Add wasm_bindgen::script_url

Author: lukaslihotzki

crates/cli-support/src/intrinsic.rs

@@ -229,6 +229,9 @@ intrinsics! {
         #[symbol = "__wbindgen_module"]
         #[signature = fn() -> Externref]
         Module,
+        #[symbol = "__wbindgen_script_url"]
+        #[signature = fn() -> String]
+        ScriptUrl,
         #[symbol = "__wbindgen_function_table"]
         #[signature = fn() -> Externref]
         FunctionTable,

crates/cli-support/src/js/mod.rs

@@ -378,6 +378,7 @@ impl<'a> Context<'a> {
             // function.
             OutputMode::NoModules { global } => {
                 js.push_str("const __exports = {};\n");
+                js.push_str("let script_src;\n");
                 js.push_str("let wasm;\n");
                 init = self.gen_init(needs_manual_start, None)?;
                 footer.push_str(&format!("{} = Object.assign(init, __exports);\n", global));
@@ -700,14 +701,13 @@ impl<'a> Context<'a> {
                     stem = self.config.stem()?
                 ),
                 OutputMode::NoModules { .. } => "\
+                    if (typeof document === 'undefined') {
+                        script_src = location.href;
+                    } else {
+                        script_src = document.currentScript.src;
+                    }
                     if (typeof input === 'undefined') {
-                        let src;
-                        if (typeof document === 'undefined') {
-                            src = location.href;
-                        } else {
-                            src = document.currentScript.src;
-                        }
-                        input = src.replace(/\\.js$/, '_bg.wasm');
+                        input = script_src.replace(/\\.js$/, '_bg.wasm');
                     }"
                 .to_string(),
                 _ => "".to_string(),
@@ -3426,6 +3426,22 @@ impl<'a> Context<'a> {
                 format!("wasm.{}", self.export_name_of(memory))
             }
 
+            Intrinsic::ScriptUrl => {
+                assert_eq!(args.len(), 0);
+                match self.config.mode {
+                    OutputMode::Web
+                    | OutputMode::Deno
+                    | OutputMode::Node {
+                        experimental_modules: true,
+                    } => format!("import.meta.url"),
+                    OutputMode::Node {
+                        experimental_modules: false,
+                    } => format!("__filename"),
+                    OutputMode::NoModules { .. } => format!("script_src"),
+                    OutputMode::Bundler { .. } => format!("__webpack_public_path__"),
+                }
+            }
+
             Intrinsic::FunctionTable => {
                 assert_eq!(args.len(), 0);
                 let name = self.export_function_table()?;

crates/cli/tests/wasm-bindgen/main.rs

@@ -261,14 +261,13 @@ fn default_module_path_target_no_modules() {
     assert!(contents.contains(
         "\
     async function init(input) {
+        if (typeof document === 'undefined') {
+            script_src = location.href;
+        } else {
+            script_src = document.currentScript.src;
+        }
         if (typeof input === 'undefined') {
-            let src;
-            if (typeof document === 'undefined') {
-                src = location.href;
-            } else {
-                src = document.currentScript.src;
-            }
-            input = src.replace(/\\.js$/, '_bg.wasm');
+            input = script_src.replace(/\\.js$/, '_bg.wasm');
         }",
     ));
 }

examples/wasm-audio-worklet/src/dependent_module.rs

@@ -2,25 +2,11 @@ use js_sys::{Array, JsString};
 use wasm_bindgen::prelude::*;
 use web_sys::{Blob, BlobPropertyBag, Url};
 
-// This is a not-so-clean approach to get the current bindgen ES module URL
-// in Rust. This will fail at run time on bindgen targets not using ES modules.
-#[wasm_bindgen]
-extern "C" {
-    #[wasm_bindgen]
-    type ImportMeta;
-
-    #[wasm_bindgen(method, getter)]
-    fn url(this: &ImportMeta) -> JsString;
-
-    #[wasm_bindgen(js_namespace = import, js_name = meta)]
-    static IMPORT_META: ImportMeta;
-}
-
 pub fn on_the_fly(code: &str) -> Result<String, JsValue> {
     // Generate the import of the bindgen ES module, assuming `--target web`:
     let header = format!(
         "import init, * as bindgen from '{}';\n\n",
-        IMPORT_META.url(),
+        &wasm_bindgen::script_url(),
     );
 
     Url::create_object_url_with_blob(&Blob::new_with_str_sequence_and_options(

src/lib.rs

@@ -972,6 +972,7 @@ externs! {
 
         fn __wbindgen_memory() -> u32;
         fn __wbindgen_module() -> u32;
+        fn __wbindgen_script_url(ret: *mut [usize; 2]) -> ();
         fn __wbindgen_function_table() -> u32;
     }
 }
@@ -1251,6 +1252,20 @@ pub fn memory() -> JsValue {
     unsafe { JsValue::_new(__wbindgen_memory()) }
 }
 
+/// Returns the URL to the script that instantiated the wasm module.
+///
+/// On some wasm-bindgen targets, this script is a module or a bundle.
+/// Also, the returned URL is relative on some wasm-bindgen targets.
+#[cfg(feature = "std")]
+pub fn script_url() -> String {
+    unsafe {
+        let mut ret = [0; 2];
+        __wbindgen_script_url(&mut ret);
+        let data = Vec::from_raw_parts(ret[0] as *mut u8, ret[1], ret[1]);
+        String::from_utf8_unchecked(data)
+    }
+}
+
 /// Returns a handle to this wasm instance's `WebAssembly.Table` which is the
 /// indirect function table used by Rust
 pub fn function_table() -> JsValue {