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Higher level abstractions of the Compose UI primitives. This library is design system agnostic, providing the high-level building blocks for both application and design-system developers

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/*
 * 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.compose.foundation.lazy.layout

import androidx.compose.ui.layout.LayoutCoordinates
import androidx.compose.ui.layout.OnGloballyPositionedModifier
import kotlin.coroutines.Continuation
import kotlin.coroutines.resume
import kotlin.coroutines.suspendCoroutine

/**
 * Internal modifier which allows to delay some interactions (e.g. scroll) until layout is ready.
 */
internal class AwaitFirstLayoutModifier : OnGloballyPositionedModifier {
    private var wasPositioned = false
    private var continuation: Continuation? = null

    suspend fun waitForFirstLayout() {
        if (!wasPositioned) {
            val oldContinuation = continuation
            suspendCoroutine { continuation = it }
            oldContinuation?.resume(Unit)
        }
    }

    override fun onGloballyPositioned(coordinates: LayoutCoordinates) {
        if (!wasPositioned) {
            wasPositioned = true
            continuation?.resume(Unit)
            continuation = null
        }
    }
}




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