Implement reliable getLibraryFolder() and getDocumentsFolder() methods in MacPlatform

[processing-bot]

Created by: benfry

With the removal of FileManager in JDK 9+ we no longer have a means of getting the Documents and Library folders on macOS.

For now, it's possible to use System.getProperty("user.home") and tack Library or Documents onto the end of that, however I'm guessing that it won't be possible in future OS releases, or perhaps even with a signed version of the app, due to security-related changes to how file system access works.

(Appending these folder names works now even on localized systems, since the native language shown is not what's used internally by the OS.)

[processing-bot]

Created by: sampottinger

There is an open issue at https://bugs.openjdk.java.net/browse/JDK-8187981 but it doesn't seem to be getting much traction. There is an alternative to System.getProperty but it's through swing:

import java.io.FileNotFoundException;
import javax.swing.filechooser.FileSystemView;


void setup() {
  
  // Use file view to get directories
  FileSystemView view = FileSystemView.getFileSystemView();
  File homeDirectory = view.getHomeDirectory();
  
  // Try writing to home directory
  File testHomeFile = view.createFileObject(homeDirectory, "test_home.txt");
  try {
    PrintWriter writer = new PrintWriter(testHomeFile);
    writer.print("test home");
    writer.close();
  } catch (FileNotFoundException e) {
    println("File not found exception on documents.");
  }
  
  // Try writing to documents directory
  File documentsDirectory = view.getChild(homeDirectory, "Documents");
  File testDocumentsFile = view.createFileObject(documentsDirectory, "test_docs.txt");
  try {
    PrintWriter writer = new PrintWriter(testDocumentsFile);
    writer.print("test documents");
    writer.close();
  } catch (FileNotFoundException e) {
    println("File not found exception on documents.");
  }
  
}

See https://gist.github.com/sampottinger/49aef03638b150257cca919954319f01. It does work on 10.14 with a signed application.

Open to suggestions but, unfortunately, JDK 11 isn't providing an alternative as far as I can tell? @benfry - would you like me to switch out for FileSystemView or leave this ticket as is and address in a future JDK?

[processing-bot]

Created by: benfry

I think FileSystemView would be a step backwards, so we should leave it open until we have a better fix. (Want to get AWT/Swing out of there wherever possible.)

Might be something we just need to add via JNA, since it should be a single OS call.

[processing-bot]

Created by: sampottinger

I agree. :(

[processing-bot]

Created by: benfry

Since this was originally posted, I've been hearing that using the name works, and the localization is handled transparently, perhaps suggesting that it's a more stable way to handle this than expected. macOS may do all sorts of “container” things behind the scenes, but it's maybe less of a concern than I originally thought.

I don't love it, but this is at least a lower priority in that case.

Also making a note in MacPlatform to reference this issue.