feat: wasi-0.3.0 draft

wit-0.3.0-draft/monotonic-clock.wit

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+package wasi:clocks@0.3.0;
+/// WASI Monotonic Clock is a clock API intended to let users measure elapsed
+/// time.
+///
+/// It is intended to be portable at least between Unix-family platforms and
+/// Windows.
+///
+/// A monotonic clock is a clock which has an unspecified initial value, and
+/// successive reads of the clock will produce non-decreasing values.
+@since(version = 0.3.0)
+interface monotonic-clock {
+    /// An instant in time, in nanoseconds. An instant is relative to an
+    /// unspecified initial value, and can only be compared to instances from
+    /// the same monotonic-clock.
+    @since(version = 0.3.0)
+    type instant = u64;
+
+    /// A duration of time, in nanoseconds.
+    @since(version = 0.3.0)
+    type duration = u64;
+
+    /// Read the current value of the clock.
+    ///
+    /// The clock is monotonic, therefore calling this function repeatedly will
+    /// produce a sequence of non-decreasing values.
+    @since(version = 0.3.0)
+    now: func() -> instant;
+
+    /// Query the resolution of the clock. Returns the duration of time
+    /// corresponding to a clock tick.
+    @since(version = 0.3.0)
+    resolution: func() -> duration;
+
+    /// Wait until the specified instant has occurred.
+    @since(version = 0.3.0)
+    wait-until: func(
+        when: instant,
+    );
+
+    /// Wait for the specified duration has elapsed.
+    @since(version = 0.3.0)
+    wait-for: func(
+        how-long: duration,
+    );
+}

wit-0.3.0-draft/timezone.wit

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+package wasi:clocks@0.3.0;
+
+@unstable(feature = clocks-timezone)
+interface timezone {
+    @unstable(feature = clocks-timezone)
+    use wall-clock.{datetime};
+
+    /// Return information needed to display the given `datetime`. This includes
+    /// the UTC offset, the time zone name, and a flag indicating whether
+    /// daylight saving time is active.
+    ///
+    /// If the timezone cannot be determined for the given `datetime`, return a
+    /// `timezone-display` for `UTC` with a `utc-offset` of 0 and no daylight
+    /// saving time.
+    @unstable(feature = clocks-timezone)
+    display: func(when: datetime) -> timezone-display;
+
+    /// The same as `display`, but only return the UTC offset.
+    @unstable(feature = clocks-timezone)
+    utc-offset: func(when: datetime) -> s32;
+
+    /// Information useful for displaying the timezone of a specific `datetime`.
+    ///
+    /// This information may vary within a single `timezone` to reflect daylight
+    /// saving time adjustments.
+    @unstable(feature = clocks-timezone)
+    record timezone-display {
+        /// The number of seconds difference between UTC time and the local
+        /// time of the timezone.
+        ///
+        /// The returned value will always be less than 86400 which is the
+        /// number of seconds in a day (24*60*60).
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should return 0.
+        utc-offset: s32,
+
+        /// The abbreviated name of the timezone to display to a user. The name
+        /// `UTC` indicates Coordinated Universal Time. Otherwise, this should
+        /// reference local standards for the name of the time zone.
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should be the string `UTC`.
+        ///
+        /// In time zones that do not have an applicable name, a formatted
+        /// representation of the UTC offset may be returned, such as `-04:00`.
+        name: string,
+
+        /// Whether daylight saving time is active.
+        ///
+        /// In implementations that do not expose an actual time zone, this
+        /// should return false.
+        in-daylight-saving-time: bool,
+    }
+}

wit-0.3.0-draft/wall-clock.wit

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+package wasi:clocks@0.3.0;
+/// WASI Wall Clock is a clock API intended to let users query the current
+/// time. The name "wall" makes an analogy to a "clock on the wall", which
+/// is not necessarily monotonic as it may be reset.
+///
+/// It is intended to be portable at least between Unix-family platforms and
+/// Windows.
+///
+/// A wall clock is a clock which measures the date and time according to
+/// some external reference.
+///
+/// External references may be reset, so this clock is not necessarily
+/// monotonic, making it unsuitable for measuring elapsed time.
+///
+/// It is intended for reporting the current date and time for humans.
+@since(version = 0.3.0)
+interface wall-clock {
+    /// A time and date in seconds plus nanoseconds.
+    @since(version = 0.3.0)
+    record datetime {
+        seconds: u64,
+        nanoseconds: u32,
+    }
+
+    /// Read the current value of the clock.
+    ///
+    /// This clock is not monotonic, therefore calling this function repeatedly
+    /// will not necessarily produce a sequence of non-decreasing values.
+    ///
+    /// The returned timestamps represent the number of seconds since
+    /// 1970-01-01T00:00:00Z, also known as [POSIX's Seconds Since the Epoch],
+    /// also known as [Unix Time].
+    ///
+    /// The nanoseconds field of the output is always less than 1000000000.
+    ///
+    /// [POSIX's Seconds Since the Epoch]: https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xbd_chap04.html#tag_21_04_16
+    /// [Unix Time]: https://en.wikipedia.org/wiki/Unix_time
+    @since(version = 0.3.0)
+    now: func() -> datetime;
+
+    /// Query the resolution of the clock.
+    ///
+    /// The nanoseconds field of the output is always less than 1000000000.
+    @since(version = 0.3.0)
+    resolution: func() -> datetime;
+}

wit-0.3.0-draft/world.wit

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+package wasi:clocks@0.3.0;
+
+@since(version = 0.3.0)
+world imports {
+    @since(version = 0.3.0)
+    import monotonic-clock;
+    @since(version = 0.3.0)
+    import wall-clock;
+    @unstable(feature = clocks-timezone)
+    import timezone;
+}