Rename Builder to Bindgen and update API implementation

Author: kornilova203

tools/src/main/scala/org/scalanative/bindgen/Bindgen.scala

@@ -0,0 +1,163 @@
+package org.scalanative.bindgen
+
+import java.io.File
+
+import scala.collection.mutable
+import scala.sys.process.Process
+
+sealed trait Bindgen {
+
+  /**
+   * Set bindgen executable
+   */
+  def bindgenExecutable(executable: File): Bindgen
+
+  /**
+   * Set header file for which bindings will be generated
+   */
+  def header(header: File): Bindgen
+
+  /**
+   * Library to link with, e.g. -luv for libuv
+   */
+  def link(library: String): Bindgen
+
+  /**
+   * Name of Scala object that contains bindings.
+   * Default is set to library name.
+   */
+  def scalaObjectName(scalaObjectName: String): Bindgen
+
+  /**
+   * Package name of generated Scala file
+   */
+  def packageName(packageName: String): Bindgen
+
+  /**
+   * Declarations will be removed if their names
+   * contain given prefix
+   */
+  def excludePrefix(prefix: String): Bindgen
+
+  /**
+   * Additional argument to append to the compiler command line
+   */
+  def extraArg(arg: String): Bindgen
+
+  /**
+   * Additional argument to append to the compiler command line
+   */
+  def extraArgBefore(arg: String): Bindgen
+
+  /**
+   * Run binding generator
+   */
+  def generate(): Bindings
+}
+
+object Bindgen {
+  def apply(): Bindgen = Impl()
+
+  private final case class Impl() extends Bindgen {
+    private var executable: File                    = _
+    private var library: String                     = _
+    private var header: File                        = _
+    private var scalaObjectName: String             = _
+    private var packageName: String                 = _
+    private var excludePrefix: String               = _
+    private val extraArg: mutable.Seq[String]       = mutable.Seq()
+    private val extraArgBefore: mutable.Seq[String] = mutable.Seq()
+
+    def bindgenExecutable(executable: File): Bindgen = {
+      require(executable.exists())
+      this.executable = executable
+      this
+    }
+
+    def header(header: File): Bindgen = {
+      require(header.exists())
+      this.header = header
+      this
+    }
+
+    def link(library: String): Bindgen = {
+      require(!library.isEmpty)
+      this.library = library
+      this
+    }
+
+    def scalaObjectName(scalaObjectName: String): Bindgen = {
+      require(!scalaObjectName.isEmpty)
+      this.scalaObjectName = scalaObjectName
+      this
+    }
+
+    def packageName(packageName: String): Bindgen = {
+      require(!packageName.isEmpty)
+      this.packageName = packageName
+      this
+    }
+
+    def excludePrefix(prefix: String): Bindgen = {
+      require(!prefix.isEmpty)
+      excludePrefix = prefix
+      this
+    }
+
+    def extraArg(arg: String): Bindgen = {
+      require(!arg.isEmpty)
+      extraArg :+ arg
+      this
+    }
+
+    def extraArgBefore(arg: String): Bindgen = {
+      require(!arg.isEmpty)
+      extraArgBefore :+ arg
+      this
+    }
+
+    private def validateFields(): Unit = {
+      if (executable == null) {
+        throw new AssertionError("Specify bindgen executable")
+      }
+      if (header == null) {
+        throw new AssertionError("Specify header file")
+      }
+      if (library == null) {
+        throw new AssertionError("Specify library name")
+      }
+    }
+
+    def generate(): Bindings = {
+      validateFields()
+
+      if (scalaObjectName == null) {
+        scalaObjectName = library
+      }
+      var cmd = Seq(
+        executable.getAbsolutePath,
+        header.getAbsolutePath,
+        "--name",
+        scalaObjectName,
+        "--link",
+        library
+      )
+
+      if (packageName != null) {
+        cmd ++= Seq("--package", packageName)
+      }
+
+      if (excludePrefix != null) {
+        cmd :+= excludePrefix
+      }
+
+      cmd :+= "--"
+
+      // TODO: extra args
+
+      val output = Process(cmd).lineStream.mkString("\n")
+
+      new Bindings(output)
+    }
+  }
+}