| /* |
| * 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.paging.PagingSource.LoadResult.Page |
| |
| /** |
| * Load access information blob, containing information from presenter. |
| */ |
| internal data class ViewportHint( |
| /** Page index offset from initial load */ |
| val pageOffset: Int, |
| /** |
| * Original index of item in the [Page] with [pageOffset]. |
| * |
| * Three cases to consider: |
| * - [indexInPage] in Page.data.indices -> Hint references original item directly |
| * - [indexInPage] > Page.data.indices -> Hint references a placeholder after the last |
| * presented item. |
| * - [indexInPage] < 0 -> Hint references a placeholder before the first presented item. |
| */ |
| val indexInPage: Int, |
| /** |
| * Distance from hint to first loaded item: `anchorPosition - firstLoadedItemPosition` |
| * |
| * Zero indicates access at boundary |
| * Positive -> Within loaded range or in placeholders if greater than size of last page. |
| * Negative -> placeholder access. |
| */ |
| val presentedItemsBefore: Int, |
| /** |
| * Distance from hint to last presented item: `size - index - placeholdersAfter - 1` |
| * |
| * Zero indicates access at boundary |
| * Positive -> Within loaded range or in placeholders if greater than size of last page. |
| * Negative -> placeholder access. |
| */ |
| val presentedItemsAfter: Int, |
| val originalPageOffsetFirst: Int, |
| val originalPageOffsetLast: Int |
| ) |