From c6fefd73d846ae72eab8261a91ba1223d8148c34 Mon Sep 17 00:00:00 2001
From: ansuz <ansuz@transitiontech.ca>
Date: Fri, 30 Jul 2021 19:23:48 +0530
Subject: [PATCH] fix sheet conversion in Chrome

by instantiating SharedArrayBuffers in a more portable way
---
 www/common/onlyoffice/inner.js   | 25 ++++++++++++++++++++++++-
 www/common/onlyoffice/x2t/x2t.js | 15 ++++++++++-----
 2 files changed, 34 insertions(+), 6 deletions(-)

diff --git a/www/common/onlyoffice/inner.js b/www/common/onlyoffice/inner.js
index 4a0a56be0..5c57fbecc 100644
--- a/www/common/onlyoffice/inner.js
+++ b/www/common/onlyoffice/inner.js
@@ -72,8 +72,31 @@ define([
         return JSONSortify(obj);
     };
 
+    /*  Chrome 92 dropped support for SharedArrayBuffer in cross-origin contexts
+        where window.crossOriginIsolated is false.
+
+        Their blog (https://blog.chromium.org/2021/02/restriction-on-sharedarraybuffers.html)
+        isn't clear about why they're doing this, but since it's related to site-isolation
+        it seems they're trying to do vague security things.
+
+        In any case, there seems to be a workaround where you can still create them
+        by using `new WebAssembly.Memory({shared: true, ...})` instead of `new SharedArrayBuffer`.
+
+        This seems unreliable, but it's better than not being able to export, since
+        we actively rely on postMessage between iframes and therefore can't afford
+        to opt for full isolation.
+    */
+    var supportsSharedArrayBuffers = function () {
+        try {
+            return Object.prototype.toString.call(new WebAssembly.Memory({shared: true, initial: 0, maximum: 0}).buffer) === '[object SharedArrayBuffer]';
+        } catch (err) {
+            console.error(err);
+        }
+        return false;
+    };
+
     var supportsXLSX = function () {
-        return !(typeof(Atomics) === "undefined" || typeof (SharedArrayBuffer) === "undefined" || typeof(WebAssembly) === 'undefined');
+        return !(typeof(Atomics) === "undefined" || !supportsSharedArrayBuffers() /* || typeof (SharedArrayBuffer) === "undefined" */ || typeof(WebAssembly) === 'undefined');
     };
 
 
diff --git a/www/common/onlyoffice/x2t/x2t.js b/www/common/onlyoffice/x2t/x2t.js
index 181b2db8f..9c1289c56 100644
--- a/www/common/onlyoffice/x2t/x2t.js
+++ b/www/common/onlyoffice/x2t/x2t.js
@@ -1,3 +1,8 @@
+function SUPPORTS_SHARED_MEMORY() {
+    return typeof(SharedArrayBuffer) !== 'undefined';
+}
+
+
 // Support for growable heap + pthreads, where the buffer may change, so JS views
 // must be updated.
 function GROWABLE_HEAP_STORE_I8(ptr, value) {
@@ -1030,7 +1035,7 @@ if (ENVIRONMENT_IS_PTHREAD) {
    "maximum": 1073741824 / WASM_PAGE_SIZE,
    "shared": true
   });
-  if (!(wasmMemory.buffer instanceof SharedArrayBuffer)) {
+  if (Object.prototype.toString.call(wasmMemory.buffer) !== '[object SharedArrayBuffer]') {
    err("requested a shared WebAssembly.Memory but the returned buffer is not a SharedArrayBuffer, indicating that while the browser has SharedArrayBuffer it does not have WebAssembly threads support - you may need to set a flag");
    if (ENVIRONMENT_HAS_NODE) {
     console.log("(on node you may need: --experimental-wasm-threads --experimental-wasm-bulk-memory and also use a recent version)");
@@ -2161,7 +2166,7 @@ var PThread = {
  }),
  receiveObjectTransfer: (function(data) {}),
  allocateUnusedWorkers: (function(numWorkers, onFinishedLoading) {
-  if (typeof SharedArrayBuffer === "undefined") return;
+  if (!SUPPORTS_SHARED_MEMORY()) return;
   var workers = [];
   var numWorkersToCreate = numWorkers;
   if (PThread.preallocatedWorkers.length > 0) {
@@ -2276,7 +2281,7 @@ var PThread = {
   }
  }),
  createNewWorkers: (function(numWorkers) {
-  if (typeof SharedArrayBuffer === "undefined") return [];
+  if (!SUPPORTS_SHARED_MEMORY()) return [];
   var pthreadMainJs = "x2t.worker.js";
   pthreadMainJs = locateFile(pthreadMainJs);
   var newWorkers = [];
@@ -5683,7 +5688,7 @@ function _emscripten_get_sbrk_ptr() {
 }
 Module["_emscripten_get_sbrk_ptr"] = _emscripten_get_sbrk_ptr;
 function _emscripten_has_threading_support() {
- return typeof SharedArrayBuffer !== "undefined";
+ return SUPPORTS_SHARED_MEMORY();
 }
 Module["_emscripten_has_threading_support"] = _emscripten_has_threading_support;
 function _emscripten_is_main_browser_thread() {
@@ -6761,7 +6766,7 @@ function _pthread_self() {
 }
 Module["_pthread_self"] = _pthread_self;
 function _pthread_create(pthread_ptr, attr, start_routine, arg) {
- if (typeof SharedArrayBuffer === "undefined") {
+ if (!SUPPORTS_SHARED_MEMORY()) {
   err("Current environment does not support SharedArrayBuffer, pthreads are not available!");
   return 6;
  }