Add: Support wasm32-unknown-emscripten

chronotope · Mar 25, 2024 · e4b178c · e4b178c
1 parent d91b7d4
commit e4b178c
Show file tree

Hide file tree

Showing 3 changed files with 58 additions and 10 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -26,7 +26,7 @@ std = ["alloc"]
 clock = ["winapi", "iana-time-zone", "android-tzdata", "now"]
 now = ["std"]
 oldtime = []
-wasmbind = ["wasm-bindgen", "js-sys"]
+wasmbind = ["wasm-bindgen", "js-sys", "emscripten-functions"]
 unstable-locales = ["pure-rust-locales"]
 # Note that rkyv-16, rkyv-32, and rkyv-64 are mutually exclusive.
 rkyv = ["dep:rkyv", "rkyv/size_32"]
@@ -49,6 +49,9 @@ arbitrary = { version = "1.0.0", features = ["derive"], optional = true }
 wasm-bindgen = { version = "0.2", optional = true }
 js-sys = { version = "0.3", optional = true }       # contains FFI bindings for the JS Date API
 
+[target.'cfg(all(target_arch = "wasm32", target_os = "emscripten"))'.dependencies]
+emscripten-functions = { version = "0.2.1", optional = true }
+
 [target.'cfg(windows)'.dependencies]
 windows-targets = { version = "0.52", optional = true }
 

diff --git a/src/offset/local/mod.rs b/src/offset/local/mod.rs
@@ -16,7 +16,7 @@ use crate::naive::{NaiveDate, NaiveDateTime, NaiveTime};
 use crate::Date;
 use crate::{DateTime, Utc};
 
-#[cfg(unix)]
+#[cfg(all(unix, not(all(target_arch = "wasm32", feature = "wasmbind", target_os = "emscripten"))))]
 #[path = "unix.rs"]
 mod inner;
 
@@ -31,11 +31,7 @@ mod win_bindings;
 #[cfg(all(
     not(unix),
     not(windows),
-    not(all(
-        target_arch = "wasm32",
-        feature = "wasmbind",
-        not(any(target_os = "emscripten", target_os = "wasi"))
-    ))
+    not(all(target_arch = "wasm32", feature = "wasmbind", not(target_os = "wasi"),))
 ))]
 mod inner {
     use crate::{FixedOffset, MappedLocalTime, NaiveDateTime};
@@ -92,7 +88,42 @@ mod inner {
     }
 }
 
-#[cfg(unix)]
+#[cfg(all(target_arch = "wasm32", feature = "wasmbind", target_os = "emscripten"))]
+mod inner {
+    use crate::{Datelike, FixedOffset, MappedLocalTime, NaiveDateTime, Timelike};
+    use emscripten_functions::emscripten::run_script_int;
+
+    pub(super) fn offset_from_utc_datetime(utc: &NaiveDateTime) -> MappedLocalTime<FixedOffset> {
+        let offset = run_script_int(&format!(
+            "new Date(Date.UTC({}, {}, {}, {}, {}, {}, 0)).getTimezoneOffset()",
+            utc.year(),
+            utc.month0() + 1,
+            utc.day(),
+            utc.hour(),
+            utc.minute(),
+            utc.second()
+        ));
+        MappedLocalTime::Single(FixedOffset::west_opt((offset as i32) * 60).unwrap())
+    }
+
+    pub(super) fn offset_from_local_datetime(
+        local: &NaiveDateTime,
+    ) -> MappedLocalTime<FixedOffset> {
+        let offset = run_script_int(&format!(
+            "new Date({}, {}, {}, {}, {}, {}, 0).getTimezoneOffset()",
+            local.year(),
+            local.month0() + 1,
+            local.day(),
+            local.hour(),
+            local.minute(),
+            local.second()
+        ));
+        // We always get a result, even if this time does not exist or is ambiguous.
+        MappedLocalTime::Single(FixedOffset::west_opt((offset as i32) * 60).unwrap())
+    }
+}
+
+#[cfg(all(unix, not(all(target_arch = "wasm32", feature = "wasmbind", target_os = "emscripten"))))]
 mod tz_info;
 
 /// The local timescale.

diff --git a/src/offset/utc.rs b/src/offset/utc.rs
@@ -9,7 +9,7 @@ use core::fmt;
     not(all(
         target_arch = "wasm32",
         feature = "wasmbind",
-        not(any(target_os = "emscripten", target_os = "wasi"))
+        not(target_os = "wasi")
     ))
 ))]
 use std::time::{SystemTime, UNIX_EPOCH};
@@ -89,7 +89,7 @@ impl Utc {
     #[cfg(not(all(
         target_arch = "wasm32",
         feature = "wasmbind",
-        not(any(target_os = "emscripten", target_os = "wasi"))
+        not(target_os = "wasi")
     )))]
     #[must_use]
     pub fn now() -> DateTime<Utc> {
@@ -109,6 +109,20 @@ impl Utc {
         let now = js_sys::Date::new_0();
         DateTime::<Utc>::from(now)
     }
+
+    /// Returns a `DateTime` which corresponds to the current date and time.
+    #[cfg(all(
+        target_arch = "wasm32",
+        feature = "wasmbind",
+        target_os = "emscripten"
+    ))]
+    #[must_use]
+    pub fn now() -> DateTime<Utc> {
+        use emscripten_functions::emscripten::run_script_string;
+        // In order to handle number than i32, string is used to store the number
+        let now = run_script_string("Date.now().toString()").expect("Date.now() failed").parse::<i64>().unwrap();
+        Utc.timestamp_millis_opt(now).unwrap()
+    }
 }
 
 impl TimeZone for Utc {