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// Copyright Vespa.ai. 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
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