From f217cb6d8547ef7f79606fdfd26c5a5ff9420648 Mon Sep 17 00:00:00 2001
From: Philip Su <39933441+fivecar@users.noreply.github.com>
Date: Fri, 13 Dec 2024 11:59:20 -0800
Subject: [PATCH] feat: removes duplicate spec records with same URL

---
 src/index.ts       | 22 +++++++++++++++++++---
 test/index.spec.ts | 44 +++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 60 insertions(+), 6 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 4eb3f5b..7dd3c13 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -233,11 +233,25 @@ export default class DownloadQueue {
       this.getDirFilenames(),
     ]);
     const now = Date.now();
-    const loadedSpecs = specData.map(spec => spec.value as Spec);
+    const seenUrls = new Set<string>();
+    const dupeSpecIds = new Set<string>();
+    const loadedSpecs = specData.map(data => {
+      const spec = data.value as Spec;
+
+      // This deduplicates specs that might have been written multiple times,
+      // which has happened in the past based on client use mistakes.
+      if (seenUrls.has(spec.url)) {
+        dupeSpecIds.add(spec.id);
+      } else {
+        seenUrls.add(spec.url);
+      }
+      return spec;
+    });
     const deletes = loadedSpecs.filter(
       spec =>
         spec.createTime === 0 ||
-        (spec.createTime < 0 && -spec.createTime <= now)
+        (spec.createTime < 0 && -spec.createTime <= now) ||
+        dupeSpecIds.has(spec.id)
     );
     const deleteIds = new Set(deletes.map(spec => spec.id));
 
@@ -482,7 +496,9 @@ export default class DownloadQueue {
     const liveUrls = new Set(
       this.specs.filter(spec => spec.createTime > 0).map(spec => spec.url)
     );
-    const urlsToAdd = urls.filter(url => !liveUrls.has(url));
+    // Using urlSet instead of urls in the filter automatically deduplicates
+    // any URLs the caller might have duplicated.
+    const urlsToAdd = [...urlSet].filter(url => !liveUrls.has(url));
     const specsToRemove = this.specs.filter(
       spec => !urlSet.has(spec.url) && spec.createTime > 0
     );
diff --git a/test/index.spec.ts b/test/index.spec.ts
index 0ac5714..5098305 100644
--- a/test/index.spec.ts
+++ b/test/index.spec.ts
@@ -6,14 +6,14 @@ import {
   DownloadTask,
   ensureDownloadsAreRunning,
   ErrorHandler,
-  ProgressHandler
+  ProgressHandler,
 } from "@kesha-antonov/react-native-background-downloader";
 import AsyncStorage from "@react-native-async-storage/async-storage";
 import {
   addEventListener,
   fetch,
   NetInfoState,
-  NetInfoStateType
+  NetInfoStateType,
 } from "@react-native-community/netinfo";
 import { mock } from "jest-mock-extended";
 import KVFS from "key-value-file-system";
@@ -309,6 +309,44 @@ describe("DownloadQueue", () => {
       expect(unlink).toHaveBeenCalledTimes(1);
     });
 
+    it("removes duplicate specs with the same URLs", async () => {
+      const queue = new DownloadQueue();
+
+      (readdir as jest.Mock).mockImplementation(() => [
+        "foo.mp3",
+        "bar.mp3",
+        "foo.mp3",
+      ]);
+
+      await kvfs.write("/mydomain/foo", {
+        id: "foo",
+        url: "http://foo.com/a.mp3",
+        path: `${RNFS.DocumentDirectoryPath}/DownloadQueue/mydomain/foo.mp3`,
+        createTime: Date.now() - 1000,
+      });
+      await kvfs.write("/mydomain/boo", {
+        id: "boo",
+        url: "http://foo.com/b.mp3",
+        path: `${RNFS.DocumentDirectoryPath}/DownloadQueue/mydomain/boo.mp3`,
+        createTime: Date.now() - 1000,
+      });
+      await kvfs.write("/mydomain/foo2", {
+        id: "foo2",
+        url: "http://foo.com/a.mp3",
+        path: `${RNFS.DocumentDirectoryPath}/DownloadQueue/mydomain/foo.mp3`,
+        createTime: Date.now() - 800,
+      });
+      expect((await kvfs.readMulti("/mydomain/*")).length).toEqual(3);
+
+      await queue.init({ domain: "mydomain" });
+      const specs = await kvfs.readMulti("/mydomain/*");
+
+      expect(specs.length).toEqual(2);
+      expect(
+        specs.some(spec => "id" in spec && spec.id === "foo2")
+      ).toBeFalsy();
+    });
+
     it("revives still-downloading specs from previous launches", async () => {
       const queue = new DownloadQueue();
       const handlers: DownloadQueueHandlers = {
@@ -853,7 +891,7 @@ describe("DownloadQueue", () => {
           progress: (handler: ProgressHandler) => {
             progresser = handler;
             return task;
-          }
+          },
         }),
       ]);