[MultiUser] Add file access wrapper.

Adds a class that handles files access for multiple users. Will work on
integration in follow-up CL.

Test: Add unit tests.
Change-Id: Ia0af0d18970a8376edcccbe0f59e3d21e55c4f42

7 files changed, 335 insertions, 7 deletions

diff --git a/packages/SystemUI/docs/user-file-manager.md b/packages/SystemUI/docs/user-file-manager.md
new file mode 100644
index 000000000000..64f1694af50a
--- /dev/null
+++ b/packages/SystemUI/docs/user-file-manager.md
@@ -0,0 +1,13 @@
+# UserFileManager
+
+This class is used to generate file paths and SharedPreferences that is compatible for multiple
+users in SystemUI. Due to constraints in SystemUI, we can only read/write files as the system user.
+Therefore, for secondary users, we want to store secondary user specific files into the system user
+directory.
+
+## Handling User Removal
+
+This class will listen for Intent.ACTION_USER_REMOVED and remove directories that no longer
+corresponding to active users. Additionally, upon start up, the class will run the same query for
+deletion to ensure that there is no stale data.
+
diff --git a/packages/SystemUI/src/com/android/systemui/dagger/SystemUICoreStartableModule.kt b/packages/SystemUI/src/com/android/systemui/dagger/SystemUICoreStartableModule.kt
index a9f340854689..6db3e82a77b0 100644
--- a/packages/SystemUI/src/com/android/systemui/dagger/SystemUICoreStartableModule.kt
+++ b/packages/SystemUI/src/com/android/systemui/dagger/SystemUICoreStartableModule.kt
@@ -33,6 +33,7 @@ import com.android.systemui.log.SessionTracker
 import com.android.systemui.media.RingtonePlayer
 import com.android.systemui.power.PowerUI
 import com.android.systemui.recents.Recents
+import com.android.systemui.settings.dagger.MultiUserUtilsModule
 import com.android.systemui.shortcut.ShortcutKeyDispatcher
 import com.android.systemui.statusbar.notification.InstantAppNotifier
 import com.android.systemui.statusbar.phone.KeyguardLiftController
@@ -51,7 +52,7 @@ import dagger.multibindings.IntoMap
 /**
  * Collection of {@link CoreStartable}s that should be run on AOSP.
  */
-@Module
+@Module(includes = [MultiUserUtilsModule::class])
 abstract class SystemUICoreStartableModule {
     /** Inject into AuthController.  */
     @Binds
@@ -205,4 +206,4 @@ abstract class SystemUICoreStartableModule {
     @IntoMap
     @ClassKey(KeyguardLiftController::class)
     abstract fun bindKeyguardLiftController(sysui: KeyguardLiftController): CoreStartable
-}
\ No newline at end of file
+}
diff --git a/packages/SystemUI/src/com/android/systemui/dagger/SystemUIModule.java b/packages/SystemUI/src/com/android/systemui/dagger/SystemUIModule.java
index 137e28888728..c8747fcf16fb 100644
--- a/packages/SystemUI/src/com/android/systemui/dagger/SystemUIModule.java
+++ b/packages/SystemUI/src/com/android/systemui/dagger/SystemUIModule.java
@@ -50,7 +50,7 @@ import com.android.systemui.plugins.BcSmartspaceDataPlugin;
 import com.android.systemui.privacy.PrivacyModule;
 import com.android.systemui.recents.Recents;
 import com.android.systemui.screenshot.dagger.ScreenshotModule;
-import com.android.systemui.settings.dagger.SettingsModule;
+import com.android.systemui.settings.dagger.MultiUserUtilsModule;
 import com.android.systemui.smartspace.dagger.SmartspaceModule;
 import com.android.systemui.statusbar.CommandQueue;
 import com.android.systemui.statusbar.NotificationLockscreenUserManager;
@@ -127,7 +127,7 @@ import dagger.Provides;
             QsFrameTranslateModule.class,
             ScreenshotModule.class,
             SensorModule.class,
-            SettingsModule.class,
+            MultiUserUtilsModule.class,
             SettingsUtilModule.class,
             SmartRepliesInflationModule.class,
             SmartspaceModule.class,
diff --git a/packages/SystemUI/src/com/android/systemui/settings/UserFileManager.kt b/packages/SystemUI/src/com/android/systemui/settings/UserFileManager.kt
new file mode 100644
index 000000000000..aa218dbfdd43
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/settings/UserFileManager.kt
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.settings
+
+import android.content.Context
+import android.content.SharedPreferences
+import java.io.File
+
+/**
+ * Interface for retrieving file paths for file storage of system and secondary users.
+ */
+interface UserFileManager {
+    /**
+     * Return the file based on current user.
+     */
+    fun getFile(fileName: String, userId: Int): File
+    /**
+     * Get shared preferences from user.
+     */
+    fun getSharedPreferences(
+        fileName: String,
+        @Context.PreferencesMode mode: Int,
+        userId: Int
+    ): SharedPreferences
+}
diff --git a/packages/SystemUI/src/com/android/systemui/settings/UserFileManagerImpl.kt b/packages/SystemUI/src/com/android/systemui/settings/UserFileManagerImpl.kt
new file mode 100644
index 000000000000..8c8f54fe9c3d
--- /dev/null
+++ b/packages/SystemUI/src/com/android/systemui/settings/UserFileManagerImpl.kt
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.settings
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.Intent
+import android.content.IntentFilter
+import android.content.SharedPreferences
+import android.os.Environment
+import android.os.UserHandle
+import android.os.UserManager
+import android.util.Log
+import androidx.annotation.VisibleForTesting
+import com.android.systemui.CoreStartable
+import com.android.systemui.broadcast.BroadcastDispatcher
+import com.android.systemui.dagger.SysUISingleton
+import com.android.systemui.dagger.qualifiers.Background
+import com.android.systemui.util.concurrency.DelayableExecutor
+import java.io.File
+import javax.inject.Inject
+
+/**
+ * Implementation for retrieving file paths for file storage of system and secondary users.
+ * Files lie in {File Directory}/UserFileManager/{User Id} for secondary user.
+ * For system user, we use the conventional {File Directory}
+ */
+@SysUISingleton
+class UserFileManagerImpl @Inject constructor(
+    // Context of system process and system user.
+    val context: Context,
+    val userManager: UserManager,
+    val broadcastDispatcher: BroadcastDispatcher,
+    @Background val backgroundExecutor: DelayableExecutor
+) : UserFileManager, CoreStartable(context) {
+    companion object {
+        private const val FILES = "files"
+        private const val SHARED_PREFS = "shared_prefs"
+        internal const val ID = "UserFileManager"
+    }
+
+   private val broadcastReceiver = object : BroadcastReceiver() {
+        /**
+         * Listen to Intent.ACTION_USER_REMOVED to clear user data.
+         */
+        override fun onReceive(context: Context, intent: Intent) {
+            if (intent.action == Intent.ACTION_USER_REMOVED) {
+                clearDeletedUserData()
+            }
+        }
+    }
+
+    /**
+     * Poll for user-specific directories to delete upon start up.
+     */
+    override fun start() {
+        clearDeletedUserData()
+        val filter = IntentFilter().apply {
+            addAction(Intent.ACTION_USER_REMOVED)
+        }
+        broadcastDispatcher.registerReceiver(broadcastReceiver, filter, backgroundExecutor)
+    }
+
+    /**
+     * Return the file based on current user.
+     */
+    override fun getFile(fileName: String, userId: Int): File {
+        return if (UserHandle(userId).isSystem) {
+            Environment.buildPath(
+                context.filesDir,
+                fileName
+            )
+        } else {
+            Environment.buildPath(
+                context.filesDir,
+                ID,
+                userId.toString(),
+                FILES,
+                fileName
+            )
+        }
+    }
+
+    /**
+     * Get shared preferences from user.
+     */
+    override fun getSharedPreferences(
+        fileName: String,
+        @Context.PreferencesMode mode: Int,
+        userId: Int
+    ): SharedPreferences {
+        if (UserHandle(userId).isSystem) {
+            return context.getSharedPreferences(fileName, mode)
+        }
+        val secondaryUserDir = Environment.buildPath(
+            context.filesDir,
+            ID,
+            userId.toString(),
+            SHARED_PREFS,
+            fileName
+        )
+
+        return context.getSharedPreferences(secondaryUserDir, mode)
+    }
+
+    /**
+     * Remove dirs for deleted users.
+     */
+    @VisibleForTesting
+    internal fun clearDeletedUserData() {
+        backgroundExecutor.execute {
+            val file = Environment.buildPath(context.filesDir, ID)
+            if (!file.exists()) return@execute
+            val aliveUsers = userManager.aliveUsers.map { it.id.toString() }
+            val dirsToDelete = file.list().filter { !aliveUsers.contains(it) }
+
+            dirsToDelete.forEach { dir ->
+                try {
+                    val dirToDelete = Environment.buildPath(
+                        file,
+                        dir,
+                    )
+                    dirToDelete.deleteRecursively()
+                } catch (e: Exception) {
+                    Log.e(ID, "Deletion failed.", e)
+                }
+            }
+        }
+    }
+}
diff --git a/packages/SystemUI/src/com/android/systemui/settings/dagger/SettingsModule.java b/packages/SystemUI/src/com/android/systemui/settings/dagger/MultiUserUtilsModule.java
index 7084d3ffc9ff..2f62e44ba4c4 100644
--- a/packages/SystemUI/src/com/android/systemui/settings/dagger/SettingsModule.java
+++ b/packages/SystemUI/src/com/android/systemui/settings/dagger/MultiUserUtilsModule.java
@@ -21,25 +21,28 @@ import android.content.Context;
 import android.os.Handler;
 import android.os.UserManager;
 
+import com.android.systemui.CoreStartable;
 import com.android.systemui.dagger.SysUISingleton;
 import com.android.systemui.dagger.qualifiers.Background;
 import com.android.systemui.dump.DumpManager;
 import com.android.systemui.settings.UserContentResolverProvider;
 import com.android.systemui.settings.UserContextProvider;
+import com.android.systemui.settings.UserFileManager;
+import com.android.systemui.settings.UserFileManagerImpl;
 import com.android.systemui.settings.UserTracker;
 import com.android.systemui.settings.UserTrackerImpl;
 
 import dagger.Binds;
 import dagger.Module;
 import dagger.Provides;
+import dagger.multibindings.ClassKey;
+import dagger.multibindings.IntoMap;
 
 /**
  * Dagger Module for classes found within the com.android.systemui.settings package.
  */
 @Module
-public abstract class SettingsModule {
-
-
+public abstract class MultiUserUtilsModule {
     @Binds
     @SysUISingleton
     abstract UserContextProvider bindUserContextProvider(UserTracker tracker);
@@ -62,4 +65,12 @@ public abstract class SettingsModule {
         tracker.initialize(startingUser);
         return tracker;
     }
+
+    @Binds
+    @IntoMap
+    @ClassKey(UserFileManagerImpl.class)
+    abstract CoreStartable bindUserFileManagerCoreStartable(UserFileManagerImpl sysui);
+
+    @Binds
+    abstract UserFileManager bindUserFileManager(UserFileManagerImpl impl);
 }
diff --git a/packages/SystemUI/tests/src/com/android/systemui/settings/UserFileManagerImplTest.kt b/packages/SystemUI/tests/src/com/android/systemui/settings/UserFileManagerImplTest.kt
new file mode 100644
index 000000000000..73226fa0b12c
--- /dev/null
+++ b/packages/SystemUI/tests/src/com/android/systemui/settings/UserFileManagerImplTest.kt
@@ -0,0 +1,120 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.settings
+
+import android.content.BroadcastReceiver
+import android.content.Context
+import android.content.IntentFilter
+import android.os.Environment
+import android.os.UserManager
+import android.testing.AndroidTestingRunner
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.broadcast.BroadcastDispatcher
+import com.android.systemui.util.concurrency.FakeExecutor
+import com.android.systemui.util.mockito.any
+import com.android.systemui.util.mockito.eq
+import com.android.systemui.util.time.FakeSystemClock
+import com.google.common.truth.Truth.assertThat
+import java.util.concurrent.Executor
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mockito.Mock
+import org.mockito.Mockito.isNull
+import org.mockito.Mockito.spy
+import org.mockito.Mockito.verify
+import org.mockito.MockitoAnnotations
+
+@SmallTest
+@RunWith(AndroidTestingRunner::class)
+class UserFileManagerImplTest : SysuiTestCase() {
+    companion object {
+        const val TEST_FILE_NAME = "abc.txt"
+    }
+
+    lateinit var userFileManager: UserFileManagerImpl
+    lateinit var backgroundExecutor: FakeExecutor
+    @Mock
+    lateinit var userManager: UserManager
+    @Mock
+    lateinit var broadcastDispatcher: BroadcastDispatcher
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+        backgroundExecutor = FakeExecutor(FakeSystemClock())
+        userFileManager = UserFileManagerImpl(context, userManager,
+            broadcastDispatcher, backgroundExecutor)
+    }
+
+    @Test
+    fun testGetFile() {
+        assertThat(userFileManager.getFile(TEST_FILE_NAME, 0).path)
+            .isEqualTo("${context.filesDir}/$TEST_FILE_NAME")
+        assertThat(userFileManager.getFile(TEST_FILE_NAME, 11).path)
+            .isEqualTo("${context.filesDir}/${UserFileManagerImpl.ID}/11/files/$TEST_FILE_NAME")
+    }
+
+    @Test
+    fun testGetSharedPreferences() {
+        assertThat(userFileManager.getSharedPreferences(TEST_FILE_NAME, 0, 0))
+            .isNotEqualTo(userFileManager.getSharedPreferences(TEST_FILE_NAME, 0, 11))
+    }
+
+    @Test
+    fun testUserFileManagerStart() {
+        val userFileManager = spy(userFileManager)
+        userFileManager.start()
+        verify(userFileManager).clearDeletedUserData()
+        verify(broadcastDispatcher).registerReceiver(any(BroadcastReceiver::class.java),
+            any(IntentFilter::class.java),
+            any(Executor::class.java), isNull(), eq(Context.RECEIVER_EXPORTED), isNull())
+    }
+
+    @Test
+    fun testClearDeletedUserData() {
+        val dir = Environment.buildPath(
+            context.filesDir,
+            UserFileManagerImpl.ID,
+            "11",
+            "files"
+        )
+        dir.mkdirs()
+        val file = Environment.buildPath(
+            context.filesDir,
+            UserFileManagerImpl.ID,
+            "11",
+            "files",
+            TEST_FILE_NAME
+        )
+        val secondaryUserDir = Environment.buildPath(
+            context.filesDir,
+            UserFileManagerImpl.ID,
+            "11",
+        )
+        file.createNewFile()
+        assertThat(secondaryUserDir.exists()).isTrue()
+        assertThat(file.exists()).isTrue()
+        userFileManager.clearDeletedUserData()
+        assertThat(backgroundExecutor.runAllReady()).isGreaterThan(0)
+        verify(userManager).aliveUsers
+        assertThat(secondaryUserDir.exists()).isFalse()
+        assertThat(file.exists()).isFalse()
+        dir.deleteRecursively()
+    }
+}