Only implement the offset_from_ methods on Local

Author: pitdicker

src/offset/local/mod.rs

@@ -11,13 +11,11 @@ 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),
@@ -38,6 +36,14 @@ 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;
 
@@ -106,87 +112,24 @@ 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()
     }
 }
 

src/offset/local/stub.rs

@@ -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())
 }

src/offset/local/unix.rs

@@ -11,10 +11,17 @@
 use std::{cell::RefCell, collections::hash_map, env, fs, hash::Hasher, time::SystemTime};
 
 use super::tz_info::TimeZone;
-use super::{DateTime, Local, NaiveDateTime};
-use crate::{Datelike, LocalResult};
+use crate::{Datelike, FixedOffset, LocalResult, NaiveDateTime};
 
-pub(super) fn naive_to_local(d: &NaiveDateTime, local: bool) -> LocalResult<DateTime<Local>> {
+pub(super) fn offset_from_utc_datetime(utc: &NaiveDateTime) -> LocalResult<FixedOffset> {
+    get_offset(utc, false)
+}
+
+pub(super) fn offset_from_local_datetime(local: &NaiveDateTime) -> LocalResult<FixedOffset> {
+    get_offset(local, true)
+}
+
+fn get_offset(d: &NaiveDateTime, local: bool) -> LocalResult<FixedOffset> {
     TZ_INFO.with(|maybe_cache| {
         maybe_cache.borrow_mut().get_or_insert_with(Cache::default).offset(*d, local)
     })
@@ -97,7 +104,7 @@ fn current_zone(var: Option<&str>) -> TimeZone {
 }
 
 impl Cache {
-    fn offset(&mut self, d: NaiveDateTime, local: bool) -> LocalResult<DateTime<Local>> {
+    fn offset(&mut self, d: NaiveDateTime, local: bool) -> LocalResult<FixedOffset> {
         let now = SystemTime::now();
 
         match now.duration_since(self.last_checked) {
@@ -147,14 +154,13 @@ impl Cache {
                 .find_local_time_type(d.timestamp())
                 .expect("unable to select local time type")
                 .ut_offset;
-            return LocalResult::Single(DateTime::from_utc(d, offset));
+            return LocalResult::Single(offset);
         }
 
         // we pass through the year as the year of a local point in time must either be valid in that locale, or
         // the entire time was skipped in which case we will return LocalResult::None anyway.
         self.zone
             .find_local_offset_from_local(d.timestamp(), d.year())
             .expect("unable to select local time type")
-            .map(|offset| DateTime::from_utc(d - offset, offset))
     }
 }