Drop emscripten-functions dependency

Author: bschoenmaeckers

Cargo.toml

@@ -43,9 +43,6 @@ getrandom = { version = "0.2.1", features = ["js"] }
 [target.'cfg(target_os = "haiku")'.dependencies]
 iana-time-zone-haiku = { version = "0.1.1", path = "haiku" }
 
-[target.'cfg(target_os = "emscripten")'.dependencies]
-emscripten-functions = "0.3"
-
 [dev-dependencies]
 chrono-tz = "0.10.1"
 # Set a minimum, but unused, dependency on `getrandom` to ensure that cfg-if

src/tz_wasm32_emscripten.rs

@@ -1,7 +1,30 @@
 use crate::GetTimezoneError;
-use emscripten_functions::emscripten::run_script_string;
+use std::ffi::CStr;
+use std::os::raw::c_char;
+use std::ptr::NonNull;
+
+extern "C" {
+    fn emscripten_run_script_string(script: *const c_char) -> *mut c_char;
+}
 
 pub(crate) fn get_timezone_inner() -> Result<String, GetTimezoneError> {
-    run_script_string("Intl.DateTimeFormat().resolvedOptions().timeZone")
-        .ok_or_else(|| GetTimezoneError::OsError)
+    const SCRIPT: &CStr = {
+        match CStr::from_bytes_with_nul(
+            "Intl.DateTimeFormat().resolvedOptions().timeZone\0".as_bytes(),
+        ) {
+            Ok(s) => s,
+            Err(_) => panic!("Invalid UTF-8 data"),
+        }
+    };
+
+    unsafe {
+        NonNull::new(emscripten_run_script_string(SCRIPT.as_ptr()))
+            .ok_or_else(|| GetTimezoneError::OsError)
+            .and_then(|ptr| {
+                CStr::from_ptr(ptr.as_ptr())
+                    .to_owned()
+                    .into_string()
+                    .map_err(|_| GetTimezoneError::FailedParsingString)
+            })
+    }
 }