Replace setImmediate usage with yield manager

common/api/core-bentley.api.md

@@ -1527,6 +1527,23 @@ export function utf8ToString(utf8: Uint8Array): string | undefined;
 // @internal
 export function utf8ToStringPolyfill(utf8: Uint8Array): string | undefined;
 
+// @internal
+export class YieldManager {
+    constructor(options?: YieldManagerOptions);
+    // (undocumented)
+    protected actualYield(): Promise<void>;
+    // (undocumented)
+    allowYield(): Promise<void>;
+    // (undocumented)
+    options: Readonly<Required<YieldManagerOptions>>;
+}
+
+// @internal
+export interface YieldManagerOptions {
+    // (undocumented)
+    iterationsBeforeYield?: number;
+}
+
 
 // (No @packageDocumentation comment for this package)
 

common/api/summary/core-bentley.exports.csv

@@ -104,6 +104,7 @@ public;ProcessDetector
 public;PromiseReturnType
 public;ReadonlyOrderedSet
 public;ReadonlySortedArray
+alpha;RealityDataStatus
 beta;RepositoryStatus
 beta;RpcInterfaceStatus
 public;shallowClone
@@ -114,4 +115,6 @@ public;TransientIdSequence
 public;UnexpectedErrors
 public;using
 public;utf8ToString(utf8: Uint8Array): string | undefined
-internal;utf8ToStringPolyfill(utf8: Uint8Array): string | undefined
+internal;utf8ToStringPolyfill(utf8: Uint8Array): string | undefined
+internal;YieldManager
+internal;YieldManagerOptions

common/changes/@itwin/core-bentley/replace-setImmediate-with-yield-manager_2022-02-23-14-33.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-bentley",
+      "comment": "add internal YieldManager",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-bentley"
+}

common/changes/@itwin/core-transformer/replace-setImmediate-with-yield-manager_2022-02-23-14-33.json

@@ -0,0 +1,10 @@
+{
+  "changes": [
+    {
+      "packageName": "@itwin/core-transformer",
+      "comment": "",
+      "type": "none"
+    }
+  ],
+  "packageName": "@itwin/core-transformer"
+}

core/bentley/src/YieldManager.ts

@@ -0,0 +1,41 @@
+/*---------------------------------------------------------------------------------------------
+* Copyright (c) Bentley Systems, Incorporated. All rights reserved.
+* See LICENSE.md in the project root for license terms and full copyright notice.
+*--------------------------------------------------------------------------------------------*/
+
+/** @internal options for constructing yield managers */
+export interface YieldManagerOptions {
+  iterationsBeforeYield?: number;
+}
+
+/** @internal the default options when constructing yield managers */
+const defaultYieldManagerOptions: Required<YieldManagerOptions> = {
+  iterationsBeforeYield: 1000,
+};
+
+/**
+ * @internal
+ * An object allowing code to optionally yield with some frequency.
+ * useful in some intense loops that make processes unresponsive.
+ * primarily a workaround for: https://github.com/nodejs/node-addon-api/issues/1140
+ * @note see [[defaultYieldManagerOptions]], the default amount of times it must be called to cause an actual yield is 1000
+ */
+export class YieldManager {
+  public options: Readonly<Required<YieldManagerOptions>>;
+  private _counter = 0;
+
+  public constructor(options: YieldManagerOptions = {}) {
+    this.options = { ...defaultYieldManagerOptions, ...options };
+  }
+
+  public async allowYield() {
+    this._counter = (this._counter + 1) % this.options.iterationsBeforeYield;
+    if (this._counter === 0) {
+      await this.actualYield();
+    }
+  }
+
+  protected async actualYield() {
+    await new Promise((r) => setTimeout(r, 0));
+  }
+}

core/bentley/src/core-bentley.ts

@@ -33,6 +33,7 @@ export * from "./StringUtils";
 export * from "./Time";
 export * from "./UnexpectedErrors";
 export * from "./UtilityTypes";
+export * from "./YieldManager";
 
 /** @docs-package-description
  * The core-bentley package contains classes to solve problems that are common for both client and server use cases.

core/bentley/src/test/YieldManager.test.ts

@@ -0,0 +1,22 @@
+/*---------------------------------------------------------------------------------------------
+* Copyright (c) Bentley Systems, Incorporated. All rights reserved.
+* See LICENSE.md in the project root for license terms and full copyright notice.
+*--------------------------------------------------------------------------------------------*/
+import { expect } from "chai";
+import { YieldManager } from "../YieldManager";
+
+describe("YieldManager", () => {
+  it("allowYield yields once per 'iterationsBeforeYield' iterations", async () => {
+    class CountingYieldManager extends YieldManager {
+      public actualYieldCount = 0;
+      protected override async actualYield() { this.actualYieldCount++; }
+    }
+
+    const expectedYieldTimes = 5;
+    const yieldManager = new CountingYieldManager();
+    for (let i = 0; i < expectedYieldTimes * yieldManager.options.iterationsBeforeYield; ++i) {
+      await yieldManager.allowYield();
+    }
+    expect(yieldManager.actualYieldCount).to.equal(expectedYieldTimes);
+  });
+});

core/transformer/src/IModelExporter.ts

@@ -6,7 +6,7 @@
  * @module iModels
  */
 
-import { AccessToken, assert, DbResult, Id64, Id64String, IModelStatus, Logger } from "@itwin/core-bentley";
+import { AccessToken, assert, DbResult, Id64, Id64String, IModelStatus, Logger, YieldManager } from "@itwin/core-bentley";
 import { ECVersion, Schema, SchemaKey } from "@itwin/ecschema-metadata";
 import { CodeSpec, FontProps, IModel, IModelError } from "@itwin/core-common";
 import { TransformerLoggerCategory } from "./TransformerLoggerCategory";
@@ -440,6 +440,8 @@ export class IModelExporter {
     return this.trackProgress();
   }
 
+  private _yieldManager = new YieldManager();
+
   /** Export the model contents.
    * @param modelId The only required parameter
    * @param elementClassFullName Can be optionally specified if the goal is to export a subset of the model contents
@@ -475,7 +477,7 @@ export class IModelExporter {
       }
       while (DbResult.BE_SQLITE_ROW === statement.step()) {
         await this.exportElement(statement.getValue(0).getId());
-        await new Promise(setImmediate); // workaround for: https://github.com/nodejs/node-addon-api/issues/1140
+        await this._yieldManager.allowYield();
       }
     });
   }
@@ -639,7 +641,7 @@ export class IModelExporter {
         const relInstanceId: Id64String = statement.getValue(0).getId();
         const relProps: RelationshipProps = this.sourceDb.relationships.getInstanceProps(baseRelClassFullName, relInstanceId);
         await this.exportRelationship(relProps.classFullName, relInstanceId); // must call exportRelationship using the actual classFullName, not baseRelClassFullName
-        await new Promise(setImmediate); // workaround for: https://github.com/nodejs/node-addon-api/issues/1140
+        await this._yieldManager.allowYield();
       }
     });
   }

core/transformer/src/IModelTransformer.ts

@@ -7,7 +7,7 @@
  */
 import * as path from "path";
 import * as Semver from "semver";
-import { AccessToken, DbResult, Guid, Id64, Id64Set, Id64String, IModelStatus, Logger, LogLevel, MarkRequired } from "@itwin/core-bentley";
+import { AccessToken, DbResult, Guid, Id64, Id64Set, Id64String, IModelStatus, Logger, LogLevel, MarkRequired, YieldManager } from "@itwin/core-bentley";
 import * as ECSchemaMetaData from "@itwin/ecschema-metadata";
 import { Point3d, Transform } from "@itwin/core-geometry";
 import {
@@ -698,6 +698,8 @@ export class IModelTransformer extends IModelExportHandler {
     });
   }
 
+  private _yieldManager = new YieldManager();
+
   /** Detect Relationship deletes using ExternalSourceAspects in the target iModel and a *brute force* comparison against relationships in the source iModel.
    * @see processChanges
    * @note This method is called from [[processAll]] and is not needed by [[processChanges]], so it only needs to be called directly when processing a subset of an iModel.
@@ -722,7 +724,7 @@ export class IModelTransformer extends IModelExportHandler {
           }
           aspectDeleteIds.push(statement.getValue(0).getId());
         }
-        await new Promise(setImmediate); // workaround for: https://github.com/nodejs/node-addon-api/issues/1140
+        await this._yieldManager.allowYield();
       }
     });
     this.targetDb.elements.deleteAspect(aspectDeleteIds);