Improve behavior of @pm@ backups when we can't do backups

Before, we were faking a backup and just returned true, but remembering that next time, we need to do a fresh non-incremental @pm@ backup.
Now, we backup to local cache, but don't upload it. On next run, when we can do backups again, we will upload the updated cache. This simplifies things and reduces the special logic required.

app/src/main/java/com/stevesoltys/seedvault/settings/SettingsManager.kt

@@ -9,14 +9,12 @@ import androidx.annotation.UiThread
 import androidx.annotation.WorkerThread
 import androidx.documentfile.provider.DocumentFile
 import androidx.preference.PreferenceManager
-import com.stevesoltys.seedvault.MAGIC_PACKAGE_MANAGER
 import com.stevesoltys.seedvault.permitDiskReads
 import com.stevesoltys.seedvault.transport.backup.BackupCoordinator
 import java.util.concurrent.ConcurrentSkipListSet
 
 internal const val PREF_KEY_TOKEN = "token"
 internal const val PREF_KEY_BACKUP_APK = "backup_apk"
-internal const val PREF_KEY_REDO_PM = "redoPm"
 
 private const val PREF_KEY_STORAGE_URI = "storageUri"
 private const val PREF_KEY_STORAGE_NAME = "storageName"
@@ -126,15 +124,6 @@ class SettingsManager(private val context: Context) {
         return !storage.isUnavailableUsb(context) && !storage.isUnavailableNetwork(context)
     }
 
-    /**
-     * Set this to true if the next backup run for [MAGIC_PACKAGE_MANAGER]
-     * needs to be non-incremental,
-     * because we need to fake an OK backup now even though we can't do one right now.
-     */
-    var pmBackupNextTimeNonIncremental: Boolean
-        get() = prefs.getBoolean(PREF_KEY_REDO_PM, false)
-        set(value) = prefs.edit().putBoolean(PREF_KEY_REDO_PM, value).apply()
-
     fun backupApks(): Boolean {
         return prefs.getBoolean(PREF_KEY_BACKUP_APK, true)
     }

app/src/main/java/com/stevesoltys/seedvault/transport/backup/BackupCoordinator.kt

@@ -43,16 +43,14 @@ private val TAG = BackupCoordinator::class.java.simpleName
 private class CoordinatorState(
     var calledInitialize: Boolean,
     var calledClearBackupData: Boolean,
-    var skippedPmBackup: Boolean,
     var cancelReason: PackageState
 ) {
     val expectFinish: Boolean
-        get() = calledInitialize || calledClearBackupData || skippedPmBackup
+        get() = calledInitialize || calledClearBackupData
 
     fun onFinish() {
         calledInitialize = false
         calledClearBackupData = false
-        skippedPmBackup = false
         cancelReason = UNKNOWN_ERROR
     }
 }
@@ -79,7 +77,6 @@ internal class BackupCoordinator(
     private val state = CoordinatorState(
         calledInitialize = false,
         calledClearBackupData = false,
-        skippedPmBackup = false,
         cancelReason = UNKNOWN_ERROR
     )
 
@@ -236,13 +233,6 @@ internal class BackupCoordinator(
         flags: Int
     ): Int {
         state.cancelReason = UNKNOWN_ERROR
-        val packageName = packageInfo.packageName
-        // K/V backups (typically starting with package manager metadata - @pm@)
-        // are scheduled with JobInfo.Builder#setOverrideDeadline() and thus do not respect backoff.
-        // We need to reject them manually when we can not do a backup now.
-        // What else we tried can be found in: https://github.com/seedvault-app/seedvault/issues/102
-        if (packageName == MAGIC_PACKAGE_MANAGER) {
-            val isIncremental = flags and FLAG_INCREMENTAL != 0
         if (metadataManager.requiresInit) {
             // start a new restore set to upgrade from legacy format
             // by starting a clean backup with all files using the new version
@@ -253,21 +243,6 @@ internal class BackupCoordinator(
             }
             // this causes a backup error, but things should go back to normal afterwards
             return TRANSPORT_NOT_INITIALIZED
-            } else if (!settingsManager.canDoBackupNow()) {
-                // Returning anything else here (except non-incremental-required which re-tries)
-                // will make the system consider the backup state compromised
-                // and force re-initialization on next run.
-                // Errors for other packages are OK, but this one is not allowed to fail.
-                Log.w(TAG, "Skipping @pm@ backup as we can't do backup right now.")
-                state.skippedPmBackup = true
-                settingsManager.pmBackupNextTimeNonIncremental = true
-                data.close()
-                return TRANSPORT_OK
-            } else if (isIncremental && settingsManager.pmBackupNextTimeNonIncremental) {
-                settingsManager.pmBackupNextTimeNonIncremental = false
-                data.close()
-                return TRANSPORT_NON_INCREMENTAL_BACKUP_REQUIRED
-            }
         }
         val token = settingsManager.getToken() ?: error("no token in performFullBackup")
         val salt = metadataManager.salt
@@ -388,15 +363,27 @@ internal class BackupCoordinator(
             check(!full.hasState()) {
                 "K/V backup has state, but full backup has dangling state as well"
             }
-            // getCurrentPackage() not-null because we have state
+            // getCurrentPackage() not-null because we have state, call before finishing
             val packageInfo = kv.getCurrentPackage()!!
+            val packageName = packageInfo.packageName
+            // tell K/V backup to finish
+            var result = kv.finishBackup()
+            if (result == TRANSPORT_OK) {
+                val isPmBackup = packageName == MAGIC_PACKAGE_MANAGER
+                // call onPackageBackedUp for @pm@ only if we can do backups right now
+                if (!isPmBackup || settingsManager.canDoBackupNow()) {
+                    try {
                         onPackageBackedUp(packageInfo, BackupType.KV)
-            val isPmBackup = packageInfo.packageName == MAGIC_PACKAGE_MANAGER
+                    } catch (e: Exception) {
-            val result = kv.finishBackup()
+                        Log.e(TAG, "Error calling onPackageBackedUp for $packageName", e)
+                        result = TRANSPORT_PACKAGE_REJECTED
+                    }
+                }
                 // hook in here to back up APKs of apps that are otherwise not allowed for backup
-            if (result == TRANSPORT_OK && isPmBackup) {
+                if (isPmBackup && settingsManager.canDoBackupNow()) {
                     backUpApksOfNotBackedUpPackages()
                 }
+            }
             result
         }
         full.hasState() -> {
@@ -404,8 +391,17 @@ internal class BackupCoordinator(
                 "Full backup has state, but K/V backup has dangling state as well"
             }
             // getCurrentPackage() not-null because we have state
-            onPackageBackedUp(full.getCurrentPackage()!!, BackupType.FULL)
+            val packageInfo = full.getCurrentPackage()!!
-            full.finishBackup()
+            val packageName = packageInfo.packageName
+            // tell full backup to finish
+            var result = full.finishBackup()
+            try {
+                onPackageBackedUp(packageInfo, BackupType.FULL)
+            } catch (e: Exception) {
+                Log.e(TAG, "Error calling onPackageBackedUp for $packageName", e)
+                result = TRANSPORT_PACKAGE_REJECTED
+            }
+            result
         }
         state.expectFinish -> {
             state.onFinish()
@@ -472,15 +468,9 @@ internal class BackupCoordinator(
     }
 
     private suspend fun onPackageBackedUp(packageInfo: PackageInfo, type: BackupType) {
-        try {
         plugin.getMetadataOutputStream().use {
             metadataManager.onPackageBackedUp(packageInfo, type, it)
         }
-        } catch (e: IOException) {
-            Log.e(TAG, "Error while writing metadata for ${packageInfo.packageName}", e)
-            // we are not re-throwing this as there's nothing we can do now
-            // except hoping the current metadata gets written with the next package
-        }
     }
 
     private suspend fun onPackageBackupError(packageInfo: PackageInfo, type: BackupType) {

app/src/main/java/com/stevesoltys/seedvault/transport/backup/KVBackup.kt

@@ -9,6 +9,7 @@ import android.app.backup.BackupTransport.TRANSPORT_OK
 import android.content.pm.PackageInfo
 import android.os.ParcelFileDescriptor
 import android.util.Log
+import com.stevesoltys.seedvault.MAGIC_PACKAGE_MANAGER
 import com.stevesoltys.seedvault.crypto.Crypto
 import com.stevesoltys.seedvault.header.VERSION
 import com.stevesoltys.seedvault.header.getADForKV
@@ -126,7 +127,18 @@ internal class KVBackup(
                 Log.e(TAG, "Exception reading backup input", result.exception)
                 return backupError(TRANSPORT_ERROR)
             }
-            state.needsUpload = true
+            state.needsUpload = if (state.packageInfo.packageName == MAGIC_PACKAGE_MANAGER) {
+                // Don't upload, if we currently can't do backups.
+                // If we tried, we would fail @pm@ backup which causes the system to do a re-init.
+                // See: https://github.com/seedvault-app/seedvault/issues/102
+                // K/V backups (typically starting with package manager metadata - @pm@)
+                // are scheduled with JobInfo.Builder#setOverrideDeadline()
+                // and thus do not respect backoff.
+                settingsManager.canDoBackupNow()
+            } else {
+                // all other packages always need upload
+                true
+            }
             val op = (result as Result.Ok).result
             if (op.value == null) {
                 Log.e(TAG, "Deleting record with key ${op.key}")
@@ -190,10 +202,11 @@ internal class KVBackup(
     suspend fun finishBackup(): Int {
         val state = this.state ?: error("No state in finishBackup")
         val packageName = state.packageInfo.packageName
-        Log.i(TAG, "Finish K/V Backup of $packageName")
+        Log.i(TAG, "Finish K/V Backup of $packageName - needs upload: ${state.needsUpload}")
 
         return try {
             if (state.needsUpload) uploadDb(state.token, state.name, packageName, state.db)
+            else state.db.close()
             TRANSPORT_OK
         } catch (e: IOException) {
             TRANSPORT_ERROR

app/src/test/java/com/stevesoltys/seedvault/transport/CoordinatorIntegrationTest.kt

@@ -121,6 +121,7 @@ internal class CoordinatorIntegrationTest : TransportTest() {
         val value2 = CapturingSlot<ByteArray>()
         val bOutputStream = ByteArrayOutputStream()
 
+        every { metadataManager.requiresInit } returns false
         every { settingsManager.getToken() } returns token
         every { metadataManager.salt } returns salt
         // read one key/value record and write it to output stream
@@ -197,6 +198,7 @@ internal class CoordinatorIntegrationTest : TransportTest() {
         val appData = ByteArray(size).apply { Random.nextBytes(this) }
         val bOutputStream = ByteArrayOutputStream()
 
+        every { metadataManager.requiresInit } returns false
         every { settingsManager.getToken() } returns token
         every { metadataManager.salt } returns salt
         // read one key/value record and write it to output stream

app/src/test/java/com/stevesoltys/seedvault/transport/backup/BackupCoordinatorTest.kt

@@ -1,8 +1,6 @@
 package com.stevesoltys.seedvault.transport.backup
 
-import android.app.backup.BackupTransport.FLAG_INCREMENTAL
 import android.app.backup.BackupTransport.TRANSPORT_ERROR
-import android.app.backup.BackupTransport.TRANSPORT_NON_INCREMENTAL_BACKUP_REQUIRED
 import android.app.backup.BackupTransport.TRANSPORT_NOT_INITIALIZED
 import android.app.backup.BackupTransport.TRANSPORT_OK
 import android.app.backup.BackupTransport.TRANSPORT_PACKAGE_REJECTED
@@ -112,9 +110,12 @@ internal class BackupCoordinatorTest : BackupTest() {
 
     @Test
     fun `error notification when device initialization fails`() = runBlocking {
+        val maybeTrue = Random.nextBoolean()
+
         every { settingsManager.getToken() } returns token
         coEvery { plugin.initializeDevice() } throws IOException()
-        every { settingsManager.canDoBackupNow() } returns true
+        every { metadataManager.requiresInit } returns maybeTrue
+        every { settingsManager.canDoBackupNow() } returns !maybeTrue
         every { notificationManager.onBackupError() } just Runs
 
         assertEquals(TRANSPORT_ERROR, backup.initializeDevice())
@@ -132,6 +133,7 @@ internal class BackupCoordinatorTest : BackupTest() {
         runBlocking {
             every { settingsManager.getToken() } returns token
             coEvery { plugin.initializeDevice() } throws IOException()
+            every { metadataManager.requiresInit } returns false
             every { settingsManager.canDoBackupNow() } returns false
 
             assertEquals(TRANSPORT_ERROR, backup.initializeDevice())
@@ -144,29 +146,6 @@ internal class BackupCoordinatorTest : BackupTest() {
             }
         }
 
-    @Test
-    fun `performIncrementalBackup fakes @pm@ when no backup possible`() = runBlocking {
-        val packageInfo = PackageInfo().apply { packageName = MAGIC_PACKAGE_MANAGER }
-
-        every { settingsManager.canDoBackupNow() } returns false
-        every { settingsManager.pmBackupNextTimeNonIncremental = true } just Runs
-        every { data.close() } just Runs
-
-        // returns OK even though we can't do backups
-        assertEquals(TRANSPORT_OK, backup.performIncrementalBackup(packageInfo, data, 0))
-
-        every { settingsManager.canDoBackupNow() } returns true
-        every { metadataManager.requiresInit } returns false
-        every { settingsManager.pmBackupNextTimeNonIncremental } returns true
-        every { settingsManager.pmBackupNextTimeNonIncremental = false } just Runs
-
-        // now that we can do backups again, it requests a full non-incremental backup of @pm@
-        assertEquals(
-            TRANSPORT_NON_INCREMENTAL_BACKUP_REQUIRED,
-            backup.performIncrementalBackup(packageInfo, data, FLAG_INCREMENTAL)
-        )
-    }
-
     @Test
     fun `performIncrementalBackup of @pm@ causes re-init when legacy format`() = runBlocking {
         val packageInfo = PackageInfo().apply { packageName = MAGIC_PACKAGE_MANAGER }
@@ -255,24 +234,34 @@ internal class BackupCoordinatorTest : BackupTest() {
 
     @Test
     fun `finish backup delegates to KV plugin if it has state`() = runBlocking {
-        val result = Random.nextInt()
-
         every { kv.hasState() } returns true
         every { full.hasState() } returns false
         every { kv.getCurrentPackage() } returns packageInfo
+        coEvery { kv.finishBackup() } returns TRANSPORT_OK
         every { settingsManager.getToken() } returns token
         coEvery { plugin.getOutputStream(token, FILE_BACKUP_METADATA) } returns metadataOutputStream
         every {
             metadataManager.onPackageBackedUp(packageInfo, BackupType.KV, metadataOutputStream)
         } just Runs
-        coEvery { kv.finishBackup() } returns result
         every { metadataOutputStream.close() } just Runs
 
-        assertEquals(result, backup.finishBackup())
+        assertEquals(TRANSPORT_OK, backup.finishBackup())
 
         verify { metadataOutputStream.close() }
     }
 
+    @Test
+    fun `finish backup does not upload @pm@ metadata, if it can't do backups`() = runBlocking {
+        every { kv.hasState() } returns true
+        every { full.hasState() } returns false
+        every { kv.getCurrentPackage() } returns pmPackageInfo
+
+        coEvery { kv.finishBackup() } returns TRANSPORT_OK
+        every { settingsManager.canDoBackupNow() } returns false
+
+        assertEquals(TRANSPORT_OK, backup.finishBackup())
+    }
+
     @Test
     fun `finish backup delegates to full plugin if it has state`() = runBlocking {
         val result = Random.nextInt()
@@ -280,12 +269,12 @@ internal class BackupCoordinatorTest : BackupTest() {
         every { kv.hasState() } returns false
         every { full.hasState() } returns true
         every { full.getCurrentPackage() } returns packageInfo
+        every { full.finishBackup() } returns result
         every { settingsManager.getToken() } returns token
         coEvery { plugin.getOutputStream(token, FILE_BACKUP_METADATA) } returns metadataOutputStream
         every {
             metadataManager.onPackageBackedUp(packageInfo, BackupType.FULL, metadataOutputStream)
         } just Runs
-        every { full.finishBackup() } returns result
         every { metadataOutputStream.close() } just Runs
 
         assertEquals(result, backup.finishBackup())

app/src/test/java/com/stevesoltys/seedvault/transport/backup/KVBackupTest.kt

@@ -16,6 +16,7 @@ import com.stevesoltys.seedvault.plugins.StoragePlugin
 import io.mockk.CapturingSlot
 import io.mockk.Runs
 import io.mockk.coEvery
+import io.mockk.coVerify
 import io.mockk.every
 import io.mockk.just
 import io.mockk.mockk
@@ -116,6 +117,7 @@ internal class KVBackupTest : BackupTest() {
         assertTrue(backup.hasState())
 
         verify { data.close() }
+        every { db.close() } just Runs
 
         assertEquals(TRANSPORT_OK, backup.finishBackup())
         assertFalse(backup.hasState())
@@ -153,6 +155,9 @@ internal class KVBackupTest : BackupTest() {
 
         assertEquals(TRANSPORT_OK, backup.performBackup(packageInfo, data, 0, token, salt))
         assertTrue(backup.hasState())
+
+        every { db.close() } just Runs
+
         assertEquals(TRANSPORT_OK, backup.finishBackup())
         assertFalse(backup.hasState())
     }
@@ -221,6 +226,29 @@ internal class KVBackupTest : BackupTest() {
         }
     }
 
+    @Test
+    fun `no upload when we back up @pm@ while we can't do backups`() = runBlocking {
+        every { dbManager.existsDb(pmPackageInfo.packageName) } returns false
+        every { crypto.getNameForPackage(salt, pmPackageInfo.packageName) } returns name
+        every { dbManager.getDb(pmPackageInfo.packageName) } returns db
+        every { settingsManager.canDoBackupNow() } returns false
+        every { db.put(key, dataValue) } just Runs
+        getDataInput(listOf(true, false))
+
+        assertEquals(TRANSPORT_OK, backup.performBackup(pmPackageInfo, data, 0, token, salt))
+        assertTrue(backup.hasState())
+        assertEquals(pmPackageInfo, backup.getCurrentPackage())
+
+        every { db.close() } just Runs
+
+        assertEquals(TRANSPORT_OK, backup.finishBackup())
+        assertFalse(backup.hasState())
+
+        coVerify(exactly = 0) {
+            plugin.getOutputStream(token, name)
+        }
+    }
+
     private fun singleRecordBackup(hasDataForPackage: Boolean = false) {
         initPlugin(hasDataForPackage)
         every { db.put(key, dataValue) } just Runs