Allow construction of OffsetQueryPagingSource with Long (#3409)

extensions/android-paging3/android-test/src/test/java/app/cash/sqldelight/paging3/OffsetQueryPagingSourceTest.kt

@@ -629,14 +629,40 @@ class OffsetQueryPagingSourceTest {
     assertTrue(pagingSource.jumpingSupported)
   }
 
-  private fun query(limit: Int, offset: Int) = object : Query<TestItem>(
+  @Test
+  fun load_initialEmptyLoad_QueryPagingSourceLong() = runTest {
+    val pagingSource = QueryPagingSource(
+      countQueryLong(),
+      transacter,
+      EmptyCoroutineContext,
+      ::queryLong,
+    )
+    val result = pagingSource.refresh() as LoadResult.Page
+
+    assertTrue(result.data.isEmpty())
+
+    // now add items
+    insertItems(ITEMS_LIST)
+
+    // invalidate pagingSource to imitate invalidation from running refreshVersionSync
+    pagingSource.invalidate()
+    assertTrue(pagingSource.invalid)
+
+    // this refresh should check pagingSource's invalid status, realize it is invalid, and
+    // return a LoadResult.Invalid
+    assertThat(pagingSource.refresh()).isInstanceOf(LoadResult.Invalid::class.java)
+  }
+
+  private fun query(limit: Int, offset: Int) = queryLong(limit.toLong(), offset.toLong())
+
+  private fun queryLong(limit: Long, offset: Long) = object : Query<TestItem>(
     { cursor ->
       TestItem(cursor.getLong(0)!!)
     },
   ) {
     override fun <R> execute(mapper: (SqlCursor) -> R) = driver.executeQuery(1, "SELECT id FROM TestItem LIMIT ? OFFSET ?", mapper, 2) {
-      bindLong(0, limit.toLong())
-      bindLong(1, offset.toLong())
+      bindLong(0, limit)
+      bindLong(1, offset)
     }
 
     override fun addListener(listener: Listener) = driver.addListener(listener, arrayOf("TestItem"))
@@ -653,6 +679,16 @@ class OffsetQueryPagingSourceTest {
     { it.getLong(0)!!.toInt() },
   )
 
+  private fun countQueryLong() = Query(
+    2,
+    arrayOf("TestItem"),
+    driver,
+    "Test.sq",
+    "count",
+    "SELECT count(*) FROM TestItem",
+    { it.getLong(0)!! },
+  )
+
   private fun insertItems(items: List<TestItem>) {
     items.forEach {
       driver.execute(0, "INSERT INTO TestItem (id) VALUES (?)", 1) {

extensions/android-paging3/src/main/java/app/cash/sqldelight/paging3/QueryPagingSource.kt

@@ -19,6 +19,7 @@ import androidx.paging.PagingConfig
 import androidx.paging.PagingSource
 import app.cash.sqldelight.Query
 import app.cash.sqldelight.Transacter
+import app.cash.sqldelight.db.SqlCursor
 import kotlinx.coroutines.Dispatchers
 import kotlin.coroutines.CoroutineContext
 import kotlin.properties.Delegates
@@ -58,6 +59,7 @@ internal abstract class QueryPagingSource<Key : Any, RowType : Any> :
  * Queries will be executed on [context].
  */
 @Suppress("FunctionName")
+@JvmName("QueryPagingSourceInt")
 fun <RowType : Any> QueryPagingSource(
   countQuery: Query<Int>,
   transacter: Transacter,
@@ -70,6 +72,36 @@ fun <RowType : Any> QueryPagingSource(
   context,
 )
 
+/**
+ * Variant of [QueryPagingSource] that accepts a [Long] instead of an [Int] for [countQuery]
+ * and [queryProvider].
+ *
+ * If the result of [countQuery] exceeds [Int.MAX_VALUE], then the count will be truncated
+ * to the least significant 32 bits of this [Long] value.
+ *
+ * @see toInt
+ */
+@Suppress("FunctionName")
+@JvmName("QueryPagingSourceLong")
+fun <RowType : Any> QueryPagingSource(
+  countQuery: Query<Long>,
+  transacter: Transacter,
+  context: CoroutineContext = Dispatchers.IO,
+  queryProvider: (limit: Long, offset: Long) -> Query<RowType>,
+): PagingSource<Int, RowType> = OffsetQueryPagingSource(
+  { limit, offset -> queryProvider(limit.toLong(), offset.toLong()) },
+  countQuery.toInt(),
+  transacter,
+  context,
+)
+
+private fun Query<Long>.toInt(): Query<Int> =
+  object : Query<Int>({ cursor -> mapper(cursor).toInt() }) {
+    override fun <R> execute(mapper: (SqlCursor) -> R) = this@toInt.execute(mapper)
+    override fun addListener(listener: Listener) = this@toInt.addListener(listener)
+    override fun removeListener(listener: Listener) = this@toInt.removeListener(listener)
+  }
+
 /**
  * Create a [PagingSource] that pages through results according to queries generated by
  * [queryProvider]. Queries returned by [queryProvider] should expected to do keyset paging.