Update from Google.

--
MOE_MIGRATED_REVID=85702957

1 files changed, 103 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java
new file mode 100644
index 0000000000..fc668db87a
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/vfs/ReadonlyFileSystem.java
@@ -0,0 +1,103 @@
+// Copyright 2014 Google Inc. All rights reserved.
+//
+// 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.devtools.build.lib.vfs;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+/**
+ * An abstract partial implementation of FileSystem for read-only
+ * implementations.
+ *
+ * <p>Any ReadonlyFileSystem does not support the following:
+ * <ul>
+ * <li>{@link #createDirectory(Path)}</li>
+ * <li>{@link #createSymbolicLink(Path, PathFragment)}</li>
+ * <li>{@link #delete(Path)}</li>
+ * <li>{@link #getOutputStream(Path)}</li>
+ * <li>{@link #renameTo(Path, Path)}</li>
+ * <li>{@link #setExecutable(Path, boolean)}</li>
+ * <li>{@link #setLastModifiedTime(Path, long)}</li>
+ * <li>{@link #setWritable(Path, boolean)}</li>
+ * </ul>
+ * The above calls will always result in an {@link IOException}.
+ */
+public abstract class ReadonlyFileSystem extends FileSystem {
+
+  protected ReadonlyFileSystem() {
+  }
+
+  protected IOException modificationException() {
+    String longname = this.getClass().getName();
+    String shortname = longname.substring(longname.lastIndexOf(".") + 1);
+    return new IOException(
+        shortname + " does not support mutating operations");
+  }
+
+  @Override
+  protected OutputStream getOutputStream(Path path, boolean append) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void setReadable(Path path, boolean readable) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void setWritable(Path path, boolean writable) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void setExecutable(Path path, boolean executable) {
+    throw new UnsupportedOperationException("setExecutable");
+  }
+
+  @Override
+  public boolean supportsModifications() {
+    return false;
+  }
+
+  @Override
+  public boolean supportsSymbolicLinks() {
+    return false;
+  }
+
+  @Override
+  protected boolean createDirectory(Path path) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void createSymbolicLink(Path linkPath, PathFragment targetFragment) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void renameTo(Path sourcePath, Path targetPath) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected boolean delete(Path path) throws IOException {
+    throw modificationException();
+  }
+
+  @Override
+  protected void setLastModifiedTime(Path path, long newTime) throws IOException {
+    throw modificationException();
+  }
+
+}