Merge pull request #1278 from alexcrichton/examples

alexcrichton · web-flow · commit 8f695782fbef · 2019-02-19T16:14:32.000-06:00
Update idioms of a few examples
diff --git a/examples/no_modules/index.html b/examples/no_modules/index.html
@@ -3,19 +3,6 @@
     <meta content="text/html;charset=utf-8" http-equiv="Content-Type"/>
   </head>
   <body>
-    <script>
-      // The `--no-modules`-generated JS from `wasm-bindgen` attempts to use
-      // `WebAssembly.instantiateStreaming` to instantiate the wasm module,
-      // but this doesn't work with `file://` urls. This example is frequently
-      // viewed by simply opening `index.html` in a browser (with a `file://`
-      // url), so it would fail if we were to call this function!
-      //
-      // Work around this for now by deleting the function to ensure that the
-      // `no_modules.js` script doesn't have access to it. You won't need this
-      // hack when deploying over HTTP.
-      delete WebAssembly.instantiateStreaming;
-    </script>
-
     <!-- this is the JS generated by the `wasm-bindgen` CLI tool -->
     <script src='./pkg/no_modules.js'></script>
 
diff --git a/examples/raytrace-parallel/index.html b/examples/raytrace-parallel/index.html
@@ -216,7 +216,6 @@
     <canvas id='canvas'></canvas>
 
     <script>
-      delete WebAssembly.instantiateStreaming;
       document.getElementById('render').disabled = true;
       document.getElementById('concurrency').disabled = true;
     </script>
diff --git a/examples/wasm-in-wasm/src/lib.rs b/examples/wasm-in-wasm/src/lib.rs
@@ -18,20 +18,19 @@ const WASM: &[u8] = include_bytes!("add.wasm");
 #[wasm_bindgen(start)]
 pub fn run() -> Result<(), JsValue> {
     console_log!("instantiating a new wasm module directly");
-    let my_memory = wasm_bindgen::memory()
-        .dyn_into::<WebAssembly::Memory>()
-        .unwrap();
-
-    // Note that this is somewhat dangerous, once we look at our
-    // `WebAssembly.Memory` buffer then if we allocate more pages for ourself
-    // (aka do a memory allocation in Rust) it'll cause the buffer to change.
-    // That means we can't actually do any memory allocations after we do this
-    // until we pass it back to JS.
-    let my_memory = Uint8Array::new(&my_memory.buffer()).subarray(
-        WASM.as_ptr() as u32,
-        WASM.as_ptr() as u32 + WASM.len() as u32,
-    );
-    let a = WebAssembly::Module::new(my_memory.as_ref())?;
+
+    // Note that `Uint8Array::view` this is somewhat dangerous (hence the
+    // `unsafe`!). This is creating a raw view into our module's
+    // `WebAssembly.Memory` buffer, but if we allocate more pages for ourself
+    // (aka do a memory allocation in Rust) it'll cause the buffer to change,
+    // causing the `Uint8Array` to be invalid.
+    //
+    // As a result, after `Uint8Array::view` we have to be very careful not to
+    // do any memory allocations before it's next used.
+    let a = unsafe {
+        let array = Uint8Array::view(WASM);
+        WebAssembly::Module::new(array.as_ref())?
+    };
     let b = WebAssembly::Instance::new(&a, &Object::new())?;
     let c = b.exports();
 
