[fenix] Closes https://github.com/mozilla-mobile/fenix/issues/24276: updating pagination library, changing history related classes

app/src/main/java/org/mozilla/fenix/components/history/PagedHistoryProvider.kt

@@ -76,9 +76,9 @@ interface PagedHistoryProvider {
      *
      * @param offset How much to offset the list by
      * @param numberOfItems How many items to fetch
-     * @param onComplete A callback that returns the list of [HistoryDB]
+     * @return list of [HistoryDB]
      */
-    fun getHistory(offset: Int, numberOfItems: Int, onComplete: (List<HistoryDB>) -> Unit)
+    fun getHistory(offset: Int, numberOfItems: Int): List<HistoryDB>
 }
 
 /**
@@ -112,15 +112,11 @@ class DefaultPagedHistoryProvider(
 
     @Volatile private var historyGroups: List<HistoryDB.Group>? = null
 
-    @Suppress("LongMethod")
     override fun getHistory(
         offset: Int,
-        numberOfItems: Int,
-        onComplete: (List<HistoryDB>) -> Unit,
-    ) {
-        // A PagedList DataSource runs on a background thread automatically.
-        // If we run this in our own coroutineScope it breaks the PagedList
-        runBlockingIncrement {
+        numberOfItems: Int
+    ): List<HistoryDB> {
+        return runBlockingIncrement {
             // We need to re-fetch all the history metadata if the offset resets back at 0
             // in the case of a pull to refresh.
             if (historyGroups == null || offset == 0) {
@@ -146,7 +142,7 @@ class DefaultPagedHistoryProvider(
                     .toList()
             }
 
-            onComplete(getHistoryAndSearchGroups(offset, numberOfItems))
+            getHistoryAndSearchGroups(offset, numberOfItems)
         }
     }
 

app/src/main/java/org/mozilla/fenix/library/history/HistoryAdapter.kt

@@ -6,14 +6,14 @@ package org.mozilla.fenix.library.history
 
 import android.view.LayoutInflater
 import android.view.ViewGroup
-import androidx.paging.PagedListAdapter
+import androidx.paging.PagingDataAdapter
 import androidx.recyclerview.widget.DiffUtil
 import org.mozilla.fenix.selection.SelectionHolder
 import org.mozilla.fenix.library.history.viewholders.HistoryListItemViewHolder
 
 class HistoryAdapter(
     private val historyInteractor: HistoryInteractor,
-) : PagedListAdapter<History, HistoryListItemViewHolder>(historyDiffCallback),
+) : PagingDataAdapter<History, HistoryListItemViewHolder>(historyDiffCallback),
     SelectionHolder<History> {
 
     private var mode: HistoryFragmentState.Mode = HistoryFragmentState.Mode.Normal

app/src/main/java/org/mozilla/fenix/library/history/HistoryDataSource.kt

@@ -5,38 +5,40 @@
 package org.mozilla.fenix.library.history
 
 import androidx.annotation.VisibleForTesting
-import androidx.paging.ItemKeyedDataSource
+import androidx.paging.PagingSource
+import androidx.paging.PagingState
 import org.mozilla.fenix.components.history.HistoryDB
 import org.mozilla.fenix.components.history.PagedHistoryProvider
 
 class HistoryDataSource(
-    private val historyProvider: PagedHistoryProvider
-) : ItemKeyedDataSource<Int, History>() {
+    private val historyProvider: PagedHistoryProvider,
+    private val onZeroItemsLoaded: () -> Unit
+) : PagingSource<Int, History>() {
 
-    // Because the pagination is not based off of the key
-    // we want to start at 1, not 0 to be able to send the correct offset
-    // to the `historyProvider.getHistory` call.
-    override fun getKey(item: History): Int = item.position + 1
+    // having any value but null creates visual glitches in case or swipe to refresh and immediate
+    // scroll down
+    override fun getRefreshKey(state: PagingState<Int, History>): Int? = null
 
-    override fun loadInitial(
-        params: LoadInitialParams<Int>,
-        callback: LoadInitialCallback<History>
-    ) {
-        historyProvider.getHistory(INITIAL_OFFSET, params.requestedLoadSize) { history ->
-            callback.onResult(history.positionWithOffset(INITIAL_OFFSET))
+    // params.key is expected to be null for the initial load or a refresh
+    override suspend fun load(params: LoadParams<Int>): LoadResult<Int, History> {
+        val offset = params.key ?: 0
+        val historyItems = historyProvider.getHistory(offset, params.loadSize).run {
+            positionWithOffset(offset)
         }
+        val nextOffset = if (historyItems.isEmpty()) {
+            if (params.key == null) {
+                onZeroItemsLoaded.invoke()
             }
-
-    override fun loadAfter(params: LoadParams<Int>, callback: LoadCallback<History>) {
-        historyProvider.getHistory(params.key, params.requestedLoadSize) { history ->
-            callback.onResult(history.positionWithOffset(params.key))
+            null
+        } else {
+            (offset + historyItems.size) + 1
         }
-    }
-
-    override fun loadBefore(params: LoadParams<Int>, callback: LoadCallback<History>) { /* noop */ }
-
-    companion object {
-        internal const val INITIAL_OFFSET = 0
+        // prevKey is needed in case load would work upwards, so passing null is fine
+        return LoadResult.Page(
+            data = historyItems,
+            prevKey = null,
+            nextKey = nextOffset
+        )
     }
 }
 

app/src/main/java/org/mozilla/fenix/library/history/HistoryDataSourceFactory.kt

@@ -1,21 +0,0 @@
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-package org.mozilla.fenix.library.history
-
-import androidx.lifecycle.MutableLiveData
-import androidx.paging.DataSource
-import org.mozilla.fenix.components.history.PagedHistoryProvider
-
-class HistoryDataSourceFactory(
-    private val historyProvider: PagedHistoryProvider
-) : DataSource.Factory<Int, History>() {
-    val datasource = MutableLiveData<HistoryDataSource>()
-
-    override fun create(): DataSource<Int, History> {
-        val datasource = HistoryDataSource(historyProvider)
-        this.datasource.postValue(datasource)
-        return datasource
-    }
-}

app/src/main/java/org/mozilla/fenix/library/history/HistoryFragment.kt

@@ -15,11 +15,13 @@ import android.view.View
 import android.view.ViewGroup
 import androidx.appcompat.app.AlertDialog
 import androidx.lifecycle.lifecycleScope
+import androidx.lifecycle.viewModelScope
 import androidx.navigation.NavDirections
 import androidx.navigation.fragment.findNavController
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers.IO
 import kotlinx.coroutines.Dispatchers.Main
+import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.launch
 import mozilla.components.browser.state.action.EngineAction
 import mozilla.components.browser.state.action.HistoryMetadataAction
@@ -158,10 +160,11 @@ class HistoryFragment : LibraryPageFragment<History>(), UserInteractionHandler {
                 historyView::updateEmptyState
             )
 
-            model.history.observe(
-                viewLifecycleOwner,
-                historyView.historyAdapter::submitList
-            )
+            model.viewModelScope.launch {
+                model.history.collect {
+                    historyView.historyAdapter.submitData(it)
+                }
+            }
         }
     }
 
@@ -322,7 +325,7 @@ class HistoryFragment : LibraryPageFragment<History>(), UserInteractionHandler {
                         requireComponents.core.historyStorage.deleteEverything()
                         deleteOpenTabsEngineHistory(requireComponents.core.store)
                         launch(Main) {
-                            viewModel.invalidate()
+                            historyView.historyAdapter.refresh()
                             historyStore.dispatch(HistoryFragmentAction.ExitDeletionMode)
                             showSnackBar(
                                 requireView(),
@@ -411,6 +414,6 @@ class HistoryFragment : LibraryPageFragment<History>(), UserInteractionHandler {
     private suspend fun syncHistory() {
         val accountManager = requireComponents.backgroundServices.accountManager
         accountManager.syncNow(SyncReason.User)
-        viewModel.invalidate()
+        historyView.historyAdapter.refresh()
     }
 }

app/src/main/java/org/mozilla/fenix/library/history/HistoryView.kt

@@ -61,7 +61,7 @@ class HistoryView(
 
         historyAdapter.updatePendingDeletionIds(state.pendingDeletionIds)
 
-        updateEmptyState(state.pendingDeletionIds.size != historyAdapter.currentList?.size)
+        updateEmptyState(state.pendingDeletionIds.size != historyAdapter.itemCount)
 
         historyAdapter.updateMode(state.mode)
         val first = layoutManager.findFirstVisibleItemPosition()

app/src/main/java/org/mozilla/fenix/library/history/HistoryViewModel.kt

@@ -4,33 +4,28 @@
 
 package org.mozilla.fenix.library.history
 
-import androidx.lifecycle.LiveData
 import androidx.lifecycle.MutableLiveData
 import androidx.lifecycle.ViewModel
-import androidx.paging.LivePagedListBuilder
-import androidx.paging.PagedList
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import kotlinx.coroutines.flow.Flow
 import org.mozilla.fenix.components.history.PagedHistoryProvider
 
 class HistoryViewModel(historyProvider: PagedHistoryProvider) : ViewModel() {
-    var history: LiveData<PagedList<History>>
+    var history: Flow<PagingData<History>>
     var userHasHistory = MutableLiveData(true)
-    private val datasource: LiveData<HistoryDataSource>
 
     init {
-        val historyDataSourceFactory = HistoryDataSourceFactory(historyProvider)
-        datasource = historyDataSourceFactory.datasource
-
-        history = LivePagedListBuilder(historyDataSourceFactory, PAGE_SIZE)
-            .setBoundaryCallback(object : PagedList.BoundaryCallback<History>() {
-                override fun onZeroItemsLoaded() {
-                    userHasHistory.value = false
-                }
-            })
-            .build()
-    }
-
-    fun invalidate() {
-        datasource.value?.invalidate()
+        history = Pager(
+            PagingConfig(PAGE_SIZE),
+            null
+        ) {
+            HistoryDataSource(
+                historyProvider = historyProvider,
+                onZeroItemsLoaded = { userHasHistory.value = false }
+            )
+        }.flow
     }
 
     companion object {

app/src/main/java/org/mozilla/fenix/settings/sitepermissions/SitePermissionsExceptionsFragment.kt

@@ -17,8 +17,6 @@ import android.widget.TextView
 import androidx.appcompat.app.AlertDialog
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.lifecycleScope
-import androidx.paging.LivePagedListBuilder
-import androidx.paging.PagedListAdapter
 import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -36,6 +34,7 @@ import org.mozilla.fenix.ext.nav
 
 private const val MAX_ITEMS_PER_PAGE = 50
 
+@Suppress("DEPRECATION")
 class SitePermissionsExceptionsFragment :
     Fragment(R.layout.fragment_site_permissions_exceptions), View.OnClickListener {
     private lateinit var emptyContainerMessage: View
@@ -63,7 +62,7 @@ class SitePermissionsExceptionsFragment :
 
             withContext(Main) {
                 val adapter = ExceptionsAdapter(this@SitePermissionsExceptionsFragment)
-                val liveData = LivePagedListBuilder(sitePermissionsPaged, MAX_ITEMS_PER_PAGE).build()
+                val liveData = androidx.paging.LivePagedListBuilder(sitePermissionsPaged, MAX_ITEMS_PER_PAGE).build()
 
                 liveData.observe(
                     viewLifecycleOwner,
@@ -135,8 +134,9 @@ class SitePermissionsExceptionsFragment :
 class SitePermissionsViewHolder(val view: View, val iconView: ImageView, val siteTextView: TextView) :
     RecyclerView.ViewHolder(view)
 
+@Suppress("DEPRECATION")
 class ExceptionsAdapter(private val clickListener: View.OnClickListener) :
-    PagedListAdapter<SitePermissions, SitePermissionsViewHolder>(diffCallback) {
+    androidx.paging.PagedListAdapter<SitePermissions, SitePermissionsViewHolder>(diffCallback) {
 
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): SitePermissionsViewHolder {
         val context = parent.context

buildSrc/src/main/java/Dependencies.kt

@@ -35,7 +35,7 @@ object Versions {
     const val androidx_navigation = "2.3.3"
     const val androidx_recyclerview = "1.2.1"
     const val androidx_core = "1.3.2"
-    const val androidx_paging = "2.1.2"
+    const val androidx_paging = "3.1.0"
     const val androidx_transition = "1.4.0"
     const val androidx_work = "2.7.1"
     const val androidx_datastore = "1.0.0"