Allow for linking targeted files.

Author: raphw

byte-buddy-dep/src/main/java/net/bytebuddy/build/Plugin.java

@@ -3713,13 +3713,26 @@ class ForFolder implements Target, Sink {
                  */
                 private final File folder;
 
+                private final boolean link;
+
                 /**
                  * Creates a new target for a folder.
                  *
                  * @param folder The folder that is represented by this instance.
                  */
                 public ForFolder(File folder) {
+                    this(folder, false);
+                }
+
+                /**
+                 * Creates a new target for a folder.
+                 *
+                 * @param folder The folder that is represented by this instance.
+                 * @param link   {@code true} if retained files should be linked and not copied.
+                 */
+                public ForFolder(File folder, boolean link) {
                     this.folder = folder;
+                    this.link = link;
                 }
 
                 /**
@@ -3789,7 +3802,11 @@ public void retain(Source.Element element) throws IOException {
                         } else if (!target.getParentFile().isDirectory() && !target.getParentFile().mkdirs()) {
                             throw new IOException("Could not create directory: " + target.getParent());
                         } else if (resolved != null && !resolved.equals(target)) {
-                            FileSystem.getInstance().copy(resolved, target);
+                            if (link) {
+                                FileSystem.getInstance().link(resolved, target);
+                            } else {
+                                FileSystem.getInstance().copy(resolved, target);
+                            }
                         } else if (!target.equals(resolved)) {
                             InputStream inputStream = element.getInputStream();
                             try {
@@ -3889,7 +3906,7 @@ interface Materializable {
                 void materialize(Target.Sink sink,
                                  List<TypeDescription> transformed,
                                  Map<TypeDescription,
-                                 List<Throwable>> failed,
+                                         List<Throwable>> failed,
                                  List<String> unresolved) throws IOException;
 
                 /**
@@ -3925,7 +3942,7 @@ protected ForTransformedElement(@MaybeNull ClassFileVersion classFileVersion, Dy
                     public void materialize(Target.Sink sink,
                                             List<TypeDescription> transformed,
                                             Map<TypeDescription,
-                                            List<Throwable>> failed,
+                                                    List<Throwable>> failed,
                                             List<String> unresolved) throws IOException {
                         if (classFileVersion == null) {
                             sink.store(dynamicType.getAllTypes());
@@ -3961,7 +3978,7 @@ protected ForRetainedElement(Source.Element element) {
                     public void materialize(Target.Sink sink,
                                             List<TypeDescription> transformed,
                                             Map<TypeDescription,
-                                            List<Throwable>> failed,
+                                                    List<Throwable>> failed,
                                             List<String> unresolved) throws IOException {
                         sink.retain(element);
                     }
@@ -4006,7 +4023,7 @@ protected ForFailedElement(Source.Element element, TypeDescription typeDescripti
                     public void materialize(Target.Sink sink,
                                             List<TypeDescription> transformed,
                                             Map<TypeDescription,
-                                            List<Throwable>> failed,
+                                                    List<Throwable>> failed,
                                             List<String> unresolved) throws IOException {
                         sink.retain(element);
                         failed.put(typeDescription, errored);
@@ -4045,7 +4062,7 @@ protected ForUnresolvedElement(Source.Element element, String typeName) {
                     public void materialize(Target.Sink sink,
                                             List<TypeDescription> transformed,
                                             Map<TypeDescription,
-                                            List<Throwable>> failed,
+                                                    List<Throwable>> failed,
                                             List<String> unresolved) throws IOException {
                         sink.retain(element);
                         unresolved.add(typeName);

byte-buddy-dep/src/main/java/net/bytebuddy/utility/FileSystem.java

@@ -65,6 +65,17 @@ private static <T> T doPrivileged(PrivilegedAction<T> action) {
      */
     public abstract void copy(File source, File target) throws IOException;
 
+    /**
+     * Links a file as a hard-link. If linking is not supported, a copy is made.
+     *
+     * @param source The source file.
+     * @param target The target file.
+     * @throws IOException If an I/O exception occurs.
+     */
+    public void link(File source, File target) throws IOException {
+        copy(source, target);
+    }
+
     /**
      * Moves a file.
      *
@@ -150,6 +161,11 @@ public void copy(File source, File target) throws IOException {
             FILES.copy(DISPATCHER.toPath(source), DISPATCHER.toPath(target), option);
         }
 
+        @Override
+        public void link(File source, File target) throws IOException {
+            FILES.createLink(FILES.deleteIfExists(DISPATCHER.toPath(target)), DISPATCHER.toPath(source));
+        }
+
         @Override
         public void move(File source, File target) throws IOException {
             Object[] option = STANDARD_COPY_OPTION.toArray(1);
@@ -193,6 +209,18 @@ Object copy(@JavaDispatcher.Proxied("java.nio.file.Path") Object source,
                         @JavaDispatcher.Proxied("java.nio.file.Path") Object target,
                         @JavaDispatcher.Proxied("java.nio.file.CopyOption") Object[] option) throws IOException;
 
+            /**
+             * Links a file.
+             *
+             * @param source The source {@code java.nio.file.Path}.
+             * @param target The target {@code java.nio.file.Path}.
+             * @return The copied file.
+             * @throws IOException If an I/O exception occurs.
+             */
+            @JavaDispatcher.IsStatic
+            Object createLink(@JavaDispatcher.Proxied("java.nio.file.Path") Object source,
+                              @JavaDispatcher.Proxied("java.nio.file.Path") Object target) throws IOException;
+
             /**
              * Moves a file.
              *
@@ -206,6 +234,16 @@ Object copy(@JavaDispatcher.Proxied("java.nio.file.Path") Object source,
             Object move(@JavaDispatcher.Proxied("java.nio.file.Path") Object source,
                         @JavaDispatcher.Proxied("java.nio.file.Path") Object target,
                         @JavaDispatcher.Proxied("java.nio.file.CopyOption") Object[] option) throws IOException;
+
+            /**
+             * Deletes a file if it exists.
+             *
+             * @param file The {@code java.nio.file.Path} to delete if it exists.
+             * @return The supplied file.
+             * @throws IOException If an I/O exception occurs.
+             */
+            @JavaDispatcher.IsStatic
+            Object deleteIfExists(@JavaDispatcher.Proxied("java.nio.file.Path") Object file) throws IOException;
         }
 
         /**