/*
 * Copyright 2019 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.paging

import androidx.annotation.RestrictTo
import androidx.paging.futures.DirectDispatcher
import kotlinx.coroutines.CoroutineScope

/**
 * InitialPagedList is an empty placeholder that's sent at the front of a stream of PagedLists.
 *
 * It's used solely for listening to [PagedList.LoadType.REFRESH] loading events, and retrying
 * any errors that occur during initial load.
 *
 * @hide
 */
@RestrictTo(RestrictTo.Scope.LIBRARY)
class InitialPagedList<K : Any, V : Any>(
    pagedSource: PagedSource<K, V>,
    coroutineScope: CoroutineScope,
    config: Config,
    initialKey: K?
) : ContiguousPagedList<K, V>(
    pagedSource,
    coroutineScope,
    DirectDispatcher,
    DirectDispatcher,
    null,
    config,
    PagedSource.LoadResult.empty(),
    0 // no previous load, so pass 0
) {
    override val lastKey = initialKey
}