Add a file-repository for better organizing files

Docspell now must use a new api for accessing files.

Issue: #1379

modules/common/src/main/scala/docspell/common/FileCategory.scala

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2020 Eike K. & Contributors
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+package docspell.common
+
+import cats.data.NonEmptyList
+
+import docspell.common
+
+import io.circe.{Decoder, Encoder}
+
+/** This is used to have a rough idea for what a file is used in the system. It is part of
+  * the file-key to identify a file, backends could ignore it, since the file-id (the last
+  * part of the file-key) should be globally unique anyways.
+  */
+sealed trait FileCategory { self: Product =>
+  final def id: Ident =
+    Ident.unsafe(self.productPrefix.toLowerCase)
+
+  def toFileKey(collective: Ident, fileId: Ident): FileKey =
+    common.FileKey(collective, this, fileId)
+}
+
+object FileCategory {
+  // Impl note: Changing constants here requires a database migration!
+
+  case object AttachmentSource extends FileCategory
+  case object AttachmentConvert extends FileCategory
+  case object PreviewImage extends FileCategory
+  case object Classifier extends FileCategory
+
+  val all: NonEmptyList[FileCategory] =
+    NonEmptyList.of(AttachmentSource, AttachmentConvert, PreviewImage, Classifier)
+
+  def fromString(str: String): Either[String, FileCategory] =
+    all.find(_.id.id == str).toRight(s"Unknown category: $str")
+
+  implicit val jsonDecoder: Decoder[FileCategory] =
+    Decoder[String].emap(fromString)
+
+  implicit val jsonEncoder: Encoder[FileCategory] =
+    Encoder[String].contramap(_.id.id)
+}

modules/common/src/main/scala/docspell/common/FileKey.scala

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2020 Eike K. & Contributors
+ *
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+package docspell.common
+
+import io.circe.generic.semiauto.{deriveDecoder, deriveEncoder}
+import io.circe.{Decoder, Encoder}
+
+case class FileKey(collective: Ident, category: FileCategory, id: Ident)
+
+object FileKey {
+
+  implicit val jsonDecoder: Decoder[FileKey] =
+    deriveDecoder[FileKey]
+
+  implicit val jsonEncoder: Encoder[FileKey] =
+    deriveEncoder[FileKey]
+}

modules/common/src/main/scala/docspell/common/Ident.scala

@@ -25,13 +25,15 @@ case class Ident(id: String) {
     !isEmpty
 
   def /(next: Ident): Ident =
-    new Ident(id + "." + next.id)
+    new Ident(id + Ident.concatChar + next.id)
 }
 
 object Ident {
+  private val concatChar = '.'
   implicit val identEq: Eq[Ident] =
     Eq.by(_.id)
 
+  // Note, the slash *must not* be part of valid characters
   val chars: Set[Char] = (('A' to 'Z') ++ ('a' to 'z') ++ ('0' to '9') ++ "-_.@").toSet
 
   def randomUUID[F[_]: Sync]: F[Ident] =
@@ -75,5 +77,4 @@ object Ident {
 
   implicit val order: Order[Ident] =
     Order.by(_.id)
-
 }

modules/common/src/main/scala/docspell/common/ProcessItemArgs.scala

@@ -60,7 +60,7 @@ object ProcessItemArgs {
     implicit val jsonDecoder: Decoder[ProcessMeta] = deriveDecoder[ProcessMeta]
   }
 
-  case class File(name: Option[String], fileMetaId: Ident)
+  case class File(name: Option[String], fileMetaId: FileKey)
   object File {
     implicit val jsonEncoder: Encoder[File] = deriveEncoder[File]
     implicit val jsonDecoder: Decoder[File] = deriveDecoder[File]