Add concept-storage with a basic history storage interface

Author: Grisha Kruglov

automation/taskcluster/artifacts.yml

@@ -25,6 +25,9 @@
         public/build/concept.engine.maven.zip:
           path: /build/android-components/components/concept/engine/build/target.maven.zip
           name: concept-engine
+        public/build/concept.storage.maven.zip:
+          path: /build/android-components/components/concept/storage/build/target.maven.zip
+          name: concept-storage
         public/build/concept.toolbar.maven.zip:
           path: /build/android-components/components/concept/toolbar/build/target.maven.zip
           name: concept-toolbar

components/concept/storage/README.md

@@ -0,0 +1,27 @@
+# [Android Components](../../../README.md) > Concept > Storage
+
+The `concept-storage` component contains interfaces and abstract classes that describe a "core data" storage layer.
+
+This abstraction makes it possible to build components that work independently of the storage layer being used.
+
+Currently an [in-memory storage implementation](../../browser/storage-memory) is available.
+
+## Usage
+
+### Setting up the dependency
+
+Use Gradle to download the library from [maven.mozilla.org](https://maven.mozilla.org/) ([Setup repository](../../../README.md#maven-repository)):
+
+```Groovy
+implementation "org.mozilla.components:concept-storage:{latest-version}"
+```
+
+### Integration
+
+One way to interact with a `concept-storage` component is via [feature-storage](../../features/storage/README.md), which provides "glue" implementations that make use of storage. For example, a `features.storage.HistoryTrackingFeature` allows a `concept.engine.Engine` to keep track of visits and page meta information.
+
+## License
+
+    This Source Code Form is subject to the terms of the Mozilla Public
+    License, v. 2.0. If a copy of the MPL was not distributed with this
+    file, You can obtain one at http://mozilla.org/MPL/2.0/

components/concept/storage/build.gradle

@@ -0,0 +1,40 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+
+android {
+    compileSdkVersion Config.compileSdkVersion
+
+    defaultConfig {
+        minSdkVersion Config.minSdkVersion
+        targetSdkVersion Config.targetSdkVersion
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+}
+
+dependencies {
+    implementation Deps.kotlin_stdlib
+    implementation Deps.support_annotations
+
+    // We expose this as API because we are using Observable in our public API and do not want every
+    // consumer to have to manually import "base".
+    api project(':support-base')
+
+    testImplementation Deps.testing_junit
+    testImplementation Deps.testing_robolectric
+    testImplementation Deps.testing_mockito
+
+    testImplementation project(':support-test')
+}
+
+apply from: '../../../publish.gradle'
+ext.configurePublish(Config.componentsGroupId, archivesBaseName, gradle.componentDescriptions[archivesBaseName])

components/concept/storage/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

components/concept/storage/src/main/AndroidManifest.xml

@@ -0,0 +1,5 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="mozilla.components.concept.storage" />

components/concept/storage/src/main/java/mozilla/components/concept/storage/HistoryStorage.kt

@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package mozilla.components.concept.storage
+
+/**
+ * An interface which defines read/write methods for history data.
+ */
+interface HistoryStorage {
+    /**
+     * Records a visit to a page.
+     * @param uri of the page which was visited.
+     * @param visitType type of the visit, see [VisitType].
+     */
+    fun recordVisit(uri: String, visitType: VisitType)
+
+    /**
+     * Records an observation about a page.
+     * @param uri of the page for which to record an observation.
+     * @param observation a [PageObservation] which encapsulates meta data observed about the page.
+     */
+    fun recordObservation(uri: String, observation: PageObservation)
+
+    /**
+     * Maps a list of page URIs to a list of booleans indicating if each URI was visited.
+     * @param uris a list of page URIs about which "visited" information is being requested.
+     * @param callback will be invoked with a list of booleans indicating visited status of each
+     * corresponding page URI from [uris].
+     */
+    fun getVisited(uris: List<String>, callback: (List<Boolean>) -> Unit)
+
+    /**
+     * Retrieves a list of all visited pages.
+     * @param callback will be invoked with a list of all visited page URIs.
+     */
+    fun getVisited(callback: (List<String>) -> Unit)
+}
+
+data class PageObservation(val title: String?)
+
+/**
+ * Visit type constants as defined by Desktop Firefox.
+ */
+@SuppressWarnings("MagicNumber")
+enum class VisitType(val type: Int) {
+    // User followed a link.
+    LINK(1),
+    // User typed a URL or selected it from the UI (autocomplete results, etc).
+    TYPED(2),
+    RELOAD(9)
+}

settings.gradle

@@ -22,6 +22,7 @@ setupProject(':concept-awesomebar', 'components/concept/awesomebar', 'An abstrac
 setupProject(':concept-toolbar', 'components/concept/toolbar', 'An abstract definition of a toolbar component.')
 setupProject(':concept-tabstray', 'components/concept/tabstray', 'An abstract definition of a tabs tray component.')
 setupProject(':concept-engine', 'components/concept/engine', 'An abstract layer hiding the actual browser engine implementation.')
+setupProject(':concept-storage', 'components/concept/storage', 'An abstract definition of a browser storage layer.')
 
 ////////////////////////////////////////////////////////////////////////////////////////////////////
 // Features