MulticastConsumer.kt
/*
* Copyright 2023 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.layout.adapter.extensions
import android.content.Context
import androidx.annotation.GuardedBy
import androidx.core.util.Consumer
import androidx.window.extensions.core.util.function.Consumer as OEMConsumer
import androidx.window.extensions.layout.WindowLayoutInfo as OEMWindowLayoutInfo
import androidx.window.layout.WindowLayoutInfo
import java.util.concurrent.locks.ReentrantLock
import kotlin.concurrent.withLock
/**
* A [Consumer] that handles multicasting to multiple [Consumer]s downstream.
*/
internal class MulticastConsumer(
private val context: Context
) : Consumer<OEMWindowLayoutInfo>, OEMConsumer<OEMWindowLayoutInfo> {
private val multicastConsumerLock = ReentrantLock()
@GuardedBy("lock")
private var lastKnownValue: WindowLayoutInfo? = null
@GuardedBy("lock")
private val registeredListeners = mutableSetOf<Consumer<WindowLayoutInfo>>()
override fun accept(value: OEMWindowLayoutInfo) {
multicastConsumerLock.withLock {
val newValue = ExtensionsWindowLayoutInfoAdapter.translate(context, value)
lastKnownValue = newValue
registeredListeners.forEach { consumer -> consumer.accept(newValue) }
}
}
fun addListener(listener: Consumer<WindowLayoutInfo>) {
multicastConsumerLock.withLock {
lastKnownValue?.let { value -> listener.accept(value) }
registeredListeners.add(listener)
}
}
fun removeListener(listener: Consumer<WindowLayoutInfo>) {
multicastConsumerLock.withLock {
registeredListeners.remove(listener)
}
}
fun isEmpty(): Boolean {
return registeredListeners.isEmpty()
}
}