3 * \file GraphicsCache.h
4 * This file is part of LyX, the document processor.
5 * Licence details can be found in the file COPYING.
8 * \author Angus Leeming
10 * Full author contact details are available in file CREDITS.
12 * lyx::graphics::Cache is the manager of the image cache.
13 * It is responsible for creating the lyx::graphics::CacheItem's
14 * and maintaining them.
16 * lyx::graphics::Cache is a singleton class. It is possible to have only one
17 * instance of it at any moment.
20 #ifndef GRAPHICSCACHE_H
21 #define GRAPHICSCACHE_H
23 #include <boost/utility.hpp>
24 #include <boost/scoped_ptr.hpp>
25 #include <boost/shared_ptr.hpp>
33 namespace support { class FileName; }
39 class Cache : boost::noncopyable {
42 /// This is a singleton class. Get the instance.
45 /** Which graphics formats can be loaded directly by the image loader.
46 * Other formats can be loaded if a converter to a loadable format
49 std::vector<std::string> loadableFormats() const;
51 /// Add a graphics file to the cache.
52 void add(support::FileName const & file) const;
54 /// Remove a file from the cache.
55 void remove(support::FileName const & file) const;
57 /// Returns \c true if the file is in the cache.
58 bool inCache(support::FileName const & file) const;
60 /** Get the cache item associated with file.
61 * Returns an empty container if there is no such item.
63 * IMPORTANT: whatever uses an image must make a local copy of this
64 * ItemPtr. The boost::shared_ptr<>::use_count() function is
65 * used to ascertain whether or not to remove the item from the cache
66 * when remove(file) is called.
68 * You have been warned!
70 typedef boost::shared_ptr<CacheItem> ItemPtr;
72 ItemPtr const item(support::FileName const & file) const;
75 /** Make the c-tor, d-tor private so we can control how many objects
82 /// Use the Pimpl idiom to hide the internals.
84 /// The pointer never changes although *pimpl_'s contents may.
85 boost::scoped_ptr<Impl> const pimpl_;
88 } // namespace graphics
91 #endif // GRAPHICSCACHE_H