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/* This file is part of JnaFileChooser.
 *
 * JnaFileChooser is free software: you can redistribute it and/or modify it
 * under the terms of the new BSD license.
 *
 * JnaFileChooser is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.
 */
package anlavn.ui.filechooser;

import java.awt.Window;
import java.io.File;

import com.sun.jna.Memory;
import com.sun.jna.Native;
import com.sun.jna.Pointer;

/**
 * The native Windows folder browser.
 *
 * Example: WindowsFolderBrowser fb = new WindowsFolderBrowser(); File dir =
 * fb.showDialog(parentWindow); if (dir != null) { // do something with dir }
 */
public class WindowsFolderBrowser {

    private String title;

    /**
     * creates a new folder browser
     */
    public WindowsFolderBrowser() {
        title = null;
    }

    /**
     * creates a new folder browser with text that can be used as title or to
     * give instructions to the user
     *
     * @param title text that will be displayed at the top of the dialog
     */
    public WindowsFolderBrowser(String title) {
        this.title = title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    /**
     * displays the dialog to the user
     *
     * @param parent the parent window
     *
     * @return the selected directory or null if the user canceled the dialog
     */
    public File showDialog(Window parent) {
        Ole32.OleInitialize(null);
        final Shell32.BrowseInfo params = new Shell32.BrowseInfo();
        params.hwndOwner = Native.getWindowPointer(parent);
        params.ulFlags
                = // disable the OK button if the user selects a virtual PIDL
                Shell32.BIF_RETURNONLYFSDIRS
                | // BIF_USENEWUI is only available as of Windows 2000/Me (Shell32.dll 5.0)
                // but I guess no one is using older versions anymore anyway right?!
                // I don't know what happens if this is executed where it's
                // not supported.
                Shell32.BIF_USENEWUI;
        if (title != null) {
            params.lpszTitle = title;
        }
        final Pointer pidl = Shell32.SHBrowseForFolder(params);
        if (pidl != null) {
            // MAX_PATH is 260 on Windows XP x32 so 4kB should
            // be more than big enough
            final Pointer path = new Memory(1024 * 4);
            Shell32.SHGetPathFromIDListW(pidl, path);
            final String filePath = path.getWideString(0);
            final File file = new File(filePath);
            Ole32.CoTaskMemFree(pidl);
            return file;
        }
        return null;
    }
}