Closes #7023 - Add HistoryState to content state

components/browser/engine-gecko-beta/src/main/java/mozilla/components/browser/engine/gecko/GeckoEngineSession.kt

@@ -22,6 +22,7 @@ import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.Settings
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.history.HistoryTrackingDelegate
 import mozilla.components.concept.engine.manifest.WebAppManifestParser
 import mozilla.components.concept.engine.request.RequestInterceptor
@@ -580,6 +581,14 @@ class GeckoEngineSession(
                 visits.toBooleanArray()
             }
         }
+
+        override fun onHistoryStateChange(
+            session: GeckoSession,
+            historyList: GeckoSession.HistoryDelegate.HistoryList
+        ) {
+            val items = historyList.map { HistoryItem(title = it.title, uri = it.uri) }
+            notifyObservers { onHistoryStateChanged(items, historyList.currentIndex) }
+        }
     }
 
     @Suppress("ComplexMethod")

components/browser/engine-gecko-nightly/src/main/java/mozilla/components/browser/engine/gecko/GeckoEngineSession.kt

@@ -22,6 +22,7 @@ import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.Settings
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.history.HistoryTrackingDelegate
 import mozilla.components.concept.engine.manifest.WebAppManifestParser
 import mozilla.components.concept.engine.request.RequestInterceptor
@@ -592,6 +593,14 @@ class GeckoEngineSession(
                 visits.toBooleanArray()
             }
         }
+
+        override fun onHistoryStateChange(
+            session: GeckoSession,
+            historyList: GeckoSession.HistoryDelegate.HistoryList
+        ) {
+            val items = historyList.map { HistoryItem(title = it.title, uri = it.uri) }
+            notifyObservers { onHistoryStateChanged(items, historyList.currentIndex) }
+        }
     }
 
     @Suppress("ComplexMethod")

components/browser/engine-gecko/src/main/java/mozilla/components/browser/engine/gecko/GeckoEngineSession.kt

@@ -20,6 +20,7 @@ import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.Settings
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.history.HistoryTrackingDelegate
 import mozilla.components.concept.engine.manifest.WebAppManifestParser
 import mozilla.components.concept.engine.request.RequestInterceptor
@@ -578,6 +579,14 @@ class GeckoEngineSession(
                 visits.toBooleanArray()
             }
         }
+
+        override fun onHistoryStateChange(
+            session: GeckoSession,
+            historyList: GeckoSession.HistoryDelegate.HistoryList
+        ) {
+            val items = historyList.map { HistoryItem(title = it.title, uri = it.uri) }
+            notifyObservers { onHistoryStateChanged(items, historyList.currentIndex) }
+        }
     }
 
     @Suppress("ComplexMethod")

components/browser/session/src/main/java/mozilla/components/browser/session/engine/EngineObserver.kt

@@ -23,6 +23,7 @@ import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.concept.engine.EngineSession
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.media.Media
 import mozilla.components.concept.engine.media.RecordingDevice
@@ -285,4 +286,12 @@ internal class EngineObserver(
     override fun onRecordingStateChanged(devices: List<RecordingDevice>) {
         session.recordingDevices = devices
     }
+
+    override fun onHistoryStateChanged(historyList: List<HistoryItem>, currentIndex: Int) {
+        store?.dispatch(ContentAction.UpdateHistoryStateAction(
+            session.id,
+            historyList,
+            currentIndex
+        ))
+    }
 }

components/browser/session/src/test/java/mozilla/components/browser/session/engine/EngineObserverTest.kt

@@ -18,6 +18,7 @@ import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.Settings
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.media.Media
 import mozilla.components.concept.engine.permission.PermissionRequest
@@ -704,4 +705,36 @@ class EngineObserverTest {
 
         assertEquals("", session.searchTerms)
     }
+
+    @Test
+    fun `onHistoryStateChanged dispatches UpdateHistoryStateAction`() {
+        val session = Session("")
+        val store = mock(BrowserStore::class.java)
+        val observer = EngineObserver(session, store)
+        whenever(store.dispatch(any())).thenReturn(mock())
+
+        observer.onHistoryStateChanged(emptyList(), 0)
+        verify(store).dispatch(
+            ContentAction.UpdateHistoryStateAction(
+                session.id,
+                emptyList(),
+                currentIndex = 0
+            )
+        )
+
+        observer.onHistoryStateChanged(listOf(
+            HistoryItem("Firefox", "https://firefox.com"),
+            HistoryItem("Mozilla", "http://mozilla.org")
+        ), 1)
+        verify(store).dispatch(
+            ContentAction.UpdateHistoryStateAction(
+                session.id,
+                listOf(
+                    HistoryItem("Firefox", "https://firefox.com"),
+                    HistoryItem("Mozilla", "http://mozilla.org")
+                ),
+                currentIndex = 1
+            )
+        )
+    }
 }

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

@@ -22,6 +22,7 @@ import mozilla.components.concept.engine.EngineSession
 import mozilla.components.concept.engine.EngineSessionState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.media.Media
 import mozilla.components.concept.engine.prompt.PromptRequest
@@ -288,6 +289,15 @@ sealed class ContentAction : BrowserAction() {
      * Removes the [WebAppManifest] of the [ContentState] with the given [sessionId].
      */
     data class RemoveWebAppManifestAction(val sessionId: String) : ContentAction()
+
+    /**
+     * Updates the [ContentState] of the given [sessionId] to indicate the current history state.
+     */
+    data class UpdateHistoryStateAction(
+        val sessionId: String,
+        val historyList: List<HistoryItem>,
+        val currentIndex: Int
+    ) : ContentAction()
 }
 
 /**

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

@@ -9,6 +9,7 @@ import mozilla.components.browser.state.action.ContentAction
 import mozilla.components.browser.state.state.BrowserState
 import mozilla.components.browser.state.state.ContentState
 import mozilla.components.browser.state.state.SessionState
+import mozilla.components.browser.state.state.content.HistoryState
 
 internal object ContentStateReducer {
     /**
@@ -120,6 +121,9 @@ internal object ContentStateReducer {
             is ContentAction.UpdateFirstContentfulPaintStateAction -> updateContentState(state, action.sessionId) {
                 it.copy(firstContentfulPaint = action.firstContentfulPaint)
             }
+            is ContentAction.UpdateHistoryStateAction -> updateContentState(state, action.sessionId) {
+                it.copy(history = HistoryState(action.historyList, action.currentIndex))
+            }
         }
     }
 }

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

@@ -7,6 +7,7 @@ package mozilla.components.browser.state.state
 import android.graphics.Bitmap
 import mozilla.components.browser.state.state.content.DownloadState
 import mozilla.components.browser.state.state.content.FindResultState
+import mozilla.components.browser.state.state.content.HistoryState
 import mozilla.components.concept.engine.HitResult
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.prompt.PromptRequest
@@ -62,5 +63,6 @@ data class ContentState(
     val canGoBack: Boolean = false,
     val canGoForward: Boolean = false,
     val webAppManifest: WebAppManifest? = null,
-    val firstContentfulPaint: Boolean = false
+    val firstContentfulPaint: Boolean = false,
+    val history: HistoryState = HistoryState()
 )

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

@@ -0,0 +1,20 @@
+/* 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.browser.state.state.content
+
+import mozilla.components.concept.engine.history.HistoryItem
+
+/**
+ * Value type that represents browser history.
+ *
+ * @property items All the items in the browser history.
+ * @property currentIndex The index of the currently selected [HistoryItem].
+ * If this is equal to lastIndex, then there are no pages to go "forward" to.
+ * If this is 0, then there are no pages to go "back" to.
+ */
+data class HistoryState(
+    val items: List<HistoryItem> = emptyList(),
+    val currentIndex: Int = 0
+)

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

@@ -12,10 +12,12 @@ import mozilla.components.browser.state.state.SecurityInfoState
 import mozilla.components.browser.state.state.TabSessionState
 import mozilla.components.browser.state.state.content.DownloadState
 import mozilla.components.browser.state.state.content.FindResultState
+import mozilla.components.browser.state.state.content.HistoryState
 import mozilla.components.browser.state.state.createCustomTab
 import mozilla.components.browser.state.state.createTab
 import mozilla.components.browser.state.store.BrowserStore
 import mozilla.components.concept.engine.HitResult
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.prompt.PromptRequest
 import mozilla.components.concept.engine.window.WindowRequest
@@ -600,4 +602,25 @@ class ContentActionTest {
 
         assertNull(tab.content.webAppManifest)
     }
+
+    @Test
+    fun `UpdateHistoryStateAction updates history state`() {
+        val historyState = HistoryState(
+            items = listOf(
+                HistoryItem("Mozilla", "https://mozilla.org"),
+                HistoryItem("Firefox", "https://firefox.com")
+            ),
+            currentIndex = 1
+        )
+
+        assertNotEquals(historyState, tab.content.history)
+        assertNotEquals(historyState, otherTab.content.history)
+
+        store.dispatch(
+            ContentAction.UpdateHistoryStateAction(tab.id, historyState.items, historyState.currentIndex)
+        ).joinBlocking()
+
+        assertEquals(historyState, tab.content.history)
+        assertNotEquals(historyState, otherTab.content.history)
+    }
 }

components/concept/engine/src/main/java/mozilla/components/concept/engine/EngineSession.kt

@@ -11,6 +11,7 @@ import mozilla.components.concept.engine.EngineSession.TrackingProtectionPolicy.
 import mozilla.components.concept.engine.EngineSession.TrackingProtectionPolicy.CookiePolicy.ACCEPT_ALL
 import mozilla.components.concept.engine.EngineSession.TrackingProtectionPolicy.CookiePolicy.ACCEPT_NON_TRACKERS
 import mozilla.components.concept.engine.content.blocking.Tracker
+import mozilla.components.concept.engine.history.HistoryItem
 import mozilla.components.concept.engine.manifest.WebAppManifest
 import mozilla.components.concept.engine.media.Media
 import mozilla.components.concept.engine.media.RecordingDevice
@@ -122,6 +123,14 @@ abstract class EngineSession(
             cookie: String? = null,
             userAgent: String? = null
         ) = Unit
+
+        /**
+         * Event to indicate that this session has changed its history state.
+         *
+         * @param historyList The list of items in the session history.
+         * @param currentIndex Index of the current page in the history list.
+         */
+        fun onHistoryStateChanged(historyList: List<HistoryItem>, currentIndex: Int) = Unit
     }
 
     /**

components/concept/engine/src/main/java/mozilla/components/concept/engine/history/HistoryItem.kt

@@ -0,0 +1,15 @@
+/* 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.engine.history
+
+/**
+ * A representation of an entry in browser history.
+ * @property title The title of this history element.
+ * @property uri The URI of this history element.
+ */
+data class HistoryItem(
+    val title: String,
+    val uri: String
+)

components/concept/engine/src/test/java/mozilla/components/concept/engine/EngineSessionTest.kt

@@ -25,6 +25,7 @@ import org.mockito.Mockito.verifyNoMoreInteractions
 import org.mockito.Mockito.verifyZeroInteractions
 import mozilla.components.concept.engine.EngineSession.TrackingProtectionPolicy.TrackingCategory
 import mozilla.components.concept.engine.EngineSession.TrackingProtectionPolicy.CookiePolicy
+import mozilla.components.concept.engine.history.HistoryItem
 import java.lang.reflect.Modifier
 
 class EngineSessionTest {
@@ -552,6 +553,28 @@ class EngineSessionTest {
         )
     }
 
+    @Test
+    fun `registered observer will be notified about history state`() {
+        val session = spy(DummyEngineSession())
+
+        val observer = mock(EngineSession.Observer::class.java)
+        session.register(observer)
+
+        session.notifyInternalObservers {
+            onHistoryStateChanged(
+                listOf(HistoryItem("Firefox download", "https://download.mozilla.org")),
+                currentIndex = 0
+            )
+        }
+
+        verify(observer).onHistoryStateChanged(
+            historyList = listOf(
+                HistoryItem("Firefox download", "https://download.mozilla.org")
+            ),
+            currentIndex = 0
+        )
+    }
+
     @Test
     fun `tracking protection policies have correct categories`() {
 

docs/changelog.md

@@ -15,6 +15,12 @@ permalink: /changelog/
 * **feature-media**
   * Adds `MediaFullscreenOrientationFeature` to autorotate activity while in fullscreen based on media aspect ratio.
 
+* **concept-engine**
+  * Adds `onHistoryStateChanged` method and corresponding `HistoryItem` data class.
+
+* **browser-state**
+  * Adds `history` to `ContentState` to check the back and forward history list.
+
 # 42.0.0
 
 * [Commits](https://github.com/mozilla-mobile/android-components/compare/v41.0.0...42.0.0)