Make APK backup self-healing

app/src/main/java/com/stevesoltys/seedvault/repo/BlobCache.kt

@@ -62,6 +62,15 @@ class BlobCache(
      */
     operator fun get(chunkId: String): Blob? = blobMap[chunkId]
 
+    /**
+     * Should only be called after [populateCache] has returned.
+     *
+     * @return true if all [chunkIds] are in cache, or false if one or more is missing.
+     */
+    fun containsAll(chunkIds: List<String>): Boolean = chunkIds.all { chunkId ->
+        blobMap.containsKey(chunkId)
+    }
+
     /**
      * Should get called for all new blobs as soon as they've been saved to the backend.
      */

app/src/main/java/com/stevesoltys/seedvault/worker/ApkBackup.kt

@@ -19,6 +19,7 @@ import com.stevesoltys.seedvault.proto.Snapshot.Blob
 import com.stevesoltys.seedvault.proto.SnapshotKt.split
 import com.stevesoltys.seedvault.repo.AppBackupManager
 import com.stevesoltys.seedvault.repo.BackupReceiver
+import com.stevesoltys.seedvault.repo.BlobCache
 import com.stevesoltys.seedvault.repo.forProto
 import com.stevesoltys.seedvault.repo.hexFromProto
 import com.stevesoltys.seedvault.settings.SettingsManager
@@ -37,6 +38,7 @@ internal class ApkBackup(
     private val backupReceiver: BackupReceiver,
     private val appBackupManager: AppBackupManager,
     private val settingsManager: SettingsManager,
+    private val blobCache: BlobCache,
 ) {
 
     private val snapshotCreator
@@ -101,22 +103,26 @@ internal class ApkBackup(
         if (!needsBackup && oldApk != null) {
             // We could also check if there are new feature module splits to back up,
             // but we rely on the app themselves to re-download those, if needed after restore.
+
+            val chunkIds = oldApk.splitsList.flatMap {
+                it.chunkIdsList.map { chunkId -> chunkId.hexFromProto() }
+            }
+            if (blobCache.containsAll(chunkIds)) {
                 Log.d(
                     TAG, "Package $packageName with version $version" +
                         " already has a backup ($backedUpVersion)" +
                         " with the same signature. Not backing it up."
                 )
-            // build up blobMap from old snapshot
-            val chunkIds = oldApk.splitsList.flatMap {
-                it.chunkIdsList.map { chunkId -> chunkId.hexFromProto() }
-            }
+                // all blobs are cached, i.e. still on backend, so no new backup needed
                 val blobMap = chunkIds.associateWith { chunkId ->
                     latestSnapshot.blobsMap[chunkId] ?: error("Missing blob for $chunkId")
                 }
-            // TODO could also check if all blobs are (still) available in BlobCache
                 // important: add old APK to snapshot or it wouldn't be part of backup
                 snapshotCreator.onApkBackedUp(packageInfo, oldApk, blobMap)
                 return
+            } else {
+                Log.w(TAG, "Blobs for APKs of $packageName have issues in backend. Fixing...")
+            }
         }
 
         // builder for Apk object

app/src/main/java/com/stevesoltys/seedvault/worker/WorkerModule.kt

@@ -33,6 +33,7 @@ val workerModule = module {
             backupReceiver = get(),
             appBackupManager = get(),
             settingsManager = get(),
+            blobCache = get(),
         )
     }
     single {

app/src/test/java/com/stevesoltys/seedvault/restore/install/ApkBackupRestoreTest.kt

@@ -24,6 +24,7 @@ import com.stevesoltys.seedvault.metadata.PackageMetadataMap
 import com.stevesoltys.seedvault.proto.Snapshot
 import com.stevesoltys.seedvault.repo.AppBackupManager
 import com.stevesoltys.seedvault.repo.BackupReceiver
+import com.stevesoltys.seedvault.repo.BlobCache
 import com.stevesoltys.seedvault.repo.Loader
 import com.stevesoltys.seedvault.repo.SnapshotCreator
 import com.stevesoltys.seedvault.repo.SnapshotManager
@@ -70,6 +71,7 @@ internal class ApkBackupRestoreTest : TransportTest() {
     private val backupStateManager: BackupStateManager = mockk()
     private val backupReceiver: BackupReceiver = mockk()
     private val appBackupManager: AppBackupManager = mockk()
+    private val blobCache: BlobCache = mockk()
     private val snapshotManager: SnapshotManager = mockk()
     private val snapshotCreator: SnapshotCreator = mockk()
     private val loader: Loader = mockk()
@@ -81,7 +83,8 @@ internal class ApkBackupRestoreTest : TransportTest() {
     private val apkInstaller: ApkInstaller = mockk()
     private val installRestriction: InstallRestriction = mockk()
 
-    private val apkBackup = ApkBackup(pm, backupReceiver, appBackupManager, settingsManager)
+    private val apkBackup =
+        ApkBackup(pm, backupReceiver, appBackupManager, settingsManager, blobCache)
     private val apkRestore: ApkRestore = ApkRestore(
         context = strictContext,
         backupManager = backupManager,

app/src/test/java/com/stevesoltys/seedvault/worker/ApkBackupTest.kt

@@ -23,7 +23,9 @@ import com.stevesoltys.seedvault.proto.copy
 import com.stevesoltys.seedvault.repo.AppBackupManager
 import com.stevesoltys.seedvault.repo.BackupData
 import com.stevesoltys.seedvault.repo.BackupReceiver
+import com.stevesoltys.seedvault.repo.BlobCache
 import com.stevesoltys.seedvault.repo.SnapshotCreator
+import com.stevesoltys.seedvault.repo.hexFromProto
 import com.stevesoltys.seedvault.transport.backup.BackupTest
 import io.mockk.Runs
 import io.mockk.coEvery
@@ -51,9 +53,11 @@ internal class ApkBackupTest : BackupTest() {
     private val pm: PackageManager = mockk()
     private val backupReceiver: BackupReceiver = mockk()
     private val appBackupManager: AppBackupManager = mockk()
+    private val blobCache: BlobCache = mockk()
     private val snapshotCreator: SnapshotCreator = mockk()
 
-    private val apkBackup = ApkBackup(pm, backupReceiver, appBackupManager, settingsManager)
+    private val apkBackup =
+        ApkBackup(pm, backupReceiver, appBackupManager, settingsManager, blobCache)
 
     private val signatureBytes = byteArrayOf(0x01, 0x02, 0x03)
     private val signatureHash = byteArrayOf(0x03, 0x02, 0x01)
@@ -110,7 +114,9 @@ internal class ApkBackupTest : BackupTest() {
         val apk = apk.copy { versionCode = packageInfo.longVersionCode }
         val app = app { this.apk = apk }
         val s = snapshot.copy { apps.put(packageName, app) }
+        val chunkIds = apk.splitsList.flatMap { it.chunkIdsList.hexFromProto() }
         expectChecks()
+        every { blobCache.containsAll(chunkIds) } returns true
         every {
             snapshotCreator.onApkBackedUp(packageInfo, apk, blobMap)
         } just Runs
@@ -162,6 +168,47 @@ internal class ApkBackupTest : BackupTest() {
             }
         }
 
+    @Test
+    fun `does back up the same version when blobs are missing from cache`(@TempDir tmpDir: Path) =
+        runBlocking {
+            val tmpFile = File(tmpDir.toAbsolutePath().toString())
+            packageInfo.applicationInfo!!.sourceDir = File(tmpFile, "test.apk").apply {
+                assertTrue(createNewFile())
+            }.absolutePath
+            val apk = apk.copy {
+                versionCode = packageInfo.longVersionCode
+                splits.clear()
+                splits.add(baseSplit)
+            }
+            val app = app { this.apk = apk }
+            val s = snapshot.copy { apps.put(packageName, app) }
+            val chunkIds = apk.splitsList.flatMap { it.chunkIdsList.hexFromProto() }
+            expectChecks()
+            every { blobCache.containsAll(chunkIds) } returns false // blobs missing here
+
+            every {
+                pm.getInstallSourceInfo(packageInfo.packageName)
+            } returns InstallSourceInfo(null, null, null, apk.installer)
+            coEvery {
+                backupReceiver.readFromStream("APK backup $packageName ", any())
+            } returns apkBackupData
+
+            every {
+                snapshotCreator.onApkBackedUp(packageInfo, match<Snapshot.Apk> {
+                    it.installer == apk.installer
+                }, apkBackupData.blobMap)
+            } just Runs
+
+            apkBackup.backupApkIfNecessary(packageInfo, s)
+
+            coVerify {
+                backupReceiver.readFromStream("APK backup $packageName ", any())
+                snapshotCreator.onApkBackedUp(packageInfo, match<Snapshot.Apk> {
+                    it.installer == apk.installer
+                }, apkBackupData.blobMap)
+            }
+        }
+
     @Test
     fun `throws exception when APK doesn't exist`() {
         packageInfo.applicationInfo!!.sourceDir = "/tmp/doesNotExist"