input.parsers.IdlImportParser.scala Maven / Gradle / Ivy

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package avrohugger
package input
package parsers

import java.io.File
import scala.util.matching.Regex.Match

object IdlImportParser {

  def stripComments(fileContents: String): String = {
    val multiLinePattern = """/\*.*\*/""".r
    val singleLinePattern = """//.*$""".r
    val noSingleLines = singleLinePattern.replaceAllIn(fileContents, "")
    val commentFree = multiLinePattern.replaceAllIn(noSingleLines, "")
    commentFree
  }

  def getImportedFiles(infile: File, classLoader: ClassLoader): List[File] = {
    def readFile(file: File): String = {
      var count = 0
      val maxTries = 3
      try {
        count += 1
        val file = scala.io.Source.fromFile(infile)
        val fileContents: String = stripComments(file.mkString)
        file.close
        // if file is empty, try again, it was there when we read idl
        if (fileContents.isEmpty && (count < maxTries)) readFile(infile)
        else fileContents
      } catch { // if file is not found, try again, it was there when we read idl
        case e: java.io.FileNotFoundException => {
          if (count < maxTries) readFile(infile)
          else sys.error("File to found: " + infile)
        }
      }
    }

    val path = infile.getParent + "/"
    val contents = readFile(infile)
    val avdlPattern = """import[ \t]+idl[ \t]+"([^"]*\.avdl)"[ \t]*;""".r
    val avprPattern = """import[ \t]+protocol[ \t]+"([^"]*\.avpr)"[ \t]*;""".r
    val avscPattern = """import[ \t]+schema[ \t]+"([^"]*\.avsc)"[ \t]*;""".r
    val idlMatches = avdlPattern.findAllIn(contents).matchData.toList
    val protocolMatches = avprPattern.findAllIn(contents).matchData.toList
    val schemaMatches = avscPattern.findAllIn(contents).matchData.toList
    val importMatches = idlMatches ::: protocolMatches ::: schemaMatches

    val (localImports, nonLocalMatches): (List[File], List[Match]) =
      importMatches.foldLeft((List.empty[File], List.empty[Match])) {
        case ((ai, am), m) =>
          val f = new File(path + m.group(1))
          if (f.exists) (ai :+ f, am)
          else (ai, am :+ m)
      }

    val classpathImports: List[File] = nonLocalMatches.flatMap { m =>
      Option(classLoader.getResource(m.group(1))).map(resource => {
        new File(resource.getFile)
      })
    }.filter(_.exists)

    val importedFiles = classpathImports ++ localImports
    importedFiles
  }

}