Adds persisted backstack

vector/src/main/java/im/vector/app/SpaceStateHandlerImpl.kt

@@ -23,6 +23,7 @@ import im.vector.app.core.utils.BehaviorDataSource
 import im.vector.app.features.analytics.AnalyticsTracker
 import im.vector.app.features.analytics.plan.UserProperties
 import im.vector.app.features.session.coroutineScope
+import im.vector.app.features.settings.VectorPreferences
 import im.vector.app.features.ui.UiStateRepository
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
@@ -52,7 +53,8 @@ class SpaceStateHandlerImpl @Inject constructor(
         private val sessionDataSource: ActiveSessionDataSource,
         private val uiStateRepository: UiStateRepository,
         private val activeSessionHolder: ActiveSessionHolder,
-        private val analyticsTracker: AnalyticsTracker
+        private val analyticsTracker: AnalyticsTracker,
+        private val vectorPreferences: VectorPreferences,
 ) : SpaceStateHandler {
 
     private val coroutineScope = CoroutineScope(SupervisorJob() + Dispatchers.Main)
@@ -82,7 +84,7 @@ class SpaceStateHandlerImpl @Inject constructor(
         }
 
         if (isForwardNavigation) {
-            spaceBackstack.addLast(currentSpace?.roomId)
+            addToBackstacks(spaceSummary)
         }
 
         if (persistNow) {
@@ -104,6 +106,15 @@ class SpaceStateHandlerImpl @Inject constructor(
         }
     }
 
+    private fun addToBackstacks(space: RoomSummary?) {
+        val spaceId = space?.roomId ?: ROOT_SPACE_ID
+        spaceBackstack.addLast(spaceId)
+
+        val currentPersistedBackstack = vectorPreferences.getPersistedSpaceBackstack().toMutableList()
+        currentPersistedBackstack.add(spaceId)
+        vectorPreferences.setPersistedSpaceBackstack(currentPersistedBackstack)
+    }
+
     private fun observeActiveSession() {
         sessionDataSource.stream()
                 .distinctUntilChanged()
@@ -144,4 +155,8 @@ class SpaceStateHandlerImpl @Inject constructor(
         val session = activeSessionHolder.getSafeActiveSession() ?: return
         uiStateRepository.storeSelectedSpace(selectedSpaceDataSource.currentValue?.orNull()?.roomId, session.sessionId)
     }
+
+    companion object {
+        private const val ROOT_SPACE_ID = "ROOT"
+    }
 }

vector/src/main/java/im/vector/app/features/settings/VectorPreferences.kt

@@ -25,6 +25,7 @@ import androidx.core.content.edit
 import com.squareup.seismic.ShakeDetector
 import im.vector.app.R
 import im.vector.app.core.di.DefaultSharedPreferences
+import im.vector.app.core.extensions.join
 import im.vector.app.core.resources.BuildMeta
 import im.vector.app.core.time.Clock
 import im.vector.app.features.disclaimer.SHARED_PREF_KEY
@@ -77,6 +78,7 @@ class VectorPreferences @Inject constructor(
         const val SETTINGS_ALLOW_INTEGRATIONS_KEY = "SETTINGS_ALLOW_INTEGRATIONS_KEY"
         const val SETTINGS_INTEGRATION_MANAGER_UI_URL_KEY = "SETTINGS_INTEGRATION_MANAGER_UI_URL_KEY"
         const val SETTINGS_SECURE_MESSAGE_RECOVERY_PREFERENCE_KEY = "SETTINGS_SECURE_MESSAGE_RECOVERY_PREFERENCE_KEY"
+        const val SETTINGS_PERSISTED_SPACE_BACKSTACK = "SETTINGS_PERSISTED_SPACE_BACKSTACK"
 
         const val SETTINGS_CRYPTOGRAPHY_HS_ADMIN_DISABLED_E2E_DEFAULT = "SETTINGS_CRYPTOGRAPHY_HS_ADMIN_DISABLED_E2E_DEFAULT"
 //        const val SETTINGS_SECURE_BACKUP_RESET_PREFERENCE_KEY = "SETTINGS_SECURE_BACKUP_RESET_PREFERENCE_KEY"
@@ -1113,6 +1115,25 @@ class VectorPreferences @Inject constructor(
                 .apply()
     }
 
+    /**
+     * Sets the space backstack that is used for up navigation
+     * This needs to be persisted because navigating up through spaces should work across sessions
+     *
+     * Only the IDs of the spaces are stored
+     */
+    fun setPersistedSpaceBackstack(spaceBackstack: List<String>) {
+        val spaceIdsJoined = spaceBackstack.joinToString(",")
+        defaultPrefs.edit().putString(SETTINGS_PERSISTED_SPACE_BACKSTACK, spaceIdsJoined).apply()
+    }
+
+    /**
+     * Gets the space backstack used for up navigation
+     */
+    fun getPersistedSpaceBackstack(): List<String> {
+        val spaceIdsJoined = defaultPrefs.getString(SETTINGS_PERSISTED_SPACE_BACKSTACK, null)
+        return spaceIdsJoined?.split(",").orEmpty()
+    }
+
     fun showLiveSenderInfo(): Boolean {
         return defaultPrefs.getBoolean(SETTINGS_TIMELINE_SHOW_LIVE_SENDER_INFO, getDefault(R.bool.settings_timeline_show_live_sender_info_default))
     }