[PM-11661]Add New Reseed - Fill Buffer Behind Feature Flag (#10905)

* Add New Reseed - Fill Buffer Behind Feature Flag

* Add Tests

* Lint

apps/browser/src/background/main.background.ts

@@ -1463,7 +1463,14 @@ export default class MainBackground {
     });
 
     if (needStorageReseed) {
-      await this.reseedStorage();
+      await this.reseedStorage(
+        await firstValueFrom(
+          this.configService.userCachedFeatureFlag$(
+            FeatureFlag.StorageReseedRefactor,
+            userBeingLoggedOut,
+          ),
+        ),
+      );
     }
 
     if (BrowserApi.isManifestVersion(3)) {
@@ -1518,7 +1525,7 @@ export default class MainBackground {
     await SafariApp.sendMessageToApp("showPopover", null, true);
   }
 
-  async reseedStorage() {
+  async reseedStorage(doFillBuffer: boolean) {
     if (
       !this.platformUtilsService.isChrome() &&
       !this.platformUtilsService.isVivaldi() &&
@@ -1527,7 +1534,11 @@ export default class MainBackground {
       return;
     }
 
-    await this.storageService.reseed();
+    if (doFillBuffer) {
+      await this.storageService.fillBuffer();
+    } else {
+      await this.storageService.reseed();
+    }
   }
 
   async clearClipboard(clipboardValue: string, clearMs: number) {

apps/browser/src/background/runtime.background.ts

@@ -1,4 +1,4 @@
-import { firstValueFrom, map, mergeMap } from "rxjs";
+import { firstValueFrom, map, mergeMap, of, switchMap } from "rxjs";
 
 import { NotificationsService } from "@bitwarden/common/abstractions/notifications.service";
 import { AccountService } from "@bitwarden/common/auth/abstractions/account.service";
@@ -272,9 +272,25 @@ export default class RuntimeBackground {
         await this.main.refreshBadge();
         await this.main.refreshMenu();
         break;
-      case "bgReseedStorage":
+      case "bgReseedStorage": {
-        await this.main.reseedStorage();
+        const doFillBuffer = await firstValueFrom(
+          this.accountService.activeAccount$.pipe(
+            switchMap((account) => {
+              if (account == null) {
+                return of(false);
+              }
+
+              return this.configService.userCachedFeatureFlag$(
+                FeatureFlag.StorageReseedRefactor,
+                account.id,
+              );
+            }),
+          ),
+        );
+
+        await this.main.reseedStorage(doFillBuffer);
         break;
+      }
       case "authResult": {
         const env = await firstValueFrom(this.environmentService.environment$);
         const vaultUrl = env.getWebVaultUrl();

apps/browser/src/platform/services/browser-local-storage.service.ts

@@ -32,6 +32,46 @@ export default class BrowserLocalStorageService extends AbstractChromeStorageSer
     }
   }
 
+  async fillBuffer() {
+    // Write 4MB of data in chrome.storage.local, log files will hold 4MB of data (by default)
+    // before forcing a compaction. To force a compaction and have it remove previously saved data,
+    // we want to fill it's buffer so that anything newly marked for deletion is gone.
+    // https://github.com/google/leveldb/blob/main/doc/impl.md#log-files
+    // It's important that if Google uses a different buffer length that we match that, as far as I can tell
+    // Google uses the default value in Chromium:
+    // https://github.com/chromium/chromium/blob/148774efa6b3a047369af6179a4248566b39d68f/components/value_store/lazy_leveldb.cc#L65-L66
+    const fakeData = "0".repeat(1024 * 1024); // 1MB of data
+    await new Promise<void>((resolve, reject) => {
+      this.chromeStorageApi.set(
+        {
+          fake_data_1: fakeData,
+          fake_data_2: fakeData,
+          fake_data_3: fakeData,
+          fake_data_4: fakeData,
+        },
+        () => {
+          if (chrome.runtime.lastError) {
+            return reject(chrome.runtime.lastError);
+          }
+
+          resolve();
+        },
+      );
+    });
+    await new Promise<void>((resolve, reject) => {
+      this.chromeStorageApi.remove(
+        ["fake_data_1", "fake_data_2", "fake_data_3", "fake_data_4"],
+        () => {
+          if (chrome.runtime.lastError) {
+            return reject(chrome.runtime.lastError);
+          }
+
+          resolve();
+        },
+      );
+    });
+  }
+
   override async get<T>(key: string): Promise<T> {
     await this.awaitReseed();
     return super.get(key);

libs/common/src/enums/feature-flag.enum.ts

@@ -34,6 +34,7 @@ export enum FeatureFlag {
   AccountDeprovisioning = "pm-10308-account-deprovisioning",
   NotificationBarAddLoginImprovements = "notification-bar-add-login-improvements",
   AC2476_DeprecateStripeSourcesAPI = "AC-2476-deprecate-stripe-sources-api",
+  StorageReseedRefactor = "storage-reseed-refactor",
   CipherKeyEncryption = "cipher-key-encryption",
 }
 
@@ -76,6 +77,7 @@ export const DefaultFeatureFlagValue = {
   [FeatureFlag.EnableUpgradePasswordManagerSub]: FALSE,
   [FeatureFlag.GenerateIdentityFillScriptRefactor]: FALSE,
   [FeatureFlag.DelayFido2PageScriptInitWithinMv2]: FALSE,
+  [FeatureFlag.StorageReseedRefactor]: FALSE,
   [FeatureFlag.AccountDeprovisioning]: FALSE,
   [FeatureFlag.NotificationBarAddLoginImprovements]: FALSE,
   [FeatureFlag.AC2476_DeprecateStripeSourcesAPI]: FALSE,

libs/common/src/platform/abstractions/config/config.service.ts

@@ -2,6 +2,7 @@ import { Observable } from "rxjs";
 import { SemVer } from "semver";
 
 import { FeatureFlag, FeatureFlagValueType } from "../../../enums/feature-flag.enum";
+import { UserId } from "../../../types/guid";
 import { Region } from "../environment.service";
 
 import { ServerConfig } from "./server-config";
@@ -17,6 +18,18 @@ export abstract class ConfigService {
    * @returns An observable that emits the value of the feature flag, updates as the server config changes
    */
   getFeatureFlag$: <Flag extends FeatureFlag>(key: Flag) => Observable<FeatureFlagValueType<Flag>>;
+
+  /**
+   * Retrieves the cached feature flag value for a give user. This will NOT call to the server to get
+   * the most up to date feature flag.
+   * @param key The feature flag key to get the value for.
+   * @param userId The user id of the user to get the feature flag value for.
+   */
+  abstract userCachedFeatureFlag$<Flag extends FeatureFlag>(
+    key: Flag,
+    userId: UserId,
+  ): Observable<FeatureFlagValueType<Flag>>;
+
   /**
    * Retrieves the value of a feature flag for the currently active user
    * @param key The feature flag to retrieve

libs/common/src/platform/models/response/server-config.response.ts

@@ -1,3 +1,4 @@
+import { AllowedFeatureFlagTypes } from "../../../enums/feature-flag.enum";
 import { BaseResponse } from "../../../models/response/base.response";
 import { Region } from "../../abstractions/environment.service";
 
@@ -6,7 +7,7 @@ export class ServerConfigResponse extends BaseResponse {
   gitHash: string;
   server: ThirdPartyServerConfigResponse;
   environment: EnvironmentServerConfigResponse;
-  featureStates: { [key: string]: string } = {};
+  featureStates: { [key: string]: AllowedFeatureFlagTypes } = {};
 
   constructor(response: any) {
     super(response);

libs/common/src/platform/services/config/config.service.spec.ts

@@ -16,6 +16,7 @@ import {
 import { subscribeTo } from "../../../../spec/observable-tracker";
 import { AuthService } from "../../../auth/abstractions/auth.service";
 import { AuthenticationStatus } from "../../../auth/enums/authentication-status";
+import { FeatureFlag } from "../../../enums/feature-flag.enum";
 import { UserId } from "../../../types/guid";
 import { ConfigApiServiceAbstraction } from "../../abstractions/config/config-api.service.abstraction";
 import { ServerConfig } from "../../abstractions/config/server-config";
@@ -277,6 +278,48 @@ describe("ConfigService", () => {
     });
   });
 
+  describe("userCachedFeatureFlag$", () => {
+    it("maps saved user config to a feature flag", async () => {
+      const updateFeature = (value: boolean) => {
+        return new ServerConfig(
+          new ServerConfigData({
+            featureStates: {
+              "test-feature": value,
+            },
+          }),
+        );
+      };
+
+      const configService = new DefaultConfigService(
+        configApiService,
+        environmentService,
+        logService,
+        stateProvider,
+        authService,
+      );
+
+      userState.nextState(null);
+
+      const promise = firstValueFrom(
+        configService
+          .userCachedFeatureFlag$("test-feature" as FeatureFlag, userId)
+          .pipe(bufferCount(3)),
+      );
+
+      userState.nextState(updateFeature(true));
+      userState.nextState(updateFeature(false));
+
+      const values = await promise;
+
+      // We wouldn't normally expect this to be undefined, the logic
+      // should normally return the feature flags default value but since
+      // we are faking a feature flag key, undefined is expected
+      expect(values[0]).toBe(undefined);
+      expect(values[1]).toBe(true);
+      expect(values[2]).toBe(false);
+    });
+  });
+
   describe("slow configuration", () => {
     const environmentSubject = new BehaviorSubject<Environment>(null);
 

libs/common/src/platform/services/config/default-config.service.ts

@@ -115,16 +115,27 @@ export class DefaultConfigService implements ConfigService {
 
   getFeatureFlag$<Flag extends FeatureFlag>(key: Flag) {
     return this.serverConfig$.pipe(
-      map((serverConfig) => {
+      map((serverConfig) => this.getFeatureFlagValue(serverConfig, key)),
-        if (serverConfig?.featureStates == null || serverConfig.featureStates[key] == null) {
-          return DefaultFeatureFlagValue[key];
-        }
-
-        return serverConfig.featureStates[key] as FeatureFlagValueType<Flag>;
-      }),
     );
   }
 
+  private getFeatureFlagValue<Flag extends FeatureFlag>(
+    serverConfig: ServerConfig | null,
+    flag: Flag,
+  ) {
+    if (serverConfig?.featureStates == null || serverConfig.featureStates[flag] == null) {
+      return DefaultFeatureFlagValue[flag];
+    }
+
+    return serverConfig.featureStates[flag] as FeatureFlagValueType<Flag>;
+  }
+
+  userCachedFeatureFlag$<Flag extends FeatureFlag>(key: Flag, userId: UserId) {
+    return this.stateProvider
+      .getUser(userId, USER_SERVER_CONFIG)
+      .state$.pipe(map((config) => this.getFeatureFlagValue(config, key)));
+  }
+
   async getFeatureFlag<Flag extends FeatureFlag>(key: Flag) {
     return await firstValueFrom(this.getFeatureFlag$(key));
   }