fix(AWSMobileClient): Fixing a crash when getTokens is called while tokenOperations is being iterated. #4563
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royjit
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Feb 17, 2023
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We need to test these scenarios in AWSMobileClient and Amplify v1.
- Successful fetching of tokens
- Successful fetching of tokens after it is expired, AWSMobileClient should refresh the tokens automatically if refresh token is valid
- Receive token expired notification in case refresh token is invalid
| @@ -88,6 +88,8 @@ final public class AWSMobileClient: _AWSMobileClient { | |||
| var userPassword: String? = nil | |||
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| var tokenOperations:NSHashTable<FetchUserPoolTokensOperation> = NSHashTable.weakObjects() | |||
| let tokenOperationsQueue: DispatchQueue = DispatchQueue(label:"AWSMobileClient.tokenOperationsQueue", | |||
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There is similarly named queue tokenFetchOperationQueue and can be confusing. Should we rename this queueToAccessTokenOperations or some other name?
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Agreed, it becomes confusing.
So I instead decided to encapsulate this behaviour inside a new WeakHashTable class
…he tokenOperations are being iterated.
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royjit
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Feb 27, 2023
gabek
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…okenOperations is being iterated. (aws-amplify#4563)
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Issue #, if available:
#4486
Description of changes:
Calling
AWSMobileClient.getTokens(_:)at the same time a user is signing out/in could result in a crash, since thetokenOperationsis Iterated when the auth state changes.This happens because
NSHashTable's operations are not thread safe, so I'm creating atokenOperationsQueuequeue that we can use to read/write from the collection. I'm setting its.concurrentattribute so reads can be done concurrently, but setting the.barrierflag when actually inserting values.I've also wrapped this implementation in a new class called
WeakHashTable, so it reduces the change of misuse in the future (e.g. if we add another read/write from the collection in a different place without using the queue)Check points:
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.