Merge pull request #3055 from DataDog/aleksandr-gringauz/RUM-13082/fallback-to-DdRumContentProvider

RUM-13082: Fall back to DdRumContentProvider creation time

Author: aleksandr-gringauz

dd-sdk-android-core/src/main/kotlin/com/datadog/android/core/internal/time/DefaultAppStartTimeProvider.kt

@@ -13,6 +13,7 @@ import android.os.SystemClock
 import com.datadog.android.core.internal.system.BuildSdkVersionProvider
 import com.datadog.android.rum.DdRumContentProvider
 import java.util.concurrent.TimeUnit
+import kotlin.time.Duration.Companion.seconds
 
 internal class DefaultAppStartTimeProvider(
     buildSdkVersionProvider: BuildSdkVersionProvider = BuildSdkVersionProvider.DEFAULT
@@ -23,12 +24,26 @@ internal class DefaultAppStartTimeProvider(
         when {
             buildSdkVersionProvider.version >= Build.VERSION_CODES.N -> {
                 val diffMs = SystemClock.elapsedRealtime() - Process.getStartElapsedRealtime()
-                System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(diffMs)
+                val result = System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(diffMs)
+
+                /**
+                 * Occasionally [Process.getStartElapsedRealtime] returns buggy values. We filter them and fall back
+                 * to the time of creation of [DdRumContentProvider].
+                 */
+                if (DdRumContentProvider.createTimeNs - result > PROCESS_START_TO_CP_START_DIFF_THRESHOLD_NS) {
+                    DdRumContentProvider.createTimeNs
+                } else {
+                    result
+                }
             }
             else -> DdRumContentProvider.createTimeNs
         }
     }
 
     override val appUptimeNs: Long
         get() = System.nanoTime() - appStartTimeNs
+
+    companion object {
+        internal val PROCESS_START_TO_CP_START_DIFF_THRESHOLD_NS = 10.seconds.inWholeNanoseconds
+    }
 }

dd-sdk-android-core/src/test/kotlin/com/datadog/android/core/internal/time/DefaultAppStartTimeProviderTest.kt

@@ -11,6 +11,7 @@ import android.os.Process
 import android.os.SystemClock
 import com.datadog.android.core.internal.system.BuildSdkVersionProvider
 import com.datadog.android.rum.DdRumContentProvider
+import fr.xgouchet.elmyr.Forge
 import fr.xgouchet.elmyr.annotation.IntForgery
 import fr.xgouchet.elmyr.junit5.ForgeExtension
 import org.assertj.core.api.Assertions.assertThat
@@ -29,13 +30,19 @@ import java.util.concurrent.TimeUnit
 class DefaultAppStartTimeProviderTest {
     @Test
     fun `M return process start time W appStartTime { N+ }`(
-        @IntForgery(min = Build.VERSION_CODES.N) apiVersion: Int
+        @IntForgery(min = Build.VERSION_CODES.N) apiVersion: Int,
+        forge: Forge
     ) {
         // GIVEN
         val mockBuildSdkVersionProvider: BuildSdkVersionProvider = mock()
         whenever(mockBuildSdkVersionProvider.version) doReturn apiVersion
+
         val diffMs = SystemClock.elapsedRealtime() - Process.getStartElapsedRealtime()
         val startTimeNs = System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(diffMs)
+
+        DdRumContentProvider.createTimeNs = startTimeNs +
+            forge.aLong(min = 0, max = DefaultAppStartTimeProvider.PROCESS_START_TO_CP_START_DIFF_THRESHOLD_NS)
+
         val testedProvider = DefaultAppStartTimeProvider(mockBuildSdkVersionProvider)
 
         // WHEN
@@ -46,6 +53,31 @@ class DefaultAppStartTimeProviderTest {
             .isCloseTo(startTimeNs, Offset.offset(TimeUnit.MILLISECONDS.toNanos(100)))
     }
 
+    @Test
+    fun `M fall back to DdRumContentProvider W appStartTime { N+ getStartElapsedRealtime returns buggy value }`(
+        @IntForgery(min = Build.VERSION_CODES.N) apiVersion: Int,
+        forge: Forge
+    ) {
+        // GIVEN
+        val mockBuildSdkVersionProvider: BuildSdkVersionProvider = mock()
+        whenever(mockBuildSdkVersionProvider.version) doReturn apiVersion
+
+        val diffMs = SystemClock.elapsedRealtime() - Process.getStartElapsedRealtime()
+        val startTimeNs = System.nanoTime() - TimeUnit.MILLISECONDS.toNanos(diffMs)
+
+        DdRumContentProvider.createTimeNs = startTimeNs +
+            forge.aLong(min = DefaultAppStartTimeProvider.PROCESS_START_TO_CP_START_DIFF_THRESHOLD_NS)
+
+        val testedProvider = DefaultAppStartTimeProvider(mockBuildSdkVersionProvider)
+
+        // WHEN
+        val providedStartTime = testedProvider.appStartTimeNs
+
+        // THEN
+        assertThat(providedStartTime)
+            .isCloseTo(DdRumContentProvider.createTimeNs, Offset.offset(TimeUnit.MILLISECONDS.toNanos(100)))
+    }
+
     @Test
     fun `M return content provider load time W appStartTime { Legacy }`(
         @IntForgery(min = Build.VERSION_CODES.M, max = Build.VERSION_CODES.N) apiVersion: Int

dd-sdk-android-internal/api/apiSurface

@@ -135,6 +135,6 @@ class com.datadog.android.rum.DdRumContentProvider : android.content.ContentProv
   override fun update(android.net.Uri, android.content.ContentValues?, String?, Array<String>?): Int
   companion object 
     var processImportance: Int
-    val createTimeNs: Long
+    var createTimeNs: Long
 annotation com.datadog.tools.annotation.NoOpImplementation
   constructor(Boolean = false)

dd-sdk-android-internal/api/dd-sdk-android-internal.api

@@ -349,6 +349,7 @@ public final class com/datadog/android/rum/DdRumContentProvider : android/conten
 public final class com/datadog/android/rum/DdRumContentProvider$Companion {
 	public final fun getCreateTimeNs ()J
 	public final fun getProcessImportance ()I
+	public final fun setCreateTimeNs (J)V
 	public final fun setProcessImportance (I)V
 }
 

dd-sdk-android-internal/src/main/java/com/datadog/android/rum/DdRumContentProvider.kt

@@ -76,7 +76,8 @@ class DdRumContentProvider : ContentProvider() {
 
         /**
          * fallback for APIs below Android N, see [DefaultAppStartTimeProvider].
+         * Should be set from the outside only in tests.
          */
-        val createTimeNs: Long = System.nanoTime()
+        var createTimeNs: Long = System.nanoTime()
     }
 }