1 files changed, 130 insertions, 0 deletions
diff --git a/fsa/src/vespa/fsamanagers/metadatahandle.h b/fsa/src/vespa/fsamanagers/metadatahandle.h
new file mode 100644
index 00000000000..8603caedfb7
--- /dev/null
+++ b/fsa/src/vespa/fsamanagers/metadatahandle.h
@@ -0,0 +1,130 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+/**
+ * @author  Peter Boros
+ * @date    2004/10/01
+ * @version $Id$
+ * @file    metadatamanager.h
+ * @brief   Metadata handle class definition.
+ *
+ */
+
+#pragma once
+
+#include <string>
+
+#include "refcountable.h"
+#include <vespa/fsa/metadata.h>
+
+namespace fsa {
+
+// {{{ class MetaData::Handle
+
+/**
+ * @class Handle
+ * @brief MetaData handle.
+ *
+ * A Handle looks like a MetaData, but copies are cheap; the actual
+ * MetaData objects are refcounted and Handle copies merely copy the
+ * MetaData pointer and increment the refcount.
+ */
+class MetaData::Handle {
+
+private:
+
+  /**
+   * @brief Unimplemented private default constructor.
+   */
+  Handle();
+  /**
+   * @brief Unimplemented private assignment operator.
+   */
+  Handle& operator=(const Handle&);
+
+  class RefCountableMetaData: public MetaData, public RefCountable<MetaData> {
+  public:
+    RefCountableMetaData(const char *datafile, FileAccessMethod fam = FILE_ACCESS_UNDEF) : MetaData(datafile,fam) {}
+  };
+
+  RefCountableMetaData *_metaData; /**< The MetaData object itself. */
+
+public:
+
+  /**
+   * @brief Copy constructor.
+   *
+   * Duplicate a handle (and add new reference to the MetaData object.
+   *
+   * @param h Reference to existing Metadata::Handle.
+   */
+  Handle(const Handle& h) : _metaData(h._metaData)
+  {
+    _metaData->addReference();
+  }
+
+  /**
+   * @brief Constructor.
+   *
+   * Create a new MetaData object (loaded from file) and add reference.
+   *
+   * @param datafile Name of the file containing the metadata.
+   * @param fam File access mode (read or mmap). If not set, the
+   *            global preferred access mode will be used.
+   */
+  Handle(const char *datafile, FileAccessMethod fam = FILE_ACCESS_UNDEF) :
+    _metaData(new RefCountableMetaData(datafile,fam))
+  {
+    _metaData->addReference();
+  }
+
+  /**
+   * @brief Constructor.
+   *
+   * Create a new MetaData object (loaded from file) and add reference.
+   *
+   * @param datafile Name of the file containing the metadata.
+   * @param fam File access mode (read or mmap). If not set, the
+   *            global preferred access mode will be used.
+   */
+  Handle(const std::string &datafile, FileAccessMethod fam = FILE_ACCESS_UNDEF) :
+    _metaData(new RefCountableMetaData(datafile.c_str(),fam))
+  {
+    _metaData->addReference();
+  }
+
+  /**
+   * @brief Destructor.
+   */
+  ~Handle(void)
+  {
+    _metaData->removeReference();
+  }
+
+  /**
+   * @brief Dereference operator, provides access to Metadata
+   *        methods.
+   *
+   * @return Reference to the Metadata object.
+   */
+  const MetaData& operator*() const { return *_metaData; }
+
+  /**
+   * @brief Dereference operator, provides access to Metadata
+   *        methods.
+   *
+   * @return Pointer the Metadata object.
+   */
+  const MetaData* operator->() const { return _metaData; }
+
+  /**
+   * @brief Proxy methods
+   */
+  uint32_t user(unsigned int idx) const
+  {
+    return _metaData->user(idx);
+  }
+};
+
+// }}}
+
+} // namespace fsa
+