2 files changed, 94 insertions, 0 deletions
diff --git a/comm/chat/protocols/matrix/lib/p-retry/index.js b/comm/chat/protocols/matrix/lib/p-retry/index.js
new file mode 100644
index 0000000000..3679399db8
--- /dev/null
+++ b/comm/chat/protocols/matrix/lib/p-retry/index.js
@@ -0,0 +1,85 @@
+'use strict';
+const retry = require('retry');
+
+const networkErrorMsgs = [
+	'Failed to fetch', // Chrome
+	'NetworkError when attempting to fetch resource.', // Firefox
+	'The Internet connection appears to be offline.', // Safari
+	'Network request failed' // `cross-fetch`
+];
+
+class AbortError extends Error {
+	constructor(message) {
+		super();
+
+		if (message instanceof Error) {
+			this.originalError = message;
+			({message} = message);
+		} else {
+			this.originalError = new Error(message);
+			this.originalError.stack = this.stack;
+		}
+
+		this.name = 'AbortError';
+		this.message = message;
+	}
+}
+
+const decorateErrorWithCounts = (error, attemptNumber, options) => {
+	// Minus 1 from attemptNumber because the first attempt does not count as a retry
+	const retriesLeft = options.retries - (attemptNumber - 1);
+
+	error.attemptNumber = attemptNumber;
+	error.retriesLeft = retriesLeft;
+	return error;
+};
+
+const isNetworkError = errorMessage => networkErrorMsgs.includes(errorMessage);
+
+const pRetry = (input, options) => new Promise((resolve, reject) => {
+	options = {
+		onFailedAttempt: () => {},
+		retries: 10,
+		...options
+	};
+
+	const operation = retry.operation(options);
+
+	operation.attempt(async attemptNumber => {
+		try {
+			resolve(await input(attemptNumber));
+		} catch (error) {
+			if (!(error instanceof Error)) {
+				reject(new TypeError(`Non-error was thrown: "${error}". You should only throw errors.`));
+				return;
+			}
+
+			if (error instanceof AbortError) {
+				operation.stop();
+				reject(error.originalError);
+			} else if (error instanceof TypeError && !isNetworkError(error.message)) {
+				operation.stop();
+				reject(error);
+			} else {
+				decorateErrorWithCounts(error, attemptNumber, options);
+
+				try {
+					await options.onFailedAttempt(error);
+				} catch (error) {
+					reject(error);
+					return;
+				}
+
+				if (!operation.retry(error)) {
+					reject(operation.mainError());
+				}
+			}
+		}
+	});
+});
+
+module.exports = pRetry;
+// TODO: remove this in the next major version
+module.exports.default = pRetry;
+
+module.exports.AbortError = AbortError;
diff --git a/comm/chat/protocols/matrix/lib/p-retry/license b/comm/chat/protocols/matrix/lib/p-retry/license
new file mode 100644
index 0000000000..e7af2f7710
--- /dev/null
+++ b/comm/chat/protocols/matrix/lib/p-retry/license
@@ -0,0 +1,9 @@
+MIT License
+
+Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.