LayoutNodeEntity.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.compose.ui.node
import androidx.compose.ui.Modifier
import androidx.compose.ui.unit.IntSize
/**
* Base class for entities in [LayoutNodeWrapper]. a [LayoutNodeEntity] is
* a node in a linked list referenced from [EntityList].
*/
internal open class LayoutNodeEntity<T : LayoutNodeEntity<T, M>, M : Modifier>(
val layoutNodeWrapper: LayoutNodeWrapper,
val modifier: M
) {
/**
* The next element in the list. [next] is the element that is wrapped
* by this [LayoutNodeEntity].
*/
var next: T? = null
/**
* Convenience access to [LayoutNode]
*/
val layoutNode: LayoutNode
get() = layoutNodeWrapper.layoutNode
/**
* Convenience access to [LayoutNodeWrapper.size]
*/
val size: IntSize
get() = layoutNodeWrapper.size
/**
* `true` only when the entity is attached to the hierarchy.
*/
var isAttached = false
private set
/**
* Called when the entity is attached to the layout hierarchy.
*/
open fun onAttach() {
isAttached = true
}
/**
* Called when the entity has been detached from the layout hierarchy.
*/
open fun onDetach() {
isAttached = false
}
}