From 954e7444086e4345c767585574d6cec9a2d83cb3 Mon Sep 17 00:00:00 2001
From: Eugene Yokota <eed3si9n@gmail.com>
Date: Mon, 22 Aug 2016 02:38:46 -0400
Subject: [PATCH] Adds templateResolvers and `new` command

This adds `new` command, which helps create a new build definition. The
`new` command is extensible via a mechanism called the template
resolver,
which evaluates the arbitrary arguments passed to the command to find
and run a template.

As a reference implementation [Giter8][g8] is provided as follows:

    sbt new eed3si9n/hello.g8

This will run eed3si9n/hello.g8 using Giter8.

  [g8]: http://www.foundweekends.org/giter8/
---
 build.sbt                                     |  2 +-
 .../main/scala/sbt/BasicCommandStrings.scala  |  5 +++
 .../src/main/scala/sbt/BasicCommands.scala    | 23 ++++++++++++-
 .../src/main/scala/sbt/BasicKeys.scala        |  2 ++
 main/src/main/scala/sbt/Defaults.scala        |  1 +
 .../scala/sbt/Giter8TemplateResolver.scala    | 32 +++++++++++++++++++
 main/src/main/scala/sbt/Keys.scala            |  2 ++
 main/src/main/scala/sbt/Main.scala            |  2 +-
 main/src/main/scala/sbt/PluginDiscovery.scala |  3 +-
 main/src/main/scala/sbt/Project.scala         |  8 +++--
 .../sbt/plugins/Giter8ResolverPlugin.scala    | 17 ++++++++++
 notes/0.13.13/template_cmd.md                 | 14 ++++++++
 project/Dependencies.scala                    |  2 ++
 13 files changed, 107 insertions(+), 6 deletions(-)
 create mode 100644 main/src/main/scala/sbt/Giter8TemplateResolver.scala
 create mode 100644 main/src/main/scala/sbt/plugins/Giter8ResolverPlugin.scala
 create mode 100644 notes/0.13.13/template_cmd.md

diff --git a/build.sbt b/build.sbt
index 55741a19d..9faf95b91 100644
--- a/build.sbt
+++ b/build.sbt
@@ -449,7 +449,7 @@ lazy val commandProj = (project in mainPath / "command").
   settings(
     testedBaseSettings,
     name := "Command",
-    libraryDependencies += launcherInterface
+    libraryDependencies ++= Seq(launcherInterface, templateResolverApi, giter8)
   )
 
 // Fixes scope=Scope for Setting (core defined in collectionProj) to define the settings system used in build definitions
diff --git a/main/command/src/main/scala/sbt/BasicCommandStrings.scala b/main/command/src/main/scala/sbt/BasicCommandStrings.scala
index 76f79e623..8750e027a 100644
--- a/main/command/src/main/scala/sbt/BasicCommandStrings.scala
+++ b/main/command/src/main/scala/sbt/BasicCommandStrings.scala
@@ -14,6 +14,7 @@ object BasicCommandStrings {
   val CompletionsCommand = "completions"
   val Exit = "exit"
   val Quit = "quit"
+  val TemplateCommand = "new"
 
   /** The command name to terminate the program.*/
   val TerminateAction: String = Exit
@@ -35,6 +36,10 @@ object BasicCommandStrings {
   def CompletionsDetailed = "Displays a list of completions for the given argument string (run 'completions <string>')."
   def CompletionsBrief = (CompletionsCommand, CompletionsDetailed)
 
+  def templateBrief = (TemplateCommand, "Creates a new sbt build.")
+  def templateDetailed = TemplateCommand + """ [--options] <template>
+  Create a new sbt build based on the given template."""
+
   def HistoryHelpBrief = (HistoryCommands.Start -> "History command help.  Lists and describes all history commands.")
   def historyHelp = Help(Nil, (HistoryHelpBrief +: HistoryCommands.descriptions).toMap, Set(HistoryCommands.Start))
 
diff --git a/main/command/src/main/scala/sbt/BasicCommands.scala b/main/command/src/main/scala/sbt/BasicCommands.scala
index ec81efba9..ea359fa16 100644
--- a/main/command/src/main/scala/sbt/BasicCommands.scala
+++ b/main/command/src/main/scala/sbt/BasicCommands.scala
@@ -16,7 +16,7 @@ import java.io.File
 import scala.util.control.NonFatal
 
 object BasicCommands {
-  lazy val allBasicCommands = Seq(nop, ignore, help, completionsCommand, multi, ifLast, append, setOnFailure, clearOnFailure, stashOnFailure, popOnFailure, reboot, call, early, exit, continuous, history, shell, read, alias) ++ compatCommands
+  lazy val allBasicCommands = Seq(nop, ignore, help, completionsCommand, templateCommand, multi, ifLast, append, setOnFailure, clearOnFailure, stashOnFailure, popOnFailure, reboot, call, early, exit, continuous, history, shell, read, alias) ++ compatCommands
 
   def nop = Command.custom(s => success(() => s))
   def ignore = Command.command(FailureWall)(idFun)
@@ -69,6 +69,27 @@ object BasicCommands {
     state
   }
 
+  def templateCommand = Command.make(TemplateCommand, templateBrief, templateDetailed)(templateCommandParser)
+  def templateCommandParser(state: State) =
+    {
+      val p = token(Space).* ~> repsep(StringBasic, token(Space))
+      val trs = (state get templateResolvers) match {
+        case Some(trs) => trs.toList
+        case None      => Nil
+      }
+      applyEffect(p)({ inputArg =>
+        val arguments = inputArg.toList ++ state.remainingCommands
+        trs find { tr =>
+          tr.isDefined(arguments.toArray)
+        } match {
+          case Some(tr) => tr.run(arguments.toArray)
+          case None =>
+            System.err.println("Template not found for: " + arguments.mkString(" "))
+        }
+        "exit" :: state.copy(remainingCommands = Nil)
+      })
+    }
+
   def multiParser(s: State): Parser[Seq[String]] =
     {
       val nonSemi = token(charClass(_ != ';').+, hide = const(true))
diff --git a/main/command/src/main/scala/sbt/BasicKeys.scala b/main/command/src/main/scala/sbt/BasicKeys.scala
index 6e7779558..7634afaca 100644
--- a/main/command/src/main/scala/sbt/BasicKeys.scala
+++ b/main/command/src/main/scala/sbt/BasicKeys.scala
@@ -1,6 +1,7 @@
 package sbt
 
 import java.io.File
+import sbt.template.TemplateResolver
 
 object BasicKeys {
   val historyPath = AttributeKey[Option[File]]("history", "The location where command line history is persisted.", 40)
@@ -10,4 +11,5 @@ object BasicKeys {
   private[sbt] val classLoaderCache = AttributeKey[classpath.ClassLoaderCache]("class-loader-cache", "Caches class loaders based on the classpath entries and last modified times.", 10)
   private[sbt] val OnFailureStack = AttributeKey[List[Option[String]]]("on-failure-stack", "Stack that remembers on-failure handlers.", 10)
   private[sbt] val explicitGlobalLogLevels = AttributeKey[Boolean]("explicit-global-log-levels", "True if the global logging levels were explicitly set by the user.", 10)
+  private[sbt] val templateResolvers = AttributeKey[Seq[TemplateResolver]]("templateResolvers", "List of template resolvers.", 1000)
 }
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index a62384785..69fe76cca 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -160,6 +160,7 @@ object Defaults extends BuildCommon {
     maxErrors :== 100,
     fork :== false,
     initialize :== {},
+    templateResolvers :== Nil,
     forcegc :== sys.props.get("sbt.task.forcegc").map(java.lang.Boolean.parseBoolean).getOrElse(GCUtil.defaultForceGarbageCollection),
     minForcegcInterval :== GCUtil.defaultMinForcegcInterval
   ))
diff --git a/main/src/main/scala/sbt/Giter8TemplateResolver.scala b/main/src/main/scala/sbt/Giter8TemplateResolver.scala
new file mode 100644
index 000000000..463ca15cb
--- /dev/null
+++ b/main/src/main/scala/sbt/Giter8TemplateResolver.scala
@@ -0,0 +1,32 @@
+package sbt
+
+import sbt.template.TemplateResolver
+
+object Giter8TemplateResolver extends TemplateResolver {
+  def isDefined(args0: Array[String]): Boolean =
+    {
+      val args = args0.toList filterNot { _.startsWith("-") }
+      // Mandate .g8
+      val Github = """^([^\s/]+)/([^\s/]+?)(?:\.g8)$""".r
+      val Local = """^file://(\S+)(?:\.g8)(?:/)?$""".r
+      object GitUrl {
+        val NativeUrl = "^(git[@|://].*)$".r
+        val HttpsUrl = "^(https://.*)$".r
+        val HttpUrl = "^(http://.*)$".r
+        val SshUrl = "^(ssh://.*)$".r
+        def unapplySeq(s: Any): Option[List[String]] =
+          NativeUrl.unapplySeq(s) orElse
+            HttpsUrl.unapplySeq(s) orElse
+            HttpUrl.unapplySeq(s) orElse
+            SshUrl.unapplySeq(s)
+      }
+      args.headOption match {
+        case Some(Github(_, _)) => true
+        case Some(Local(_))     => true
+        case GitUrl(uri)        => uri contains (".g8")
+        case _                  => false
+      }
+    }
+  def run(args: Array[String]): Unit =
+    giter8.Giter8.run(args)
+}
diff --git a/main/src/main/scala/sbt/Keys.scala b/main/src/main/scala/sbt/Keys.scala
index 566d8ed49..2385f3aef 100644
--- a/main/src/main/scala/sbt/Keys.scala
+++ b/main/src/main/scala/sbt/Keys.scala
@@ -20,6 +20,7 @@ import testing.Framework
 import Configurations.CompilerPlugin
 import Types.Id
 import KeyRanks._
+import sbt.template.TemplateResolver
 
 object Keys {
   val TraceValues = "-1 to disable, 0 for up to the first sbt frame, or a positive number to set the maximum number of frames shown."
@@ -345,6 +346,7 @@ object Keys {
   val sbtVersion = SettingKey[String]("sbt-version", "Provides the version of sbt.  This setting should be not be modified.", AMinusSetting)
   val sbtBinaryVersion = SettingKey[String]("sbt-binary-version", "Defines the binary compatibility version substring.", BPlusSetting)
   val skip = TaskKey[Boolean]("skip", "For tasks that support it (currently only 'compile' and 'update'), setting skip to true will force the task to not to do its work.  This exact semantics may vary by task.", BSetting)
+  val templateResolvers = SettingKey[Seq[TemplateResolver]]("templateResolvers", "Template resolvers used for 'new'.", BSetting)
 
   // special
   val sessionVars = AttributeKey[SessionVar.Map]("session-vars", "Bindings that exist for the duration of the session.", Invisible)
diff --git a/main/src/main/scala/sbt/Main.scala b/main/src/main/scala/sbt/Main.scala
index 88302aed1..8554c3a72 100644
--- a/main/src/main/scala/sbt/Main.scala
+++ b/main/src/main/scala/sbt/Main.scala
@@ -83,7 +83,7 @@ object BuiltinCommands {
 
   def ConsoleCommands: Seq[Command] = Seq(ignore, exit, IvyConsole.command, setLogLevel, early, act, nop)
   def ScriptCommands: Seq[Command] = Seq(ignore, exit, Script.command, setLogLevel, early, act, nop)
-  def DefaultCommands: Seq[Command] = Seq(ignore, help, completionsCommand, about, tasks, settingsCommand, loadProject,
+  def DefaultCommands: Seq[Command] = Seq(ignore, help, completionsCommand, about, tasks, settingsCommand, loadProject, templateCommand,
     projects, project, reboot, read, history, set, sessionCommand, inspect, loadProjectImpl, loadFailed, Cross.crossBuild, Cross.switchVersion,
     setOnFailure, clearOnFailure, stashOnFailure, popOnFailure, setLogLevel, plugin, plugins,
     ifLast, multi, shell, continuous, eval, alias, append, last, lastGrep, export, boot, nop, call, exit, early, initialize, act) ++
diff --git a/main/src/main/scala/sbt/PluginDiscovery.scala b/main/src/main/scala/sbt/PluginDiscovery.scala
index ad453d50c..5c8bca228 100644
--- a/main/src/main/scala/sbt/PluginDiscovery.scala
+++ b/main/src/main/scala/sbt/PluginDiscovery.scala
@@ -32,7 +32,8 @@ object PluginDiscovery {
         "sbt.plugins.IvyPlugin" -> sbt.plugins.IvyPlugin,
         "sbt.plugins.JvmPlugin" -> sbt.plugins.JvmPlugin,
         "sbt.plugins.CorePlugin" -> sbt.plugins.CorePlugin,
-        "sbt.plugins.JUnitXmlReportPlugin" -> sbt.plugins.JUnitXmlReportPlugin
+        "sbt.plugins.JUnitXmlReportPlugin" -> sbt.plugins.JUnitXmlReportPlugin,
+        "sbt.plugins.Giter8TemplatePlugin" -> sbt.plugins.Giter8TemplatePlugin
       )
       val detectedAutoPugins = discover[AutoPlugin](AutoPlugins)
       val allAutoPlugins = (defaultAutoPlugins ++ detectedAutoPugins.modules) map {
diff --git a/main/src/main/scala/sbt/Project.scala b/main/src/main/scala/sbt/Project.scala
index 5ad063dc0..8198dddde 100755
--- a/main/src/main/scala/sbt/Project.scala
+++ b/main/src/main/scala/sbt/Project.scala
@@ -7,11 +7,12 @@ import java.io.File
 import java.net.URI
 import java.util.Locale
 import Project.{ Initialize => _, Setting => _, _ }
-import Keys.{ appConfiguration, stateBuildStructure, commands, configuration, historyPath, projectCommand, sessionSettings, shellPrompt, thisProject, thisProjectRef, watch }
+import Keys.{ appConfiguration, stateBuildStructure, commands, configuration, historyPath, projectCommand, sessionSettings, shellPrompt, templateResolvers, thisProject, thisProjectRef, watch }
 import Scope.{ GlobalScope, ThisScope }
 import Def.{ Flattened, Initialize, ScopedKey, Setting }
 import Types.{ const, idFun }
 import complete.DefaultParsers
+import sbt.template.TemplateResolver
 
 import language.experimental.macros
 
@@ -337,10 +338,13 @@ object Project extends ProjectExtra {
       val allCommands = commandsIn(ref) ++ commandsIn(BuildRef(ref.build)) ++ (commands in Global get structure.data toList)
       val history = get(historyPath) flatMap idFun
       val prompt = get(shellPrompt)
+      val trs = (templateResolvers in Global get structure.data).toList.flatten
       val watched = get(watch)
       val commandDefs = allCommands.distinct.flatten[Command].map(_ tag (projectCommand, true))
       val newDefinedCommands = commandDefs ++ BasicCommands.removeTagged(s.definedCommands, projectCommand)
-      val newAttrs = setCond(Watched.Configuration, watched, s.attributes).put(historyPath.key, history)
+      val newAttrs = setCond(Watched.Configuration, watched, s.attributes).
+        put(historyPath.key, history).
+        put(templateResolvers.key, trs)
       s.copy(attributes = setCond(shellPrompt.key, prompt, newAttrs), definedCommands = newDefinedCommands)
     }
   def setCond[T](key: AttributeKey[T], vopt: Option[T], attributes: AttributeMap): AttributeMap =
diff --git a/main/src/main/scala/sbt/plugins/Giter8ResolverPlugin.scala b/main/src/main/scala/sbt/plugins/Giter8ResolverPlugin.scala
new file mode 100644
index 000000000..0edb572b7
--- /dev/null
+++ b/main/src/main/scala/sbt/plugins/Giter8ResolverPlugin.scala
@@ -0,0 +1,17 @@
+package sbt
+package plugins
+
+import Def.Setting
+import Keys._
+
+/** An experimental plugin that adds the ability for Giter8 templates to be resolved
+ */
+object Giter8TemplatePlugin extends AutoPlugin {
+  override def requires = CorePlugin
+  override def trigger = allRequirements
+
+  override lazy val globalSettings: Seq[Setting[_]] =
+    Seq(
+      templateResolvers += Giter8TemplateResolver
+    )
+}
diff --git a/notes/0.13.13/template_cmd.md b/notes/0.13.13/template_cmd.md
new file mode 100644
index 000000000..31e755a4b
--- /dev/null
+++ b/notes/0.13.13/template_cmd.md
@@ -0,0 +1,14 @@
+
+### new command and templateResolvers
+
+sbt 0.13.13 adds `new` command, which helps create a new build definition.
+The `new` command is extensible via a mechanism called the template resolver,
+which evaluates the arguments passed to the command to find and run a template.
+As a reference implementation [Giter8][g8] is provided as follows:
+
+    sbt new eed3si9n/hello.g8
+
+This will run eed3si9n/hello.g8 using Giter8.
+
+  [@eed3si9n]: https://github.com/eed3si9n
+  [g8]: http://www.foundweekends.org/giter8/
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 90f875ec3..e3d3da933 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -21,6 +21,8 @@ object Dependencies {
   lazy val junit = "junit" % "junit" % "4.11"
   lazy val launcherInterface = "org.scala-sbt" % "launcher-interface" % "1.0.0-M1"
   lazy val rawLauncher = "org.scala-sbt" % "launcher" % "1.0.0-M1"
+  lazy val templateResolverApi = "org.scala-sbt" % "template-resolver" % "0.1"
+  lazy val giter8 = "org.foundweekends.giter8" %% "giter8" % "0.7.0"
 
   private def scala211Module(name: String, moduleVersion: String) =
     Def.setting {