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Diffstat (limited to 'toolkit/components/extensions/ExtensionStorageIDB.sys.mjs')
| -rw-r--r-- | toolkit/components/extensions/ExtensionStorageIDB.sys.mjs | 865 |
1 files changed, 865 insertions, 0 deletions
diff --git a/toolkit/components/extensions/ExtensionStorageIDB.sys.mjs b/toolkit/components/extensions/ExtensionStorageIDB.sys.mjs new file mode 100644 index 0000000000..1be5bf2689 --- /dev/null +++ b/toolkit/components/extensions/ExtensionStorageIDB.sys.mjs @@ -0,0 +1,865 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +export let ExtensionStorageIDB; +import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs"; +import { IndexedDB } from "resource://gre/modules/IndexedDB.sys.mjs"; + +const lazy = {}; + +ChromeUtils.defineESModuleGetters(lazy, { + ExtensionStorage: "resource://gre/modules/ExtensionStorage.sys.mjs", + ExtensionUtils: "resource://gre/modules/ExtensionUtils.sys.mjs", + getTrimmedString: "resource://gre/modules/ExtensionTelemetry.sys.mjs", +}); + +// The userContextID reserved for the extension storage (its purpose is ensuring that the IndexedDB +// storage used by the browser.storage.local API is not directly accessible from the extension code, +// it is defined and reserved as "userContextIdInternal.webextStorageLocal" in ContextualIdentityService.sys.mjs). +const WEBEXT_STORAGE_USER_CONTEXT_ID = -1 >>> 0; + +const IDB_NAME = "webExtensions-storage-local"; +const IDB_DATA_STORENAME = "storage-local-data"; +const IDB_VERSION = 1; +const IDB_MIGRATE_RESULT_HISTOGRAM = + "WEBEXT_STORAGE_LOCAL_IDB_MIGRATE_RESULT_COUNT"; + +// Whether or not the installed extensions should be migrated to the storage.local IndexedDB backend. +const BACKEND_ENABLED_PREF = + "extensions.webextensions.ExtensionStorageIDB.enabled"; +const IDB_MIGRATED_PREF_BRANCH = + "extensions.webextensions.ExtensionStorageIDB.migrated"; + +class DataMigrationAbortedError extends Error { + get name() { + return "DataMigrationAbortedError"; + } +} + +var ErrorsTelemetry = { + initialized: false, + + lazyInit() { + if (this.initialized) { + return; + } + this.initialized = true; + + // Ensure that these telemetry events category is enabled. + Services.telemetry.setEventRecordingEnabled("extensions.data", true); + + this.resultHistogram = Services.telemetry.getHistogramById( + IDB_MIGRATE_RESULT_HISTOGRAM + ); + }, + + /** + * Get the DOMException error name for a given error object. + * + * @param {Error | undefined} error + * The Error object to convert into a string, or undefined if there was no error. + * + * @returns {string | undefined} + * The DOMException error name (sliced to a maximum of 80 chars), + * "OtherError" if the error object is not a DOMException instance, + * or `undefined` if there wasn't an error. + */ + getErrorName(error) { + if (!error) { + return undefined; + } + + if ( + DOMException.isInstance(error) || + error instanceof DataMigrationAbortedError + ) { + if (error.name.length > 80) { + return lazy.getTrimmedString(error.name); + } + + return error.name; + } + + return "OtherError"; + }, + + /** + * Record telemetry related to a data migration result. + * + * @param {object} telemetryData + * @param {string} telemetryData.backend + * The backend selected ("JSONFile" or "IndexedDB"). + * @param {boolean} telemetryData.dataMigrated + * Old extension data has been migrated successfully. + * @param {string} telemetryData.extensionId + * The id of the extension migrated. + * @param {Error | undefined} telemetryData.error + * The error raised during the data migration, if any. + * @param {boolean} telemetryData.hasJSONFile + * The extension has an existing JSONFile to migrate. + * @param {boolean} telemetryData.hasOldData + * The extension's JSONFile wasn't empty. + * @param {string} telemetryData.histogramCategory + * The histogram category for the result ("success" or "failure"). + */ + recordDataMigrationResult(telemetryData) { + try { + const { + backend, + dataMigrated, + extensionId, + error, + hasJSONFile, + hasOldData, + histogramCategory, + } = telemetryData; + + this.lazyInit(); + this.resultHistogram.add(histogramCategory); + + const extra = { backend }; + + if (dataMigrated != null) { + extra.data_migrated = dataMigrated ? "y" : "n"; + } + + if (hasJSONFile != null) { + extra.has_jsonfile = hasJSONFile ? "y" : "n"; + } + + if (hasOldData != null) { + extra.has_olddata = hasOldData ? "y" : "n"; + } + + if (error) { + extra.error_name = this.getErrorName(error); + } + + Services.telemetry.recordEvent( + "extensions.data", + "migrateResult", + "storageLocal", + lazy.getTrimmedString(extensionId), + extra + ); + } catch (err) { + // Report any telemetry error on the browser console, but + // we treat it as a non-fatal error and we don't re-throw + // it to the caller. + Cu.reportError(err); + } + }, + + /** + * Record telemetry related to the unexpected errors raised while executing + * a storage.local API call. + * + * @param {object} options + * @param {string} options.extensionId + * The id of the extension migrated. + * @param {string} options.storageMethod + * The storage.local API method being run. + * @param {Error} options.error + * The unexpected error raised during the API call. + */ + recordStorageLocalError({ extensionId, storageMethod, error }) { + this.lazyInit(); + + Services.telemetry.recordEvent( + "extensions.data", + "storageLocalError", + storageMethod, + lazy.getTrimmedString(extensionId), + { error_name: this.getErrorName(error) } + ); + }, +}; + +class ExtensionStorageLocalIDB extends IndexedDB { + onupgradeneeded(event) { + if (event.oldVersion < 1) { + this.createObjectStore(IDB_DATA_STORENAME); + } + } + + static openForPrincipal(storagePrincipal) { + // The db is opened using an extension principal isolated in a reserved user context id. + return super.openForPrincipal(storagePrincipal, IDB_NAME, IDB_VERSION); + } + + async isEmpty() { + const cursor = await this.objectStore( + IDB_DATA_STORENAME, + "readonly" + ).openKeyCursor(); + return cursor.done; + } + + /** + * Asynchronously sets the values of the given storage items. + * + * @param {object} items + * The storage items to set. For each property in the object, + * the storage value for that property is set to its value in + * said object. Any values which are StructuredCloneHolder + * instances are deserialized before being stored. + * @param {object} options + * @param {Function} options.serialize + * Set to a function which will be used to serialize the values into + * a StructuredCloneHolder object (if appropriate) and being sent + * across the processes (it is also used to detect data cloning errors + * and raise an appropriate error to the caller). + * + * @returns {Promise<null|object>} + * Return a promise which resolves to the computed "changes" object + * or null. + */ + async set(items, { serialize } = {}) { + const changes = {}; + let changed = false; + + // Explicitly create a transaction, so that we can explicitly abort it + // as soon as one of the put requests fails. + const transaction = this.transaction(IDB_DATA_STORENAME, "readwrite"); + const objectStore = transaction.objectStore( + IDB_DATA_STORENAME, + "readwrite" + ); + const transactionCompleted = transaction.promiseComplete(); + + if (!serialize) { + serialize = (name, anonymizedName, value) => value; + } + + for (let key of Object.keys(items)) { + try { + let oldValue = await objectStore.get(key); + + await objectStore.put(items[key], key); + + changes[key] = { + oldValue: + oldValue && serialize(`old/${key}`, `old/<anonymized>`, oldValue), + newValue: serialize(`new/${key}`, `new/<anonymized>`, items[key]), + }; + changed = true; + } catch (err) { + transactionCompleted.catch(err => { + // We ignore this rejection because we are explicitly aborting the transaction, + // the transaction.error will be null, and we throw the original error below. + }); + transaction.abort(); + + throw err; + } + } + + await transactionCompleted; + + return changed ? changes : null; + } + + /** + * Asynchronously retrieves the values for the given storage items. + * + * @param {Array<string>|object|null} [keysOrItems] + * The storage items to get. If an array, the value of each key + * in the array is returned. If null, the values of all items + * are returned. If an object, the value for each key in the + * object is returned, or that key's value if the item is not + * set. + * @returns {Promise<object>} + * An object which has a property for each requested key, + * containing that key's value as stored in the IndexedDB + * storage. + */ + async get(keysOrItems) { + let keys; + let defaultValues; + + if (typeof keysOrItems === "string") { + keys = [keysOrItems]; + } else if (Array.isArray(keysOrItems)) { + keys = keysOrItems; + } else if (keysOrItems && typeof keysOrItems === "object") { + keys = Object.keys(keysOrItems); + defaultValues = keysOrItems; + } + + const result = {}; + + // Retrieve all the stored data using a cursor when browser.storage.local.get() + // has been called with no keys. + if (keys == null) { + const cursor = await this.objectStore( + IDB_DATA_STORENAME, + "readonly" + ).openCursor(); + while (!cursor.done) { + result[cursor.key] = cursor.value; + await cursor.continue(); + } + } else { + const objectStore = this.objectStore(IDB_DATA_STORENAME); + for (let key of keys) { + const storedValue = await objectStore.get(key); + if (storedValue === undefined) { + if (defaultValues && defaultValues[key] !== undefined) { + result[key] = defaultValues[key]; + } + } else { + result[key] = storedValue; + } + } + } + + return result; + } + + /** + * Asynchronously removes the given storage items. + * + * @param {string|Array<string>} keys + * A string key of a list of storage items keys to remove. + * @returns {Promise<object>} + * Returns an object which contains applied changes. + */ + async remove(keys) { + // Ensure that keys is an array of strings. + keys = [].concat(keys); + + if (keys.length === 0) { + // Early exit if there is nothing to remove. + return null; + } + + const changes = {}; + let changed = false; + + const objectStore = this.objectStore(IDB_DATA_STORENAME, "readwrite"); + + let promises = []; + + for (let key of keys) { + promises.push( + objectStore.getKey(key).then(async foundKey => { + if (foundKey === key) { + changed = true; + changes[key] = { oldValue: await objectStore.get(key) }; + return objectStore.delete(key); + } + }) + ); + } + + await Promise.all(promises); + + return changed ? changes : null; + } + + /** + * Asynchronously clears all storage entries. + * + * @returns {Promise<object>} + * Returns an object which contains applied changes. + */ + async clear() { + const changes = {}; + let changed = false; + + const objectStore = this.objectStore(IDB_DATA_STORENAME, "readwrite"); + + const cursor = await objectStore.openCursor(); + while (!cursor.done) { + changes[cursor.key] = { oldValue: cursor.value }; + changed = true; + await cursor.continue(); + } + + await objectStore.clear(); + + return changed ? changes : null; + } +} + +/** + * Migrate the data stored in the JSONFile backend to the IDB Backend. + * + * Returns a promise which is resolved once the data migration has been + * completed and the new IDB backend can be enabled. + * Rejects if the data has been read successfully from the JSONFile backend + * but it failed to be saved in the new IDB backend. + * + * This method is called only from the main process (where the file + * can be opened). + * + * @param {Extension} extension + * The extension to migrate to the new IDB backend. + * @param {nsIPrincipal} storagePrincipal + * The "internally reserved" extension storagePrincipal to be used to create + * the ExtensionStorageLocalIDB instance. + */ +async function migrateJSONFileData(extension, storagePrincipal) { + let oldStoragePath; + let oldStorageExists; + let idbConn; + let jsonFile; + let hasEmptyIDB; + let nonFatalError; + let dataMigrateCompleted = false; + let hasOldData = false; + + function abortIfShuttingDown() { + if (extension.hasShutdown || Services.startup.shuttingDown) { + throw new DataMigrationAbortedError("extension or app is shutting down"); + } + } + + if (ExtensionStorageIDB.isMigratedExtension(extension)) { + return; + } + + try { + abortIfShuttingDown(); + idbConn = await ExtensionStorageIDB.open( + storagePrincipal, + extension.hasPermission("unlimitedStorage") + ); + abortIfShuttingDown(); + + hasEmptyIDB = await idbConn.isEmpty(); + + if (!hasEmptyIDB) { + // If the IDB backend is enabled and there is data already stored in the IDB backend, + // there is no "going back": any data that has not been migrated will be still on disk + // but it is not going to be migrated anymore, it could be eventually used to allow + // a user to manually retrieve the old data file). + ExtensionStorageIDB.setMigratedExtensionPref(extension, true); + return; + } + } catch (err) { + extension.logWarning( + `storage.local data migration cancelled, unable to open IDB connection: ${err.message}::${err.stack}` + ); + + ErrorsTelemetry.recordDataMigrationResult({ + backend: "JSONFile", + extensionId: extension.id, + error: err, + histogramCategory: "failure", + }); + + throw err; + } + + try { + abortIfShuttingDown(); + + oldStoragePath = lazy.ExtensionStorage.getStorageFile(extension.id); + oldStorageExists = await IOUtils.exists(oldStoragePath).catch(fileErr => { + // If we can't access the oldStoragePath here, then extension is also going to be unable to + // access it, and so we log the error but we don't stop the extension from switching to + // the IndexedDB backend. + extension.logWarning( + `Unable to access extension storage.local data file: ${fileErr.message}::${fileErr.stack}` + ); + return false; + }); + + // Migrate any data stored in the JSONFile backend (if any), and remove the old data file + // if the migration has been completed successfully. + if (oldStorageExists) { + // Do not load the old JSON file content if shutting down is already in progress. + abortIfShuttingDown(); + + Services.console.logStringMessage( + `Migrating storage.local data for ${extension.policy.debugName}...` + ); + + jsonFile = await lazy.ExtensionStorage.getFile(extension.id); + + abortIfShuttingDown(); + + const data = {}; + for (let [key, value] of jsonFile.data.entries()) { + data[key] = value; + hasOldData = true; + } + + await idbConn.set(data); + Services.console.logStringMessage( + `storage.local data successfully migrated to IDB Backend for ${extension.policy.debugName}.` + ); + } + + dataMigrateCompleted = true; + } catch (err) { + extension.logWarning( + `Error on migrating storage.local data file: ${err.message}::${err.stack}` + ); + + if (oldStorageExists && !dataMigrateCompleted) { + ErrorsTelemetry.recordDataMigrationResult({ + backend: "JSONFile", + dataMigrated: dataMigrateCompleted, + extensionId: extension.id, + error: err, + hasJSONFile: oldStorageExists, + hasOldData, + histogramCategory: "failure", + }); + + // If the data failed to be stored into the IndexedDB backend, then we clear the IndexedDB + // backend to allow the extension to retry the migration on its next startup, and reject + // the data migration promise explicitly (which would prevent the new backend + // from being enabled for this session). + await new Promise(resolve => { + let req = Services.qms.clearStoragesForPrincipal(storagePrincipal); + req.callback = resolve; + }); + + throw err; + } + + // This error is not preventing the extension from switching to the IndexedDB backend, + // but we may still want to know that it has been triggered and include it into the + // telemetry data collected for the extension. + nonFatalError = err; + } finally { + // Clear the jsonFilePromise cached by the ExtensionStorage. + await lazy.ExtensionStorage.clearCachedFile(extension.id).catch(err => { + extension.logWarning(err.message); + }); + } + + // If the IDB backend has been enabled, rename the old storage.local data file, but + // do not prevent the extension from switching to the IndexedDB backend if it fails. + if (oldStorageExists && dataMigrateCompleted) { + try { + // Only migrate the file when it actually exists (e.g. the file name is not going to exist + // when it is corrupted, because JSONFile internally rename it to `.corrupt`. + if (await IOUtils.exists(oldStoragePath)) { + const uniquePath = await IOUtils.createUniqueFile( + PathUtils.parent(oldStoragePath), + `${PathUtils.filename(oldStoragePath)}.migrated` + ); + await IOUtils.move(oldStoragePath, uniquePath); + } + } catch (err) { + nonFatalError = err; + extension.logWarning(err.message); + } + } + + ExtensionStorageIDB.setMigratedExtensionPref(extension, true); + + ErrorsTelemetry.recordDataMigrationResult({ + backend: "IndexedDB", + dataMigrated: dataMigrateCompleted, + extensionId: extension.id, + error: nonFatalError, + hasJSONFile: oldStorageExists, + hasOldData, + histogramCategory: "success", + }); +} + +/** + * This ExtensionStorage class implements a backend for the storage.local API which + * uses IndexedDB to store the data. + */ +ExtensionStorageIDB = { + BACKEND_ENABLED_PREF, + IDB_MIGRATED_PREF_BRANCH, + IDB_MIGRATE_RESULT_HISTOGRAM, + + // Map<extension-id, Set<Function>> + listeners: new Map(), + + // Keep track if the IDB backend has been selected or not for a running extension + // (the selected backend should never change while the extension is running, even if the + // related preference has been changed in the meantime): + // + // WeakMap<extension -> Promise<boolean> + selectedBackendPromises: new WeakMap(), + + init() { + XPCOMUtils.defineLazyPreferenceGetter( + this, + "isBackendEnabled", + BACKEND_ENABLED_PREF, + false + ); + }, + + isMigratedExtension(extension) { + return Services.prefs.getBoolPref( + `${IDB_MIGRATED_PREF_BRANCH}.${extension.id}`, + false + ); + }, + + setMigratedExtensionPref(extension, val) { + Services.prefs.setBoolPref( + `${IDB_MIGRATED_PREF_BRANCH}.${extension.id}`, + !!val + ); + }, + + clearMigratedExtensionPref(extensionId) { + Services.prefs.clearUserPref(`${IDB_MIGRATED_PREF_BRANCH}.${extensionId}`); + }, + + getStoragePrincipal(extension) { + return extension.createPrincipal(extension.baseURI, { + userContextId: WEBEXT_STORAGE_USER_CONTEXT_ID, + }); + }, + + /** + * Select the preferred backend and return a promise which is resolved once the + * selected backend is ready to be used (e.g. if the extension is switching from + * the old JSONFile storage to the new IDB backend, any previously stored data will + * be migrated to the backend before the promise is resolved). + * + * This method is called from both the main and child (content or extension) processes: + * - an extension child context will call this method lazily, when the browser.storage.local + * is being used for the first time, and it will result into asking the main process + * to call the same method in the main process + * - on the main process side, it will check if the new IDB backend can be used (and if it can, + * it will migrate any existing data into the new backend, which needs to happen in the + * main process where the file can directly be accessed) + * + * The result will be cached while the extension is still running, and so an extension + * child context is going to ask the main process only once per child process, and on the + * main process side the backend selection and data migration will happen only once. + * + * @param {BaseContext} context + * The extension context that is selecting the storage backend. + * + * @returns {Promise<object>} + * Returns a promise which resolves to an object which provides a + * `backendEnabled` boolean property, and if it is true the extension should use + * the IDB backend and the object also includes a `storagePrincipal` property + * of type nsIPrincipal, otherwise `backendEnabled` will be false when the + * extension should use the old JSONFile backend (e.g. because the IDB backend has + * not been enabled from the preference). + */ + selectBackend(context) { + const { extension } = context; + + if (!this.selectedBackendPromises.has(extension)) { + let promise; + + if (context.childManager) { + return context.childManager + .callParentAsyncFunction("storage.local.IDBBackend.selectBackend", []) + .then(parentResult => { + let result; + + if (!parentResult.backendEnabled) { + result = { backendEnabled: false }; + } else { + result = { + ...parentResult, + // In the child process, we need to deserialize the storagePrincipal + // from the StructuredCloneHolder used to send it across the processes. + storagePrincipal: parentResult.storagePrincipal.deserialize( + this, + true + ), + }; + } + + // Cache the result once we know that it has been resolved. The promise returned by + // context.childManager.callParentAsyncFunction will be dead when context.cloneScope + // is destroyed. To keep a promise alive in the cache, we wrap the result in an + // independent promise. + this.selectedBackendPromises.set( + extension, + Promise.resolve(result) + ); + + return result; + }); + } + + // If migrating to the IDB backend is not enabled by the preference, then we + // don't need to migrate any data and the new backend is not enabled. + if (!this.isBackendEnabled) { + promise = Promise.resolve({ backendEnabled: false }); + } else { + // In the main process, lazily create a storagePrincipal isolated in a + // reserved user context id (its purpose is ensuring that the IndexedDB storage used + // by the browser.storage.local API is not directly accessible from the extension code). + const storagePrincipal = this.getStoragePrincipal(extension); + + // Serialize the nsIPrincipal object into a StructuredCloneHolder related to the privileged + // js global, ready to be sent to the child processes. + const serializedPrincipal = new StructuredCloneHolder( + "ExtensionStorageIDB/selectBackend/serializedPrincipal", + null, + storagePrincipal, + this + ); + + promise = migrateJSONFileData(extension, storagePrincipal) + .then(() => { + extension.setSharedData("storageIDBBackend", true); + extension.setSharedData("storageIDBPrincipal", storagePrincipal); + Services.ppmm.sharedData.flush(); + return { + backendEnabled: true, + storagePrincipal: serializedPrincipal, + }; + }) + .catch(err => { + // If the data migration promise is rejected, the old data has been read + // successfully from the old JSONFile backend but it failed to be saved + // into the IndexedDB backend (which is likely unrelated to the kind of + // data stored and more likely a general issue with the IndexedDB backend) + // In this case we keep the JSONFile backend enabled for this session + // and we will retry to migrate to the IDB Backend the next time the + // extension is being started. + // TODO Bug 1465129: This should be a very unlikely scenario, some telemetry + // data about it may be useful. + extension.logWarning( + "JSONFile backend is being kept enabled by an unexpected " + + `IDBBackend failure: ${err.message}::${err.stack}` + ); + extension.setSharedData("storageIDBBackend", false); + Services.ppmm.sharedData.flush(); + + return { backendEnabled: false }; + }); + } + + this.selectedBackendPromises.set(extension, promise); + } + + return this.selectedBackendPromises.get(extension); + }, + + persist(storagePrincipal) { + return new Promise((resolve, reject) => { + const request = Services.qms.persist(storagePrincipal); + request.callback = () => { + if (request.resultCode === Cr.NS_OK) { + resolve(); + } else { + reject( + new Error( + `Failed to persist storage for principal: ${storagePrincipal.originNoSuffix}` + ) + ); + } + }; + }); + }, + + /** + * Open a connection to the IDB storage.local db for a given extension. + * given extension. + * + * @param {nsIPrincipal} storagePrincipal + * The "internally reserved" extension storagePrincipal to be used to create + * the ExtensionStorageLocalIDB instance. + * @param {boolean} persisted + * A boolean which indicates if the storage should be set into persistent mode. + * + * @returns {Promise<ExtensionStorageLocalIDB>} + * Return a promise which resolves to the opened IDB connection. + */ + open(storagePrincipal, persisted) { + if (!storagePrincipal) { + return Promise.reject(new Error("Unexpected empty principal")); + } + let setPersistentMode = persisted + ? this.persist(storagePrincipal) + : Promise.resolve(); + return setPersistentMode.then(() => + ExtensionStorageLocalIDB.openForPrincipal(storagePrincipal) + ); + }, + + /** + * Ensure that an error originated from the ExtensionStorageIDB methods is normalized + * into an ExtensionError (e.g. DataCloneError and QuotaExceededError instances raised + * from the internal IndexedDB operations have to be converted into an ExtensionError + * to be accessible to the extension code). + * + * @param {object} params + * @param {Error|ExtensionError|DOMException} params.error + * The error object to normalize. + * @param {string} params.extensionId + * The id of the extension that was executing the storage.local method. + * @param {string} params.storageMethod + * The storage method being executed when the error has been thrown + * (used to keep track of the unexpected error incidence in telemetry). + * + * @returns {ExtensionError} + * Return an ExtensionError error instance. + */ + normalizeStorageError({ error, extensionId, storageMethod }) { + const { ExtensionError } = lazy.ExtensionUtils; + + if (error instanceof ExtensionError) { + return error; + } + + let errorMessage; + + if (DOMException.isInstance(error)) { + switch (error.name) { + case "DataCloneError": + errorMessage = String(error); + break; + case "QuotaExceededError": + errorMessage = `${error.name}: storage.local API call exceeded its quota limitations.`; + break; + } + } + + if (!errorMessage) { + Cu.reportError(error); + + errorMessage = "An unexpected error occurred"; + + ErrorsTelemetry.recordStorageLocalError({ + error, + extensionId, + storageMethod, + }); + } + + return new ExtensionError(errorMessage); + }, + + addOnChangedListener(extensionId, listener) { + let listeners = this.listeners.get(extensionId) || new Set(); + listeners.add(listener); + this.listeners.set(extensionId, listeners); + }, + + removeOnChangedListener(extensionId, listener) { + let listeners = this.listeners.get(extensionId); + listeners.delete(listener); + }, + + notifyListeners(extensionId, changes) { + let listeners = this.listeners.get(extensionId); + if (listeners) { + for (let listener of listeners) { + listener(changes); + } + } + }, + + hasListeners(extensionId) { + let listeners = this.listeners.get(extensionId); + return listeners && listeners.size > 0; + }, +}; + +ExtensionStorageIDB.init(); |