chrono-lc/src/lib.rs

368 lines
13 KiB
Rust

//! This is an extension to chrono's date and time formatting to automatically translate
//! dates to a specified locale or language
//!
//! ## Usage
//!
//! Put this in your Cargo.toml:
//!
//! ```toml
//! [dependencies]
//! chrono = "0.4"
//! chrono_locale = { git = "https://github.com/0x5eal/chrono-locale.git", rev = "ff1df09" }
//! ```
//!
//! Then put this in your `lib.rs` or `main.rs`:
//!
//! ```rust
//! extern crate chrono;
//! extern crate chrono_locale;
//!
//! use chrono::prelude::*;
//! use chrono_locale::LocaleDate;
//! ```
//!
//! You can choose to import just parts of chrono instead of the whole prelude.
//! Please see ['chrono`'s documentation](https://docs.rs/chrono/).
//!
//! To format a chrono `Date` or `DateTime` object, you can use the `formatl` method:
//!
//! ```rust
//! # extern crate chrono;
//! # extern crate chrono_locale;
//! # use chrono::prelude::*;
//! # use chrono_locale::LocaleDate;
//!
//! let dt = FixedOffset::east(34200).ymd(2001, 7, 8).and_hms_nano(0, 34, 59, 1_026_490_708);
//! println!("{}", dt.formatl("%c", "fr"));
//! ```
//!
//! All of [chrono's formatting placeholders](https://docs.rs/chrono/0.4.6/chrono/format/strftime/index.html)
//! work except for `%3f`, `%6f` and `%9f` (but `%.3f`, `%.6f` and `%.9f` work normally)
//!
//! ## Locale format
//!
//! The `formatl` method supports locales in different formats, based on ISO-639-1 and ISO-3166.
//! It accepts any format where they are separated by `-` or `_`:
//!
//! - en_GB
//! - it-IT
//! - fr-fr
//! - PT_br
//!
//! The translated string will be first searched in the complete locale definition, then in the fallbacks.
//! For example: by requesting `it_IT` it will first try in `it-it`, then in `it` and, if it still
//! doesn't find it, it will use the default: `C` (english)
//!
#[macro_use]
extern crate lazy_static;
extern crate chrono;
extern crate num_integer;
use std::collections::HashMap;
use std::fmt;
use chrono::format::{Fixed, Item, Numeric, Pad, StrftimeItems};
use chrono::{Datelike, FixedOffset, NaiveDate, NaiveTime, Offset, TimeZone, Timelike};
use num_integer::{div_floor, mod_floor};
mod locales;
pub trait LocaleDate {
fn formatl<'a>(&self, fmt: &'a str, locale: &str) -> DelayedFormatL10n<StrftimeItems<'a>>;
}
impl LocaleDate for chrono::NaiveDate {
fn formatl<'a>(&self, fmt: &'a str, locale: &str) -> DelayedFormatL10n<StrftimeItems<'a>> {
DelayedFormatL10n::new(Some(*self), None, StrftimeItems::new(fmt), locale)
}
}
impl LocaleDate for chrono::NaiveDateTime {
fn formatl<'a>(&self, fmt: &'a str, locale: &str) -> DelayedFormatL10n<StrftimeItems<'a>> {
DelayedFormatL10n::new(Some(self.date()), Some(self.time()), StrftimeItems::new(fmt), locale)
}
}
impl<Tz: TimeZone> LocaleDate for chrono::DateTime<Tz> {
fn formatl<'a>(&self, fmt: &'a str, locale: &str) -> DelayedFormatL10n<StrftimeItems<'a>> {
let local = self.naive_local();
let offset = self.offset().fix();
DelayedFormatL10n::new_with_offset(Some(local.date()), Some(local.time()), &offset, StrftimeItems::new(fmt), locale)
}
}
/// A *temporary* object which can be used as an argument to `format!` or others.
/// This is normally constructed via `format` methods of each date and time type.
#[derive(Debug)]
pub struct DelayedFormatL10n<I> {
/// The locale to format the date in
locale: String,
/// The date view, if any.
date: Option<NaiveDate>,
/// The time view, if any.
time: Option<NaiveTime>,
/// The name and local-to-UTC difference for the offset (timezone), if any.
off: Option<(String, FixedOffset)>,
/// An iterator returning formatting items.
items: I,
}
impl<'a, I: Iterator<Item = Item<'a>> + Clone> DelayedFormatL10n<I> {
/// Makes a new `DelayedFormatL10n` value out of local date and time.
pub fn new(date: Option<NaiveDate>, time: Option<NaiveTime>, items: I, locale: &str) -> DelayedFormatL10n<I> {
DelayedFormatL10n {
date,
time,
off: None,
items,
locale: locale.to_owned(),
}
}
/// Makes a new `DelayedFormatL10n` value out of local date and time and UTC offset.
pub fn new_with_offset(date: Option<NaiveDate>, time: Option<NaiveTime>, offset: &FixedOffset, items: I, locale: &str) -> DelayedFormatL10n<I> {
let name_and_diff = (offset.to_string(), offset.to_owned());
DelayedFormatL10n {
date,
time,
off: Some(name_and_diff),
items,
locale: locale.to_owned(),
}
}
}
impl<'a, I: Iterator<Item = Item<'a>> + Clone> fmt::Display for DelayedFormatL10n<I> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
format_l10n(
f,
self.date.as_ref(),
self.time.as_ref(),
self.off.as_ref(),
self.items.clone(),
&self.locale,
)
}
}
/// This function is nearly entirely copied from chrono's format()
/// internal formats (3, 6 and 9-digits nanoseconds) have been disabled due to lack of access to chrono internals
pub fn format_l10n<'a, I>(
w: &mut fmt::Formatter,
date: Option<&NaiveDate>,
time: Option<&NaiveTime>,
off: Option<&(String, FixedOffset)>,
items: I,
locale: &str,
) -> fmt::Result
where
I: Iterator<Item = Item<'a>>,
{
let locale = locale.to_lowercase().replace("_", "-");
for item in items {
match item {
Item::Literal(s) | Item::Space(s) => write!(w, "{}", s)?,
Item::OwnedLiteral(ref s) | Item::OwnedSpace(ref s) => write!(w, "{}", s)?,
Item::Numeric(spec, pad) => {
use self::Numeric::*;
let week_from_sun = |d: &NaiveDate| (d.ordinal() as i32 - d.weekday().num_days_from_sunday() as i32 + 7) / 7;
let week_from_mon = |d: &NaiveDate| (d.ordinal() as i32 - d.weekday().num_days_from_monday() as i32 + 7) / 7;
let (width, v) = match spec {
Year => (4, date.map(|d| i64::from(d.year()))),
YearDiv100 => (2, date.map(|d| div_floor(i64::from(d.year()), 100))),
YearMod100 => (2, date.map(|d| mod_floor(i64::from(d.year()), 100))),
IsoYear => (4, date.map(|d| i64::from(d.iso_week().year()))),
IsoYearDiv100 => (2, date.map(|d| div_floor(i64::from(d.iso_week().year()), 100))),
IsoYearMod100 => (2, date.map(|d| mod_floor(i64::from(d.iso_week().year()), 100))),
Month => (2, date.map(|d| i64::from(d.month()))),
Day => (2, date.map(|d| i64::from(d.day()))),
WeekFromSun => (2, date.map(|d| i64::from(week_from_sun(d)))),
WeekFromMon => (2, date.map(|d| i64::from(week_from_mon(d)))),
IsoWeek => (2, date.map(|d| i64::from(d.iso_week().week()))),
NumDaysFromSun => (1, date.map(|d| i64::from(d.weekday().num_days_from_sunday()))),
WeekdayFromMon => (1, date.map(|d| i64::from(d.weekday().number_from_monday()))),
Ordinal => (3, date.map(|d| i64::from(d.ordinal()))),
Hour => (2, time.map(|t| i64::from(t.hour()))),
Hour12 => (2, time.map(|t| i64::from(t.hour12().1))),
Minute => (2, time.map(|t| i64::from(t.minute()))),
Second => (2, time.map(|t| i64::from(t.second() + t.nanosecond() / 1_000_000_000))),
Nanosecond => (9, time.map(|t| i64::from(t.nanosecond() % 1_000_000_000))),
Timestamp => (
1,
match (date, time, off) {
(Some(d), Some(t), None) => Some(d.and_time(*t).timestamp()),
(Some(d), Some(t), Some(&(_, off))) => Some((d.and_time(*t) - off).timestamp()),
(_, _, _) => None,
},
),
// for the future expansion
Internal(_) => (1, None),
};
if let Some(v) = v {
if (spec == Year || spec == IsoYear) && !(0 <= v && v < 10_000) {
// non-four-digit years require an explicit sign as per ISO 8601
match pad {
Pad::None => write!(w, "{:+}", v)?,
Pad::Zero => write!(w, "{:+01$}", v, width + 1)?,
Pad::Space => write!(w, "{:+1$}", v, width + 1)?,
}
} else {
match pad {
Pad::None => write!(w, "{}", v)?,
Pad::Zero => write!(w, "{:01$}", v, width)?,
Pad::Space => write!(w, "{:1$}", v, width)?,
}
}
} else {
return Err(fmt::Error); // insufficient arguments for given format
}
}
Item::Fixed(spec) => {
use self::Fixed::*;
/// Prints an offset from UTC in the format of `+HHMM` or `+HH:MM`.
/// `Z` instead of `+00[:]00` is allowed when `allow_zulu` is true.
fn write_local_minus_utc(w: &mut fmt::Formatter, off: FixedOffset, allow_zulu: bool, use_colon: bool) -> fmt::Result {
let off = off.local_minus_utc();
if !allow_zulu || off != 0 {
let (sign, off) = if off < 0 { ('-', -off) } else { ('+', off) };
if use_colon {
write!(w, "{}{:02}:{:02}", sign, off / 3600, off / 60 % 60)
} else {
write!(w, "{}{:02}{:02}", sign, off / 3600, off / 60 % 60)
}
} else {
write!(w, "Z")
}
}
let ret = match spec {
ShortMonthName => date.map(|d| write!(w, "{}", short_month(d.month0() as usize, &locale))),
LongMonthName => date.map(|d| write!(w, "{}", long_month(d.month0() as usize, &locale))),
ShortWeekdayName => date.map(|d| write!(w, "{}", short_weekday(d.weekday().num_days_from_monday() as usize, &locale))),
LongWeekdayName => date.map(|d| write!(w, "{}", long_weekday(d.weekday().num_days_from_monday() as usize, &locale))),
LowerAmPm => time.map(|t| write!(w, "{}", ampm(t.hour12().0 as usize, &locale))),
UpperAmPm => time.map(|t| write!(w, "{}", ampm(t.hour12().0 as usize + 2, &locale))),
Nanosecond => time.map(|t| {
let nano = t.nanosecond() % 1_000_000_000;
if nano == 0 {
Ok(())
} else if nano % 1_000_000 == 0 {
write!(w, ".{:03}", nano / 1_000_000)
} else if nano % 1_000 == 0 {
write!(w, ".{:06}", nano / 1_000)
} else {
write!(w, ".{:09}", nano)
}
}),
Nanosecond3 => time.map(|t| {
let nano = t.nanosecond() % 1_000_000_000;
write!(w, ".{:03}", nano / 1_000_000)
}),
Nanosecond6 => time.map(|t| {
let nano = t.nanosecond() % 1_000_000_000;
write!(w, ".{:06}", nano / 1_000)
}),
Nanosecond9 => time.map(|t| {
let nano = t.nanosecond() % 1_000_000_000;
write!(w, ".{:09}", nano)
}),
Internal(_) => panic!("Internal is not supported"),
TimezoneName => off.map(|&(ref name, _)| write!(w, "{}", *name)),
TimezoneOffsetColon => off.map(|&(_, off)| write_local_minus_utc(w, off, false, true)),
TimezoneOffsetColonZ => off.map(|&(_, off)| write_local_minus_utc(w, off, true, true)),
TimezoneOffsetDoubleColon => off.map(|&(_, off)| write_local_minus_utc(w, off, false, true)),
TimezoneOffsetTripleColon => off.map(|&(_, off)| write_local_minus_utc(w, off, false, true)),
TimezoneOffset => off.map(|&(_, off)| write_local_minus_utc(w, off, false, false)),
TimezoneOffsetZ => off.map(|&(_, off)| write_local_minus_utc(w, off, true, false)),
RFC2822 =>
// same to `%a, %e %b %Y %H:%M:%S %z`
{
if let (Some(d), Some(t), Some(&(_, off))) = (date, time, off) {
let sec = t.second() + t.nanosecond() / 1_000_000_000;
write!(
w,
"{}, {:2} {} {:04} {:02}:{:02}:{:02} ",
short_weekday(d.weekday().num_days_from_monday() as usize, &locale),
d.day(),
short_month(d.month0() as usize, &locale),
d.year(),
t.hour(),
t.minute(),
sec
)?;
Some(write_local_minus_utc(w, off, false, false))
} else {
None
}
}
RFC3339 =>
// same to `%Y-%m-%dT%H:%M:%S%.f%:z`
{
if let (Some(d), Some(t), Some(&(_, off))) = (date, time, off) {
// reuse `Debug` impls which already print ISO 8601 format.
// this is faster in this way.
write!(w, "{:?}T{:?}", d, t)?;
Some(write_local_minus_utc(w, off, false, true))
} else {
None
}
}
};
match ret {
Some(ret) => ret?,
None => return Err(fmt::Error), // insufficient arguments for given format
}
}
Item::Error => return Err(fmt::Error),
}
}
Ok(())
}
fn short_month(key: usize, locale: &str) -> &'static str {
find_key(key, &locales::LOCALES.short_months, locale).expect("Internal error: missing short months in the C locale")
}
fn long_month(key: usize, locale: &str) -> &'static str {
find_key(key, &locales::LOCALES.long_months, locale).expect("Internal error: missing long months in the C locale")
}
fn short_weekday(key: usize, locale: &str) -> &'static str {
find_key(key, &locales::LOCALES.short_weekdays, locale).expect("Internal error: missing short weekdays in the C locale")
}
fn long_weekday(key: usize, locale: &str) -> &'static str {
find_key(key, &locales::LOCALES.long_weekdays, locale).expect("Internal error: missing long weekdays in the C locale")
}
fn ampm(key: usize, locale: &str) -> &'static str {
find_key(key, &locales::LOCALES.ampm, locale).expect("Internal error: missing AM/PM in the C locale")
}
fn find_key(key: usize, data: &'static HashMap<String, Vec<&'static str>>, locale: &str) -> Option<&'static &'static str> {
data.get(locale)
.and_then(|res| res.get(key))
.or_else(|| {
if locale.contains('-') {
locale
.split('-')
.collect::<Vec<&str>>()
.get(0)
.cloned()
.and_then(|locale| data.get(locale).and_then(|res| res.get(key)))
} else {
None
}
})
.or_else(|| data.get("C").and_then(|res| res.get(key)))
}