Merge executors to master (#4322)

* Add qualifier support to firebase components. (#3180)

* Add qualifier support to firebase components.

Details: go/firebase-component-qualifiers

* fix errorprone error.

* change copyright year.

* Register executors as components. (#4288)

* Register executors as components.

The intent for those is to be used by all Firebase SDKs and forbid
creating their own at will.

* Add copyrights.

* add more copyrights

* ktlintformat

* gJF

* ktlint

* Address review comments.

* Adds generally useful executors (#4305)

Namely, SequentialExecutor and directExecutor.

* Enable strict mode for executors. (#4303)

Any violations would kill the app in debug builds of firebase-common,
and log a warning in release builds. This is done to fail tests that
incorrectly use executors while not affecting 3p apps in release builds.

Additionally correctly set thread priorities in an Android specific way.

* Enable thread pool linter check. (#4297)

* Enable thread pool linter check.

All violations are now suppressed, bugs filed to fix each product.

* ktlint

* Remove init

* Fix copyright

Author: vkryachko

appcheck/firebase-appcheck-debug/src/main/java/com/google/firebase/appcheck/debug/internal/DebugAppCheckProvider.java

@@ -16,6 +16,7 @@
 
 import static com.google.android.gms.common.internal.Preconditions.checkNotNull;
 
+import android.annotation.SuppressLint;
 import android.util.Log;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
@@ -45,6 +46,8 @@ public class DebugAppCheckProvider implements AppCheckProvider {
   private final RetryManager retryManager;
   private final Task<String> debugSecretTask;
 
+  // TODO(b/258273630): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   public DebugAppCheckProvider(@NonNull FirebaseApp firebaseApp, @Nullable String debugSecret) {
     checkNotNull(firebaseApp);
     this.networkClient = new NetworkClient(firebaseApp);

appcheck/firebase-appcheck-playintegrity/src/main/java/com/google/firebase/appcheck/playintegrity/internal/PlayIntegrityAppCheckProvider.java

@@ -14,6 +14,7 @@
 
 package com.google.firebase.appcheck.playintegrity.internal;
 
+import android.annotation.SuppressLint;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 import com.google.android.gms.tasks.Task;
@@ -41,6 +42,8 @@ public class PlayIntegrityAppCheckProvider implements AppCheckProvider {
   private final ExecutorService backgroundExecutor;
   private final RetryManager retryManager;
 
+  // TODO(b/258273630): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   public PlayIntegrityAppCheckProvider(@NonNull FirebaseApp firebaseApp) {
     this(
         firebaseApp.getOptions().getGcmSenderId(),

appcheck/firebase-appcheck-safetynet/src/main/java/com/google/firebase/appcheck/safetynet/internal/SafetyNetAppCheckProvider.java

@@ -17,6 +17,7 @@
 import static com.google.android.gms.common.internal.Preconditions.checkNotEmpty;
 import static com.google.android.gms.common.internal.Preconditions.checkNotNull;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
@@ -56,6 +57,8 @@ public class SafetyNetAppCheckProvider implements AppCheckProvider {
   private final String apiKey;
 
   /** @param firebaseApp the FirebaseApp to which this Factory is tied. */
+  // TODO(b/258273630): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   public SafetyNetAppCheckProvider(@NonNull FirebaseApp firebaseApp) {
     this(
         firebaseApp,

appcheck/firebase-appcheck/src/main/java/com/google/firebase/appcheck/internal/DefaultFirebaseAppCheck.java

@@ -16,6 +16,7 @@
 
 import static com.google.android.gms.common.internal.Preconditions.checkNotNull;
 
+import android.annotation.SuppressLint;
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
@@ -57,6 +58,8 @@ public class DefaultFirebaseAppCheck extends FirebaseAppCheck {
   private AppCheckProvider appCheckProvider;
   private AppCheckToken cachedToken;
 
+  // TODO(b/258273630): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   public DefaultFirebaseAppCheck(
       @NonNull FirebaseApp firebaseApp,
       @NonNull Provider<HeartBeatController> heartBeatController) {

appcheck/firebase-appcheck/src/main/java/com/google/firebase/appcheck/internal/DefaultTokenRefresher.java

@@ -18,6 +18,7 @@
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.SECONDS;
 
+import android.annotation.SuppressLint;
 import androidx.annotation.NonNull;
 import androidx.annotation.VisibleForTesting;
 import com.google.android.gms.tasks.OnFailureListener;
@@ -41,6 +42,8 @@ public class DefaultTokenRefresher {
   private volatile ScheduledFuture<?> refreshFuture;
   private volatile long delayAfterFailureSeconds;
 
+  // TODO(b/258273630): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   DefaultTokenRefresher(@NonNull DefaultFirebaseAppCheck firebaseAppCheck) {
     this(checkNotNull(firebaseAppCheck), Executors.newScheduledThreadPool(/* corePoolSize= */ 1));
   }

firebase-annotations/firebase-annotations.gradle

@@ -29,3 +29,7 @@ java {
 tasks.withType(JavaCompile) {
     options.compilerArgs << "-Werror"
 }
+
+dependencies {
+    implementation 'javax.inject:javax.inject:1'
+}

firebase-annotations/src/main/java/com/google/firebase/annotations/concurrent/Background.java

@@ -0,0 +1,30 @@
+// Copyright 2022 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.annotations.concurrent;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+/**
+ * An executor/coroutine dispatcher for long running tasks including disk IO, heavy CPU
+ * computations.
+ *
+ * <p>For operations that can block for long periods of time, like network requests, use the {@link
+ * Blocking} executor.
+ */
+@Qualifier
+@Target({ElementType.PARAMETER, ElementType.METHOD, ElementType.FIELD})
+public @interface Background {}

firebase-annotations/src/main/java/com/google/firebase/annotations/concurrent/Blocking.java

@@ -0,0 +1,27 @@
+// Copyright 2022 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.annotations.concurrent;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+/**
+ * An executor/coroutine dispatcher for tasks that can block for long periods of time, e.g network
+ * IO.
+ */
+@Qualifier
+@Target({ElementType.PARAMETER, ElementType.METHOD, ElementType.FIELD})
+public @interface Blocking {}

firebase-annotations/src/main/java/com/google/firebase/annotations/concurrent/Lightweight.java

@@ -0,0 +1,26 @@
+// Copyright 2022 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.annotations.concurrent;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+/**
+ * An executor/coroutine dispatcher for lightweight tasks that never block (on IO or other tasks).
+ */
+@Qualifier
+@Target({ElementType.PARAMETER, ElementType.METHOD, ElementType.FIELD})
+public @interface Lightweight {}

firebase-annotations/src/main/java/com/google/firebase/annotations/concurrent/UiThread.java

@@ -0,0 +1,24 @@
+// Copyright 2022 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.annotations.concurrent;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Target;
+import javax.inject.Qualifier;
+
+/** An executor/coroutine dispatcher for work that must run on the UI thread. */
+@Qualifier
+@Target({ElementType.PARAMETER, ElementType.METHOD, ElementType.FIELD})
+public @interface UiThread {}

firebase-appdistribution/src/main/java/com/google/firebase/appdistribution/impl/AabUpdater.java

@@ -19,6 +19,7 @@
 import static com.google.firebase.appdistribution.impl.TaskUtils.runAsyncInTask;
 import static com.google.firebase.appdistribution.impl.TaskUtils.safeSetTaskException;
 
+import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.Intent;
 import android.net.Uri;
@@ -52,6 +53,8 @@ class AabUpdater {
   @GuardedBy("updateAabLock")
   private boolean hasBeenSentToPlayForCurrentTask = false;
 
+  // TODO(b/258264924): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   AabUpdater() {
     this(
         FirebaseAppDistributionLifecycleNotifier.getInstance(),

firebase-appdistribution/src/main/java/com/google/firebase/appdistribution/impl/ApkUpdater.java

@@ -19,6 +19,7 @@
 import static com.google.firebase.appdistribution.impl.TaskUtils.safeSetTaskException;
 import static com.google.firebase.appdistribution.impl.TaskUtils.safeSetTaskResult;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
@@ -62,6 +63,8 @@ class ApkUpdater {
 
   private final Object updateTaskLock = new Object();
 
+  // TODO(b/258264924): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   public ApkUpdater(@NonNull FirebaseApp firebaseApp, @NonNull ApkInstaller apkInstaller) {
     this(
         Executors.newSingleThreadExecutor(),

firebase-appdistribution/src/main/java/com/google/firebase/appdistribution/impl/FirebaseAppDistributionTesterApiClient.java

@@ -16,6 +16,7 @@
 
 import static com.google.firebase.appdistribution.impl.TaskUtils.runAsyncInTask;
 
+import android.annotation.SuppressLint;
 import androidx.annotation.NonNull;
 import com.google.android.gms.tasks.Task;
 import com.google.android.gms.tasks.Tasks;
@@ -63,6 +64,9 @@ private interface FidDependentJob<TResult> {
   private final FirebaseApp firebaseApp;
   private final Provider<FirebaseInstallationsApi> firebaseInstallationsApiProvider;
   private final TesterApiHttpClient testerApiHttpClient;
+
+  // TODO(b/258264924): Migrate to go/firebase-android-executors
+  @SuppressLint("ThreadPoolCreation")
   private final Executor taskExecutor = Executors.newSingleThreadExecutor();
 
   FirebaseAppDistributionTesterApiClient(

firebase-common/firebase-common.gradle

@@ -62,10 +62,11 @@ android {
 }
 
 dependencies {
-    // TODO(vkryachko): have sdks depend on components directly once components are released.
+    implementation project(':firebase-annotations')
     implementation project(':firebase-components')
     implementation 'com.google.android.gms:play-services-basement:18.1.0'
     implementation "com.google.android.gms:play-services-tasks:18.0.1"
+    implementation 'androidx.concurrent:concurrent-futures:1.1.0'
 
     // FirebaseApp references storage, so storage needs to be on classpath when dokka runs.
     javadocClasspath project(path: ':firebase-storage')

firebase-common/ktx/ktx.gradle

@@ -38,6 +38,7 @@ android {
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlinVersion"
 
+    implementation project(':firebase-annotations')
     implementation project(':firebase-common')
     implementation project(':firebase-components')
     implementation 'androidx.annotation:annotation:1.1.0'

firebase-common/ktx/src/main/kotlin/com/google/firebase/ktx/Firebase.kt

@@ -17,9 +17,18 @@ import android.content.Context
 import androidx.annotation.Keep
 import com.google.firebase.FirebaseApp
 import com.google.firebase.FirebaseOptions
+import com.google.firebase.annotations.concurrent.Background
+import com.google.firebase.annotations.concurrent.Blocking
+import com.google.firebase.annotations.concurrent.Lightweight
+import com.google.firebase.annotations.concurrent.UiThread
 import com.google.firebase.components.Component
 import com.google.firebase.components.ComponentRegistrar
+import com.google.firebase.components.Dependency
+import com.google.firebase.components.Qualified
 import com.google.firebase.platforminfo.LibraryVersionComponent
+import java.util.concurrent.Executor
+import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.asCoroutineDispatcher
 
 /**
  * Single access point to all firebase SDKs from Kotlin.
@@ -56,6 +65,20 @@ internal const val LIBRARY_NAME: String = "fire-core-ktx"
 @Keep
 class FirebaseCommonKtxRegistrar : ComponentRegistrar {
   override fun getComponents(): List<Component<*>> {
-    return listOf(LibraryVersionComponent.create(LIBRARY_NAME, BuildConfig.VERSION_NAME))
+    return listOf(
+      LibraryVersionComponent.create(LIBRARY_NAME, BuildConfig.VERSION_NAME),
+      coroutineDispatcher<Background>(),
+      coroutineDispatcher<Lightweight>(),
+      coroutineDispatcher<Blocking>(),
+      coroutineDispatcher<UiThread>()
+    )
   }
 }
+
+private inline fun <reified T : Annotation> coroutineDispatcher(): Component<CoroutineDispatcher> =
+  Component.builder(Qualified.qualified(T::class.java, CoroutineDispatcher::class.java))
+    .add(Dependency.required(Qualified.qualified(T::class.java, Executor::class.java)))
+    .factory { c ->
+      c.get(Qualified.qualified(T::class.java, Executor::class.java)).asCoroutineDispatcher()
+    }
+    .build()

firebase-common/src/main/java/com/google/firebase/FirebaseApp.java

@@ -23,8 +23,6 @@
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.os.Build;
-import android.os.Handler;
-import android.os.Looper;
 import android.text.TextUtils;
 import android.util.Log;
 import androidx.annotation.GuardedBy;
@@ -47,6 +45,7 @@
 import com.google.firebase.components.ComponentRegistrar;
 import com.google.firebase.components.ComponentRuntime;
 import com.google.firebase.components.Lazy;
+import com.google.firebase.concurrent.ExecutorsRegistrar;
 import com.google.firebase.events.Publisher;
 import com.google.firebase.heartbeatinfo.DefaultHeartBeatController;
 import com.google.firebase.inject.Provider;
@@ -59,7 +58,6 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -97,16 +95,10 @@ public class FirebaseApp {
 
   private static final Object LOCK = new Object();
 
-  private static final Executor UI_EXECUTOR = new UiExecutor();
-
   /** A map of (name, FirebaseApp) instances. */
   @GuardedBy("LOCK")
   static final Map<String, FirebaseApp> INSTANCES = new ArrayMap<>();
 
-  private static final String FIREBASE_ANDROID = "fire-android";
-  private static final String FIREBASE_COMMON = "fire-core";
-  private static final String KOTLIN = "kotlin";
-
   private final Context applicationContext;
   private final String name;
   private final FirebaseOptions options;
@@ -427,9 +419,10 @@ protected FirebaseApp(Context applicationContext, String name, FirebaseOptions o
 
     FirebaseTrace.pushTrace("Runtime");
     componentRuntime =
-        ComponentRuntime.builder(UI_EXECUTOR)
+        ComponentRuntime.builder(com.google.firebase.concurrent.UiExecutor.INSTANCE)
             .addLazyComponentRegistrars(registrars)
             .addComponentRegistrar(new FirebaseCommonRegistrar())
+            .addComponentRegistrar(new ExecutorsRegistrar())
             .addComponent(Component.of(applicationContext, Context.class))
             .addComponent(Component.of(this, FirebaseApp.class))
             .addComponent(Component.of(options, FirebaseOptions.class))
@@ -712,14 +705,4 @@ public void onBackgroundStateChanged(boolean background) {
       }
     }
   }
-
-  private static class UiExecutor implements Executor {
-
-    private static final Handler HANDLER = new Handler(Looper.getMainLooper());
-
-    @Override
-    public void execute(@NonNull Runnable command) {
-      HANDLER.post(command);
-    }
-  }
 }