Revert "Remove code which loads legacy libolm", in Tchap we are still…

… using it for content scanner

This reverts commit 7c7cbe6.

src/vector/index.ts

@@ -135,6 +135,7 @@ async function start(): Promise<void> {
  rageshakePromise,
  setupLogStorage,
  preparePlatform,
+ loadOlm,
  loadConfig,
  loadLanguage,
  loadTheme,
@@ -179,6 +180,7 @@ async function start(): Promise<void> {
  }
  }
 
+ const loadOlmPromise = loadOlm();
  // set the platform for react sdk
  preparePlatform();
  // load config requires the platform to be ready
@@ -248,6 +250,7 @@ async function start(): Promise<void> {
  // app load critical path starts here
  // assert things started successfully
  // ##################################
+ await loadOlmPromise;
  await loadModulesPromise;
  await loadThemePromise;
  await loadLanguagePromise;

src/vector/init.tsx

@@ -17,6 +17,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+// eslint-disable-next-line @typescript-eslint/ban-ts-comment
+// @ts-ignore
+import olmWasmPath from "@matrix-org/olm/olm.wasm";
+import Olm from "@matrix-org/olm";
 import * as ReactDOM from "react-dom";
 import * as React from "react";
 import * as languageHandler from "matrix-react-sdk/src/languageHandler";
@@ -72,6 +76,48 @@ export async function loadConfig(): Promise<void> {
  }
 }
 
+export function loadOlm(): Promise<void> {
+ /* 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, but as far as I can tell this is
+ * completely impossible with webpack. We do, however, use a hashed
+ * filename to avoid caching issues.
+ */
+ return Olm.init({
+ locateFile: () => olmWasmPath,
+ })
+ .then(() => {
+ logger.log("Using WebAssembly Olm");
+ })
+ .catch((wasmLoadError) => {
+ logger.log("Failed to load Olm: trying legacy version", wasmLoadError);
+ return new Promise((resolve, reject) => {
+ const s = document.createElement("script");
+ s.src = "olm_legacy.js"; // XXX: This should be cache-busted too
+ 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(() => {
+ logger.log("Using legacy Olm");
+ })
+ .catch((legacyLoadError) => {
+ logger.log("Both WebAssembly and asm.js Olm failed!", legacyLoadError);
+ });
+ });
+}
+
 export async function loadLanguage(): Promise<void> {
  const prefLang = SettingsStore.getValue("language", null, /*excludeDefault=*/ true);
  let langs: string[] = [];

webpack.config.js

@@ -287,6 +287,10 @@ module.exports = (env, argv) => {
  // there is no need for webpack to parse them - they can just be
  // included as-is.
  /highlight\.js[\\/]lib[\\/]languages/,
+
+ // olm takes ages for webpack to process, and it's already heavily
+ // optimised, so there is little to gain by us uglifying it.
+ /olm[\\/](javascript[\\/])?olm\.js$/,
  ],
  rules: [
  useHMR && {
@@ -452,6 +456,20 @@ module.exports = (env, argv) => {
  },
  ],
  },
+ {
+ // the olm library wants to load its own wasm, rather than have webpack do it.
+ // We therefore use the `file-loader` to tell webpack to dump the contents to
+ // a separate file and return the name, and override the default `type` for `.wasm` files
+ // (which is `webassembly/experimental` under webpack 4) to stop webpack trying to interpret
+ // the filename as webassembly. (see also https://github.com/webpack/webpack/issues/6725)
+ test: /olm\.wasm$/,
+ loader: "file-loader",
+ type: "javascript/auto",
+ options: {
+ name: "[name].[hash:7].[ext]",
+ outputPath: ".",
+ },
+ },
  {
  // Fix up the name of the opus-recorder worker (react-sdk dependency).
  // We more or less just want it to be clear it's for opus and not something else.
@@ -493,11 +511,8 @@ module.exports = (env, argv) => {
  },
  },
  {
- // The decoderWorker wants to load its own wasm, rather than have webpack do it.
- // We therefore use the `file-loader` to tell webpack to dump the contents to
- // a separate file and return the name, and override the default `type` for `.wasm` files
- // (which is `webassembly/experimental` under webpack 4) to stop webpack trying to interpret
- // the filename as webassembly. (see also https://github.com/webpack/webpack/issues/6725)
+ // Same deal as olm.wasm: the decoderWorker wants to load the wasm artifact
+ // itself.
  test: /decoderWorker\.min\.wasm$/,
  loader: "file-loader",
  type: "javascript/auto",
@@ -748,6 +763,7 @@ module.exports = (env, argv) => {
  { from: "vector-icons/**", context: path.resolve(__dirname, "res") },
  { from: "decoder-ring/**", context: path.resolve(__dirname, "res") },
  { from: "media/**", context: path.resolve(__dirname, "node_modules/matrix-react-sdk/res/") },
+ "node_modules/@matrix-org/olm/olm_legacy.js",
  { from: "config.json", noErrorOnMissing: true },
  "contribute.json",
  ],