ModifierLocalConsumerNode.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.ModifierLocalConsumer
import androidx.compose.ui.modifier.ModifierLocalReadScope
internal class ModifierLocalConsumerNode(
wrapped: LayoutNodeWrapper,
modifier: ModifierLocalConsumer
) : DelegatingLayoutNodeWrapper<ModifierLocalConsumer>(wrapped, modifier), ModifierLocalReadScope {
override fun onModifierChanged() {
super.onModifierChanged()
notifyConsumerOfChanges()
}
override fun attach() {
super.attach()
notifyConsumerOfChanges()
}
override val <T> ModifierLocal<T>.current: T
get() = onModifierLocalRead(this)
private fun notifyConsumerOfChanges() {
// If the node is not attached, we don't notify the consumers.
// Ultimately when the node is attached, this function will be called again.
if (!isAttached) return
layoutNode.requireOwner().snapshotObserver.observeReads(this, onReadValuesChanged) {
modifier.onModifierLocalsUpdated(this)
}
}
companion object {
val onReadValuesChanged: (ModifierLocalConsumerNode) -> Unit = { node ->
node.notifyConsumerOfChanges()
}
}
}