Merge pull request #32 from github/getFileBySourceArchiveName

Replace getEncodedFile with getFileBySourceArchiveName predicate

ql/src/printAst.ql

@@ -20,13 +20,23 @@ external string selectedSourceFile();
  * output of `.getFile()` on locatable entities.
  */
 cached
-File getEncodedFile(string name) { result.getAbsolutePath().replaceAll(":", "_") = name }
+File getFileBySourceArchiveName(string name) {
+  // The name provided for a file in the source archive by the VS Code extension
+  // has some differences from the absolute path in the database:
+  // 1. colons are replaced by underscores
+  // 2. there's a leading slash, even for Windows paths: "C:/foo/bar" ->
+  //    "/C_/foo/bar"
+  // 3. double slashes in UNC prefixes are replaced with a single slash
+  // We can handle 2 and 3 together by unconditionally adding a leading slash
+  // before replacing double slashes.
+  name = ("/" + result.getAbsolutePath().replaceAll(":", "_")).replaceAll("//", "/")
+}
 
 /**
  * Overrides the configuration to print only nodes in the selected source file.
  */
 class Cfg extends PrintAstConfiguration {
   override predicate shouldPrintNode(AstNode n) {
-    n.getLocation().getFile() = getEncodedFile(selectedSourceFile())
+    n.getLocation().getFile() = getFileBySourceArchiveName(selectedSourceFile())
   }
 }