ActivityEmbeddingController.kt

/*
 * Copyright 2022 The Android Open Source Project
 *
 * 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 androidx.window.embedding

import android.app.Activity
import android.content.Context
import java.util.concurrent.locks.ReentrantLock
import kotlin.concurrent.withLock

/** A singleton controller that allows checking the current [Activity] embedding status. */
class ActivityEmbeddingController private constructor(applicationContext: Context) {
    private val embeddingBackend: EmbeddingBackend = ExtensionEmbeddingBackend
        .getInstance(applicationContext)

    /**
     * Checks if the [activity] is embedded and its presentation may be customized by the host
     * process of the task this [activity] is associated with.
     *
     * @param activity the [Activity] to check.
     */
    // TODO(b/204399167) Migrate to a Flow
    fun isActivityEmbedded(activity: Activity): Boolean =
        embeddingBackend.isActivityEmbedded(activity)

    companion object {
        @Volatile
        private var globalInstance: ActivityEmbeddingController? = null
        private val globalLock = ReentrantLock()

        /**
         * Obtains the singleton instance of [ActivityEmbeddingController].
         *
         * @param context the [Context] to initialize the controller with
         */
        @JvmStatic
        fun getInstance(context: Context): ActivityEmbeddingController {
            globalLock.withLock {
                if (globalInstance == null) {
                    globalInstance = ActivityEmbeddingController(context.applicationContext)
                }
                return globalInstance!!
            }
        }
    }
}