst: i32,

/// Identifies the time zone that was used to compute this broken-down time
/// value, including any adjustment for Daylight Saving Time. This is the
/// number of seconds east of UTC. For example, for U.S. Pacific Daylight
/// Time, the value is `-7*60*60 = -25200`.
tm_utcoff: i32,

/// Nanoseconds after the second - [0, 10<sup>9</sup> - 1]
tm_nsec: i32,
}

fn time_to_tm(ts: i64, tm: &mut Tm) {
let leapyear = |year| -> bool { year % 4 == 0 && (year % 100 != 0 || year % 400 == 0) };

static YTAB: [[i64; 12]; 2] = [
[31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
[31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
];

let mut year = 1970;

let dayclock = ts % 86400;
let mut dayno = ts / 86400;

tm.tm_sec = (dayclock % 60) as i32;
tm.tm_min = ((dayclock % 3600) / 60) as i32;
tm.tm_hour = (dayclock / 3600) as i32;
tm.tm_wday = ((dayno + 4) % 7) as i32;
loop {
let yearsize = if leapyear(year) { 366 } else { 365 };
if dayno >= yearsize {
dayno -= yearsize;
year += 1;
} else {
break;
}
}
tm.tm_year = (year - 1900) as i32;
tm.tm_yday = dayno as i32;
let mut mon = 0;
while dayno >= YTAB[if leapyear(year) { 1 } else { 0 }][mon] {
dayno -= YTAB[if leapyear(year) { 1 } else { 0 }][mon];
mon += 1;
}
tm.tm_mon = mon as i32;
tm.tm_mday = dayno as i32 + 1;
tm.tm_isdst = 0;
}

fn tm_to_time(tm: &Tm) -> i64 {
let mut y = tm.tm_year as i64 + 1900;
let mut m = tm.tm_mon as i64 + 1;
if m <= 2 {
y -= 1;
m += 12;
}
let d = tm.tm_mday as i64;
let h = tm.tm_hour as i64;
let mi = tm.tm_min as i64;
let s = tm.tm_sec as i64;
(365 * y + y / 4 - y / 100 + y / 400 + 3 * (m + 1) / 5 + 30 * m + d - 719561) * 86400
+ 3600 * h
+ 60 * mi
+ s
}

pub(super) fn time_to_local_tm(sec: i64, tm: &mut Tm) {
// FIXME: Add timezone logic
time_to_tm(sec, tm);
}

pub(super) fn utc_tm_to_time(tm: &Tm) -> i64 {
tm_to_time(tm)
pub(super) fn offset_from_utc_datetime(_utc_time: &NaiveDateTime) -> LocalResult<FixedOffset> {
LocalResult::Single(FixedOffset::east_opt(0).unwrap())
}

pub(super) fn local_tm_to_time(tm: &Tm) -> i64 {
// FIXME: Add timezone logic
tm_to_time(tm)
pub(super) fn offset_from_local_datetime(_local_time: &NaiveDateTime) -> LocalResult<FixedOffset> {
LocalResult::Single(FixedOffset::east_opt(0).unwrap())
}
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