For #4780 switch off private mode (#5614)

* Do not launch in Private Mode

When the app launches do not launch in Private Mode in order to prevent usage leaks to other users of the device.

* Issue #4780: add comments to use private mode

* For #4780: write tests for clear private mode on create app

* For #4780: clear private mode when privacy notification is removed

app/src/main/java/org/mozilla/fenix/FenixApplication.kt

@@ -36,6 +36,7 @@ import org.mozilla.fenix.components.Components
 import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.session.NotificationSessionObserver
 import org.mozilla.fenix.session.VisibilityLifecycleCallback
+import org.mozilla.fenix.utils.Settings
 import java.io.File
 
 @SuppressLint("Registered")
@@ -115,6 +116,10 @@ open class FenixApplication : Application() {
         if ((System.currentTimeMillis() - settings().lastPlacesStorageMaintenance) > ONE_DAY_MILLIS) {
             runStorageMaintenance()
         }
+
+        // This needs to be called before the theme is set. No BrowsingModeManager is available
+        // at this point, which is why this is set directly
+        maybeClearPrivateMode()
     }
 
     private fun runStorageMaintenance() {
@@ -126,6 +131,14 @@ open class FenixApplication : Application() {
         settings().lastPlacesStorageMaintenance = System.currentTimeMillis()
     }
 
+    /**
+     * Clears private mode. This is done in order to avoid leaking the fact that
+     * private mode was in use during the previous session.
+     */
+    fun maybeClearPrivateMode(settings: Settings = settings()) {
+        if (!settings.alwaysOpenInPrivateMode) settings.usePrivateMode = false
+    }
+
     private fun registerRxExceptionHandling() {
         RxJavaPlugins.setErrorHandler {
             throw it.cause ?: it

app/src/main/java/org/mozilla/fenix/session/SessionNotificationService.kt

@@ -22,6 +22,7 @@ import mozilla.components.support.utils.ThreadUtils
 import org.mozilla.fenix.R
 import org.mozilla.fenix.HomeActivity
 import org.mozilla.fenix.components.metrics.Event
+import org.mozilla.fenix.ext.application
 import org.mozilla.fenix.ext.components
 import org.mozilla.fenix.ext.metrics
 import org.mozilla.fenix.ext.sessionsOfType
@@ -62,6 +63,11 @@ class SessionNotificationService : Service() {
     override fun onTaskRemoved(rootIntent: Intent) {
         components.core.sessionManager.removeAndCloseAllPrivateSessions()
 
+        // This is currently safe because we remove this service while destroying activities. If
+        // this service is ever removed while HomeActivity is still active, this could cause
+        // theming issues. See usePrivateMode kdoc
+        baseContext.application.maybeClearPrivateMode()
+
         stopForeground(true)
         stopSelf()
     }

app/src/main/java/org/mozilla/fenix/utils/Settings.kt

@@ -22,6 +22,7 @@ import org.mozilla.fenix.BuildConfig
 import org.mozilla.fenix.Config
 import org.mozilla.fenix.FeatureFlags
 import org.mozilla.fenix.R
+import org.mozilla.fenix.browser.browsingmode.BrowsingModeManager
 import org.mozilla.fenix.components.metrics.MozillaProductDetector
 import org.mozilla.fenix.ext.getPreferenceKey
 import org.mozilla.fenix.settings.PhoneFeature
@@ -82,6 +83,13 @@ class Settings private constructor(
         default = ""
     )
 
+    /**
+     * Warning: when possible, prefer to set this via [BrowsingModeManager].
+     *
+     * [BrowsingModeManager] defines a callback to be hit whenever this setting changes. For
+     * example, setting this value directly at the wrong time could cause the private theme to
+     * not be applied.
+     */
     var usePrivateMode by booleanPreference(
         appContext.getPreferenceKey(R.string.pref_key_private_mode),
         default = false

app/src/test/java/org/mozilla/fenix/FenixApplicationTest.kt

@@ -0,0 +1,49 @@
+package org.mozilla.fenix
+
+import io.mockk.MockKAnnotations
+import io.mockk.every
+import io.mockk.impl.annotations.MockK
+import io.mockk.just
+import io.mockk.runs
+import io.mockk.verify
+import kotlinx.coroutines.ObsoleteCoroutinesApi
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.mozilla.fenix.utils.Settings
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.annotation.Config
+
+@ObsoleteCoroutinesApi
+@RunWith(RobolectricTestRunner::class)
+@Config(application = TestApplication::class)
+class FenixApplicationTest {
+
+    lateinit var application: FenixApplication
+    @MockK lateinit var settings: Settings
+
+    @Before
+    fun before() {
+        MockKAnnotations.init(this)
+        every { settings setProperty "usePrivateMode" value any<Boolean>() } just runs
+        application = TestApplication()
+    }
+
+    @Test
+    fun `GIVEN alwaysOpenInPrivateMode is active WHEN maybeClearPrivateMode is called THEN private mode should not be changed`() {
+        every { settings.alwaysOpenInPrivateMode } returns true
+
+        application.maybeClearPrivateMode(settings)
+
+        verify(exactly = 0) { settings.usePrivateMode = any<Boolean>() }
+    }
+
+    @Test
+    fun `GIVEN alwaysOpenInPrivateMode is inactive WHEN maybeClearPrivateMode is called THEN private mode should be disabled`() {
+        every { settings.alwaysOpenInPrivateMode } returns false
+
+        application.maybeClearPrivateMode(settings)
+
+        verify(exactly = 1) { settings.usePrivateMode = false }
+    }
+}