Support following symbolic links to files

This implements the necessary support to allow plexus-archiver to
archive the contents of symlinks (instead of the symbolic links
themselves), depending on the (already-extant) follow-symlinks flag.

Closes: codehaus-plexus#37

Signed-off-by: mirabilos <[email protected]>

Author: mirabilos

src/main/java/org/codehaus/plexus/components/io/attributes/FileAttributes.java

@@ -71,8 +71,13 @@ public FileAttributes( @Nonnull File file, @Nonnull Map<Integer, String> userCac
                            @Nonnull Map<Integer, String> groupCache )
         throws IOException
     {
+        this( file.toPath(), userCache, groupCache );
+    }
 
-        Path path = file.toPath();
+    public FileAttributes( @Nonnull Path path, @Nonnull Map<Integer, String> userCache,
+                           @Nonnull Map<Integer, String> groupCache )
+        throws IOException
+    {
         Set<String> views = path.getFileSystem().supportedFileAttributeViews();
         String names;
         if ( views.contains( "unix" ) )

src/main/java/org/codehaus/plexus/components/io/resources/PlexusIoFileResourceCollection.java

@@ -27,6 +27,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Comparator;
 import java.util.HashMap;
@@ -158,8 +159,13 @@ private void addResources( List<PlexusIoResource> result, String[] resources )
         {
             String sourceDir = name.replace( '\\', '/' );
             File f = new File( dir, sourceDir );
+            Path p = f.toPath();
+            if ( isFollowingSymLinks() )
+            {
+                p = p.toRealPath();
+            }
 
-            FileAttributes fattrs = new FileAttributes( f, cache1, cache2 );
+            FileAttributes fattrs = new FileAttributes( p, cache1, cache2 );
             PlexusIoResourceAttributes attrs = mergeAttributes( fattrs, fattrs.isDirectory() );
 
             String remappedName = getName( name );