feat: implement RenewFetchError for improved fetch handling and update download engine methods for cloning

Author: ido-pluto

src/download/download-engine/download-file/download-engine-file.ts

@@ -252,7 +252,7 @@ export default class DownloadEngineFile extends EventEmitter<DownloadEngineFileE
 
         const streamPromises = new Set<Promise<void>>();
 
-        for (let i = this._progress.part; i < this.file.parts.length && !this.options.skipExisting; i++) {
+        for (let i = this._progress.part; i < this.file.parts.length; i++) {
             if (this._closed) return;
             // If we are starting a new part, we need to reset the progress
             if (i > this._progress.part || !this._activePart.acceptRange) {
@@ -470,11 +470,10 @@ export default class DownloadEngineFile extends EventEmitter<DownloadEngineFileE
         this.emit0("closed");
     }
 
-    public finished(comment?: string) {
-        if (comment) {
-            this.options.comment = pushComment(comment, this.options.comment);
-        }
-        this._downloadStatus = DownloadStatus.Finished;
+    public markAsCloned() {
+        this.options.comment = pushComment("cloned", this.options.comment);
+        this._progressStatus.downloadFlags!.push(DownloadFlags.Cloned);
+        this._progress.part = this.file.parts.length - 1;
     }
 
     public [Symbol.dispose]() {

src/download/download-engine/download-file/progress-status-file.ts

@@ -28,6 +28,7 @@ export enum DownloadStatus {
 
 export enum DownloadFlags {
     Existing = "Existing",
+    Cloned = "Cloned",
     DownloadSequence = "DownloadSequence"
 }
 

src/download/download-engine/engine/download-engine-nodejs.ts

@@ -66,7 +66,7 @@ export default class DownloadEngineNodejs<T extends DownloadEngineWriteStreamNod
                     await fs.unlink(this.options.writeStream.path);
                 } catch { }
                 await reflinkFile(this.options.fullPartURLInternal[0].url, this.options.writeStream.path);
-                this._engine.finished("cloned");
+                this._engine.markAsCloned();
             } catch { }
         };
 

src/download/download-engine/streams/download-engine-fetch-stream/base-download-engine-fetch-stream.ts

@@ -8,6 +8,7 @@ import {sleepPromise} from "../../utils/sleepPromise.js";
 import HttpError from "./errors/http-error.js";
 import StatusCodeError from "./errors/status-code-error.js";
 import {retryAsyncStatementSimple} from "./utils/retry-async-statement.js";
+import {RenewFetchError} from "./errors/RenewFetchError.js";
 
 export const MIN_LENGTH_FOR_MORE_INFO_REQUEST = 1024 * 1024 * 3; // 3MB
 
@@ -280,6 +281,14 @@ export default abstract class BaseDownloadEngineFetchStream extends EventEmitter
                         callback(...args);
                     });
                 } catch (error: any) {
+                    if (this.paused){
+                        await this.paused;
+
+                        if (error instanceof RenewFetchError){
+                            continue;
+                        }
+                    }
+
                     if (error?.name === "AbortError" && this.aborted) return;
 
                     this.errorCount.value++;

src/download/download-engine/streams/download-engine-fetch-stream/download-engine-fetch-stream-fetch.ts

@@ -8,6 +8,7 @@ import BaseDownloadEngineFetchStream, {
 } from "./base-download-engine-fetch-stream.js";
 import {EmptyStreamTimeoutError} from "./errors/EmptyStreamTimeoutError.js";
 import InvalidContentLengthError from "./errors/invalid-content-length-error.js";
+import {RenewFetchError} from "./errors/RenewFetchError.js";
 import StatusCodeError from "./errors/status-code-error.js";
 import {browserCheck} from "./utils/browserCheck.js";
 import {parseContentDisposition} from "./utils/content-disposition.js";
@@ -161,8 +162,8 @@ export default class DownloadEngineFetchStreamFetch extends BaseDownloadEngineFe
             if (this.paused) {
                 clearWatchdog();
                 smartSplit.closeAndSendLeftoversIfLengthIsUnknown();
+                reject(new RenewFetchError("Fetch paused"));
                 this._activeController?.abort();
-                this.paused.then(resolve);
                 return;
             }
 

src/download/download-engine/streams/download-engine-fetch-stream/download-engine-fetch-stream-xhr.ts

@@ -72,6 +72,8 @@ export default class DownloadEngineFetchStreamXhr extends BaseDownloadEngineFetc
             let aborted = false;
 
             const clearStreamNotResponding = () => {
+                lastChunkReceived = Date.now();
+                waitingForChunk = false;
                 if (streamNotRespondedInTime) {
                     streamNotRespondedInTime = false;
                     this.emit0("streamNotRespondingOff");
@@ -106,8 +108,6 @@ export default class DownloadEngineFetchStreamXhr extends BaseDownloadEngineFetc
             };
 
             xhr.onload = () => {
-                lastChunkReceived = Date.now();
-                waitingForChunk = false;
                 clearStreamNotResponding();
                 clearWatchDog();
 

src/download/download-engine/streams/download-engine-fetch-stream/errors/RenewFetchError.ts

@@ -0,0 +1,6 @@
+import FetchStreamError from "./fetch-stream-error.js";
+
+// error used to signal that fetch should be renewed, this is used internally
+export class RenewFetchError extends FetchStreamError {
+
+}