Make parse_dateime::parse_datetime::from_str accept relative time

philolo1 · philolo1 · commit 82ea54a75f2a · 2023-08-21T20:24:54.000+09:00
diff --git a/src/parse_datetime.rs b/src/parse_datetime.rs
@@ -5,6 +5,8 @@ use chrono::{DateTime, FixedOffset, Local, LocalResult, NaiveDateTime, TimeZone}
 
 use crate::ParseDurationError;
 
+use crate::from_str as parse_relative_time;
+
 /// Formats that parse input can take.
 /// Taken from `touch` coreutils
 mod format {
@@ -46,6 +48,8 @@ mod format {
 ///
 /// * ISO formats
 /// * timezone offsets, e.g., "UTC-0100"
+/// * unix timestamps, e.g., "@12"
+/// * relative time to now, e.g. "+1 hour"
 ///
 /// # Returns
 ///
@@ -123,6 +127,15 @@ pub fn from_str<S: AsRef<str> + Clone>(s: S) -> Result<DateTime<FixedOffset>, Pa
         }
     }
 
+    // Parse relative time.
+    if let Ok(relative_time) = parse_relative_time(s.as_ref()) {
+        let current_time = DateTime::<FixedOffset>::from(Local::now());
+
+        if let Some(date_time) = current_time.checked_add_signed(relative_time) {
+            return Ok(date_time);
+        }
+    }
+
     // Default parse and failure
     s.as_ref()
         .parse()
@@ -243,6 +256,46 @@ mod tests {
         }
     }
 
+    #[cfg(test)]
+    mod relative_time {
+        use chrono::Local;
+
+        use crate::{parse_datetime::from_str, ParseDurationError};
+
+        #[test]
+        fn test_positive_offsets() {
+            let relative_times = vec![
+                "today",
+                "yesterday",
+                "1 minute",
+                "3 hours",
+                "1 year 3 months",
+            ];
+
+            for relative_time in relative_times {
+                assert_eq!(from_str(relative_time).is_ok(), true);
+            }
+        }
+
+        #[test]
+        fn test_partial_offset() {
+            let offsets = vec!["UTC+00:15", "UTC+0015", "Z+00:15", "Z+0015"];
+            let expected = format!("{}{}", Local::now().format("%Y%m%d"), "0000+0015");
+            for offset in offsets {
+                let actual = from_str(offset).unwrap();
+                assert_eq!(expected, format!("{}", actual.format("%Y%m%d%H%M%z")));
+            }
+        }
+
+        #[test]
+        fn invalid_offset_format() {
+            let invalid_offsets = vec!["+0700", "UTC+2", "Z-1", "UTC+01005"];
+            for offset in invalid_offsets {
+                assert_eq!(from_str(offset), Err(ParseDurationError::InvalidInput));
+            }
+        }
+    }
+
     /// Used to test example code presented in the README.
     mod readme_test {
         use crate::parse_datetime::from_str;
