1 files changed, 121 insertions, 0 deletions
diff --git a/scalalib/src/Dep.scala b/scalalib/src/Dep.scala
new file mode 100644
index 00000000..714fa21e
--- /dev/null
+++ b/scalalib/src/Dep.scala
@@ -0,0 +1,121 @@
+package mill.scalalib
+import mill.util.JsonFormatters._
+import upickle.default.{macroRW, ReadWriter => RW}
+
+import CrossVersion._
+
+case class Dep(dep: coursier.Dependency, cross: CrossVersion, force: Boolean) {
+  import mill.scalalib.api.Util.isDotty
+
+  def artifactName(binaryVersion: String, fullVersion: String, platformSuffix: String) = {
+    val suffix = cross.suffixString(binaryVersion, fullVersion, platformSuffix)
+    dep.module.name + suffix
+  }
+  def configure(attributes: coursier.Attributes): Dep = copy(dep = dep.copy(attributes = attributes))
+  def forceVersion(): Dep = copy(force = true)
+  def exclude(exclusions: (String, String)*) = copy(dep = dep.copy(exclusions = dep.exclusions ++ exclusions))
+  def excludeOrg(organizations: String*): Dep = exclude(organizations.map(_ -> "*"): _*)
+  def excludeName(names: String*): Dep = exclude(names.map("*" -> _): _*)
+  def toDependency(binaryVersion: String, fullVersion: String, platformSuffix: String) =
+    dep.copy(module = dep.module.copy(name = artifactName(binaryVersion, fullVersion, platformSuffix)))
+  def withConfiguration(configuration: String): Dep = copy(dep = dep.copy(configuration = configuration))
+
+  /**
+    * If scalaVersion is a Dotty version, replace the cross-version suffix
+    * by the Scala 2.x version that the Dotty version is retro-compatible with,
+    * otherwise do nothing.
+    *
+    * This setting is useful when your build contains dependencies that have only
+    * been published with Scala 2.x, if you have:
+    * {{{
+    * def ivyDeps = Agg(ivy"a::b:c")
+    * }}}
+    * you can replace it by:
+    * {{{
+    * def ivyDeps = Agg(ivy"a::b:c".withDottyCompat(scalaVersion()))
+    * }}}
+    * This will have no effect when compiling with Scala 2.x, but when compiling
+    * with Dotty this will change the cross-version to a Scala 2.x one. This
+    * works because Dotty is currently retro-compatible with Scala 2.x.
+    */
+  def withDottyCompat(scalaVersion: String): Dep =
+    cross match {
+      case cross: Binary if isDotty(scalaVersion) =>
+        copy(cross = Constant(value = "_2.12", platformed = cross.platformed))
+      case _ =>
+        this
+    }
+}
+
+object Dep {
+
+  val DefaultConfiguration = "default(compile)"
+
+  implicit def parse(signature: String): Dep = {
+    val parts = signature.split(';')
+    val module = parts.head
+    val attributes = parts.tail.foldLeft(coursier.Attributes()) { (as, s) =>
+      s.split('=') match {
+        case Array("classifier", v) => as.copy(classifier = v)
+        case Array(k, v) => throw new Exception(s"Unrecognized attribute: [$s]")
+        case _ => throw new Exception(s"Unable to parse attribute specifier: [$s]")
+      }
+    }
+    (module.split(':') match {
+      case Array(a, b, c) => Dep(a, b, c, cross = empty(platformed = false))
+      case Array(a, b, "", c) => Dep(a, b, c, cross = empty(platformed = true))
+      case Array(a, "", b, c) => Dep(a, b, c, cross = Binary(platformed = false))
+      case Array(a, "", b, "", c) => Dep(a, b, c, cross = Binary(platformed = true))
+      case Array(a, "", "", b, c) => Dep(a, b, c, cross = Full(platformed = false))
+      case Array(a, "", "", b, "", c) => Dep(a, b, c, cross = Full(platformed = true))
+      case _ => throw new Exception(s"Unable to parse signature: [$signature]")
+    }).configure(attributes = attributes)
+  }
+  def apply(org: String, name: String, version: String, cross: CrossVersion, force: Boolean = false): Dep = {
+    apply(coursier.Dependency(coursier.Module(org, name), version, DefaultConfiguration), cross, force)
+  }
+  implicit def rw: RW[Dep] = macroRW
+}
+
+sealed trait CrossVersion {
+  /** If true, the cross-version suffix should start with a platform suffix if it exists */
+  def platformed: Boolean
+
+  def isBinary: Boolean =
+    this.isInstanceOf[Binary]
+  def isConstant: Boolean =
+    this.isInstanceOf[Constant]
+  def isFull: Boolean =
+    this.isInstanceOf[Full]
+
+  /** The string that should be appended to the module name to get the artifact name */
+  def suffixString(binaryVersion: String, fullVersion: String, platformSuffix: String): String = {
+    val firstSuffix = if (platformed) platformSuffix else ""
+    this match {
+      case cross: Constant =>
+        s"${firstSuffix}${cross.value}"
+      case cross: Binary =>
+        s"${firstSuffix}_${binaryVersion}"
+      case cross: Full =>
+        s"${firstSuffix}_${fullVersion}"
+    }
+  }
+}
+object CrossVersion {
+  case class Constant(value: String, platformed: Boolean) extends CrossVersion
+  object Constant {
+     implicit def rw: RW[Constant] = macroRW
+  }
+  case class Binary(platformed: Boolean) extends CrossVersion
+  object Binary {
+     implicit def rw: RW[Binary] = macroRW
+  }
+  case class Full(platformed: Boolean) extends CrossVersion
+  object Full {
+     implicit def rw: RW[Full] = macroRW
+  }
+
+  def empty(platformed: Boolean) = Constant(value = "", platformed)
+
+  implicit def rw: RW[CrossVersion] = RW.merge(Constant.rw, Binary.rw, Full.rw)
+}