Merge commit '2c4b142503bd2d871e6818b5cab8c38627d9e4a0' as 'examples/scala-js'

1 files changed, 88 insertions, 0 deletions

diff --git a/examples/scala-js/tools/jvm/src/main/scala/scala/scalajs/tools/sourcemap/SourceMapper.scala b/examples/scala-js/tools/jvm/src/main/scala/scala/scalajs/tools/sourcemap/SourceMapper.scala
new file mode 100644
index 0000000..6f856a9
--- /dev/null
+++ b/examples/scala-js/tools/jvm/src/main/scala/scala/scalajs/tools/sourcemap/SourceMapper.scala
@@ -0,0 +1,88 @@
+/*                     __                                               *\
+**     ________ ___   / /  ___      __ ____  Scala.js sbt plugin        **
+**    / __/ __// _ | / /  / _ | __ / // __/  (c) 2013, LAMP/EPFL        **
+**  __\ \/ /__/ __ |/ /__/ __ |/_// /_\ \    http://scala-js.org/       **
+** /____/\___/_/ |_/____/_/ | |__/ /____/                               **
+**                          |/____/                                     **
+\*                                                                      */
+
+
+package scala.scalajs.tools.sourcemap
+
+import scala.scalajs.tools.classpath._
+
+import com.google.debugging.sourcemap._
+
+class SourceMapper(classpath: CompleteClasspath) {
+
+  def map(ste: StackTraceElement, columnNumber: Int): StackTraceElement = {
+    val mapped = for {
+      sourceMap <- findSourceMap(ste.getFileName)
+    } yield map(ste, columnNumber, sourceMap)
+
+    mapped.getOrElse(ste)
+  }
+
+  def map(ste: StackTraceElement, columnNumber: Int,
+      sourceMap: String): StackTraceElement = {
+
+    val sourceMapConsumer =
+      SourceMapConsumerFactory
+        .parse(sourceMap)
+        .asInstanceOf[SourceMapConsumerV3]
+
+    /* **Attention**
+     * - StackTrace positions are 1-based
+     * - SourceMapConsumer.getMappingForLine() is 1-based
+     */
+
+    val lineNumber = ste.getLineNumber
+    val column =
+      if (columnNumber == -1) getFirstColumn(sourceMapConsumer, lineNumber)
+      else columnNumber
+
+    val originalMapping =
+      sourceMapConsumer.getMappingForLine(lineNumber, column)
+
+    if (originalMapping != null) {
+      new StackTraceElement(
+          ste.getClassName,
+          ste.getMethodName,
+          originalMapping.getOriginalFile,
+          originalMapping.getLineNumber)
+    } else ste
+  }
+
+  /** both `lineNumber` and the resulting column are 1-based */
+  private def getFirstColumn(sourceMapConsumer: SourceMapConsumerV3,
+      lineNumber1Based: Int) = {
+
+    /* **Attention**
+     * - SourceMapConsumerV3.EntryVisitor is 0-based!!!
+     */
+
+    val lineNumber = lineNumber1Based - 1
+
+    var column: Option[Int] = None
+
+    sourceMapConsumer.visitMappings(
+      new SourceMapConsumerV3.EntryVisitor {
+        def visit(sourceName: String,
+          symbolName: String,
+          sourceStartPosition: FilePosition,
+          startPosition: FilePosition,
+          endPosition: FilePosition): Unit =
+          if (!column.isDefined && startPosition.getLine == lineNumber)
+            column = Some(startPosition.getColumn)
+      })
+
+    val column0Based = column.getOrElse(0)
+    column0Based + 1
+  }
+
+  private def findSourceMap(path: String) = {
+    val candidates = classpath.allCode.filter(_.path == path)
+    if (candidates.size != 1) None // better no sourcemap than a wrong one
+    else candidates.head.sourceMap
+  }
+}