formatter[datetime]: fix timezone abbreviation (%Z)

Fixes greshake#1965
bim9262 · May 25, 2024 · 6d2a269 · 6d2a269
1 parent ba873a2
commit 6d2a269
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Showing 3 changed files with 73 additions and 7 deletions.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -41,6 +41,7 @@ env_logger = "0.11"
 futures = { version = "0.3", default-features = false }
 glob = { version = "0.3.1", optional = true }
 hyper = "0.14"
+iana-time-zone = "0.1.60"
 icu_calendar = { version = "1.3.0", optional = true }
 icu_datetime = { version = "1.3.0", optional = true }
 icu_locid = { version = "1.3.0", optional = true }

diff --git a/src/formatting/formatter/datetime.rs b/src/formatting/formatter/datetime.rs
@@ -1,11 +1,14 @@
 use chrono::format::{Item, StrftimeItems};
-use chrono::{DateTime, Local, Locale, TimeZone};
+use chrono::{format, DateTime, Datelike, Local, LocalResult, Locale, TimeZone, Timelike};
+use chrono_tz::{OffsetName, Tz};
 use once_cell::sync::Lazy;
 
 use std::fmt::Display;
 
 use super::*;
 
+make_log_macro!(debug, "datetime");
+
 const DEFAULT_DATETIME_FORMAT: &str = "%a %d/%m %R";
 
 pub static DEFAULT_DATETIME_FORMATTER: Lazy<DatetimeFormatter> =
@@ -100,6 +103,57 @@ impl DatetimeFormatter {
     }
 }
 
+pub(crate) trait TimezoneName {
+    fn timezone_name(datetime: &DateTime<Self>) -> Item
+    where
+        Self: TimeZone;
+}
+
+impl TimezoneName for Tz {
+    fn timezone_name(datetime: &DateTime<Tz>) -> Item {
+        Item::OwnedLiteral(datetime.offset().abbreviation().into())
+    }
+}
+
+impl TimezoneName for Local {
+    fn timezone_name(datetime: &DateTime<Local>) -> Item {
+        let fallback = Item::Fixed(format::Fixed::TimezoneName);
+        let tz_name = match iana_time_zone::get_timezone() {
+            Ok(tz_name) => tz_name,
+            _ => {
+                debug!("Could not get local timezone");
+                return fallback;
+            }
+        };
+        let tz = match tz_name.parse::<Tz>() {
+            Ok(tz) => tz,
+            Err(e) => {
+                debug!("{}", e);
+                return fallback;
+            }
+        };
+
+        match tz.with_ymd_and_hms(
+            datetime.year(),
+            datetime.month(),
+            datetime.day(),
+            datetime.hour(),
+            datetime.minute(),
+            datetime.second(),
+        ) {
+            LocalResult::Single(tz_datetime) => Tz::timezone_name(&tz_datetime).to_owned(),
+            LocalResult::Ambiguous(..) => {
+                debug!("Timezone is ambiguous");
+                fallback
+            }
+            LocalResult::None => {
+                debug!("Timezone is none");
+                fallback
+            }
+        }
+    }
+}
+
 impl Formatter for DatetimeFormatter {
     fn format(&self, val: &Value, _config: &SharedConfig) -> Result<String, FormatError> {
         #[allow(clippy::unnecessary_wraps)]
@@ -108,20 +162,30 @@ impl Formatter for DatetimeFormatter {
             datetime: DateTime<T>,
         ) -> Result<String, FormatError>
         where
-            T: TimeZone,
+            T: TimeZone + TimezoneName,
             T::Offset: Display,
         {
             Ok(match this {
-                DatetimeFormatter::Chrono { items, locale } => match *locale {
-                    Some(locale) => datetime.format_localized_with_items(items.iter(), locale),
-                    None => datetime.format_with_items(items.iter()),
+                DatetimeFormatter::Chrono { items, locale } => {
+                    let mut new_items = Vec::with_capacity(items.len());
+                    for item in items {
+                        new_items.push(match item {
+                            Item::Fixed(format::Fixed::TimezoneName) => T::timezone_name(&datetime),
+                            item => item.to_owned(),
+                        });
+                    }
+                    match *locale {
+                        Some(locale) => datetime
+                            .format_localized_with_items(new_items.iter(), locale)
+                            .to_string(),
+                        None => datetime.format_with_items(new_items.iter()).to_string(),
+                    }
                 }
-                .to_string(),
                 #[cfg(feature = "icu_calendar")]
                 DatetimeFormatter::Icu { locale, length } => {
                     use chrono::Datelike as _;
                     let date = icu_calendar::Date::try_new_iso_date(
-                        datetime.year_ce().1 as i32,
+                        datetime.year(),
                         datetime.month() as u8,
                         datetime.day() as u8,
                     )