@ledgerhq/live-common
Version:
Common ground for the Ledger Live apps
68 lines • 2.99 kB
JavaScript
import { AppNotFound, UserRefusedOnDevice, restoreAppStorage, restoreAppStorageCommit, restoreAppStorageInit, } from "@ledgerhq/device-core";
import { Observable, catchError, from, of, switchMap } from "rxjs";
import { RestoreAppDataEventType } from "./types";
/**
* Restores the application data for a specific app on a Ledger device.
*
* @param transport - The transport object used to communicate with the Ledger device.
* @param appName - The name of the application to restore.
* @param appData - The data to restore.
* @returns An observable that emits RestoreAppDataEvent according to the restore process.
*/
export function restoreAppData(transport, appName, appData) {
const obs = new Observable(subscriber => {
const chunkData = Buffer.from(appData, "base64");
const backupSize = chunkData.length;
const sub = from(restoreAppStorageInit(transport, appName, backupSize))
.pipe(switchMap(async () => {
// Initialize the restore process
subscriber.next({ type: RestoreAppDataEventType.AppDataInitialized });
// Restore app data by chunks
const MAX_CHUNK_SIZE = 255;
let offset = 0;
while (offset < backupSize) {
subscriber.next({
type: RestoreAppDataEventType.Progress,
data: Number((offset / backupSize).toFixed(2)),
});
const chunkSize = Math.min(MAX_CHUNK_SIZE, backupSize - offset);
const chunk = chunkData.subarray(offset, offset + chunkSize);
await restoreAppStorage(transport, chunk);
offset += chunkSize;
}
// Commit the restore process, last step
await restoreAppStorageCommit(transport);
subscriber.next({
type: RestoreAppDataEventType.AppDataRestored,
});
subscriber.complete();
}), catchError(e => {
// No app data found on the app or the app does not support it
if (e instanceof AppNotFound) {
subscriber.next({
type: RestoreAppDataEventType.NoAppDataToRestore,
});
subscriber.complete();
return of(null);
}
// User refused on device
if (e instanceof UserRefusedOnDevice) {
// NOTE: Display a message to the user to retry the restore process
// If he does not, we should delete the app data (in another flow)
subscriber.next({
type: RestoreAppDataEventType.UserRefused,
});
subscriber.complete();
return of(null);
}
subscriber.complete();
throw e;
}))
.subscribe();
return () => {
sub.unsubscribe();
};
});
return obs;
}
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