Support WebAssembly version of Olm

package.json

@@ -146,7 +146,7 @@
     "webpack-dev-server": "^3.1.9"
   },
   "optionalDependencies": {
-    "olm": "https://matrix.org/packages/npm/olm/olm-2.2.1.tgz"
+    "olm": "https://matrix.org/packages/npm/olm/olm-3.0.0.tgz"
   },
   "build": {
     "appId": "im.riot.app",

scripts/copy-res.js

@@ -57,6 +57,11 @@ const COPY_LIST = [
     ["res/themes/**", "webapp/themes"],
     ["node_modules/emojione/assets/svg/*", "webapp/emojione/svg/"],
     ["node_modules/emojione/assets/png/*", "webapp/emojione/png/"],
+    // XXX: This is tied quite heavily to the matching olm.js so it really should be
+    // in the bundle dir with the js to avoid caching issues giving us wasm that
+    // doesn't match our js, but I cannot find any way to get webpack to do this.
+    ["node_modules/olm/olm.wasm", "webapp", { directwatch: 1 }],
+    ["node_modules/olm/olm_legacy.js", "webapp", { directwatch: 1 }],
     ["./config.json", "webapp", { directwatch: 1 }],
 ];
 

src/vector/index.js

@@ -54,6 +54,8 @@ import SettingsStore, {SettingLevel} from "matrix-react-sdk/lib/settings/Setting
 import Tinter from 'matrix-react-sdk/lib/Tinter';
 import SdkConfig from "matrix-react-sdk/lib/SdkConfig";
 
+import Olm from 'olm';
+
 import rageshake from "matrix-react-sdk/lib/rageshake/rageshake";
 
 import CallHandler from 'matrix-react-sdk/lib/CallHandler';
@@ -231,6 +233,8 @@ async function loadApp() {
 
     window.addEventListener('hashchange', onHashChange);
 
+    await loadOlm();
+
     await loadLanguage();
 
     const fragparts = parseQsFromFragment(window.location);
@@ -353,6 +357,42 @@ async function loadApp() {
     }
 }
 
+function loadOlm() {
+    /* Load Olm. We try the WebAssembly version first, and then the legacy,
+     * asm.js version if that fails. For this reason we need to wait for this
+     * to finish before continuing to load the rest of the app. In future
+     * we could somehow pass a promise down to react-sdk and have it wait on
+     * that so olm can be loading in parallel with the rest of the app.
+     *
+     * We also need to tell the Olm js to look for its wasm file at the same
+     * level as index.html. It really should be in the same place as the js,
+     * ie. in the bundle directory, to avoid caching issues, but as far as I
+     * can tell this is completely impossible with webpack.
+     */
+    return Olm.init({
+        locateFile: () => 'olm.wasm',
+    }).then(() => {
+        console.log("Using WebAssembly Olm");
+    }).catch((e) => {
+        console.log("Failed to load Olm: trying legacy version");
+        return new Promise((resolve, reject) => {
+            const s = document.createElement('script');
+            s.src = 'olm_legacy.js';
+            s.onload = resolve;
+            s.onerror = reject;
+            document.body.appendChild(s);
+        }).then(() => {
+            // Init window.Olm, ie. the one just loaded by the script tag,
+            // not 'Olm' which is still the failed wasm version.
+            return window.Olm.init();
+        }).then(() => {
+            console.log("Using legacy Olm");
+        }).catch((e) => {
+            console.log("Both WebAssembly and asm.js Olm failed!", e);
+        });
+    });
+}
+
 async function loadLanguage() {
     const prefLang = SettingsStore.getValue("language", null, /*excludeDefault=*/true);
     let langs = [];

webpack.config.js

@@ -15,15 +15,6 @@ module.exports = {
 
         "mobileguide": "./src/vector/mobile_guide/index.js",
 
-        // We ship olm.js as a separate lump of javascript. This makes it get
-        // loaded via a separate <script/> tag in index.html (which loads it
-        // into the browser global `Olm`, where js-sdk expects to find it).
-        //
-        // (we should probably make js-sdk load it asynchronously at some
-        // point, so that it doesn't block the pageload, but that is a separate
-        // problem)
-        "olm": "./src/vector/olm-loader.js",
-
         // CSS themes
         "theme-light":  "./node_modules/matrix-react-sdk/res/themes/light/css/light.scss",
         "theme-dark":   "./node_modules/matrix-react-sdk/res/themes/dark/css/dark.scss",
@@ -171,12 +162,3 @@ module.exports = {
         inline: false,
     },
 };
-
-// olm is an optional dependency. Ignore it if it's not installed, to avoid a
-// scary-looking error.
-try {
-    require('olm');
-} catch (e) {
-    console.log("Olm is not installed; not shipping it");
-    delete(module.exports.entry["olm"]);
-}