Add timezone host functions.

Author: cdmurph32

Cargo.lock

@@ -125,6 +125,12 @@ authors = ["The Wasmtime Project Developers"]
 edition = "2021"
 rust-version = "1.71.0"
 
+[patch.crates-io]
+cap-std = { path = "../cap-std/cap-std" }
+cap-fs-ext = { path = "../cap-std/cap-fs-ext" }
+cap-time-ext = { path = "../cap-std/cap-time-ext" }
+cap-net-ext = { path = "../cap-std/cap-net-ext" }
+
 [workspace.dependencies]
 wasmtime-wmemcheck = { path = "crates/wmemcheck", version = "=13.0.0" }
 wasmtime = { path = "crates/wasmtime", version = "13.0.0", default-features = false }
@@ -254,6 +260,8 @@ futures = { version = "0.3.27", default-features = false }
 indexmap = "2.0.0"
 pretty_env_logger = "0.5.0"
 syn = "2.0.25"
+chrono = "0.4.26"
+chrono-tz = "0.8.3"
 
 [features]
 default = [

Cargo.toml

@@ -38,6 +38,8 @@ bitflags = { workspace = true, optional = true }
 async-trait = { workspace = true, optional = true }
 system-interface = { workspace = true, optional = true}
 futures = { workspace = true, optional = true }
+chrono = { workspace = true, optional = true }
+chrono-tz = { workspace = true, optional = true }
 
 [dev-dependencies]
 tokio = { workspace = true, features = ["time", "sync", "io-std", "io-util", "rt", "rt-multi-thread", "net", "macros"] }
@@ -77,6 +79,8 @@ preview2 = [
     'dep:rustix',
     'dep:tokio',
     'dep:futures',
+    'dep:chrono',
+    'dep:chrono-tz',
 ]
 preview1-on-preview2 = [
     "preview2",

crates/wasi/Cargo.toml

@@ -1,4 +1,5 @@
 pub mod host;
+use crate::preview2::bindings::clocks::timezone::TimezoneDisplay;
 use cap_std::time::Duration;
 
 pub trait HostWallClock: Send + Sync {
@@ -10,3 +11,8 @@ pub trait HostMonotonicClock: Send + Sync {
     fn resolution(&self) -> u64;
     fn now(&self) -> u64;
 }
+
+pub trait HostTimezone: Send + Sync {
+    fn display(&self, datetime: Duration) -> TimezoneDisplay;
+    fn utc_offset(&self, datetime: Duration) -> i32;
+}