You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
fix: fix the race condition when calling readAsDataURL after new Blob(blobs) (#34096)
Summary:
```js
async () => {
let blobs = [];
for (let i = 0; i < 4; i++) {
const res = await fetch();
blobs = [...blobs, await res.blob()]
}
const blob = new Blob(blobs); // <<<<<<<<<<<<<<< a
return await new Promise((resolve, reject) => {
const fileReader = new FileReader();
fileReader.onload = async () => {
await RNFS.writeFile(destPath, (fileReader.result as string).split(',')[1], 'base64');
resolve(destPath);
};
fileReader.onabort = () => {
reject('');
};
fileReader.onerror = (event) => {
reject('');
};
fileReader.readAsDataURL(blob); // <<<<<<<<<<<<<<< b
});
}
```
Sometime `fileReader.readAsDataURL` is unable to get blob from the dictionary after `new Blob(blobs)` and then reject with `Unable to resolve data for blob: blobId` in iOS or `The specified blob is invalid` in android. Because line `a` and `b` can be run in different thread. `new Blob([])` is in progress and `fileReader.readAsDataURL` accesses the blob dictionary ahead of the blob creation.
The expected behaviour is it should finish new Blob([]) first and then readAsDataURL(blob)
To fix that, there should be a lock inside the method `createFromParts`. For iOS, It needs to be a recursive_mutex to allow same thread to acquire lock
## Changelog
<!-- Help reviewers and the release process by writing your own changelog entry. For an example, see:
https://github.com/facebook/react-native/wiki/Changelog
-->
[iOS] [Fixed] - fix the race condition when calling readAsDataURL after new Blob(blobs)
Pull Request resolved: #34096
Reviewed By: cipolleschi
Differential Revision: D37514981
Pulled By: javache
fbshipit-source-id: 4bf84ece99871276ecaa5aa1849b9145ff44dbf4
0 commit comments