From c8975f55bfa52f73efd03682074ea63c307a02dd Mon Sep 17 00:00:00 2001
From: Ax333l <main@axelen.xyz>
Date: Sat, 13 Jul 2024 22:57:49 +0200
Subject: [PATCH] add assertions

---
 .../repository/DownloadedAppRepository.kt     | 19 ++++++++++++++-----
 .../plugin/downloader/DownloadScope.kt        |  2 +-
 .../downloader/example/ExamplePlugins.kt      |  6 +++---
 3 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/app/src/main/java/app/revanced/manager/domain/repository/DownloadedAppRepository.kt b/app/src/main/java/app/revanced/manager/domain/repository/DownloadedAppRepository.kt
index a5c3a3ee..3f005bb3 100644
--- a/app/src/main/java/app/revanced/manager/domain/repository/DownloadedAppRepository.kt
+++ b/app/src/main/java/app/revanced/manager/domain/repository/DownloadedAppRepository.kt
@@ -31,16 +31,25 @@ class DownloadedAppRepository(app: Application, db: AppDatabase) {
 
         // Converted integers cannot contain / or .. unlike the package name or version, so they are safer to use here.
         val relativePath = File(generateUid().toString())
-        val savePath = dir.resolve(relativePath).also { it.mkdirs() }
+        val saveDir = dir.resolve(relativePath).also { it.mkdirs() }
+        val targetFile = saveDir.resolve("base.apk")
 
         try {
             val scope = object : DownloadScope {
-                override val saveLocation = savePath.resolve("base.apk")
-                override suspend fun reportProgress(bytesReceived: Int, bytesTotal: Int?) = onDownload(bytesReceived.megaBytes to bytesTotal?.megaBytes)
+                override val targetFile = targetFile
+                override suspend fun reportProgress(bytesReceived: Int, bytesTotal: Int?) {
+                    require(bytesReceived >= 0) { "bytesReceived must not be negative" }
+                    require(bytesTotal == null || bytesTotal >= bytesReceived) { "bytesTotal must be greater than or equal to bytesReceived" }
+                    require(bytesTotal != 0) { "bytesTotal must not be zero" }
+
+                    onDownload(bytesReceived.megaBytes to bytesTotal?.megaBytes)
+                }
             }
 
             plugin.download(scope, app)
 
+            if (!targetFile.exists()) throw Exception("Downloader did not download any files")
+
             dao.insert(
                 DownloadedApp(
                     packageName = app.packageName,
@@ -49,12 +58,12 @@ class DownloadedAppRepository(app: Application, db: AppDatabase) {
                 )
             )
         } catch (e: Exception) {
-            savePath.deleteRecursively()
+            saveDir.deleteRecursively()
             throw e
         }
 
         // Return the Apk file.
-        return getApkFileForDir(savePath)
+        return getApkFileForDir(saveDir)
     }
 
     suspend fun get(packageName: String, version: String) = dao.get(packageName, version)
diff --git a/downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/DownloadScope.kt b/downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/DownloadScope.kt
index a5a08a77..05f139da 100644
--- a/downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/DownloadScope.kt
+++ b/downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/DownloadScope.kt
@@ -6,7 +6,7 @@ interface DownloadScope {
     /**
      * The location where the downloaded APK should be saved.
      */
-    val saveLocation: File
+    val targetFile: File
 
     /**
      * A callback for reporting download progress
diff --git a/example-downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/example/ExamplePlugins.kt b/example-downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/example/ExamplePlugins.kt
index 6a9a09dd..4be09a68 100644
--- a/example-downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/example/ExamplePlugins.kt
+++ b/example-downloader-plugin/src/main/java/app/revanced/manager/plugin/downloader/example/ExamplePlugins.kt
@@ -43,11 +43,11 @@ private fun installedAppDownloader(context: DownloaderContext) = downloader<Inst
     }
 
     download {
-        Files.copy(Path(it.apkPath), saveLocation.toPath(), StandardCopyOption.REPLACE_EXISTING)
+        Files.copy(Path(it.apkPath), targetFile.toPath(), StandardCopyOption.REPLACE_EXISTING)
     }
 }
 
-private val Int.megabytes get() = times(1_000_000)
+private val Int.megaBytes get() = times(1_000_000)
 
 val examplePaginatedDownloader = paginatedDownloader {
     versionPager { packageName, versionHint ->
@@ -81,7 +81,7 @@ val examplePaginatedDownloader = paginatedDownloader {
 
     download {
         for (i in 0..5) {
-            reportProgress(i.megabytes , 5.megabytes)
+            reportProgress(i.megaBytes , 5.megaBytes)
             delay(1000L)
         }