Ensure that ReadableStreams are cancelled with actual Errors

There's a number of spots in the current code, and tests, where `cancel` methods are not called with appropriate arguments (leading to Promises not being rejected with Errors as intended).
In some cases the cancel `reason` is implicitly set to `undefined`, and in others the cancel `reason` is just a plain String. To address this inconsistency, the patch changes things such that cancelling is done with `AbortException`s everywhere instead.

src/core/chunked_stream.js

@@ -567,14 +567,13 @@ class ChunkedStreamManager {
     return Math.floor((end - 1) / this.chunkSize) + 1;
   }
 
-  abort() {
+  abort(reason) {
     this.aborted = true;
     if (this.pdfNetworkStream) {
-      this.pdfNetworkStream.cancelAllRequests('abort');
+      this.pdfNetworkStream.cancelAllRequests(reason);
     }
     for (const requestId in this.promisesByRequest) {
-      this.promisesByRequest[requestId].reject(
-        new Error('Request was aborted'));
+      this.promisesByRequest[requestId].reject(reason);
     }
   }
 }

src/core/pdf_manager.js

@@ -97,7 +97,7 @@ class BasePdfManager {
     this._password = password;
   }
 
-  terminate() {
+  terminate(reason) {
     unreachable('Abstract method `terminate` called');
   }
 }
@@ -134,7 +134,7 @@ class LocalPdfManager extends BasePdfManager {
     return this._loadedStreamPromise;
   }
 
-  terminate() {}
+  terminate(reason) {}
 }
 
 class NetworkPdfManager extends BasePdfManager {
@@ -188,8 +188,8 @@ class NetworkPdfManager extends BasePdfManager {
     return this.streamManager.onLoadedStream();
   }
 
-  terminate() {
-    this.streamManager.abort();
+  terminate(reason) {
+    this.streamManager.abort(reason);
   }
 }
 

src/core/worker.js

@@ -14,10 +14,10 @@
  */
 
 import {
-  arrayByteLength, arraysToBytes, createPromiseCapability, getVerbosityLevel,
-  info, InvalidPDFException, MissingPDFException, PasswordException,
-  setVerbosityLevel, UnexpectedResponseException, UnknownErrorException,
-  UNSUPPORTED_FEATURES, VerbosityLevel, warn
+  AbortException, arrayByteLength, arraysToBytes, createPromiseCapability,
+  getVerbosityLevel, info, InvalidPDFException, MissingPDFException,
+  PasswordException, setVerbosityLevel, UnexpectedResponseException,
+  UnknownErrorException, UNSUPPORTED_FEATURES, VerbosityLevel, warn
 } from '../shared/util';
 import { clearPrimitiveCaches, Ref } from './primitives';
 import { LocalPdfManager, NetworkPdfManager } from './pdf_manager';
@@ -274,8 +274,8 @@ var WorkerMessageHandler = {
         cancelXHRs = null;
       });
 
-      cancelXHRs = function () {
-        pdfStream.cancelAllRequests('abort');
+      cancelXHRs = function(reason) {
+        pdfStream.cancelAllRequests(reason);
       };
 
       return pdfManagerCapability.promise;
@@ -349,7 +349,7 @@ var WorkerMessageHandler = {
         if (terminated) {
           // We were in a process of setting up the manager, but it got
           // terminated in the middle.
-          newPdfManager.terminate();
+          newPdfManager.terminate(new AbortException('Worker was terminated.'));
           throw new Error('Worker was terminated');
         }
         pdfManager = newPdfManager;
@@ -579,11 +579,11 @@ var WorkerMessageHandler = {
     handler.on('Terminate', function wphTerminate(data) {
       terminated = true;
       if (pdfManager) {
-        pdfManager.terminate();
+        pdfManager.terminate(new AbortException('Worker was terminated.'));
         pdfManager = null;
       }
       if (cancelXHRs) {
-        cancelXHRs();
+        cancelXHRs(new AbortException('Worker was terminated.'));
       }
       clearPrimitiveCaches();
 

src/display/api.js

@@ -16,10 +16,11 @@
 /* eslint no-var: error */
 
 import {
-  assert, createPromiseCapability, getVerbosityLevel, info, InvalidPDFException,
-  isArrayBuffer, isSameOrigin, MissingPDFException, NativeImageDecoding,
-  PasswordException, setVerbosityLevel, shadow, stringToBytes,
-  UnexpectedResponseException, UnknownErrorException, unreachable, URL, warn
+  AbortException, assert, createPromiseCapability, getVerbosityLevel, info,
+  InvalidPDFException, isArrayBuffer, isSameOrigin, MissingPDFException,
+  NativeImageDecoding, PasswordException, setVerbosityLevel, shadow,
+  stringToBytes, UnexpectedResponseException, UnknownErrorException,
+  unreachable, URL, warn
 } from '../shared/util';
 import {
   deprecated, DOMCanvasFactory, DOMCMapReaderFactory, DummyStatTimer,
@@ -1768,7 +1769,8 @@ class WorkerTransport {
     Promise.all(waitOn).then(() => {
       this.fontLoader.clear();
       if (this._networkStream) {
-        this._networkStream.cancelAllRequests();
+        this._networkStream.cancelAllRequests(
+          new AbortException('Worker was terminated.'));
       }
 
       if (this.messageHandler) {

test/unit/fetch_stream_spec.js

@@ -14,6 +14,7 @@
  */
 /* eslint no-var: error */
 
+import { AbortException } from '../../src/shared/util';
 import { PDFFetchStream } from '../../src/display/fetch_stream';
 
 describe('fetch_stream', function() {
@@ -72,7 +73,7 @@ describe('fetch_stream', function() {
       isStreamingSupported = fullReader.isStreamingSupported;
       isRangeSupported = fullReader.isRangeSupported;
       // We shall be able to close full reader without any issue.
-      fullReader.cancel(new Error('Don\'t need full reader'));
+      fullReader.cancel(new AbortException('Don\'t need fullReader.'));
       fullReaderCancelled = true;
     });
 

test/unit/message_handler_spec.js

@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-import { createPromiseCapability } from '../../src/shared/util';
+import { AbortException, createPromiseCapability } from '../../src/shared/util';
 import { LoopbackPort } from '../../src/display/api';
 import { MessageHandler } from '../../src/shared/message_handler';
 
@@ -124,7 +124,7 @@ describe('message_handler', function () {
         return sleep(10);
       }).then(() => {
         expect(log).toEqual('01p2');
-        return reader.cancel();
+        return reader.cancel(new AbortException('reader cancelled.'));
       }).then(() => {
         expect(log).toEqual('01p2c4');
         done();

test/unit/network_spec.js

@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 
+import { AbortException } from '../../src/shared/util';
 import { PDFNetworkStream } from '../../src/display/network';
 
 describe('network', function() {
@@ -79,7 +80,7 @@ describe('network', function() {
       isStreamingSupported = fullReader.isStreamingSupported;
       isRangeSupported = fullReader.isRangeSupported;
       // we shall be able to close the full reader without issues
-      fullReader.cancel('Don\'t need full reader');
+      fullReader.cancel(new AbortException('Don\'t need fullReader.'));
       fullReaderCancelled = true;
     });
 

test/unit/node_stream_spec.js

@@ -14,7 +14,7 @@
  */
 /* globals __non_webpack_require__ */
 
-import { assert } from '../../src/shared/util';
+import { AbortException, assert } from '../../src/shared/util';
 import isNodeJS from '../../src/shared/is_node';
 import { PDFNodeStream } from '../../src/display/node_stream';
 
@@ -167,14 +167,14 @@ describe('node_stream', function() {
       isStreamingSupported1 = fullReader1.isStreamingSupported;
       isRangeSupported1 = fullReader1.isRangeSupported;
       // we shall be able to close the full reader without issues
-      fullReader1.cancel('Don\'t need full reader');
+      fullReader1.cancel(new AbortException('Don\'t need fullReader1.'));
       fullReaderCancelled1 = true;
     });
 
     let promise2 = fullReader2.headersReady.then(function () {
       isStreamingSupported2 = fullReader2.isStreamingSupported;
       isRangeSupported2 = fullReader2.isRangeSupported;
-      fullReader2.cancel('Don\'t need full reader');
+      fullReader2.cancel(new AbortException('Don\'t need fullReader2.'));
       fullReaderCancelled2 = true;
     });