From 3e90312b3f2d912bf27e91b454a6ef21a81a2fc5 Mon Sep 17 00:00:00 2001
From: Jakob Odersky <jodersky@gmail.com>
Date: Fri, 4 Dec 2015 20:50:53 -0800
Subject: initial commit

---
 .../main/scala/ch/jodersky/jni/NativeLoader.scala  | 75 ++++++++++++++++++++++
 .../src/main/scala/ch/jodersky/jni/Platform.scala  | 50 +++++++++++++++
 2 files changed, 125 insertions(+)
 create mode 100644 jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala
 create mode 100644 jni-library/src/main/scala/ch/jodersky/jni/Platform.scala

(limited to 'jni-library/src/main/scala/ch')

diff --git a/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala b/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala
new file mode 100644
index 0000000..46d4b2d
--- /dev/null
+++ b/jni-library/src/main/scala/ch/jodersky/jni/NativeLoader.scala
@@ -0,0 +1,75 @@
+package ch.jodersky.jni
+
+import java.io.{File, FileOutputStream, InputStream, OutputStream}
+import scala.io.Source
+
+/**
+  * Provides enhanced native library loading functionality. 
+  */
+object NativeLoader {
+
+  /** Name of the shared library file that is contained in a jar. */
+  final val LibraryName = "library"
+
+  final val BufferSize = 4096
+
+  /** Extract a resource from this class loader to a temporary file. */
+  private def extract(path: String): Option[File] = {
+    var in: Option[InputStream] = None
+    var out: Option[OutputStream] = None
+
+    try {
+      in = Option(NativeLoader.getClass.getResourceAsStream(path))
+      if (in.isEmpty) return None
+
+      val file = File.createTempFile(path, "")
+      out = Some(new FileOutputStream(file))
+
+      val buffer = new Array[Byte](BufferSize)
+      var length = -1;
+      do {
+        length = in.get.read(buffer)
+        if (length != -1) out.get.write(buffer, 0, length)
+      } while (length != -1)
+
+      Some(file)
+    } finally {
+      in.foreach(_.close)
+      out.foreach(_.close)
+    }
+  }
+
+  private def loadError(msg: String): Nothing = throw new UnsatisfiedLinkError(
+    "Error during native library extraction " +
+      "(this can happen if your platform is not supported): " +
+      msg
+  )
+
+  def fullLibraryPath(libraryPath: String, platform: Platform) = {
+    libraryPath + "/native/" + platform.id  + "/" + LibraryName
+  }
+
+  private def loadFromJar(libraryPath: String): Unit = {
+    val platform = Platform.current.getOrElse{
+      loadError("Cannot determine current platform.")
+    }
+
+    val resource = fullLibraryPath(libraryPath, platform)
+
+    val file = extract(resource) getOrElse loadError(
+      s"Shared library $resource not found."
+    )
+    System.load(file.getAbsolutePath())
+  }
+
+  /**
+   * Load a native library from the available library path or fall back
+   * to extracting and loading a native library from available resources.
+   */
+  def load(library: String, libraryPath: String): Unit = try {
+    System.loadLibrary(library)
+  } catch {
+    case ex: UnsatisfiedLinkError => loadFromJar(libraryPath)
+  }
+
+}
diff --git a/jni-library/src/main/scala/ch/jodersky/jni/Platform.scala b/jni-library/src/main/scala/ch/jodersky/jni/Platform.scala
new file mode 100644
index 0000000..db1662d
--- /dev/null
+++ b/jni-library/src/main/scala/ch/jodersky/jni/Platform.scala
@@ -0,0 +1,50 @@
+package ch.jodersky.jni
+
+import java.io.IOException
+import scala.sys.process.Process
+
+/**
+ * A platform is the representation of an architecture-kernel combination.
+ * It is a somewhat ambigous concept defined as the set of all system configurations
+ * capable of running a native binary.
+ */
+case class Platform private (arch: String, kernel: String) {
+
+  /**
+   * String representation of this platform. It is inspired by Autotools' platform
+   * triplet, without the vendor field.
+   */
+  def id = arch + "-" + kernel
+
+}
+
+object Platform {
+
+  final val Unknown = Platform("unknown", "unknown")
+
+  /** Create a platform with spaces stripped and case normalized. */
+  def normalized(arch: String, kernel: String): Platform = {
+    def normalize(str: String) = str.toLowerCase.filter(!_.isWhitespace)
+    Platform(normalize(arch), normalize(kernel))
+  }
+
+  /** Run 'uname' to determine current platform. Returns None if uname does not exist. */
+  def uname: Option[Platform] = {
+    val lineOpt = try {
+      Some(Process("uname -sm").lines.head)
+    } catch {
+      case _: IOException => None
+    }
+    lineOpt.map { line =>
+      val parts = line.split(" ")
+      if (parts.length != 2) {
+        sys.error("Could not determine platform: 'uname -sm' returned unexpected string: " + line)
+      } else {
+        Platform.normalized(parts(1), parts(0))
+      }
+    }
+  }
+
+  def current = uname
+
+}
-- 
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