Convenient preconditions specific for Crashlytics concurrency

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/CrashlyticsRegistrar.java

@@ -14,6 +14,8 @@
 
 package com.google.firebase.crashlytics;
 
+import static com.google.firebase.crashlytics.internal.CrashlyticsPreconditions.StrictLevel.ASSERT;
+
 import com.google.firebase.FirebaseApp;
 import com.google.firebase.analytics.connector.AnalyticsConnector;
 import com.google.firebase.annotations.concurrent.Background;
@@ -24,7 +26,8 @@
 import com.google.firebase.components.Dependency;
 import com.google.firebase.components.Qualified;
 import com.google.firebase.crashlytics.internal.CrashlyticsNativeComponent;
-import com.google.firebase.inject.Deferred;
+import com.google.firebase.crashlytics.internal.CrashlyticsPreconditions;
+import com.google.firebase.crashlytics.internal.Logger;
 import com.google.firebase.installations.FirebaseInstallationsApi;
 import com.google.firebase.platforminfo.LibraryVersionComponent;
 import com.google.firebase.remoteconfig.interop.FirebaseRemoteConfigInterop;
@@ -66,26 +69,27 @@ public List<Component<?>> getComponents() {
   }
 
   private FirebaseCrashlytics buildCrashlytics(ComponentContainer container) {
-    FirebaseApp app = container.get(FirebaseApp.class);
-
-    Deferred<CrashlyticsNativeComponent> nativeComponent =
-        container.getDeferred(CrashlyticsNativeComponent.class);
+    // TODO(mrober): Make this a build time configuration. Do not release like this.
+    CrashlyticsPreconditions.setStrictLevel(ASSERT); // Kill the process on violation for debugging.
 
-    Deferred<AnalyticsConnector> analyticsConnector =
-        container.getDeferred(AnalyticsConnector.class);
+    // CrashlyticsPreconditions.checkMainThread();
+    long startTime = System.currentTimeMillis();
 
-    FirebaseInstallationsApi firebaseInstallations = container.get(FirebaseInstallationsApi.class);
+    FirebaseCrashlytics crashlytics =
+        FirebaseCrashlytics.init(
+            container.get(FirebaseApp.class),
+            container.get(FirebaseInstallationsApi.class),
+            container.getDeferred(CrashlyticsNativeComponent.class),
+            container.getDeferred(AnalyticsConnector.class),
+            container.getDeferred(FirebaseRemoteConfigInterop.class),
+            container.get(backgroundExecutorService),
+            container.get(blockingExecutorService));
 
-    Deferred<FirebaseRemoteConfigInterop> remoteConfigInterop =
-        container.getDeferred(FirebaseRemoteConfigInterop.class);
+    long duration = System.currentTimeMillis() - startTime;
+    if (duration > 30) {
+      Logger.getLogger().i("Initializing Crashlytics blocked main for " + duration + " ms");
+    }
 
-    return FirebaseCrashlytics.init(
-        app,
-        firebaseInstallations,
-        nativeComponent,
-        analyticsConnector,
-        remoteConfigInterop,
-        container.get(backgroundExecutorService),
-        container.get(blockingExecutorService));
+    return crashlytics;
   }
 }

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/internal/CrashlyticsPreconditions.kt

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2024 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.crashlytics.internal
+
+import android.os.Build
+import android.os.Looper
+import com.google.firebase.crashlytics.internal.CrashlyticsPreconditions.StrictLevel.ASSERT
+import com.google.firebase.crashlytics.internal.CrashlyticsPreconditions.StrictLevel.NONE
+import com.google.firebase.crashlytics.internal.CrashlyticsPreconditions.StrictLevel.THROW
+import com.google.firebase.crashlytics.internal.CrashlyticsPreconditions.StrictLevel.WARN
+
+/**
+ * Convenient preconditions specific for Crashlytics concurrency.
+ *
+ * Use GMS Core's [com.google.android.gms.common.internal.Preconditions] for general preconditions.
+ */
+internal object CrashlyticsPreconditions {
+  private val threadName
+    get() = Thread.currentThread().name
+
+  // TODO(mrober): Make this a build time configuration.
+  @JvmStatic var strictLevel: StrictLevel = NONE
+
+  @JvmStatic
+  fun checkMainThread() =
+    checkThread(::isMainThread) { "Must be called on the main thread, was called on $threadName." }
+
+  @JvmStatic
+  fun checkBlockingThread() =
+    checkThread(::isBlockingThread) {
+      "Must be called on a blocking thread, was called on $threadName."
+    }
+
+  @JvmStatic
+  fun checkBackgroundThread() =
+    checkThread(::isBackgroundThread) {
+      "Must be called on a background thread, was called on $threadName."
+    }
+
+  private fun isMainThread() =
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      Looper.getMainLooper().isCurrentThread
+    } else {
+      Looper.getMainLooper() == Looper.myLooper()
+    }
+
+  private fun isBlockingThread() = threadName.contains("Firebase Blocking Thread #")
+
+  // TODO(mrober): Remove the Crashlytics thread when fully migrated to Firebase common threads.
+  private fun isBackgroundThread() =
+    threadName.contains("Firebase Background Thread #") ||
+      threadName.contains("Crashlytics Exception Handler")
+
+  private fun checkThread(isCorrectThread: () -> Boolean, failureMessage: () -> String) {
+    if (strictLevel.level >= WARN.level && !isCorrectThread()) {
+      Logger.getLogger().w(failureMessage())
+      assert(strictLevel.level < ASSERT.level, failureMessage)
+      check(strictLevel.level < THROW.level, failureMessage)
+    }
+  }
+
+  enum class StrictLevel(val level: Int) : Comparable<StrictLevel> {
+    /** Do not check for violations. */
+    NONE(0),
+    /** Log violations as warnings. */
+    WARN(1),
+    /** Throw an exception on violation. */
+    THROW(2),
+    /** Kill the process on violation. Useful for debugging. */
+    ASSERT(3),
+  }
+}