(core) discount indirect changes for access control purposes

Summary:
This diff discounts indirect changes for access control purposes.  A UserAction that updates a cell A, which in turn causes changes in other dependent cells, will be considered a change to cell A for access control purposes.

The `engine.apply_user_actions` method now returns a `direct` array, with a boolean for each `stored` action, set to `true` if the action is attributed to the user or `false` if it is attributed to the engine.  `GranularAccess` ignores actions attributed to the engine when checking for edit rights.

Subtleties:
 * Removal of references to a removed row are considered direct changes.
 * Doesn't play well with undos as yet.  An action that indirectly modifies a cell the user doesn't have rights to may succeed, but it will not be reversible.

Test Plan: added tests, updated tests

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2806

app/gen-server/lib/Usage.ts

@@ -14,49 +14,66 @@ const USAGE_PERIOD_MS = 1 * 60 * 60 * 1000;   // log every 1 hour
  */
 export class Usage {
   private _interval: NodeJS.Timeout;
+  private _currentOperation?: Promise<void>;
 
   public constructor(private _dbManager: HomeDBManager) {
-    this._interval = setInterval(() => this.apply().catch(log.warn.bind(log)), USAGE_PERIOD_MS);
+    this._interval = setInterval(() => this.apply(), USAGE_PERIOD_MS);
     // Log once at beginning, in case we roll over servers faster than
     // the logging period for an extended length of time,
     // and to raise the visibility of this logging step so if it gets
     // slow devs notice.
-    this.apply().catch(log.warn.bind(log));
+    this.apply();
   }
 
-  public close() {
+  /**
+   * Remove any scheduled operation, and wait for the current one to complete
+   * (if one is in progress).
+   */
+  public async close() {
     clearInterval(this._interval);
+    await this._currentOperation;
   }
 
-  public async apply() {
-    const manager = this._dbManager.connection.manager;
-    // raw count of users
-    const userCount = await manager.count(User);
-    // users who have logged in at least once
-    const userWithLoginCount = await manager.createQueryBuilder()
-      .from(User, 'users')
-      .where('first_login_at is not null')
-      .getCount();
-    // raw count of organizations (excluding personal orgs)
-    const orgCount = await manager.createQueryBuilder()
-      .from(Organization, 'orgs')
-      .where('owner_id is null')
-      .getCount();
-    // organizations with subscriptions that are in a non-terminated state
-    const orgInGoodStandingCount = await manager.createQueryBuilder()
-      .from(Organization, 'orgs')
-      .leftJoin('orgs.billingAccount', 'billing_accounts')
-      .where('owner_id is null')
-      .andWhere('billing_accounts.in_good_standing = true')
-      .getCount();
-    // raw count of documents
-    const docCount = await manager.count(Document);
-    log.rawInfo('activity', {
-      docCount,
-      orgCount,
-      orgInGoodStandingCount,
-      userCount,
-      userWithLoginCount,
-    });
+  public apply() {
+    if (!this._currentOperation) {
+      this._currentOperation = this._apply()
+        .finally(() => this._currentOperation = undefined);
+    }
+  }
+
+  private async _apply(): Promise<void> {
+    try {
+      const manager = this._dbManager.connection.manager;
+      // raw count of users
+      const userCount = await manager.count(User);
+      // users who have logged in at least once
+      const userWithLoginCount = await manager.createQueryBuilder()
+        .from(User, 'users')
+        .where('first_login_at is not null')
+        .getCount();
+      // raw count of organizations (excluding personal orgs)
+      const orgCount = await manager.createQueryBuilder()
+        .from(Organization, 'orgs')
+        .where('owner_id is null')
+        .getCount();
+      // organizations with subscriptions that are in a non-terminated state
+      const orgInGoodStandingCount = await manager.createQueryBuilder()
+        .from(Organization, 'orgs')
+        .leftJoin('orgs.billingAccount', 'billing_accounts')
+        .where('owner_id is null')
+        .andWhere('billing_accounts.in_good_standing = true')
+        .getCount();
+      // raw count of documents
+      const docCount = await manager.count(Document);
+      log.rawInfo('activity', {
+        docCount,
+        orgCount,
+        orgInGoodStandingCount,
+        userCount,
+        userWithLoginCount,
+      });
+    } catch (e) {
+      log.warn("Error in Usage._apply", e);
+    }
   }
 }