Closes issue #7762: Adds support for persisting/restoring downloads.

components/browser/state/src/main/java/mozilla/components/browser/state/action/BrowserAction.kt

@@ -207,7 +207,7 @@ sealed class ContentAction : BrowserAction() {
     /**
      * Removes the [DownloadState] of the [ContentState] with the given [sessionId].
      */
-    data class ConsumeDownloadAction(val sessionId: String, val downloadId: Long) : ContentAction()
+    data class ConsumeDownloadAction(val sessionId: String, val downloadId: String) : ContentAction()
 
     /**
      * Updates the [HitResult] of the [ContentState] with the given [sessionId].
@@ -700,7 +700,7 @@ sealed class DownloadAction : BrowserAction() {
     /**
      * Updates the [BrowserState] to remove the download with the provided [downloadId].
      */
-    data class RemoveDownloadAction(val downloadId: Long) : DownloadAction()
+    data class RemoveDownloadAction(val downloadId: String) : DownloadAction()
 
     /**
      * Updates the [BrowserState] to remove all downloads.
@@ -711,6 +711,16 @@ sealed class DownloadAction : BrowserAction() {
      * Updates the provided [download] on the [BrowserState].
      */
     data class UpdateDownloadAction(val download: DownloadState) : DownloadAction()
+
+    /**
+     * Restores the [BrowserState.downloads] state from the storage.
+     */
+    object RestoreDownloadsStateAction : DownloadAction()
+
+    /**
+     * Restores the given [download] from the storage.
+     */
+    data class RestoreDownloadStateAction(val download: DownloadState) : DownloadAction()
 }
 
 /**

components/browser/state/src/main/java/mozilla/components/browser/state/reducer/DownloadStateReducer.kt

@@ -25,6 +25,8 @@ internal object DownloadStateReducer {
             is DownloadAction.RemoveAllDownloadsAction -> {
                 state.copy(downloads = emptyMap())
             }
+            is DownloadAction.RestoreDownloadsStateAction -> state
+            is DownloadAction.RestoreDownloadStateAction -> updateDownloads(state, action.download)
         }
     }
 

components/browser/state/src/main/java/mozilla/components/browser/state/state/BrowserState.kt

@@ -28,6 +28,6 @@ data class BrowserState(
     val containers: Map<String, ContainerState> = emptyMap(),
     val extensions: Map<String, WebExtensionState> = emptyMap(),
     val media: MediaState = MediaState(),
-    val downloads: Map<Long, DownloadState> = emptyMap(),
+    val downloads: Map<String, DownloadState> = emptyMap(),
     val search: SearchState = SearchState()
 ) : State

components/browser/state/src/main/java/mozilla/components/browser/state/state/content/DownloadState.kt

@@ -7,7 +7,7 @@ package mozilla.components.browser.state.state.content
 import android.os.Environment
 import android.os.Parcelable
 import kotlinx.android.parcel.Parcelize
-import kotlin.random.Random
+import java.util.UUID
 
 /**
  * Value type that represents a download request.
@@ -24,7 +24,7 @@ import kotlin.random.Random
  * @property referrerUrl The site that linked to this download.
  * @property skipConfirmation Whether or not the confirmation dialog should be shown before the download begins.
  * @property id The unique identifier of this download.
- * @property sessionId Identifier of the session that spawned the download.
+ * @property createdTime A timestamp when the download was created.
  * @
  */
 @Suppress("Deprecation")
@@ -40,40 +40,42 @@ data class DownloadState(
     val destinationDirectory: String = Environment.DIRECTORY_DOWNLOADS,
     val referrerUrl: String? = null,
     val skipConfirmation: Boolean = false,
-    val id: Long = Random.nextLong(),
-    val sessionId: String? = null
+    val id: String = UUID.randomUUID().toString(),
+    val sessionId: String? = null,
+    val createdTime: Long = System.currentTimeMillis()
 ) : Parcelable {
     val filePath: String get() =
         Environment.getExternalStoragePublicDirectory(destinationDirectory).path + "/" + fileName
 
     /**
      * Status that represents every state that a download can be in.
      */
-    enum class Status {
+    @Suppress("MagicNumber")
+    enum class Status(val id: Int) {
         /**
          * Indicates that the download is in the first state after creation but not yet [DOWNLOADING].
          */
-        INITIATED,
+        INITIATED(1),
         /**
          * Indicates that an [INITIATED] download is now actively being downloaded.
          */
-        DOWNLOADING,
+        DOWNLOADING(2),
         /**
          * Indicates that the download that has been [DOWNLOADING] has been paused.
          */
-        PAUSED,
+        PAUSED(3),
         /**
          * Indicates that the download that has been [DOWNLOADING] has been cancelled.
          */
-        CANCELLED,
+        CANCELLED(4),
         /**
          * Indicates that the download that has been [DOWNLOADING] has moved to failed because
          * something unexpected has happened.
          */
-        FAILED,
+        FAILED(5),
         /**
          * Indicates that the [DOWNLOADING] download has been completed.
          */
-        COMPLETED
+        COMPLETED(6)
     }
 }

components/browser/state/src/test/java/mozilla/components/browser/state/action/ContentActionTest.kt

@@ -349,7 +349,7 @@ class ContentActionTest {
     @Test
     fun `ConsumeDownloadAction removes download`() {
         val download = DownloadState(
-            id = 1337L,
+            id = "1337",
             url = "https://www.mozilla.org", sessionId = tab.id
         )
 
@@ -360,7 +360,7 @@ class ContentActionTest {
         assertEquals(download, tab.content.download)
 
         store.dispatch(
-            ContentAction.ConsumeDownloadAction(tab.id, downloadId = 1337)
+            ContentAction.ConsumeDownloadAction(tab.id, downloadId = "1337")
         ).joinBlocking()
 
         assertNull(tab.content.download)
@@ -369,7 +369,7 @@ class ContentActionTest {
     @Test
     fun `ConsumeDownloadAction does not remove download with different id`() {
         val download = DownloadState(
-            id = 1337L,
+            id = "1337",
             url = "https://www.mozilla.org", sessionId = tab.id
         )
 
@@ -380,7 +380,7 @@ class ContentActionTest {
         assertEquals(download, tab.content.download)
 
         store.dispatch(
-            ContentAction.ConsumeDownloadAction(tab.id, downloadId = 4223)
+            ContentAction.ConsumeDownloadAction(tab.id, downloadId = "4223")
         ).joinBlocking()
 
         assertNotNull(tab.content.download)

components/browser/state/src/test/java/mozilla/components/browser/state/action/DownloadActionTest.kt

@@ -11,6 +11,7 @@ import mozilla.components.support.test.ext.joinBlocking
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
+import org.junit.Assert.assertSame
 import org.junit.Test
 
 class DownloadActionTest {
@@ -30,6 +31,30 @@ class DownloadActionTest {
         assertEquals(2, store.state.downloads.size)
     }
 
+    @Test
+    fun `RestoreDownloadStateAction adds download`() {
+        val store = BrowserStore(BrowserState())
+
+        val download1 = DownloadState("https://mozilla.org/download1", destinationDirectory = "")
+        store.dispatch(DownloadAction.RestoreDownloadStateAction(download1)).joinBlocking()
+        assertEquals(download1, store.state.downloads[download1.id])
+        assertEquals(1, store.state.downloads.size)
+
+        val download2 = DownloadState("https://mozilla.org/download2", destinationDirectory = "")
+        store.dispatch(DownloadAction.RestoreDownloadStateAction(download2)).joinBlocking()
+        assertEquals(download2, store.state.downloads[download2.id])
+        assertEquals(2, store.state.downloads.size)
+    }
+
+    @Test
+    fun `RestoreDownloadsStateAction does nothing`() {
+        val store = BrowserStore(BrowserState())
+
+        val state = store.state
+        store.dispatch(DownloadAction.RestoreDownloadsStateAction).joinBlocking()
+        assertSame(store.state, state)
+    }
+
     @Test
     fun `RemoveDownloadAction removes download`() {
         val store = BrowserStore(BrowserState())

components/feature/downloads/build.gradle

@@ -5,13 +5,21 @@
 apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 apply plugin: 'kotlin-android-extensions'
+apply plugin: 'kotlin-kapt'
 
 android {
     compileSdkVersion config.compileSdkVersion
 
     defaultConfig {
         minSdkVersion config.minSdkVersion
         targetSdkVersion config.targetSdkVersion
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+        kapt {
+            arguments {
+                arg("room.schemaLocation", "$projectDir/schemas".toString())
+            }
+        }
     }
 
     buildTypes {
@@ -20,6 +28,10 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+
+    sourceSets {
+        androidTest.assets.srcDirs += files("$projectDir/schemas".toString())
+    }
 }
 
 tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
@@ -43,6 +55,11 @@ dependencies {
     implementation Dependencies.kotlin_stdlib
     implementation Dependencies.androidx_recyclerview
     implementation Dependencies.androidx_constraintlayout
+    implementation Dependencies.androidx_room_runtime
+    implementation Dependencies.androidx_paging
+    implementation Dependencies.androidx_lifecycle_livedata
+
+    kapt Dependencies.androidx_room_compiler
 
     testImplementation Dependencies.androidx_test_core
     testImplementation Dependencies.androidx_test_junit
@@ -52,6 +69,16 @@ dependencies {
     testImplementation project(':concept-engine')
     testImplementation project(':support-test')
     testImplementation project(':support-test-libstate')
+
+    androidTestImplementation project(':support-android-test')
+
+    androidTestImplementation Dependencies.androidx_room_testing
+    androidTestImplementation Dependencies.androidx_arch_core_testing
+    androidTestImplementation Dependencies.androidx_test_core
+    androidTestImplementation Dependencies.androidx_test_runner
+    androidTestImplementation Dependencies.androidx_test_rules
+    androidTestImplementation Dependencies.testing_coroutines
+
 }
 
 apply from: '../../../publish.gradle'

components/feature/downloads/schemas/mozilla.components.feature.downloads.db.DownloadsDatabase/1.json

@@ -0,0 +1,76 @@
+{
+  "formatVersion": 1,
+  "database": {
+    "version": 1,
+    "identityHash": "342d0e5d0a0fcde72b88ac4585caf842",
+    "entities": [
+      {
+        "tableName": "downloads",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` TEXT NOT NULL, `url` TEXT NOT NULL, `file_name` TEXT, `content_type` TEXT, `content_length` INTEGER, `status` INTEGER NOT NULL, `destination_directory` TEXT NOT NULL, `created_at` INTEGER NOT NULL, PRIMARY KEY(`id`))",
+        "fields": [
+          {
+            "fieldPath": "id",
+            "columnName": "id",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "url",
+            "columnName": "url",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "fileName",
+            "columnName": "file_name",
+            "affinity": "TEXT",
+            "notNull": false
+          },
+          {
+            "fieldPath": "contentType",
+            "columnName": "content_type",
+            "affinity": "TEXT",
+            "notNull": false
+          },
+          {
+            "fieldPath": "contentLength",
+            "columnName": "content_length",
+            "affinity": "INTEGER",
+            "notNull": false
+          },
+          {
+            "fieldPath": "status",
+            "columnName": "status",
+            "affinity": "INTEGER",
+            "notNull": true
+          },
+          {
+            "fieldPath": "destinationDirectory",
+            "columnName": "destination_directory",
+            "affinity": "TEXT",
+            "notNull": true
+          },
+          {
+            "fieldPath": "createdAt",
+            "columnName": "created_at",
+            "affinity": "INTEGER",
+            "notNull": true
+          }
+        ],
+        "primaryKey": {
+          "columnNames": [
+            "id"
+          ],
+          "autoGenerate": false
+        },
+        "indices": [],
+        "foreignKeys": []
+      }
+    ],
+    "views": [],
+    "setupQueries": [
+      "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '342d0e5d0a0fcde72b88ac4585caf842')"
+    ]
+  }
+}