1 files changed, 89 insertions, 0 deletions

diff --git a/comm/chat/protocols/matrix/lib/matrix-sdk/ReEmitter.js b/comm/chat/protocols/matrix/lib/matrix-sdk/ReEmitter.js
new file mode 100644
index 0000000000..17a2e986f3
--- /dev/null
+++ b/comm/chat/protocols/matrix/lib/matrix-sdk/ReEmitter.js
@@ -0,0 +1,89 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.TypedReEmitter = exports.ReEmitter = void 0;
+function _defineProperty(obj, key, value) { key = _toPropertyKey(key); if (key in obj) { Object.defineProperty(obj, key, { value: value, enumerable: true, configurable: true, writable: true }); } else { obj[key] = value; } return obj; }
+function _toPropertyKey(arg) { var key = _toPrimitive(arg, "string"); return typeof key === "symbol" ? key : String(key); }
+function _toPrimitive(input, hint) { if (typeof input !== "object" || input === null) return input; var prim = input[Symbol.toPrimitive]; if (prim !== undefined) { var res = prim.call(input, hint || "default"); if (typeof res !== "object") return res; throw new TypeError("@@toPrimitive must return a primitive value."); } return (hint === "string" ? String : Number)(input); }
+/*
+Copyright 2015, 2016 OpenMarket Ltd
+Copyright 2017 Vector Creations Ltd
+Copyright 2017 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// eslint-disable-next-line no-restricted-imports
+
+class ReEmitter {
+  constructor(target) {
+    this.target = target;
+    // Map from emitter to event name to re-emitter
+    _defineProperty(this, "reEmitters", new WeakMap());
+  }
+  reEmit(source, eventNames) {
+    let reEmittersByEvent = this.reEmitters.get(source);
+    if (!reEmittersByEvent) {
+      reEmittersByEvent = new Map();
+      this.reEmitters.set(source, reEmittersByEvent);
+    }
+    for (const eventName of eventNames) {
+      if (reEmittersByEvent.has(eventName)) continue;
+
+      // We include the source as the last argument for event handlers which may need it,
+      // such as read receipt listeners on the client class which won't have the context
+      // of the room.
+      const forSource = (...args) => {
+        // EventEmitter special cases 'error' to make the emit function throw if no
+        // handler is attached, which sort of makes sense for making sure that something
+        // handles an error, but for re-emitting, there could be a listener on the original
+        // source object so the test doesn't really work. We *could* try to replicate the
+        // same logic and throw if there is no listener on either the source or the target,
+        // but this behaviour is fairly undesireable for us anyway: the main place we throw
+        // 'error' events is for calls, where error events are usually emitted some time
+        // later by a different part of the code where 'emit' throwing because the app hasn't
+        // added an error handler isn't terribly helpful. (A better fix in retrospect may
+        // have been to just avoid using the event name 'error', but backwards compat...)
+        if (eventName === "error" && this.target.listenerCount("error") === 0) return;
+        this.target.emit(eventName, ...args, source);
+      };
+      source.on(eventName, forSource);
+      reEmittersByEvent.set(eventName, forSource);
+    }
+  }
+  stopReEmitting(source, eventNames) {
+    const reEmittersByEvent = this.reEmitters.get(source);
+    if (!reEmittersByEvent) return; // We were never re-emitting these events in the first place
+
+    for (const eventName of eventNames) {
+      source.off(eventName, reEmittersByEvent.get(eventName));
+      reEmittersByEvent.delete(eventName);
+    }
+    if (reEmittersByEvent.size === 0) this.reEmitters.delete(source);
+  }
+}
+exports.ReEmitter = ReEmitter;
+class TypedReEmitter extends ReEmitter {
+  constructor(target) {
+    super(target);
+  }
+  reEmit(source, eventNames) {
+    super.reEmit(source, eventNames);
+  }
+  stopReEmitting(source, eventNames) {
+    super.stopReEmitting(source, eventNames);
+  }
+}
+exports.TypedReEmitter = TypedReEmitter;
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