ModifierLocalProviderNode.kt
/*
* Copyright 2021 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.ModifierLocal
import androidx.compose.ui.modifier.ModifierLocalProvider
internal class ModifierLocalProviderNode <T> (
wrapped: LayoutNodeWrapper,
modifier: ModifierLocalProvider<T>
) : DelegatingLayoutNodeWrapper<ModifierLocalProvider<T>>(wrapped, modifier), () -> Unit {
override fun attach() {
super.attach()
// Invalidate children that read this ModifierLocal
layoutNode.owner?.registerOnEndApplyChangesListener(this)
}
override fun detach() {
// Notify anyone who has read from me that the value has changed
wrapped.invalidateConsumersOf(modifier.key)
super.detach()
}
override fun onModifierChanged() {
super.onModifierChanged()
layoutNode.owner?.registerOnEndApplyChangesListener(this)
}
override fun invalidateConsumersOf(local: ModifierLocal<*>) {
// If this provides a value for local, we don't have to notify the sub-tree
if (modifier.key != local) {
super.invalidateConsumersOf(local)
}
}
override fun findModifierLocalProvider(local: ModifierLocal<*>): ModifierLocalProviderNode<*>? {
if (modifier.key == local) {
return this
}
return super.findModifierLocalProvider(local)
}
/**
* The listener for [UiApplier.onEndChanges].
*/
override fun invoke() {
if (isAttached) {
wrapped.invalidateConsumersOf(modifier.key)
}
}
}