For #18836: add getStartupStateForStartedActivity method.

app/src/main/java/org/mozilla/fenix/perf/StartupStateProvider.kt

@@ -25,6 +25,36 @@ class StartupStateProvider(
     private val startReasonProvider: AppStartReasonProvider
 ) {
 
+    /**
+     * The restoration state of the application upon this most recent start up. See the
+     * [Fenix perf glossary](https://wiki.mozilla.org/index.php?title=Performance/Fenix/Glossary)
+     * for specific definitions.
+     */
+    enum class StartupState {
+        COLD, WARM, HOT,
+
+        /**
+         * A start up state where we weren't able to bucket it into the other categories.
+         * This includes, but is not limited to:
+         * - if the activity this is called from is not currently started
+         * - if the currently started activity is not the first started activity
+         */
+        UNKNOWN;
+    }
+
+    /**
+     * Returns the [StartupState] for the currently started activity. Note: the state will be
+     * [StartupState.UNKNOWN] if the currently started activity is not the first started activity.
+     *
+     * This method must be called after the foreground Activity is STARTED.
+     */
+    fun getStartupStateForStartedActivity(activityClass: Class<out Activity>): StartupState = when {
+        isColdStartForStartedActivity(activityClass) -> StartupState.COLD
+        isWarmStartForStartedActivity(activityClass) -> StartupState.WARM
+        isHotStartForStartedActivity(activityClass) -> StartupState.HOT
+        else -> StartupState.UNKNOWN
+    }
+
     /**
      * Returns true if the current startup state is COLD and the currently started activity is the
      * first started activity (i.e. we can use it for performance measurements).

app/src/test/java/org/mozilla/fenix/perf/StartupStateProviderTest.kt

@@ -7,6 +7,7 @@ package org.mozilla.fenix.perf
 import io.mockk.MockKAnnotations
 import io.mockk.every
 import io.mockk.impl.annotations.MockK
+import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.Before
@@ -15,6 +16,7 @@ import org.mozilla.fenix.HomeActivity
 import org.mozilla.fenix.IntentReceiverActivity
 import org.mozilla.fenix.perf.AppStartReasonProvider.StartReason
 import org.mozilla.fenix.perf.StartupActivityLog.LogEntry
+import org.mozilla.fenix.perf.StartupStateProvider.StartupState
 
 class StartupStateProviderTest {
 
@@ -237,6 +239,41 @@ class StartupStateProviderTest {
         assertFalse(provider.isHotStartForStartedActivity(homeActivityClass))
     }
 
+    @Test
+    fun `GIVEN the app started for an activity WHEN it is a cold start THEN get startup state is cold`() {
+        forEachColdStartEntries { index ->
+            assertEquals("$index", StartupState.COLD, provider.getStartupStateForStartedActivity(homeActivityClass))
+        }
+    }
+
+    @Test
+    fun `WHEN it is a warm start THEN get startup state is warm`() {
+        forEachWarmStartEntries { index ->
+            assertEquals("$index", StartupState.WARM, provider.getStartupStateForStartedActivity(homeActivityClass))
+        }
+    }
+
+    @Test
+    fun `WHEN it is a hot start THEN get startup state is hot`() {
+        forEachHotStartEntries { index ->
+            assertEquals("$index", StartupState.HOT, provider.getStartupStateForStartedActivity(homeActivityClass))
+        }
+    }
+
+    @Test
+    fun `WHEN two activities are started THEN get startup state is unknown`() {
+        logEntries.addAll(listOf(
+            LogEntry.ActivityCreated(irActivityClass),
+            LogEntry.ActivityStarted(irActivityClass),
+            LogEntry.AppStarted,
+            LogEntry.ActivityCreated(homeActivityClass),
+            LogEntry.ActivityStarted(homeActivityClass),
+            LogEntry.ActivityStopped(irActivityClass)
+        ))
+
+        assertEquals(StartupState.UNKNOWN, provider.getStartupStateForStartedActivity(homeActivityClass))
+    }
+
     private fun forEachColdStartEntries(block: (index: Int) -> Unit) {
         // These entries mimic observed behavior.
         //