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blob.scala
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blob.scala
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// Copyright (c) 2013-2018 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.free
import cats.~>
import cats.effect.{ Async, ExitCase }
import cats.free.{ Free => FF } // alias because some algebras have an op called Free
import java.io.InputStream
import java.io.OutputStream
import java.sql.Blob
@SuppressWarnings(Array("org.wartremover.warts.Overloading"))
object blob { module =>
// Algebra of operations for Blob. Each accepts a visitor as an alternatie to pattern-matching.
sealed trait BlobOp[A] {
def visit[F[_]](v: BlobOp.Visitor[F]): F[A]
}
// Free monad over BlobOp.
type BlobIO[A] = FF[BlobOp, A]
// Module of instances and constructors of BlobOp.
object BlobOp {
// Given a Blob we can embed a BlobIO program in any algebra that understands embedding.
implicit val BlobOpEmbeddable: Embeddable[BlobOp, Blob] =
new Embeddable[BlobOp, Blob] {
def embed[A](j: Blob, fa: FF[BlobOp, A]) = Embedded.Blob(j, fa)
}
// Interface for a natural tansformation BlobOp ~> F encoded via the visitor pattern.
// This approach is much more efficient than pattern-matching for large algebras.
trait Visitor[F[_]] extends (BlobOp ~> F) {
final def apply[A](fa: BlobOp[A]): F[A] = fa.visit(this)
// Common
def raw[A](f: Blob => A): F[A]
def embed[A](e: Embedded[A]): F[A]
def delay[A](a: () => A): F[A]
def handleErrorWith[A](fa: BlobIO[A], f: Throwable => BlobIO[A]): F[A]
def async[A](k: (Either[Throwable, A] => Unit) => Unit): F[A]
def asyncF[A](k: (Either[Throwable, A] => Unit) => BlobIO[Unit]): F[A]
def bracketCase[A, B](acquire: BlobIO[A])(use: A => BlobIO[B])(release: (A, ExitCase[Throwable]) => BlobIO[Unit]): F[B]
// Blob
def free: F[Unit]
def getBinaryStream: F[InputStream]
def getBinaryStream(a: Long, b: Long): F[InputStream]
def getBytes(a: Long, b: Int): F[Array[Byte]]
def length: F[Long]
def position(a: Array[Byte], b: Long): F[Long]
def position(a: Blob, b: Long): F[Long]
def setBinaryStream(a: Long): F[OutputStream]
def setBytes(a: Long, b: Array[Byte]): F[Int]
def setBytes(a: Long, b: Array[Byte], c: Int, d: Int): F[Int]
def truncate(a: Long): F[Unit]
}
// Common operations for all algebras.
final case class Raw[A](f: Blob => A) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.raw(f)
}
final case class Embed[A](e: Embedded[A]) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.embed(e)
}
final case class Delay[A](a: () => A) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.delay(a)
}
final case class HandleErrorWith[A](fa: BlobIO[A], f: Throwable => BlobIO[A]) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.handleErrorWith(fa, f)
}
final case class Async1[A](k: (Either[Throwable, A] => Unit) => Unit) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.async(k)
}
final case class AsyncF[A](k: (Either[Throwable, A] => Unit) => BlobIO[Unit]) extends BlobOp[A] {
def visit[F[_]](v: Visitor[F]) = v.asyncF(k)
}
final case class BracketCase[A, B](acquire: BlobIO[A], use: A => BlobIO[B], release: (A, ExitCase[Throwable]) => BlobIO[Unit]) extends BlobOp[B] {
def visit[F[_]](v: Visitor[F]) = v.bracketCase(acquire)(use)(release)
}
// Blob-specific operations.
final case object Free extends BlobOp[Unit] {
def visit[F[_]](v: Visitor[F]) = v.free
}
final case object GetBinaryStream extends BlobOp[InputStream] {
def visit[F[_]](v: Visitor[F]) = v.getBinaryStream
}
final case class GetBinaryStream1(a: Long, b: Long) extends BlobOp[InputStream] {
def visit[F[_]](v: Visitor[F]) = v.getBinaryStream(a, b)
}
final case class GetBytes(a: Long, b: Int) extends BlobOp[Array[Byte]] {
def visit[F[_]](v: Visitor[F]) = v.getBytes(a, b)
}
final case object Length extends BlobOp[Long] {
def visit[F[_]](v: Visitor[F]) = v.length
}
final case class Position(a: Array[Byte], b: Long) extends BlobOp[Long] {
def visit[F[_]](v: Visitor[F]) = v.position(a, b)
}
final case class Position1(a: Blob, b: Long) extends BlobOp[Long] {
def visit[F[_]](v: Visitor[F]) = v.position(a, b)
}
final case class SetBinaryStream(a: Long) extends BlobOp[OutputStream] {
def visit[F[_]](v: Visitor[F]) = v.setBinaryStream(a)
}
final case class SetBytes(a: Long, b: Array[Byte]) extends BlobOp[Int] {
def visit[F[_]](v: Visitor[F]) = v.setBytes(a, b)
}
final case class SetBytes1(a: Long, b: Array[Byte], c: Int, d: Int) extends BlobOp[Int] {
def visit[F[_]](v: Visitor[F]) = v.setBytes(a, b, c, d)
}
final case class Truncate(a: Long) extends BlobOp[Unit] {
def visit[F[_]](v: Visitor[F]) = v.truncate(a)
}
}
import BlobOp._
// Smart constructors for operations common to all algebras.
val unit: BlobIO[Unit] = FF.pure[BlobOp, Unit](())
def pure[A](a: A): BlobIO[A] = FF.pure[BlobOp, A](a)
def raw[A](f: Blob => A): BlobIO[A] = FF.liftF(Raw(f))
def embed[F[_], J, A](j: J, fa: FF[F, A])(implicit ev: Embeddable[F, J]): FF[BlobOp, A] = FF.liftF(Embed(ev.embed(j, fa)))
def delay[A](a: => A): BlobIO[A] = FF.liftF(Delay(() => a))
def handleErrorWith[A](fa: BlobIO[A], f: Throwable => BlobIO[A]): BlobIO[A] = FF.liftF[BlobOp, A](HandleErrorWith(fa, f))
def raiseError[A](err: Throwable): BlobIO[A] = delay(throw err)
def async[A](k: (Either[Throwable, A] => Unit) => Unit): BlobIO[A] = FF.liftF[BlobOp, A](Async1(k))
def asyncF[A](k: (Either[Throwable, A] => Unit) => BlobIO[Unit]): BlobIO[A] = FF.liftF[BlobOp, A](AsyncF(k))
def bracketCase[A, B](acquire: BlobIO[A])(use: A => BlobIO[B])(release: (A, ExitCase[Throwable]) => BlobIO[Unit]): BlobIO[B] = FF.liftF[BlobOp, B](BracketCase(acquire, use, release))
// Smart constructors for Blob-specific operations.
val free: BlobIO[Unit] = FF.liftF(Free)
val getBinaryStream: BlobIO[InputStream] = FF.liftF(GetBinaryStream)
def getBinaryStream(a: Long, b: Long): BlobIO[InputStream] = FF.liftF(GetBinaryStream1(a, b))
def getBytes(a: Long, b: Int): BlobIO[Array[Byte]] = FF.liftF(GetBytes(a, b))
val length: BlobIO[Long] = FF.liftF(Length)
def position(a: Array[Byte], b: Long): BlobIO[Long] = FF.liftF(Position(a, b))
def position(a: Blob, b: Long): BlobIO[Long] = FF.liftF(Position1(a, b))
def setBinaryStream(a: Long): BlobIO[OutputStream] = FF.liftF(SetBinaryStream(a))
def setBytes(a: Long, b: Array[Byte]): BlobIO[Int] = FF.liftF(SetBytes(a, b))
def setBytes(a: Long, b: Array[Byte], c: Int, d: Int): BlobIO[Int] = FF.liftF(SetBytes1(a, b, c, d))
def truncate(a: Long): BlobIO[Unit] = FF.liftF(Truncate(a))
// BlobIO is an Async
implicit val AsyncBlobIO: Async[BlobIO] =
new Async[BlobIO] {
val M = FF.catsFreeMonadForFree[BlobOp]
def bracketCase[A, B](acquire: BlobIO[A])(use: A => BlobIO[B])(release: (A, ExitCase[Throwable]) => BlobIO[Unit]): BlobIO[B] = module.bracketCase(acquire)(use)(release)
def pure[A](x: A): BlobIO[A] = M.pure(x)
def handleErrorWith[A](fa: BlobIO[A])(f: Throwable => BlobIO[A]): BlobIO[A] = module.handleErrorWith(fa, f)
def raiseError[A](e: Throwable): BlobIO[A] = module.raiseError(e)
def async[A](k: (Either[Throwable,A] => Unit) => Unit): BlobIO[A] = module.async(k)
def asyncF[A](k: (Either[Throwable,A] => Unit) => BlobIO[Unit]): BlobIO[A] = module.asyncF(k)
def flatMap[A, B](fa: BlobIO[A])(f: A => BlobIO[B]): BlobIO[B] = M.flatMap(fa)(f)
def tailRecM[A, B](a: A)(f: A => BlobIO[Either[A, B]]): BlobIO[B] = M.tailRecM(a)(f)
def suspend[A](thunk: => BlobIO[A]): BlobIO[A] = M.flatten(module.delay(thunk))
}
}