Rename DownloadManager to DownloadEngine

Also add some documentation

app/src/main/java/com/topjohnwu/magisk/arch/BaseViewModel.kt

@@ -1,6 +1,8 @@
 package com.topjohnwu.magisk.arch
 
-import android.Manifest.permission.*
+import android.Manifest.permission.POST_NOTIFICATIONS
+import android.Manifest.permission.REQUEST_INSTALL_PACKAGES
+import android.Manifest.permission.WRITE_EXTERNAL_STORAGE
 import android.annotation.SuppressLint
 import android.os.Bundle
 import androidx.databinding.PropertyChangeRegistry

app/src/main/java/com/topjohnwu/magisk/core/JobService.kt

@@ -11,7 +11,7 @@ import androidx.core.content.getSystemService
 import com.topjohnwu.magisk.BuildConfig
 import com.topjohnwu.magisk.core.base.BaseJobService
 import com.topjohnwu.magisk.core.di.ServiceLocator
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 import com.topjohnwu.magisk.view.Notifications
 import kotlinx.coroutines.Dispatchers
@@ -22,12 +22,12 @@ import java.util.concurrent.TimeUnit
 class JobService : BaseJobService() {
 
     private var mSession: Session? = null
-    private var mDm: DownloadManager? = null
+    private var mEngine: DownloadEngine? = null
 
     @TargetApi(value = 34)
     inner class Session(
         var params: JobParameters
-    ) : DownloadManager.Session {
+    ) : DownloadEngine.Session {
 
         override val context get() = this@JobService
 
@@ -55,7 +55,7 @@ class JobService : BaseJobService() {
     private fun downloadFile(params: JobParameters): Boolean {
         params.transientExtras.classLoader = Subject::class.java.classLoader
         val subject = params.transientExtras
-            .getParcelable(DownloadManager.SUBJECT_KEY, Subject::class.java) ?:
+            .getParcelable(DownloadEngine.SUBJECT_KEY, Subject::class.java) ?:
             return false
 
         val session = mSession?.also {
@@ -64,13 +64,13 @@ class JobService : BaseJobService() {
             Session(params).also { mSession = it }
         }
 
-        val dm = mDm?.also {
+        val engine = mEngine?.also {
             it.reattach()
         } ?: run {
-            DownloadManager(session).also { mDm = it }
+            DownloadEngine(session).also { mEngine = it }
         }
 
-        dm.download(subject)
+        engine.download(subject)
         return true
     }
 

app/src/main/java/com/topjohnwu/magisk/core/Receiver.kt

@@ -6,7 +6,7 @@ import android.content.Intent
 import androidx.core.content.IntentCompat
 import com.topjohnwu.magisk.core.base.BaseReceiver
 import com.topjohnwu.magisk.core.di.ServiceLocator
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 import com.topjohnwu.magisk.view.Notifications
 import com.topjohnwu.magisk.view.Shortcuts
@@ -38,10 +38,10 @@ open class Receiver : BaseReceiver() {
         }
 
         when (intent.action ?: return) {
-            DownloadManager.ACTION -> {
+            DownloadEngine.ACTION -> {
                 IntentCompat.getParcelableExtra(
-                    intent, DownloadManager.SUBJECT_KEY, Subject::class.java)?.let {
-                        DownloadManager.start(context, it)
+                    intent, DownloadEngine.SUBJECT_KEY, Subject::class.java)?.let {
+                        DownloadEngine.start(context, it)
                     }
             }
             Intent.ACTION_PACKAGE_REPLACED -> {

app/src/main/java/com/topjohnwu/magisk/core/Service.kt

@@ -6,24 +6,24 @@ import android.os.Build
 import androidx.core.app.ServiceCompat
 import androidx.core.content.IntentCompat
 import com.topjohnwu.magisk.core.base.BaseService
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 
-class Service : BaseService(), DownloadManager.Session {
+class Service : BaseService(), DownloadEngine.Session {
 
-    private lateinit var dm: DownloadManager
+    private lateinit var mEngine: DownloadEngine
     override val context get() = this
 
     override fun onCreate() {
         super.onCreate()
-        dm = DownloadManager(this)
+        mEngine = DownloadEngine(this)
     }
 
     override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
-        if (intent.action == DownloadManager.ACTION) {
+        if (intent.action == DownloadEngine.ACTION) {
             IntentCompat
-                .getParcelableExtra(intent, DownloadManager.SUBJECT_KEY, Subject::class.java)
-                ?.let { dm.download(it) }
+                .getParcelableExtra(intent, DownloadEngine.SUBJECT_KEY, Subject::class.java)
+                ?.let { mEngine.download(it) }
         }
         return START_NOT_STICKY
     }

app/src/main/java/com/topjohnwu/magisk/core/data/NetworkServices.kt

@@ -4,7 +4,11 @@ import com.topjohnwu.magisk.core.model.BranchInfo
 import com.topjohnwu.magisk.core.model.ModuleJson
 import com.topjohnwu.magisk.core.model.UpdateInfo
 import okhttp3.ResponseBody
-import retrofit2.http.*
+import retrofit2.http.GET
+import retrofit2.http.Headers
+import retrofit2.http.Path
+import retrofit2.http.Streaming
+import retrofit2.http.Url
 
 private const val BRANCH = "branch"
 private const val REPO = "repo"

app/src/main/java/com/topjohnwu/magisk/core/data/SuLogDao.kt

@@ -1,12 +1,16 @@
 package com.topjohnwu.magisk.core.data
 
-import androidx.room.*
+import androidx.room.Dao
+import androidx.room.Database
+import androidx.room.Insert
+import androidx.room.Query
+import androidx.room.RoomDatabase
 import androidx.room.migration.Migration
 import androidx.sqlite.db.SupportSQLiteDatabase
 import com.topjohnwu.magisk.core.model.su.SuLog
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import java.util.*
+import java.util.Calendar
 
 @Database(version = 2, entities = [SuLog::class], exportSchema = false)
 abstract class SuLogDatabase : RoomDatabase() {

app/src/main/java/com/topjohnwu/magisk/core/download/DownloadEngine.kt

@@ -55,7 +55,24 @@ import java.util.zip.ZipFile
 import java.util.zip.ZipInputStream
 import java.util.zip.ZipOutputStream
 
-class DownloadManager(
+/**
+ * This class drives the execution of file downloads and notification management.
+ *
+ * Each download engine instance has to be paired with a "session" that is managed by the operating
+ * system. A session is an Android component that allows executing long lasting operations and
+ * have its state tied to a notification to show progress.
+ *
+ * A session can only have one single notification representing its state, and the operating system
+ * also uses the notification to manage the lifecycle of a session. One goal of this class is
+ * to support concurrent download tasks using only one single session, so internally it manages
+ * all active tasks and notifications and properly re-assign notifications to be attached to
+ * the session to make sure all download operations can be completed without the operating system
+ * killing the session.
+ *
+ * For API 23 - 33, we use a foreground service as a session.
+ * For API 34 and higher, we use user-initiated job services as a session.
+ */
+class DownloadEngine(
     private val session: Session
 ) {
 
@@ -96,7 +113,6 @@ class DownloadManager(
                     .putExtra(SUBJECT_KEY, subject)
             }
 
-
         @SuppressLint("InlinedApi")
         fun getPendingIntent(context: Context, subject: Subject): PendingIntent {
             val flag = PendingIntent.FLAG_IMMUTABLE or
@@ -167,7 +183,7 @@ class DownloadManager(
                 notifyFail(subject)
             }
 
-            synchronized(this@DownloadManager) {
+            synchronized(this@DownloadEngine) {
                 if (notifications.isEmpty)
                     session.stop()
             }

app/src/main/java/com/topjohnwu/magisk/core/utils/Locales.kt

@@ -12,7 +12,7 @@ import com.topjohnwu.magisk.core.createNewResources
 import com.topjohnwu.magisk.core.di.AppContext
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import java.util.*
+import java.util.Locale
 
 var currentLocale: Locale = Locale.getDefault()
 

app/src/main/java/com/topjohnwu/magisk/databinding/DataBindingAdapters.kt

@@ -8,7 +8,12 @@ import android.text.Spanned
 import android.util.TypedValue
 import android.view.View
 import android.view.ViewGroup
-import android.widget.*
+import android.widget.ArrayAdapter
+import android.widget.Button
+import android.widget.ImageView
+import android.widget.ProgressBar
+import android.widget.Spinner
+import android.widget.TextView
 import androidx.annotation.DrawableRes
 import androidx.appcompat.widget.Toolbar
 import androidx.cardview.widget.CardView
@@ -20,7 +25,11 @@ import androidx.databinding.BindingAdapter
 import androidx.databinding.InverseBindingAdapter
 import androidx.databinding.InverseBindingListener
 import androidx.interpolator.view.animation.FastOutSlowInInterpolator
-import androidx.recyclerview.widget.*
+import androidx.recyclerview.widget.DividerItemDecoration
+import androidx.recyclerview.widget.GridLayoutManager
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import androidx.recyclerview.widget.StaggeredGridLayoutManager
 import com.google.android.material.button.MaterialButton
 import com.google.android.material.card.MaterialCardView
 import com.google.android.material.chip.Chip

app/src/main/java/com/topjohnwu/magisk/databinding/MergeObservableList.kt

@@ -3,7 +3,7 @@ package com.topjohnwu.magisk.databinding
 import androidx.databinding.ListChangeRegistry
 import androidx.databinding.ObservableList
 import androidx.databinding.ObservableList.OnListChangedCallback
-import java.util.*
+import java.util.AbstractList
 
 @Suppress("UNCHECKED_CAST")
 class MergeObservableList<T> : AbstractList<T>(), ObservableList<T> {

app/src/main/java/com/topjohnwu/magisk/dialog/ManagerInstallDialog.kt

@@ -4,7 +4,7 @@ import com.topjohnwu.magisk.R
 import com.topjohnwu.magisk.core.Info
 import com.topjohnwu.magisk.core.di.AppContext
 import com.topjohnwu.magisk.core.di.ServiceLocator
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 import com.topjohnwu.magisk.view.MagiskDialog
 import java.io.File
@@ -29,7 +29,7 @@ class ManagerInstallDialog : MarkDownDialog() {
             setCancelable(true)
             setButton(MagiskDialog.ButtonType.POSITIVE) {
                 text = R.string.install
-                onClick { DownloadManager.startWithActivity(activity, Subject.App()) }
+                onClick { DownloadEngine.startWithActivity(activity, Subject.App()) }
             }
             setButton(MagiskDialog.ButtonType.NEGATIVE) {
                 text = android.R.string.cancel

app/src/main/java/com/topjohnwu/magisk/dialog/OnlineModuleInstallDialog.kt

@@ -3,7 +3,7 @@ package com.topjohnwu.magisk.dialog
 import com.topjohnwu.magisk.R
 import com.topjohnwu.magisk.core.di.ServiceLocator
 import com.topjohnwu.magisk.core.download.Action
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 import com.topjohnwu.magisk.core.model.module.OnlineModule
 import com.topjohnwu.magisk.view.MagiskDialog
@@ -24,7 +24,7 @@ class OnlineModuleInstallDialog(private val item: OnlineModule) : MarkDownDialog
             fun download(install: Boolean) {
                 val action = if (install) Action.Flash else Action.Download
                 val subject = Subject.Module(item, action)
-                DownloadManager.startWithActivity(activity, subject)
+                DownloadEngine.startWithActivity(activity, subject)
             }
 
             val title = context.getString(R.string.repo_install_title,

app/src/main/java/com/topjohnwu/magisk/ui/deny/AppProcessInfo.kt

@@ -4,7 +4,12 @@ import android.annotation.SuppressLint
 import android.content.pm.ApplicationInfo
 import android.content.pm.ComponentInfo
 import android.content.pm.PackageManager
-import android.content.pm.PackageManager.*
+import android.content.pm.PackageManager.GET_ACTIVITIES
+import android.content.pm.PackageManager.GET_PROVIDERS
+import android.content.pm.PackageManager.GET_RECEIVERS
+import android.content.pm.PackageManager.GET_SERVICES
+import android.content.pm.PackageManager.MATCH_DISABLED_COMPONENTS
+import android.content.pm.PackageManager.MATCH_UNINSTALLED_PACKAGES
 import android.content.pm.ServiceInfo
 import android.graphics.drawable.Drawable
 import android.os.Build
@@ -12,7 +17,7 @@ import android.os.Build.VERSION.SDK_INT
 import androidx.core.os.ProcessCompat
 import com.topjohnwu.magisk.core.ktx.getLabel
 import com.topjohnwu.magisk.core.utils.currentLocale
-import java.util.*
+import java.util.TreeSet
 
 class CmdlineListItem(line: String) {
     val packageName: String

app/src/main/java/com/topjohnwu/magisk/ui/flash/FlashFragment.kt

@@ -5,7 +5,11 @@ import android.content.Context
 import android.content.pm.ActivityInfo
 import android.net.Uri
 import android.os.Bundle
-import android.view.*
+import android.view.KeyEvent
+import android.view.Menu
+import android.view.MenuInflater
+import android.view.MenuItem
+import android.view.View
 import androidx.core.view.MenuProvider
 import androidx.core.view.isVisible
 import androidx.navigation.NavDeepLinkBuilder

app/src/main/java/com/topjohnwu/magisk/ui/home/HomeFragment.kt

@@ -14,7 +14,7 @@ import com.topjohnwu.magisk.R
 import com.topjohnwu.magisk.arch.BaseFragment
 import com.topjohnwu.magisk.arch.viewModel
 import com.topjohnwu.magisk.core.Info
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.databinding.FragmentHomeMd2Binding
 
 class HomeFragment : BaseFragment<FragmentHomeMd2Binding>(), MenuProvider {
@@ -25,7 +25,7 @@ class HomeFragment : BaseFragment<FragmentHomeMd2Binding>(), MenuProvider {
     override fun onStart() {
         super.onStart()
         activity?.setTitle(R.string.section_home)
-        DownloadManager.observeProgress(this, viewModel::onProgressUpdate)
+        DownloadEngine.observeProgress(this, viewModel::onProgressUpdate)
     }
 
     private fun checkTitle(text: TextView, icon: ImageView) {

app/src/main/java/com/topjohnwu/magisk/view/Notifications.kt

@@ -11,7 +11,7 @@ import androidx.core.content.getSystemService
 import androidx.core.graphics.drawable.toIcon
 import com.topjohnwu.magisk.R
 import com.topjohnwu.magisk.core.di.AppContext
-import com.topjohnwu.magisk.core.download.DownloadManager
+import com.topjohnwu.magisk.core.download.DownloadEngine
 import com.topjohnwu.magisk.core.download.Subject
 import com.topjohnwu.magisk.core.ktx.getBitmap
 import com.topjohnwu.magisk.core.ktx.selfLaunchIntent
@@ -67,7 +67,7 @@ object Notifications {
 
     fun updateAvailable() {
         AppContext.apply {
-            val intent = DownloadManager.getPendingIntent(this, Subject.App())
+            val intent = DownloadEngine.getPendingIntent(this, Subject.App())
             val bitmap = getBitmap(R.drawable.ic_magisk_outline)
             val builder = if (SDK_INT >= Build.VERSION_CODES.O) {
                 Notification.Builder(this, UPDATE_CHANNEL)