feat: Ensure installation of stock APK during root installation

library/src/androidMain/kotlin/app/revanced/library/installation/installer/LocalInstaller.kt

@@ -10,7 +10,6 @@ import android.content.pm.PackageInstaller
 import android.content.pm.PackageManager
 import android.os.Build
 import androidx.core.content.ContextCompat
-import app.revanced.library.installation.installer.Installer.Apk
 import java.io.Closeable
 import java.io.File
 
@@ -26,7 +25,7 @@ import java.io.File
 class LocalInstaller(
     private val context: Context,
     onResult: (result: LocalInstallerResult) -> Unit,
-) : Installer<Unit, Installation>(), Closeable {
+) : Installer<Unit, Installation, InstallOptions>(), Closeable {
     private val broadcastReceiver = object : BroadcastReceiver() {
         override fun onReceive(context: Context, intent: Intent) {
             val pmStatus = intent.getIntExtra(LocalInstallerService.EXTRA_STATUS, -999)
@@ -56,13 +55,14 @@ class LocalInstaller(
         )
     }
 
-    override suspend fun install(apk: Apk) {
-        logger.info("Installing ${apk.file.name}")
+    override suspend fun install(options: InstallOptions) {
+        val patchedApk = options.patchedApk
+        logger.info("Installing ${patchedApk.file.name}")
 
         val packageInstaller = context.packageManager.packageInstaller
 
         packageInstaller.openSession(packageInstaller.createSession(sessionParams)).use { session ->
-            session.writeApk(apk.file)
+            session.writeApk(patchedApk.file)
             session.commit(intentSender)
         }
     }

library/src/commonMain/kotlin/app/revanced/library/installation/command/AdbShellCommandRunner.kt

@@ -38,8 +38,9 @@ class AdbShellCommandRunner : ShellCommandRunner {
             override val output by lazy { process.inputStream.bufferedReader().readText().removeSuffix("\n") }
             override val error by lazy { process.errorStream.bufferedReader().readText() }
 
-            override fun waitFor() {
+            override fun waitFor(): RunResult {
                 process.waitFor()
+                return this
             }
         }
     }

library/src/commonMain/kotlin/app/revanced/library/installation/command/RunResult.kt

@@ -22,5 +22,5 @@ interface RunResult {
     /**
      * Waits for the command to finish.
      */
-    fun waitFor() {}
+    fun waitFor(): RunResult = this
 }

library/src/commonMain/kotlin/app/revanced/library/installation/installer/AdbInstaller.kt

@@ -18,7 +18,7 @@ import se.vidstige.jadb.managers.PackageManager.UPDATE_OWNERSHIP
  */
 class AdbInstaller(
     deviceSerial: String? = null,
-) : Installer<AdbInstallerResult, Installation>() {
+) : Installer<AdbInstallerResult, Installation, InstallOptions>() {
     private val shellCommandRunner: ShellCommandRunner
     private val packageManager: PackageManager
 
@@ -30,11 +30,13 @@ class AdbInstaller(
         logger.fine("Connected to $deviceSerial")
     }
 
-    override suspend fun install(apk: Apk): AdbInstallerResult {
+    override suspend fun install(options: InstallOptions): AdbInstallerResult {
+        val patchedApk = options.patchedApk
+
         return runPackageManager {
             val sdkVersion = shellCommandRunner(GET_SDK_VERSION).output.toInt()
-            if (sdkVersion < 34) install(apk.file)
-            else installWithOptions(apk.file, listOf(UPDATE_OWNERSHIP))
+            if (sdkVersion < 34) install(patchedApk.file)
+            else installWithOptions(patchedApk.file, listOf(UPDATE_OWNERSHIP))
         }
     }
 

library/src/commonMain/kotlin/app/revanced/library/installation/installer/Constants.kt

@@ -19,7 +19,10 @@ internal object Constants {
     const val INSTALLED_APK_PATH = "pm path $PLACEHOLDER"
     const val CREATE_INSTALLATION_PATH = "$CREATE_DIR $MOUNT_PATH"
     const val GET_SDK_VERSION = "getprop ro.build.version.sdk"
-
+    const val UNINSTALL_KEEP_DATA = "pm uninstall -k --user 0 $PLACEHOLDER"
+    const val INSTALL_STOCK_APK = "pm install -r -d --user 0 $PLACEHOLDER"
+    const val GET_INSTALLED_VERSION_CODE =
+        "dumpsys package $PLACEHOLDER | sed -n 's/.*versionCode=\\([0-9]*\\).*/\\1/p' | head -n 1"
     const val MOUNT_APK =
         "base_path=\"$MOUNTED_APK_PATH\" && " +
                 $$"mv $$TMP_FILE_PATH $base_path && " +

library/src/commonMain/kotlin/app/revanced/library/installation/installer/Installer.kt

@@ -1,6 +1,5 @@
 package app.revanced.library.installation.installer
 
-import app.revanced.library.installation.installer.Installer.Apk
 import java.io.File
 import java.util.logging.Logger
 
@@ -10,7 +9,7 @@ import java.util.logging.Logger
  * @param TInstallerResult The type of the result of the installation.
  * @param TInstallation The type of the installation.
  */
-abstract class Installer<TInstallerResult, TInstallation : Installation> internal constructor() {
+abstract class Installer<TInstallerResult, TInstallation : Installation, TInstallOptions : InstallOptions> internal constructor() {
     /**
      * The [Logger].
      */
@@ -19,11 +18,11 @@ abstract class Installer<TInstallerResult, TInstallation : Installation> interna
     /**
      * Installs the [Apk] file.
      *
-     * @param apk The [Apk] file.
+     * @param options The [InstallOptions].
      *
      * @return The result of the installation.
      */
-    abstract suspend fun install(apk: Apk): TInstallerResult
+    abstract suspend fun install(options: TInstallOptions): TInstallerResult
 
     /**
      * Uninstalls the package.
@@ -43,11 +42,5 @@ abstract class Installer<TInstallerResult, TInstallation : Installation> interna
      */
     abstract suspend fun getInstallation(packageName: String): TInstallation?
 
-    /**
-     * Apk file for [Installer].
-     *
-     * @param file The [Apk] file.
-     * @param packageName The package name of the [Apk] file.
-     */
-    class Apk(val file: File, val packageName: String? = null)
+    open class Apk(val file: File)
 }

library/src/commonMain/kotlin/app/revanced/library/installation/installer/InstallerOptions.kt

@@ -0,0 +1,5 @@
+package app.revanced.library.installation.installer
+
+open class InstallOptions(
+    val patchedApk: Installer.Apk
+)

library/src/commonMain/kotlin/app/revanced/library/installation/installer/RootInstaller.kt

@@ -4,8 +4,10 @@ import app.revanced.library.installation.command.ShellCommandRunner
 import app.revanced.library.installation.installer.Constants.CREATE_INSTALLATION_PATH
 import app.revanced.library.installation.installer.Constants.DELETE
 import app.revanced.library.installation.installer.Constants.EXISTS
+import app.revanced.library.installation.installer.Constants.GET_INSTALLED_VERSION_CODE
 import app.revanced.library.installation.installer.Constants.INSTALLED_APK_PATH
 import app.revanced.library.installation.installer.Constants.INSTALL_MOUNT_SCRIPT
+import app.revanced.library.installation.installer.Constants.INSTALL_STOCK_APK
 import app.revanced.library.installation.installer.Constants.KILL
 import app.revanced.library.installation.installer.Constants.MOUNTED_APK_PATH
 import app.revanced.library.installation.installer.Constants.MOUNT_APK
@@ -16,8 +18,6 @@ import app.revanced.library.installation.installer.Constants.RESTART
 import app.revanced.library.installation.installer.Constants.TMP_FILE_PATH
 import app.revanced.library.installation.installer.Constants.UMOUNT
 import app.revanced.library.installation.installer.Constants.invoke
-import app.revanced.library.installation.installer.Installer.Apk
-import app.revanced.library.installation.installer.RootInstaller.NoRootPermissionException
 import java.io.File
 
 /**
@@ -30,7 +30,7 @@ import java.io.File
 @Suppress("MemberVisibilityCanBePrivate")
 abstract class RootInstaller internal constructor(
     shellCommandRunnerSupplier: (RootInstaller) -> ShellCommandRunner,
-) : Installer<RootInstallerResult, RootInstallation>() {
+) : Installer<RootInstallerResult, RootInstallation, RootInstallOptions>() {
 
     /**
      * The command runner used to run commands on the device.
@@ -43,19 +43,41 @@ abstract class RootInstaller internal constructor(
     }
 
     /**
-     * Installs the given [apk] by mounting.
+     * Installs the given APK by mounting it over a stock installation.
      *
-     * @param apk The [Apk] to install.
+     * The stock APK is used to ensure a valid base for mounting. If the currently
+     * installed version differs from the expected stock version, the stock APK is
+     * installed first. If the installed version is newer than the expected version,
+     * reinstallation may be required.
      *
-     * @throws PackageNameRequiredException If the [Apk] does not have a package name.
+     * @param options The install options containing the patched APK to mount and the
+     * stock APK to use as the installation base.
+     *
+     * @throws PackageDowngradeRequiredException If the installed app version is
+     * newer than the expected stock version.
      */
-    override suspend fun install(apk: Apk): RootInstallerResult {
-        logger.info("Installing ${apk.packageName} by mounting")
+    override suspend fun install(options: RootInstallOptions): RootInstallerResult {
+        val patchedApk = options.patchedApk
+        val stockApk = options.stockApk
+        val packageName = stockApk.packageName
+        val expectedVersionCode = stockApk.versionCode
+        logger.info("Installing $packageName by mounting")
+
+        // Ensure the installed base app matches the stock APK version.
+        val installedVersionCode = getInstalledVersionCode(packageName)
+
+        if (installedVersionCode != null && installedVersionCode > expectedVersionCode) {
+            throw PackageDowngradeRequiredException(packageName)
+        }
 
-        val packageName = apk.packageName?.also { it.assertInstalled() } ?: throw PackageNameRequiredException()
+        if (installedVersionCode != expectedVersionCode) {
+            logger.info("Installing stock APK for $packageName")
+            INSTALL_STOCK_APK(stockApk.file.absolutePath)().waitFor()
+        }
+        packageName.assertInstalled()
 
         // Setup files.
-        apk.file.move(TMP_FILE_PATH)
+        patchedApk.file.move(TMP_FILE_PATH)
         CREATE_INSTALLATION_PATH().waitFor()
         MOUNT_APK(packageName)().waitFor()
 
@@ -88,7 +110,7 @@ abstract class RootInstaller internal constructor(
         val patchedApkPath = MOUNTED_APK_PATH(packageName)
 
         val patchedApkExists = EXISTS(patchedApkPath)().exitCode == 0
-        if (patchedApkExists) return null
+        if (!patchedApkExists) return null
 
         return RootInstallation(
             INSTALLED_APK_PATH(packageName)().output.ifEmpty { null },
@@ -114,7 +136,8 @@ abstract class RootInstaller internal constructor(
      *
      * @param content The content of the file.
      */
-    protected fun String.write(content: String) = shellCommandRunner.write(content.byteInputStream(), this)
+    protected fun String.write(content: String) =
+        shellCommandRunner.write(content.byteInputStream(), this)
 
     /**
      * Asserts that the package is installed.
@@ -127,8 +150,20 @@ abstract class RootInstaller internal constructor(
         }
     }
 
-    internal class FailedToFindInstalledPackageException internal constructor(packageName: String) : Exception("Failed to resolve installed APK path for package \"$packageName\"")
+    private fun getInstalledVersionCode(packageName: String): Int? {
+        val result = GET_INSTALLED_VERSION_CODE(packageName)().waitFor()
+
+        if (result.exitCode != 0) return null
+
+        return result.output.trim().toIntOrNull()
+    }
+
+    internal class PackageDowngradeRequiredException internal constructor(packageName: String) :
+        Exception("$packageName requires reinstallation for a downgrade, data wipe is likely")
+
+    internal class FailedToFindInstalledPackageException internal constructor(packageName: String) :
+        Exception("Failed to resolve installed APK path for package \"$packageName\"")
 
-    internal class PackageNameRequiredException internal constructor() : Exception("Package name is required")
-    internal class NoRootPermissionException internal constructor() : Exception("No root permission")
+    internal class NoRootPermissionException internal constructor() :
+        Exception("No root permission")
 }

library/src/commonMain/kotlin/app/revanced/library/installation/installer/RootInstallerOptions.kt

@@ -0,0 +1,10 @@
+package app.revanced.library.installation.installer
+
+import java.io.File
+
+class RootInstallOptions(
+    patchedApk: Installer.Apk,
+    val stockApk: StockApk
+) : InstallOptions(patchedApk)
+
+class StockApk(file: File, val packageName: String, val versionCode: Int) : Installer.Apk(file)