// use only once per compilation
sclass CompilerBot2 extends CompileJavaToJar {
  bool verbose = true;
  bool forceCompilation, dontCompile;
  bool useRenaming = true;
  bool addCompilationDate = true;

  bool didCompile;
  
  settable S mainClassForManifest;

  // returns jar path
  File compileSnippet(S snippetID) {
    src = getServerTranspiled2(snippetID);
    if (src == null) fail("Snippet not found or not public: " + snippetID);
    int i = src.indexOf('\n');
    dehlibs = src.substring(0, Math.max(0, i));
    if (verbose)
      print("Compiling snippet: " + snippetID + ". Libs: " + dehlibs);
    src = src.substring(i+1);
    progID = snippetID;
    ret compile();
  }

  File compile() {
    // Note: This is different from the calculation in x30
    // (might lead to programs being compiled twice)
    S md5 = md5(dehlibs + "\n" + src + "\n" + fsIOpt(progID));
    File jar = getJarFile(md5);
    
    if (verbose)
      print("Would compile " + l(src) + " chars (" + progID + "), md5=" + md5 + ", jar: " + jar);
      
    if (!dontCompile && (forceCompilation || jar.length() <= 22)) {
      // have to compile
      
      print("Have to compile");

      bool canRename = false;
      if (useRenaming) {
        LS tok = javaTok(src);
        LS mainClass = findMainClass(tok);
        canRename = mainClass != null && useDummyMainClasses() && isSnippetID(progID) && !tok_classHasModifier(mainClass, "public");
        if (verbose)
          print("useRenaming: " + useDummyMainClasses() + ", canRename: " + canRename + ", progID: " + progID);
      }
        
      //mainClassName = joinNemptiesWithDot(tok_packageName(tok), or(getClassDeclarationName(mainClass), "main"));
      //print("CompilerBot2 mainClassName " + mainClassName);
      
      destJar = jar;
      progIDForRename = canRename ? progID : null;
      progID = progID;
      run(); // in superclass
      set didCompile;
    } else {
      if (verbose)
        print("Getting classes from cache (" + jar.getAbsolutePath() + ", " + jar.length() + " bytes)");
      touchFile(jar); // so we can find the unused ones easier
    }
    
    ret jar;
  }

  // look in non-virtual JavaX-Caches first
  File getJarFile(S md5) {
    assertTrue(isMD5(md5));
    S fileName = md5 + ".jar";
    File f = newFile(destDir(), fileName);
    ret fileExists(f) ? f : userDir(appendSlash(compilerBotDestDirSubName()) + fileName);
  }
  
  /*swappable*/ File destDir() {
    ret compilerBotDestDir();
  }
  
  void addMoreFiles(File dir) {
    print("CompilerBot2 addMoreFiles: " + mainClassName);
    if (!eq(mainClassName, "main"))
      saveTextFile(newFile(dir, "main-class"), mainClassName);
    S mc = or2(mainClassForManifest, mainClassName);
    print("Using main class for manifest: " + mc);
    saveTextFile(newFile(dir, manifestPathInJar()), manifestTextForMainClass(mc));
    if (addCompilationDate)
      saveTextFile(newFile(dir, "compilation-date.txt"), dateWithSecondsUTC());
  }
}

Began life as a copy of #1005575