Add timezone host functions.

Author: cdmurph32

Cargo.lock

@@ -319,6 +319,8 @@ humantime = "2.0.0"
 postcard = { version = "1.0.8", default-features = false, features = ['alloc'] }
 criterion = { version = "0.5.0", default-features = false, features = ["html_reports", "rayon"] }
 rustc-hash = "1.1.0"
+chrono = "0.4.26"
+chrono-tz = "0.8.3"
 
 # =============================================================================
 #

Cargo.toml

@@ -1,7 +1,7 @@
 package wasi:cli@0.2.0;
 
 world imports {
-  include wasi:clocks/imports@0.2.0;
+  include wasi:clocks/imports@0.2.1;
   include wasi:filesystem/imports@0.2.0;
   include wasi:sockets/imports@0.2.0;
   include wasi:random/imports@0.2.0;

crates/wasi-http/wit/deps/cli/imports.wit

@@ -1,4 +1,4 @@
-package wasi:clocks@0.2.0;
+package wasi:clocks@0.2.1;
 /// WASI Monotonic Clock is a clock API intended to let users measure elapsed
 /// time.
 ///

crates/wasi-http/wit/deps/clocks/monotonic-clock.wit

@@ -0,0 +1,50 @@
+package wasi:clocks@0.2.1;
+
+interface 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.
+    display: func(when: datetime) -> timezone-display;
+
+    /// The same as `display`, but only return the UTC offset.
+    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.
+    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,
+    }
+}

crates/wasi-http/wit/deps/clocks/timezone.wit

@@ -1,4 +1,4 @@
-package wasi:clocks@0.2.0;
+package wasi:clocks@0.2.1;
 /// 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.

crates/wasi-http/wit/deps/clocks/wall-clock.wit

@@ -1,6 +1,7 @@
-package wasi:clocks@0.2.0;
+package wasi:clocks@0.2.1;
 
 world imports {
     import monotonic-clock;
     import wall-clock;
+    import timezone;
 }

crates/wasi-http/wit/deps/clocks/world.wit

@@ -25,7 +25,7 @@ package wasi:[email protected];
 /// [WASI filesystem path resolution]: https://github.com/WebAssembly/wasi-filesystem/blob/main/path-resolution.md
 interface types {
     use wasi:io/streams@0.2.0.{input-stream, output-stream, error};
-    use wasi:clocks/wall-clock@0.2.0.{datetime};
+    use wasi:clocks/wall-clock@0.2.1.{datetime};
 
     /// File size or length of a region within a file.
     type filesize = u64;

crates/wasi-http/wit/deps/filesystem/types.wit

@@ -6,7 +6,7 @@ package wasi:[email protected];
 /// outgoing HTTP requests.
 world proxy {
   /// HTTP proxies have access to time and randomness.
-  include wasi:clocks/imports@0.2.0;
+  include wasi:clocks/imports@0.2.1;
   import wasi:random/random@0.2.0;
 
   /// Proxies have standard output and error streams which are expected to

crates/wasi-http/wit/deps/http/proxy.wit

@@ -2,7 +2,7 @@
 /// HTTP Requests and Responses, both incoming and outgoing, as well as
 /// their headers, trailers, and bodies.
 interface types {
-  use wasi:clocks/monotonic-clock@0.2.0.{duration};
+  use wasi:clocks/monotonic-clock@0.2.1.{duration};
   use wasi:io/streams@0.2.0.{input-stream, output-stream};
   use wasi:io/error@0.2.0.{error as io-error};
   use wasi:io/poll@0.2.0.{pollable};