1 files changed, 110 insertions, 0 deletions
diff --git a/ir/src/main/scala/scala/scalajs/ir/Utils.scala b/ir/src/main/scala/scala/scalajs/ir/Utils.scala
new file mode 100644
index 0000000..d4769dc
--- /dev/null
+++ b/ir/src/main/scala/scala/scalajs/ir/Utils.scala
@@ -0,0 +1,110 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___      __ ____  Scala.js IR                **
+**    / __/ __// _ | / /  / _ | __ / // __/  (c) 2014, LAMP/EPFL        **
+**  __\ \/ /__/ __ |/ /__/ __ |/_// /_\ \    http://scala-js.org/       **
+** /____/\___/_/ |_/____/_/ | |__/ /____/                               **
+**                          |/____/                                     **
+\*                                                                      */
+
+
+package scala.scalajs.ir
+
+import java.net.URI
+
+object Utils {
+
+  /** Relativize target URI w.r.t. base URI */
+  def relativize(base0: URI, trgt0: URI): URI = {
+    val base = base0.normalize
+    val trgt = trgt0.normalize
+
+    if (base.isOpaque || !base.isAbsolute || base.getRawPath == null ||
+        trgt.isOpaque || !trgt.isAbsolute || trgt.getRawPath == null ||
+        base.getScheme != trgt.getScheme  ||
+        base.getRawAuthority != trgt.getRawAuthority)
+      trgt
+    else {
+      val trgtCmps = trgt.getRawPath.split('/')
+      val baseCmps = base.getRawPath.split('/')
+
+      val prefixLen = (trgtCmps zip baseCmps).takeWhile(t => t._1 == t._2).size
+
+      val newPathCmps =
+        List.fill(baseCmps.size - prefixLen)("..") ++ trgtCmps.drop(prefixLen)
+
+      val newPath = newPathCmps.mkString("/")
+
+      // Relative URI does not have scheme or authority
+      new URI(null, null, newPath, trgt.getRawQuery, trgt.getRawFragment)
+    }
+  }
+
+  /** Adds an empty authority to URIs with the "file" scheme without authority.
+   *  Some browsers don't fetch URIs without authority correctly.
+   */
+  def fixFileURI(uri: URI): URI =
+    if (uri.getScheme() != "file" || uri.getAuthority() != null) uri
+    else new URI("file", "", uri.getPath(), uri.getQuery(), uri.getFragment())
+
+  def escapeJS(str: String): String = {
+    /* Note that Java and JavaScript happen to use the same encoding for
+     * Unicode, namely UTF-16, which means that 1 char from Java always equals
+     * 1 char in JavaScript. */
+    val builder = new StringBuilder
+    str foreach {
+      case '\\'     => builder.append("\\\\")
+      case '"'      => builder.append("\\\"")
+      case '\u0007' => builder.append("\\a")
+      case '\u0008' => builder.append("\\b")
+      case '\u0009' => builder.append("\\t")
+      case '\u000A' => builder.append("\\n")
+      case '\u000B' => builder.append("\\v")
+      case '\u000C' => builder.append("\\f")
+      case '\u000D' => builder.append("\\r")
+      case c =>
+        if (c >= 32 && c <= 126) builder.append(c.toChar) // ASCII printable characters
+        else builder.append(f"\\u$c%04x")
+    }
+    builder.result()
+  }
+
+  /** A ByteArrayOutput stream that allows to jump back to a given
+   *  position and complete some bytes. Methods must be called in the
+   *  following order only:
+   *  - [[markJump]]
+   *  - [[jumpBack]]
+   *  - [[continue]]
+   */
+  private[ir] class JumpBackByteArrayOutputStream
+      extends java.io.ByteArrayOutputStream {
+    protected var jumpBackPos: Int = -1
+    protected var headPos: Int = -1
+
+    /** Marks the current location for a jumpback */
+    def markJump(): Unit = {
+      assert(jumpBackPos == -1)
+      assert(headPos == -1)
+      jumpBackPos = count
+    }
+
+    /** Jumps back to the mark. Returns the number of bytes jumped */
+    def jumpBack(): Int = {
+      assert(jumpBackPos >= 0)
+      assert(headPos == -1)
+      val jumped = count - jumpBackPos
+      headPos = count
+      count = jumpBackPos
+      jumpBackPos = -1
+      jumped
+    }
+
+    /** Continues to write at the head. */
+    def continue(): Unit = {
+      assert(jumpBackPos == -1)
+      assert(headPos >= 0)
+      count = headPos
+      headPos = -1
+    }
+  }
+
+}