1 files changed, 162 insertions, 0 deletions
diff --git a/jimfs/src/main/java/com/google/common/jimfs/UserDefinedAttributeProvider.java b/jimfs/src/main/java/com/google/common/jimfs/UserDefinedAttributeProvider.java
new file mode 100644
index 0000000..51cbfa6
--- /dev/null
+++ b/jimfs/src/main/java/com/google/common/jimfs/UserDefinedAttributeProvider.java
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.common.jimfs;
+
+import static com.google.common.base.Preconditions.checkNotNull;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.file.attribute.FileAttributeView;
+import java.nio.file.attribute.UserDefinedFileAttributeView;
+import java.util.List;
+
+/**
+ * Attribute provider that provides the {@link UserDefinedFileAttributeView} ("user"). Unlike most
+ * other attribute providers, this one has no pre-defined set of attributes. Rather, it allows
+ * arbitrary user defined attributes to be set (as {@code ByteBuffer} or {@code byte[]}) and read
+ * (as {@code byte[]}).
+ *
+ * @author Colin Decker
+ */
+final class UserDefinedAttributeProvider extends AttributeProvider {
+
+  UserDefinedAttributeProvider() {}
+
+  @Override
+  public String name() {
+    return "user";
+  }
+
+  @Override
+  public ImmutableSet<String> fixedAttributes() {
+    // no fixed set of attributes for this view
+    return ImmutableSet.of();
+  }
+
+  @Override
+  public boolean supports(String attribute) {
+    // any attribute name is supported
+    return true;
+  }
+
+  @Override
+  public ImmutableSet<String> attributes(File file) {
+    return userDefinedAttributes(file);
+  }
+
+  private static ImmutableSet<String> userDefinedAttributes(File file) {
+    ImmutableSet.Builder<String> builder = ImmutableSet.builder();
+    for (String attribute : file.getAttributeNames("user")) {
+      builder.add(attribute);
+    }
+    return builder.build();
+  }
+
+  @Override
+  public Object get(File file, String attribute) {
+    Object value = file.getAttribute("user", attribute);
+    if (value instanceof byte[]) {
+      byte[] bytes = (byte[]) value;
+      return bytes.clone();
+    }
+    return null;
+  }
+
+  @Override
+  public void set(File file, String view, String attribute, Object value, boolean create) {
+    checkNotNull(value);
+    checkNotCreate(view, attribute, create);
+
+    byte[] bytes;
+    if (value instanceof byte[]) {
+      bytes = ((byte[]) value).clone();
+    } else if (value instanceof ByteBuffer) {
+      // value instanceof ByteBuffer
+      ByteBuffer buffer = (ByteBuffer) value;
+      bytes = new byte[buffer.remaining()];
+      buffer.get(bytes);
+    } else {
+      throw invalidType(view, attribute, value, byte[].class, ByteBuffer.class);
+    }
+
+    file.setAttribute("user", attribute, bytes);
+  }
+
+  @Override
+  public Class<UserDefinedFileAttributeView> viewType() {
+    return UserDefinedFileAttributeView.class;
+  }
+
+  @Override
+  public UserDefinedFileAttributeView view(
+      FileLookup lookup, ImmutableMap<String, FileAttributeView> inheritedViews) {
+    return new View(lookup);
+  }
+
+  /** Implementation of {@link UserDefinedFileAttributeView}. */
+  private static class View extends AbstractAttributeView implements UserDefinedFileAttributeView {
+
+    public View(FileLookup lookup) {
+      super(lookup);
+    }
+
+    @Override
+    public String name() {
+      return "user";
+    }
+
+    @Override
+    public List<String> list() throws IOException {
+      return userDefinedAttributes(lookupFile()).asList();
+    }
+
+    private byte[] getStoredBytes(String name) throws IOException {
+      byte[] bytes = (byte[]) lookupFile().getAttribute(name(), name);
+      if (bytes == null) {
+        throw new IllegalArgumentException("attribute '" + name() + ":" + name + "' is not set");
+      }
+      return bytes;
+    }
+
+    @Override
+    public int size(String name) throws IOException {
+      return getStoredBytes(name).length;
+    }
+
+    @Override
+    public int read(String name, ByteBuffer dst) throws IOException {
+      byte[] bytes = getStoredBytes(name);
+      dst.put(bytes);
+      return bytes.length;
+    }
+
+    @Override
+    public int write(String name, ByteBuffer src) throws IOException {
+      byte[] bytes = new byte[src.remaining()];
+      src.get(bytes);
+      lookupFile().setAttribute(name(), name, bytes);
+      return bytes.length;
+    }
+
+    @Override
+    public void delete(String name) throws IOException {
+      lookupFile().deleteAttribute(name(), name);
+    }
+  }
+}