Emscripten 004

Emscripten.scala

import sbt._
import sbt.Keys._
import java.io.File
import play.Keys._
import play.PlayExceptions._
import play.PlaySourceGenerators

object EmscriptenKeys {
  val eccFiles = taskKey[PathFinder]("C/C++ files to be compiled")
  val eccCompiler = settingKey[String]("Path to Emscripten compiler")
}

object EmscriptenSettings {
  import EmscriptenKeys._
  
  val settings = Seq(
    eccCompiler := "emcc",
    eccFiles <<= (sourceDirectory in Compile) map ( _   ** "*.cpp" ),
    resourceGenerators in Compile <+= (eccFiles, eccCompiler, resourceManaged, cacheDirectory, state) map { (files, eccCompilerString, resourceManaged, cacheDirectory, state) =>
      val emscriptenCompiler = new EmscriptenCompiler(eccCompilerString)

      val results = files.get.flatMap{ f =>
        val name = f.getName.replaceAll("""\..*?$""", "")
        val outputDir = resourceManaged / "main" / "public" / name
        
        val cacheFile = cacheDirectory / name


        val (previousRelation, previousInfo) = Sync.readInfo(cacheFile)(FileInfo.lastModified.format)

        val currentInfos = Map(f -> FileInfo.lastModified(f))

        if (previousInfo != currentInfos) { //found new files

          //delete current files:
          IO.delete( (outputDir ** (name + ".*")).get)
          emscriptenCompiler.compile(f, outputDir) match {
            case Some(EmscriptenCompilerException(filename, lineNo, colNo, msg)) => 
              throw PlaySourceGenerators.reportCompilationError(state,
                AssetCompilationException(Some(file(filename)), msg, lineNo, colNo))
            case _ => 
          }

          val outputFiles = (outputDir ** (name + ".*")).get
          val relationship = Relation.empty[File, File] ++ outputFiles.map(generatedFile => f -> generatedFile)
          Sync.writeInfo(cacheFile, relationship, currentInfos)(FileInfo.lastModified.format)
          outputFiles
        } else {
          previousRelation._2s.toSeq
        }
      }
      results
    }
  )
}


object EmscriptenPlugin extends Plugin {
  import EmscriptenKeys._

  override lazy val projectSettings: Seq[Setting[_]] = EmscriptenSettings.settings

}