Refactor relativePath logic

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -335,16 +335,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
                && ctx.compilationUnit.source.exists
                && sym != defn.SourceFileAnnot
             then
-              def sourcerootPath =
-                java.nio.file.Paths.get(ctx.settings.sourceroot.value)
-                .toAbsolutePath
-                .normalize
-              val file = ctx.compilationUnit.source.file
-              val jpath = file.jpath
-              val relativePath =
-                if jpath eq null then file.path // repl and other custom tests use abstract files with no path
-                else if jpath.isAbsolute then sourcerootPath.relativize(jpath.normalize).toString
-                else jpath.normalize.toString
+              val relativePath = util.SourceFile.relativePath(ctx.compilationUnit.source)
               sym.addAnnotation(Annotation.makeSourceFile(relativePath))
           else (tree.rhs, sym.info) match
             case (rhs: LambdaTypeTree, bounds: TypeBounds) =>

compiler/src/dotty/tools/dotc/util/SourceFile.scala

@@ -191,6 +191,21 @@ object SourceFile {
     val src = new SourceFile(new VirtualFile(name, content.getBytes(StandardCharsets.UTF_8)), scala.io.Codec.UTF8)
     src._maybeInComplete = maybeIncomplete
     src
+
+  def relativePath(source: SourceFile)(using Context): String = {
+    def sourcerootPath =
+      java.nio.file.Paths.get(ctx.settings.sourceroot.value)
+      .toAbsolutePath
+      .normalize
+    val file = source.file
+    val jpath = file.jpath
+    if jpath eq null then
+      file.path // repl and other custom tests use abstract files with no path
+    else if jpath.isAbsolute then
+      sourcerootPath.relativize(jpath.normalize).toString
+    else
+      jpath.normalize.toString
+  }
 }
 
 @sharable object NoSource extends SourceFile(NoAbstractFile, Array[Char]()) {