feat: move downloads to cache when unused

This allows Android to clear these files if the space is needed by the OS.

app/src/main/kotlin/com/aliucord/manager/manager/PathManager.kt

@@ -41,18 +41,39 @@ class PathManager(
      */
     val patchingDir = context.filesDir.resolve("patching").apply { mkdirs() }
 
+    /**
+     * The internal app directory uses for downloads that should not be wiped,
+     * to be used during the patching process. When the process completes, then this
+     * is to be moved to the cache dir, to allow Android to wipe the downloads when
+     * low on storage.
+     */
+    val patchingDownloadDir = patchingDir.resolve("downloads")
+
+    /**
+     * Used as a secondary location for downloads when not currently patching.
+     * This allows Android to clear the download cache when low on storage.
+     */
+    val cacheDownloadDir = context.cacheDir.resolve("downloads")
+
+    /**
+     * A permanent location used for storing custom patching components.
+     * This does not get moved to an Android-managed cache dir when
+     * not currently patching.
+     */
+    val customComponentsDir = patchingDir.resolve("custom")
+
     /**
      * Delete all the cache dirs and recreate them.
      */
     fun clearCache() {
-        context.cacheDir.apply { deleteRecursively() && mkdirs() }
-        patchingDir.apply { deleteRecursively() && mkdirs() }
+        for (dir in arrayOf(patchingDir, cacheDownloadDir, context.cacheDir))
+            dir.deleteRecursively() && dir.mkdirs()
     }
 
     /**
      * Create a new subfolder in the Discord APK cache for a specific version.
      */
-    fun discordApkVersionCache(version: Int): File = patchingDir
+    fun discordApkVersionCache(version: Int): File = patchingDownloadDir
         .resolve("discord")
         .resolve(version.toString())
         .apply { mkdirs() }
@@ -60,39 +81,39 @@ class PathManager(
     /**
      * Resolve a specific path for a cached injector.
      */
-    fun cachedInjectorDex(version: SemVer, custom: Boolean = false) = patchingDir
+    fun cachedInjectorDex(version: SemVer, custom: Boolean = false) = patchingDownloadDir
         .resolve("injector").apply { mkdirs() }
         .resolve("$version${if (custom) ".custom" else ""}.dex")
 
     /**
      * Get all the versions of custom injector builds.
      */
-    fun customInjectorDexs() = listCustomFiles(patchingDir.resolve("injector"))
+    fun customInjectorDexs() = listCustomFiles(customComponentsDir.resolve("injector"))
 
     /**
      * Resolve a specific path for a versioned cached Aliuhook build
      */
-    fun cachedAliuhookAAR(version: SemVer) = patchingDir
+    fun cachedAliuhookAAR(version: SemVer) = patchingDownloadDir
         .resolve("aliuhook").apply { mkdirs() }
         .resolve("$version.aar")
 
     /**
      * Resolve a specific path for a versioned smali patches archive.
      */
-    fun cachedSmaliPatches(version: SemVer, custom: Boolean = false) = patchingDir
+    fun cachedSmaliPatches(version: SemVer, custom: Boolean = false) = patchingDownloadDir
         .resolve("patches").apply { mkdirs() }
         .resolve("$version${if (custom) ".custom" else ""}.zip")
 
     /**
      * Get all the versions of custom smali bundles.
      */
-    fun customSmaliPatches() = listCustomFiles(patchingDir.resolve("patches"))
+    fun customSmaliPatches() = listCustomFiles(customComponentsDir.resolve("patches"))
 
     /**
      * Singular Kotlin file of the most up-to-date version
      * since the stdlib is backwards compatible.
      */
-    fun cachedKotlinDex() = patchingDir
+    fun cachedKotlinDex() = patchingDownloadDir
         .resolve("kotlin.dex")
 
     /**
@@ -108,7 +129,7 @@ class PathManager(
 
     private companion object {
         /**
-         * List all the files that follow the ```[SemVer].custom.*``` naming scheme.
+         * List all the files in a directory that follow SemVer naming.
          */
         private fun listCustomFiles(dir: File): List<SemVer>? {
             if (!dir.exists()) return null
@@ -116,12 +137,9 @@ class PathManager(
             val files = dir.listFiles()
                 ?: throw Error("Failed to list directory")
 
-            val customVersions = files
+            return files
                 .map { it.nameWithoutExtension }
-                .filter { it.endsWith(".custom") }
-                .map { it.removeSuffix(".custom") }
-
-            return customVersions.mapNotNull(SemVer::parseOrNull)
+                .mapNotNull(SemVer::parseOrNull)
         }
     }
 }

app/src/main/kotlin/com/aliucord/manager/patcher/KotlinPatchRunner.kt

@@ -3,8 +3,7 @@ package com.aliucord.manager.patcher
 import com.aliucord.manager.patcher.steps.download.*
 import com.aliucord.manager.patcher.steps.install.*
 import com.aliucord.manager.patcher.steps.patch.*
-import com.aliucord.manager.patcher.steps.prepare.DowngradeCheckStep
-import com.aliucord.manager.patcher.steps.prepare.FetchInfoStep
+import com.aliucord.manager.patcher.steps.prepare.*
 import com.aliucord.manager.ui.screens.patchopts.PatchOptions
 import kotlinx.collections.immutable.persistentListOf
 
@@ -16,6 +15,7 @@ class KotlinPatchRunner(options: PatchOptions) : StepRunner() {
         // Prepare
         FetchInfoStep(),
         DowngradeCheckStep(options),
+        RestoreDownloadsStep(),
 
         // Download
         DownloadDiscordStep(),

app/src/main/kotlin/com/aliucord/manager/patcher/steps/install/CleanupStep.kt

@@ -6,7 +6,6 @@ import com.aliucord.manager.manager.PreferencesManager
 import com.aliucord.manager.patcher.StepRunner
 import com.aliucord.manager.patcher.steps.StepGroup
 import com.aliucord.manager.patcher.steps.base.Step
-import com.aliucord.manager.patcher.steps.base.StepState
 import org.koin.core.component.KoinComponent
 import org.koin.core.component.inject
 
@@ -21,9 +20,11 @@ class CleanupStep : Step(), KoinComponent {
     override val localizedName = R.string.patch_step_cleanup
 
     override suspend fun execute(container: StepRunner) {
+        container.log("Moving downloads back to cache")
+        paths.patchingDownloadDir.renameTo(paths.cacheDownloadDir)
+
         if (prefs.keepPatchedApks) {
-            container.log("keepPatchedApks enabled, skipping...")
-            state = StepState.Skipped
+            container.log("keepPatchedApks enabled, keeping working dir")
         } else {
             container.log("Deleting patching working dir")
             if (!paths.patchingWorkingDir().deleteRecursively())

app/src/main/kotlin/com/aliucord/manager/patcher/steps/prepare/RestoreDownloadsStep.kt

@@ -0,0 +1,35 @@
+package com.aliucord.manager.patcher.steps.prepare
+
+import androidx.compose.runtime.Stable
+import com.aliucord.manager.R
+import com.aliucord.manager.manager.PathManager
+import com.aliucord.manager.patcher.StepRunner
+import com.aliucord.manager.patcher.steps.StepGroup
+import com.aliucord.manager.patcher.steps.base.Step
+import com.aliucord.manager.patcher.steps.base.StepState
+import org.koin.core.component.KoinComponent
+import org.koin.core.component.inject
+
+/**
+ * Restores downloaded files necessary for patching from the cache dir.
+ * Refer to [PathManager.patchingDownloadDir] and [PathManager.cacheDownloadDir]
+ * for more information.
+ */
+@Stable
+class RestoreDownloadsStep : Step(), KoinComponent {
+    private val paths: PathManager by inject()
+
+    override val group = StepGroup.Prepare
+    override val localizedName = R.string.patch_step_restore_cache
+
+    override suspend fun execute(container: StepRunner) {
+        if (paths.cacheDownloadDir.exists()) {
+            container.log("Moving downloads from cache to permanent storage")
+            paths.patchingDownloadDir.deleteRecursively()
+            paths.cacheDownloadDir.renameTo(paths.patchingDownloadDir)
+        } else {
+            container.log("No download cache present")
+            state = StepState.Skipped
+        }
+    }
+}

app/src/main/res/values/strings.xml

@@ -119,6 +119,7 @@
 
   <string name="patch_step_fetch_kt_version">Fetching target Discord version</string>
   <string name="patch_step_downgrade_check">Checking for newer installations</string>
+  <string name="patch_step_restore_cache">Restoring from cache</string>
   <string name="patch_step_dl_kt_apk">Downloading Discord APK</string>
   <string name="patch_step_dl_kotlin">Downloading Kotlin library</string>
   <string name="patch_step_dl_injector">Downloading Aliucord Injector</string>