Implement new Backend.save() method that can be re-tried

seedvault-app · Jan 3, 2025 · bd58d57 · bd58d57
1 parent 73da56a
commit bd58d57
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Showing 7 changed files with 93 additions and 22 deletions.
diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/Backend.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/Backend.kt
@@ -25,8 +25,11 @@ public interface Backend {
      */
     public suspend fun getFreeSpace(): Long?
 
+    @Deprecated(message = "use save(FileHandle, BackendSaver) instead")
     public suspend fun save(handle: FileHandle): OutputStream
 
+    public suspend fun save(handle: FileHandle, saver: BackendSaver): Long
+
     public suspend fun load(handle: FileHandle): InputStream
 
     public suspend fun list(

diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/BackendFactory.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/BackendFactory.kt
@@ -12,6 +12,8 @@ import org.calyxos.seedvault.core.backends.webdav.WebDavBackend
 import org.calyxos.seedvault.core.backends.webdav.WebDavConfig
 
 public class BackendFactory {
+    // TODO: implement a backend wrapper that handles retries for transient errors
+
     public fun createSafBackend(context: Context, config: SafProperties): Backend =
         SafBackend(context, config)
 

diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/BackendSaver.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/BackendSaver.kt
@@ -0,0 +1,32 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Calyx Institute
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.calyxos.seedvault.core.backends
+
+import java.io.OutputStream
+
+/**
+ * Used to save data with [Backend]s.
+ */
+public interface BackendSaver {
+    /**
+     * The number of bytes that will be saved or `null` if unknown.
+     */
+    public val size: Long
+
+    /**
+     * The SHA256 hash (in lower-case hex string representation) the bytes to be saved have,
+     * or `null` if it isn't known.
+     */
+    public val sha256: String?
+
+    /**
+     * Called by the backend when it wants to save the data to the provided [outputStream].
+     * Can be called more than once, in case the backend encountered an error saving.
+     *
+     * @return the number of bytes saved. Should be equal to [size].
+     */
+    public fun save(outputStream: OutputStream): Long
+}
diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/BackendTest.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/BackendTest.kt
@@ -7,6 +7,7 @@ package org.calyxos.seedvault.core.backends
 
 import androidx.annotation.VisibleForTesting
 import org.calyxos.seedvault.core.toHexString
+import java.io.OutputStream
 import kotlin.random.Random
 import kotlin.test.assertContentEquals
 import kotlin.test.assertEquals
@@ -15,6 +16,7 @@ import kotlin.test.assertNotNull
 import kotlin.test.assertTrue
 
 @VisibleForTesting
+@Suppress("BlockingMethodInNonBlockingContext")
 public abstract class BackendTest {
 
     public abstract val backend: Backend
@@ -26,13 +28,8 @@ public abstract class BackendTest {
         val now = System.currentTimeMillis()
         val bytes1 = Random.nextBytes(1337)
         val bytes2 = Random.nextBytes(1337 * 8)
-        backend.save(LegacyAppBackupFile.Metadata(now)).use {
-            it.write(bytes1)
-        }
-
-        backend.save(FileBackupFileType.Snapshot(androidId, now)).use {
-            it.write(bytes2)
-        }
+        backend.save(LegacyAppBackupFile.Metadata(now), getSaver(bytes1))
+        backend.save(FileBackupFileType.Snapshot(androidId, now), getSaver(bytes2))
 
         var metadata: LegacyAppBackupFile.Metadata? = null
         var fileSnapshot: FileBackupFileType.Snapshot? = null
@@ -58,9 +55,7 @@ public abstract class BackendTest {
         val blobName = Random.nextBytes(32).toHexString()
         var blob: FileBackupFileType.Blob? = null
         val bytes3 = Random.nextBytes(1337 * 16)
-        backend.save(FileBackupFileType.Blob(androidId, blobName)).use {
-            it.write(bytes3)
-        }
+        backend.save(FileBackupFileType.Blob(androidId, blobName), getSaver(bytes3))
         backend.list(
             null,
             FileBackupFileType.Snapshot::class,
@@ -91,9 +86,7 @@ public abstract class BackendTest {
 
         val bytes4 = Random.nextBytes(1337)
         val bytes5 = Random.nextBytes(1337 * 8)
-        backend.save(AppBackupFileType.Snapshot(repoId, snapshotId)).use {
-            it.write(bytes4)
-        }
+        backend.save(AppBackupFileType.Snapshot(repoId, snapshotId), getSaver(bytes4))
 
         var appSnapshot: AppBackupFileType.Snapshot? = null
         backend.list(
@@ -108,9 +101,7 @@ public abstract class BackendTest {
         assertNotNull(appSnapshot)
         assertContentEquals(bytes4, backend.load(appSnapshot as FileHandle).readAllBytes())
 
-        backend.save(AppBackupFileType.Blob(repoId, blobId)).use {
-            it.write(bytes5)
-        }
+        backend.save(AppBackupFileType.Blob(repoId, blobId), getSaver(bytes5))
 
         var blobHandle: AppBackupFileType.Blob? = null
         backend.list(
@@ -151,9 +142,7 @@ public abstract class BackendTest {
 
         backend.remove(blob)
         try {
-            backend.save(blob).use {
-                it.write(bytes)
-            }
+            backend.save(blob, getSaver(bytes))
             assertContentEquals(bytes, backend.load(blob as FileHandle).readAllBytes())
         } finally {
             backend.remove(blob)
@@ -170,13 +159,21 @@ public abstract class BackendTest {
         val blob = AppBackupFileType.Blob(repoId, Random.nextBytes(32).toHexString())
         val bytes = Random.nextBytes(2342)
         try {
-            backend.save(blob).use {
-                it.write(bytes)
-            }
+            backend.save(blob, getSaver(bytes))
             assertContentEquals(bytes, backend.load(blob as FileHandle).readAllBytes())
         } finally {
             backend.remove(blob)
         }
     }
 
+    private fun getSaver(bytes: ByteArray) = object : BackendSaver {
+        override val size: Long = bytes.size.toLong()
+        override val sha256: String? = null
+
+        override fun save(outputStream: OutputStream): Long {
+            outputStream.write(bytes)
+            return size
+        }
+    }
+
 }
diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/saf/SafBackend.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/saf/SafBackend.kt
@@ -18,6 +18,7 @@ import io.github.oshai.kotlinlogging.KLogger
 import io.github.oshai.kotlinlogging.KotlinLogging
 import org.calyxos.seedvault.core.backends.AppBackupFileType
 import org.calyxos.seedvault.core.backends.Backend
+import org.calyxos.seedvault.core.backends.BackendSaver
 import org.calyxos.seedvault.core.backends.Constants.DIRECTORY_ROOT
 import org.calyxos.seedvault.core.backends.Constants.FILE_BACKUP_METADATA
 import org.calyxos.seedvault.core.backends.Constants.appSnapshotRegex
@@ -86,12 +87,19 @@ public class SafBackend(
         } else bytesAvailable
     }
 
+    @Deprecated("use save(FileHandle, BackendSaver) instead")
     override suspend fun save(handle: FileHandle): OutputStream {
         log.debugLog { "save($handle)" }
         val file = cache.getOrCreateFile(handle)
         return file.getOutputStream(context.contentResolver)
     }
 
+    override suspend fun save(handle: FileHandle, saver: BackendSaver): Long {
+        log.debugLog { "save($handle)" }
+        val file = cache.getOrCreateFile(handle)
+        return file.getOutputStream(context.contentResolver).use { saver.save(it) }
+    }
+
     override suspend fun load(handle: FileHandle): InputStream {
         log.debugLog { "load($handle)" }
         val file = cache.getOrCreateFile(handle)

diff --git a/core/src/main/java/org/calyxos/seedvault/core/backends/webdav/WebDavBackend.kt b/core/src/main/java/org/calyxos/seedvault/core/backends/webdav/WebDavBackend.kt
@@ -27,6 +27,7 @@ import okhttp3.RequestBody
 import okio.BufferedSink
 import org.calyxos.seedvault.core.backends.AppBackupFileType
 import org.calyxos.seedvault.core.backends.Backend
+import org.calyxos.seedvault.core.backends.BackendSaver
 import org.calyxos.seedvault.core.backends.Constants.DIRECTORY_ROOT
 import org.calyxos.seedvault.core.backends.Constants.FILE_BACKUP_METADATA
 import org.calyxos.seedvault.core.backends.Constants.appSnapshotRegex
@@ -121,6 +122,7 @@ public class WebDavBackend(
         return availableBytes
     }
 
+    @Deprecated("use save(FileHandle, BackendSaver) instead")
     override suspend fun save(handle: FileHandle): OutputStream {
         val location = handle.toHttpUrl()
         val davCollection = DavCollection(okHttpClient, location)
@@ -153,6 +155,27 @@ public class WebDavBackend(
         return pipedOutputStream
     }
 
+    override suspend fun save(handle: FileHandle, saver: BackendSaver): Long {
+        val location = handle.toHttpUrl()
+        val davCollection = DavCollection(okHttpClient, location)
+        davCollection.ensureFoldersExist(log, folders)
+
+        val body = object : RequestBody() {
+            override fun isOneShot(): Boolean = true
+            override fun contentType() = "application/octet-stream".toMediaType()
+            override fun contentLength(): Long = saver.size
+            override fun writeTo(sink: BufferedSink) {
+                saver.save(sink.outputStream())
+            }
+        }
+        return suspendCoroutine { cont ->
+            davCollection.put(body) { response ->
+                log.debugLog { "save($location) = $response" }
+                cont.resume(saver.size)
+            }
+        }
+    }
+
     override suspend fun load(handle: FileHandle): InputStream {
         val location = handle.toHttpUrl()
         val davCollection = DavCollection(okHttpClient, location)

diff --git a/storage/demo/src/main/java/de/grobox/storagebackuptester/plugin/TestSafBackend.kt b/storage/demo/src/main/java/de/grobox/storagebackuptester/plugin/TestSafBackend.kt
@@ -8,6 +8,7 @@ package de.grobox.storagebackuptester.plugin
 import android.content.Context
 import android.net.Uri
 import org.calyxos.seedvault.core.backends.Backend
+import org.calyxos.seedvault.core.backends.BackendSaver
 import org.calyxos.seedvault.core.backends.FileHandle
 import org.calyxos.seedvault.core.backends.FileInfo
 import org.calyxos.seedvault.core.backends.TopLevelFolder
@@ -47,6 +48,11 @@ class TestSafBackend(
         return delegate.save(handle)
     }
 
+    override suspend fun save(handle: FileHandle, saver: BackendSaver): Long {
+        if (getLocationUri() == null) return 0
+        return delegate.save(handle, saver)
+    }
+
     override suspend fun load(handle: FileHandle): InputStream {
         return delegate.load(handle)
     }