Implement de/serialization of schedules

Fixes #7

Cargo.toml

@@ -18,6 +18,8 @@ pin-project = "0.4.23"
 im = "15.0.0"
 chrono = { version = "0.4.15" }
 assert_matches = "1.3.0"
+serde = { version = "1.0.116", features = ["derive"] }
+serde_json = "1.0.57"
 
 [dependencies.tracing-subscriber]
 version = "0.2.11"

src/schedule.rs

@@ -1,9 +1,10 @@
 //! Scheduling for events to run at certain intervals in the future
 
 use chrono::{
-    Date, DateTime, Datelike, Duration as CDuration, Local, NaiveDateTime, NaiveTime,
-    TimeZone, Weekday,
+    Date, DateTime, Datelike, Duration as CDuration, Local, NaiveDateTime, NaiveTime, TimeZone,
+    Weekday,
 };
+use serde::{Deserialize, Serialize};
 use std::cmp;
 use std::iter::FromIterator;
 
@@ -32,7 +33,7 @@ pub fn every_day() -> WeekdaySet {
 
 /// Represents the different types of date-time bounds that can be on a schedule
 #[allow(dead_code)]
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum DateTimeBound {
     /// There is no bound (ie. the Schedule extends with no limit)
     None,
@@ -73,14 +74,250 @@ impl DateTimeBound {
 }
 
 /// A schedule that determines when an event will occur.
-#[derive(Default, Debug, Clone)]
+#[derive(Default, Debug, Clone, Serialize, Deserialize)]
 pub struct Schedule {
+    #[serde(
+        serialize_with = "ser::serialize_times",
+        deserialize_with = "ser::deserialize_times"
+    )]
     pub times: TimeSet,
+    #[serde(
+        serialize_with = "ser::serialize_weekdays",
+        deserialize_with = "ser::deserialize_weekdays"
+    )]
     pub weekdays: WeekdaySet,
     pub from: DateTimeBound,
     pub to: DateTimeBound,
 }
 
+mod ser {
+    use super::{DateTimeBound, TimeSet, WeekdaySet};
+    use chrono::{NaiveDate, NaiveTime, Weekday};
+    use serde::{Deserialize, Deserializer, Serialize, Serializer};
+    use std::{convert::TryInto, fmt};
+
+    #[derive(Default, Debug, Clone, Serialize, Deserialize)]
+    struct TimeOfDay {
+        hour: u32,
+        minute: u32,
+        second: u32,
+        #[serde(default)]
+        millisecond: u32,
+    }
+
+    impl From<&NaiveTime> for TimeOfDay {
+        fn from(time: &NaiveTime) -> Self {
+            use chrono::Timelike;
+            Self {
+                hour: time.hour(),
+                minute: time.minute(),
+                second: time.second(),
+                millisecond: time.nanosecond() / 1_000_000_u32,
+            }
+        }
+    }
+
+    #[derive(Copy, Clone, Debug)]
+    struct InvalidTimeOfDay;
+
+    impl fmt::Display for InvalidTimeOfDay {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            "invalid time of day".fmt(f)
+        }
+    }
+
+    impl TryInto<NaiveTime> for TimeOfDay {
+        type Error = InvalidTimeOfDay;
+        fn try_into(self) -> Result<NaiveTime, Self::Error> {
+            NaiveTime::from_hms_milli_opt(self.hour, self.minute, self.second, self.millisecond)
+                .ok_or(InvalidTimeOfDay)
+        }
+    }
+
+    #[allow(clippy::ptr_arg)]
+    pub fn serialize_times<S>(times: &TimeSet, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        serializer.collect_seq(times.iter().map(TimeOfDay::from))
+    }
+
+    pub fn deserialize_times<'de, D>(deserializer: D) -> Result<TimeSet, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        use serde::de::{Error, SeqAccess, Visitor};
+
+        struct TimeSetVisitor;
+
+        impl<'de> Visitor<'de> for TimeSetVisitor {
+            type Value = TimeSet;
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a sequence of time of days")
+            }
+
+            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+            where
+                A: SeqAccess<'de>,
+            {
+                let mut times = TimeSet::with_capacity(seq.size_hint().unwrap_or(0));
+                while let Some(value) = seq.next_element::<TimeOfDay>()? {
+                    let time: NaiveTime = value.try_into().map_err(A::Error::custom)?;
+                    times.push(time);
+                }
+                Ok(times)
+            }
+        }
+
+        deserializer.deserialize_seq(TimeSetVisitor)
+    }
+
+    #[allow(clippy::ptr_arg)]
+    pub fn serialize_weekdays<S>(weekdays: &WeekdaySet, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let iter = weekdays
+            .iter()
+            .map(|weekday| weekday.num_days_from_sunday());
+        serializer.collect_seq(iter)
+    }
+
+    #[derive(Copy, Clone, Debug)]
+    struct InvalidWeekday;
+
+    impl fmt::Display for InvalidWeekday {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            "invalid weekday".fmt(f)
+        }
+    }
+
+    fn weekday_from_days_from_sunday(days: u32) -> Result<Weekday, InvalidWeekday> {
+        Ok(match days {
+            0 => Weekday::Sun,
+            1 => Weekday::Mon,
+            2 => Weekday::Tue,
+            3 => Weekday::Wed,
+            4 => Weekday::Thu,
+            5 => Weekday::Fri,
+            6 => Weekday::Sat,
+            _ => return Err(InvalidWeekday),
+        })
+    }
+
+    pub fn deserialize_weekdays<'de, D>(deserializer: D) -> Result<WeekdaySet, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        use serde::de::{Error, SeqAccess, Visitor};
+
+        struct WeekdaySetVisitor;
+
+        impl<'de> Visitor<'de> for WeekdaySetVisitor {
+            type Value = WeekdaySet;
+            fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+                formatter.write_str("a sequence of integers representing weekdays")
+            }
+
+            fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+            where
+                A: SeqAccess<'de>,
+            {
+                let mut weekdays = WeekdaySet::with_capacity(seq.size_hint().unwrap_or(0));
+                while let Some(value) = seq.next_element::<u32>()? {
+                    let weekday = weekday_from_days_from_sunday(value).map_err(A::Error::custom)?;
+                    weekdays.push(weekday);
+                }
+                Ok(weekdays)
+            }
+        }
+
+        deserializer.deserialize_seq(WeekdaySetVisitor)
+    }
+
+    #[derive(Clone, Debug, Serialize, Deserialize)]
+    struct DateAndYear {
+        year: i32,
+        month: u32,
+        day: u32,
+    }
+
+    impl From<NaiveDate> for DateAndYear {
+        fn from(date: NaiveDate) -> Self {
+            use chrono::Datelike;
+            Self {
+                year: date.year(),
+                month: date.month(),
+                day: date.day(),
+            }
+        }
+    }
+
+    #[derive(Copy, Clone, Debug)]
+    struct InvalidDateAndYear;
+
+    impl fmt::Display for InvalidDateAndYear {
+        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+            "invalid date or year".fmt(f)
+        }
+    }
+
+    impl TryInto<NaiveDate> for DateAndYear {
+        type Error = InvalidDateAndYear;
+        fn try_into(self) -> Result<NaiveDate, Self::Error> {
+            NaiveDate::from_ymd_opt(self.year, self.month, self.day).ok_or(InvalidDateAndYear)
+        }
+    }
+
+    impl Serialize for DateTimeBound {
+        fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+        where
+            S: Serializer,
+        {
+            match self {
+                DateTimeBound::None => serializer.serialize_none(),
+                DateTimeBound::Yearly(date_time) => {
+                    // Discard time
+                    let mut date_of_year: DateAndYear = date_time.date().into();
+                    // Set year to 0 (since it is yearly)
+                    date_of_year.year = 0;
+
+                    date_of_year.serialize(serializer)
+                }
+                DateTimeBound::Definite(date_time) => {
+                    // Discard time
+                    let date_of_year: DateAndYear = date_time.date().into();
+
+                    date_of_year.serialize(serializer)
+                }
+            }
+        }
+    }
+
+    impl<'de> Deserialize<'de> for DateTimeBound {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: Deserializer<'de>,
+        {
+            use serde::de::Error;
+            let date_of_year: Option<DateAndYear> = Deserialize::deserialize(deserializer)?;
+            Ok(match date_of_year {
+                Some(date_of_year) => {
+                    let year = date_of_year.year;
+                    let date: NaiveDate = date_of_year.try_into().map_err(D::Error::custom)?;
+                    let date_time = date.and_hms(0, 0, 0);
+                    if year == 0 {
+                        DateTimeBound::Yearly(date_time)
+                    } else {
+                        DateTimeBound::Definite(date_time)
+                    }
+                }
+                None => DateTimeBound::None,
+            })
+        }
+    }
+}
+
 /// Gets the next date matching the `weekday` after `date`
 fn next_weekday<Tz: TimeZone>(mut date: Date<Tz>, weekday: Weekday) -> Date<Tz> {
     while date.weekday() != weekday {
@@ -174,6 +411,7 @@ impl Schedule {
 #[cfg(test)]
 mod test {
     use super::*;
+    use assert_matches::assert_matches;
     use chrono::NaiveDate;
 
     #[test]
@@ -360,4 +598,50 @@ mod test {
             assert_eq!(result, case.expected_result, "case failed: {:?}", case);
         }
     }
+
+    #[test]
+    fn test_serialize() {
+        let sched = Schedule::new(
+            vec![
+                NaiveTime::from_hms_milli(0, 0, 0, 0),
+                NaiveTime::from_hms_milli(23, 59, 59, 999),
+            ],
+            every_day(),
+            DateTimeBound::Yearly(NaiveDate::from_ymd(2020, 1, 1).and_hms(0, 0, 0)),
+            DateTimeBound::Definite(NaiveDate::from_ymd(9999, 12, 31).and_hms(23, 59, 59)),
+        );
+        let ser = serde_json::to_string(&sched).unwrap();
+        // Weekdays should match the order in `every_day()` but with sunday being 0
+        assert_eq!(
+            &ser,
+            "{\
+            \"times\":[\
+                {\"hour\":0,\"minute\":0,\"second\":0,\"millisecond\":0},\
+                {\"hour\":23,\"minute\":59,\"second\":59,\"millisecond\":999}\
+            ],\
+            \"weekdays\":[1,2,3,4,5,6,0],\
+            \"from\":{\
+                \"year\":0,\"month\":1,\"day\":1\
+            },\
+            \"to\":{\
+                \"year\":9999,\"month\":12,\"day\":31\
+            }\
+        }"
+        );
+        let sched_de: Schedule = serde_json::from_str(&ser).unwrap();
+        assert_eq!(sched.times, sched_de.times);
+        assert_eq!(sched.weekdays, sched_de.weekdays);
+        // This serialization is lossy (year is discarded for yearly)
+        // assert_eq!(sched_de.from, sched.from);
+        assert_eq!(
+            sched_de.from,
+            DateTimeBound::Yearly(NaiveDate::from_ymd(0, 1, 1).and_hms(0, 0, 0))
+        );
+        // This serialization is also lossy (time is discarded)
+        // assert_eq!(sched_de.to, sched.to);
+        assert_eq!(
+            sched_de.to,
+            DateTimeBound::Definite(NaiveDate::from_ymd(9999, 12, 31).and_hms(0, 0, 0))
+        );
+    }
 }