Wire proto3 Android Gradle BuildTask

WireBuildTask.kt

import org.gradle.api.file.FileCollection
import org.gradle.api.tasks.CacheableTask
import org.gradle.api.tasks.InputFiles
import org.gradle.api.tasks.InputFile
import org.gradle.api.tasks.JavaExec
import org.gradle.api.tasks.OutputDirectory
import java.io.File
import javax.inject.Inject

@CacheableTask
open class WireBuildTask @Inject constructor(
  @get:InputFile val compilerPath: File,
  @get:OutputDirectory val outputDirectory: File,
  @get:InputFiles val protoSource: FileCollection
) : JavaExec() {

  init {
    classpath = project.rootProject.files(compilerPath)
    args = listOf(
      "--proto_path=${protoSource.asPath}",
      "--kotlin_out=${outputDirectory.path}",
      "--android",
      protoSource.asFileTree.files.joinToString { " ${it.name}" }.trim()
    )
  }
}