| 1 | use crate::date::Date; |
|---|---|
| 2 | use std::env; |
| 3 | use std::time::{SystemTime, UNIX_EPOCH}; |
| 4 | |
| 5 | // Timestamp of 2016-03-01 00:00:00 in UTC. |
| 6 | const BASE: u64 = 1456790400; |
| 7 | const BASE_YEAR: u16 = 2016; |
| 8 | const BASE_MONTH: u8 = 3; |
| 9 | |
| 10 | // Days between leap days. |
| 11 | const CYCLE: u64 = 365 * 4 + 1; |
| 12 | |
| 13 | const DAYS_BY_MONTH: [u8; 12] = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; |
| 14 | |
| 15 | pub fn today() -> Date { |
| 16 | let default: Date = Date { |
| 17 | year: 2020, |
| 18 | month: 2, |
| 19 | day: 25, |
| 20 | }; |
| 21 | try_today().unwrap_or(default) |
| 22 | } |
| 23 | |
| 24 | fn try_today() -> Option<Date> { |
| 25 | if let Some(pkg_name) = env::var_os("CARGO_PKG_NAME") { |
| 26 | if pkg_name.to_str() == Some("rustversion-tests") { |
| 27 | return None; // Stable date for ui testing. |
| 28 | } |
| 29 | } |
| 30 | |
| 31 | let now = SystemTime::now(); |
| 32 | let since_epoch = now.duration_since(UNIX_EPOCH).ok()?; |
| 33 | let secs = since_epoch.as_secs(); |
| 34 | |
| 35 | let approx_days = secs.checked_sub(BASE)? / 60 / 60 / 24; |
| 36 | let cycle = approx_days / CYCLE; |
| 37 | let mut rem = approx_days % CYCLE; |
| 38 | |
| 39 | let mut year = BASE_YEAR + cycle as u16 * 4; |
| 40 | let mut month = BASE_MONTH; |
| 41 | loop { |
| 42 | let days_in_month = DAYS_BY_MONTH[month as usize - 1]; |
| 43 | if rem < days_in_month as u64 { |
| 44 | let day = rem as u8 + 1; |
| 45 | return Some(Date { year, month, day }); |
| 46 | } |
| 47 | rem -= days_in_month as u64; |
| 48 | year += (month == 12) as u16; |
| 49 | month = month % 12 + 1; |
| 50 | } |
| 51 | } |
| 52 |