1 files changed, 107 insertions, 0 deletions
diff --git a/src/rocksdb/env/fs_readonly.h b/src/rocksdb/env/fs_readonly.h
new file mode 100644
index 000000000..1bbe60784
--- /dev/null
+++ b/src/rocksdb/env/fs_readonly.h
@@ -0,0 +1,107 @@
+//  Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+
+#pragma once
+
+#ifndef ROCKSDB_LITE
+
+#include "rocksdb/file_system.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// A FileSystem wrapper that only allows read-only operation.
+//
+// This class has not been fully analyzed for providing strong security
+// guarantees.
+class ReadOnlyFileSystem : public FileSystemWrapper {
+  static inline IOStatus FailReadOnly() {
+    IOStatus s = IOStatus::IOError("Attempted write to ReadOnlyFileSystem");
+    assert(s.GetRetryable() == false);
+    return s;
+  }
+
+ public:
+  explicit ReadOnlyFileSystem(const std::shared_ptr<FileSystem>& base)
+      : FileSystemWrapper(base) {}
+
+  static const char* kClassName() { return "ReadOnlyFileSystem"; }
+  const char* Name() const override { return kClassName(); }
+
+  IOStatus NewWritableFile(const std::string& /*fname*/,
+                           const FileOptions& /*options*/,
+                           std::unique_ptr<FSWritableFile>* /*result*/,
+                           IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus ReuseWritableFile(const std::string& /*fname*/,
+                             const std::string& /*old_fname*/,
+                             const FileOptions& /*options*/,
+                             std::unique_ptr<FSWritableFile>* /*result*/,
+                             IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus NewRandomRWFile(const std::string& /*fname*/,
+                           const FileOptions& /*options*/,
+                           std::unique_ptr<FSRandomRWFile>* /*result*/,
+                           IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus NewDirectory(const std::string& /*dir*/,
+                        const IOOptions& /*options*/,
+                        std::unique_ptr<FSDirectory>* /*result*/,
+                        IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus DeleteFile(const std::string& /*fname*/,
+                      const IOOptions& /*options*/,
+                      IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus CreateDir(const std::string& /*dirname*/,
+                     const IOOptions& /*options*/,
+                     IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus CreateDirIfMissing(const std::string& dirname,
+                              const IOOptions& options,
+                              IODebugContext* dbg) override {
+    // Allow if dir already exists
+    bool is_dir = false;
+    IOStatus s = IsDirectory(dirname, options, &is_dir, dbg);
+    if (s.ok() && is_dir) {
+      return s;
+    } else {
+      return FailReadOnly();
+    }
+  }
+  IOStatus DeleteDir(const std::string& /*dirname*/,
+                     const IOOptions& /*options*/,
+                     IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus RenameFile(const std::string& /*src*/, const std::string& /*dest*/,
+                      const IOOptions& /*options*/,
+                      IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus LinkFile(const std::string& /*src*/, const std::string& /*dest*/,
+                    const IOOptions& /*options*/,
+                    IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus LockFile(const std::string& /*fname*/, const IOOptions& /*options*/,
+                    FileLock** /*lock*/, IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+  IOStatus NewLogger(const std::string& /*fname*/, const IOOptions& /*options*/,
+                     std::shared_ptr<Logger>* /*result*/,
+                     IODebugContext* /*dbg*/) override {
+    return FailReadOnly();
+  }
+};
+
+}  // namespace ROCKSDB_NAMESPACE
+
+#endif  // ROCKSDB_LITE