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resultset.scala
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resultset.scala
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// Copyright (c) 2013-2020 Rob Norris and Contributors
// This software is licensed under the MIT License (MIT).
// For more information see LICENSE or https://opensource.org/licenses/MIT
package doobie.hi
import cats.Alternative
import cats.Monad
import cats.data.NonEmptyList
import cats.syntax.apply.*
import cats.syntax.flatMap.*
import cats.syntax.functor.*
import cats.syntax.monad.*
import doobie.FRS
import doobie.enumerated.FetchDirection
import doobie.enumerated.Holdability
import doobie.free.resultset.ResultSetIO
import doobie.util.Read
import doobie.util.Write
import doobie.util.invariant.*
import doobie.util.stream.repeatEvalChunks
import fs2.Stream
import java.sql.ResultSetMetaData
import java.sql.SQLWarning
import scala.collection.Factory
/**
* Module of high-level constructors for `ResultSetIO` actions.
* @group Modules
*/
object resultset {
/**
* Non-strict unit for capturing effects.
* @group Constructors (Lifting)
*/
def delay[A](a: => A): ResultSetIO[A] =
FRS.delay(a)
/** @group Cursor Control */
def absolute(row: Int): ResultSetIO[Boolean] =
FRS.absolute(row)
/** @group Cursor Control */
val afterLast: ResultSetIO[Unit] =
FRS.afterLast
/** @group Cursor Control */
val beforeFirst: ResultSetIO[Unit] =
FRS.beforeFirst
/** @group Updating */
val cancelRowUpdates: ResultSetIO[Unit] =
FRS.cancelRowUpdates
/** @group Warnings */
val clearWarnings: ResultSetIO[Unit] =
FRS.clearWarnings
/** @group Updating */
val deleteRow: ResultSetIO[Unit] =
FRS.deleteRow
/** @group Cursor Control */
val first: ResultSetIO[Boolean] =
FRS.first
/**
* Read a value of type `A`.
* @group Results
*/
def get[A](implicit A: Read[A]): ResultSetIO[A] =
A.get
/**
* Consumes the remainder of the resultset, reading each row as a value of
* type `A` and accumulating them in a standard library collection via
* `CanBuildFrom`.
* @group Results
*/
@SuppressWarnings(Array("org.wartremover.warts.MutableDataStructures", "org.wartremover.warts.While"))
def build[F[_], A](implicit F: Factory[A, F[A]], A: Read[A]): ResultSetIO[F[A]] =
FRS.raw { rs =>
val b = F.newBuilder
while (rs.next) {
val _ = b += A.unsafeGet(rs, 1)
}
b.result()
}
/**
* Consumes the remainder of the resultset, reading each row as a value of
* type `(A, B)` and accumulating them in a standard library collection via
* `CanBuildFrom`.
* @group Results
*/
@SuppressWarnings(Array("org.wartremover.warts.MutableDataStructures", "org.wartremover.warts.While"))
def buildPair[F[_, _], A, B](implicit F: Factory[(A, B), F[A, B]], A: Read[(A, B)]): ResultSetIO[F[A, B]] =
FRS.raw { rs =>
val b = F.newBuilder
while (rs.next) {
val _ = b += A.unsafeGet(rs, 1)
}
b.result()
}
/**
* Consumes the remainder of the resultset, reading each row as a value of
* type `A`, mapping to `B`, and accumulating them in a standard library
* collection via `CanBuildFrom`. This unusual constructor is a workaround for
* the CanBuildFrom not having a sensible contravariant functor instance.
* @group Results
*/
@SuppressWarnings(Array("org.wartremover.warts.MutableDataStructures", "org.wartremover.warts.While"))
def buildMap[F[_], A, B](f: A => B)(implicit F: Factory[B, F[B]], A: Read[A]): ResultSetIO[F[B]] =
FRS.raw { rs =>
val b = F.newBuilder
while (rs.next) {
val _ = b += f(A.unsafeGet(rs, 1))
}
b.result()
}
/**
* Consumes the remainder of the resultset, reading each row as a value of
* type `A` and accumulating them in a `Vector`.
* @group Results
*/
def vector[A: Read]: ResultSetIO[Vector[A]] =
build[Vector, A]
/**
* Consumes the remainder of the resultset, reading each row as a value of
* type `A` and accumulating them in a `List`.
* @group Results
*/
def list[A: Read]: ResultSetIO[List[A]] =
build[List, A]
/**
* Like `getNext` but loops until the end of the resultset, gathering results
* in a `MonadPlus`.
* @group Results
*/
def accumulate[G[_]: Alternative, A: Read]: ResultSetIO[G[A]] =
get[A].whileM(next)
/**
* Updates a value of type `A`.
* @group Updating
*/
def update[A](a: A)(implicit A: Write[A]): ResultSetIO[Unit] =
A.update(a)
/**
* Similar to `next >> get` but lifted into `Option`; returns `None` when no
* more rows are available.
* @group Results
*/
def getNext[A: Read]: ResultSetIO[Option[A]] =
next >>= {
case true => get[A].map(Some(_))
case false => Monad[ResultSetIO].pure(None)
}
/**
* Similar to `getNext` but reads `chunkSize` rows at a time (the final chunk
* in a resultset may be smaller). A non-positive `chunkSize` yields an empty
* `Seq` and consumes no rows. This method delegates to `getNextChunkV` and
* widens to `Seq` for easier interoperability with streaming libraries that
* like `Seq` better.
* @group Results
*/
def getNextChunk[A: Read](chunkSize: Int): ResultSetIO[Seq[A]] =
getNextChunkV[A](chunkSize).widen[Seq[A]]
/**
* Similar to `getNext` but reads `chunkSize` rows at a time (the final chunk
* in a resultset may be smaller). A non-positive `chunkSize` yields an empty
* `Vector` and consumes no rows.
* @group Results
*/
@SuppressWarnings(Array(
"org.wartremover.warts.MutableDataStructures",
"org.wartremover.warts.Var",
"org.wartremover.warts.While",
))
def getNextChunkV[A](chunkSize: Int)(implicit A: Read[A]): ResultSetIO[Vector[A]] =
FRS.raw { rs =>
var n = chunkSize
val b = Vector.newBuilder[A]
while (n > 0 && rs.next) {
val _ = b += A.unsafeGet(rs, 1)
n -= 1
}
b.result()
}
/**
* Equivalent to `getNext`, but verifies that there is exactly one row
* remaining.
* @throws doobie.util.invariant.UnexpectedCursorPosition
* if there is not exactly one row remaining
* @group Results
*/
def getUnique[A: Read]: ResultSetIO[A] =
(getNext[A], next).tupled.flatMap {
case (Some(a), false) => FRS.delay(a)
case (Some(_), true) => FRS.raiseError(UnexpectedContinuation)
case (None, _) => FRS.raiseError(UnexpectedEnd)
}
/**
* Equivalent to `getNext`, but verifies that there is at most one row
* remaining.
* @throws doobie.util.invariant.UnexpectedContinuation
* if there is more than one row remaining
* @group Results
*/
def getOption[A: Read]: ResultSetIO[Option[A]] =
(getNext[A], next).tupled.flatMap {
case (a @ Some(_), false) => FRS.delay(a)
case (Some(_), true) => FRS.raiseError(UnexpectedContinuation)
case (None, _) => FRS.delay(None)
}
/**
* Consumes the remainder of the resultset, but verifies that there is at
* least one row remaining.
* @throws doobie.util.invariant.UnexpectedEnd
* if there is not at least one row remaining
* @group Results
*/
def nel[A: Read]: ResultSetIO[NonEmptyList[A]] =
(getNext[A], list).tupled.flatMap {
case (Some(a), as) => FRS.delay(NonEmptyList(a, as))
case (None, _) => FRS.raiseError(UnexpectedEnd)
}
/**
* Stream that reads from the `ResultSet` and returns a stream of `A`s. This
* is the preferred mechanism for dealing with query results.
* @group Results
*/
def stream[A: Read](chunkSize: Int): Stream[ResultSetIO, A] =
repeatEvalChunks(getNextChunk[A](chunkSize))
/** @group Properties */
val getFetchDirection: ResultSetIO[FetchDirection] =
FRS.getFetchDirection.flatMap(FetchDirection.fromIntF[ResultSetIO])
/** @group Properties */
val getFetchSize: ResultSetIO[Int] =
FRS.getFetchSize
/** @group Properties */
val getHoldability: ResultSetIO[Holdability] =
FRS.getHoldability.flatMap(Holdability.fromIntF[ResultSetIO])
/** @group Properties */
val getMetaData: ResultSetIO[ResultSetMetaData] =
FRS.getMetaData
/** @group Cursor Control */
val getRow: ResultSetIO[Int] =
FRS.getRow
/** @group Warnings */
val getWarnings: ResultSetIO[Option[SQLWarning]] =
FRS.getWarnings.map(Option(_))
/** @group Updating */
val insertRow: ResultSetIO[Unit] =
FRS.insertRow
/** @group Cursor Control */
val isAfterLast: ResultSetIO[Boolean] =
FRS.isAfterLast
/** @group Cursor Control */
val isBeforeFirst: ResultSetIO[Boolean] =
FRS.isBeforeFirst
/** @group Cursor Control */
val isFirst: ResultSetIO[Boolean] =
FRS.isFirst
/** @group Cursor Control */
val isLast: ResultSetIO[Boolean] =
FRS.isLast
/** @group Cursor Control */
val last: ResultSetIO[Boolean] =
FRS.last
/** @group Cursor Control */
val moveToCurrentRow: ResultSetIO[Unit] =
FRS.moveToCurrentRow
/** @group Cursor Control */
val moveToInsertRow: ResultSetIO[Unit] =
FRS.moveToInsertRow
/** @group Cursor Control */
val next: ResultSetIO[Boolean] =
FRS.next
/** @group Cursor Control */
val previous: ResultSetIO[Boolean] =
FRS.previous
/** @group Cursor Control */
val refreshRow: ResultSetIO[Unit] =
FRS.refreshRow
/** @group Cursor Control */
def relative(n: Int): ResultSetIO[Boolean] =
FRS.relative(n)
/** @group Cursor Control */
val rowDeleted: ResultSetIO[Boolean] =
FRS.rowDeleted
/** @group Cursor Control */
val rowInserted: ResultSetIO[Boolean] =
FRS.rowInserted
/** @group Cursor Control */
val rowUpdated: ResultSetIO[Boolean] =
FRS.rowUpdated
/** @group Properties */
def setFetchDirection(fd: FetchDirection): ResultSetIO[Unit] =
FRS.setFetchDirection(fd.toInt)
/** @group Properties */
def setFetchSize(n: Int): ResultSetIO[Unit] =
FRS.setFetchSize(n)
}