lyx_mirror/src/graphics/GraphicsCache.h
Angus Leeming 0d4d71dfe6 Finish the migration from namespace grfx to lyx::graphics.
git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@7334 a592a061-630c-0410-9148-cb99ea01b6c8
2003-07-21 21:30:57 +00:00

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// -*- C++ -*-
/**
* \file GraphicsCache.h
* This file is part of LyX, the document processor.
* Licence details can be found in the file COPYING.
*
* \author Baruch Even
* \author Angus Leeming
*
* Full author contact details are available in file CREDITS
*
* lyx::graphics::Cache is the manager of the image cache.
* It is responsible for creating the lyx::graphics::CacheItem's
* and maintaining them.
*
* lyx::graphics::Cache is a singleton class. It is possible to have only one
* instance of it at any moment.
*/
#ifndef GRAPHICSCACHE_H
#define GRAPHICSCACHE_H
#include "LString.h"
#include <vector>
#include <boost/utility.hpp>
#include <boost/scoped_ptr.hpp>
#include <boost/shared_ptr.hpp>
namespace lyx {
namespace graphics {
class CacheItem;
class Cache : boost::noncopyable {
public:
/// This is a singleton class. Get the instance.
static Cache & get();
/** Which graphics formats can be loaded directly by the image loader.
* Other formats can be loaded if a converter to a loadable format
* can be defined.
*/
std::vector<string> loadableFormats() const;
/// Add a graphics file to the cache.
void add(string const & file) const;
/// Remove a file from the cache.
void remove(string const & file) const;
/// Returns \c true if the file is in the cache.
bool inCache(string const & file) const;
/** Get the cache item associated with file.
* Returns an empty container if there is no such item.
*
* IMPORTANT: whatever uses an image must make a local copy of this
* ItemPtr. The boost::shared_ptr<>::use_count() function is
* used to ascertain whether or not to remove the item from the cache
* when remove(file) is called.
*
* You have been warned!
*/
typedef boost::shared_ptr<CacheItem> ItemPtr;
///
ItemPtr const item(string const & file) const;
private:
/** Make the c-tor, d-tor private so we can control how many objects
* are instantiated.
*/
Cache();
///
~Cache();
/// Use the Pimpl idiom to hide the internals.
class Impl;
/// The pointer never changes although *pimpl_'s contents may.
boost::scoped_ptr<Impl> const pimpl_;
};
} // namespace graphics
} // namespace lyx
#endif // GRAPHICSCACHE_H