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
25 #include <boost/utility.hpp>
26 #include <boost/scoped_ptr.hpp>
27 #include <boost/shared_ptr.hpp>
35 class Cache : boost::noncopyable {
38 /// This is a singleton class. Get the instance.
41 /** Which graphics formats can be loaded directly by the image loader.
42 * Other formats can be loaded if a converter to a loadable format
45 std::vector<string> loadableFormats() const;
47 /// Add a graphics file to the cache.
48 void add(string const & file) const;
50 /// Remove a file from the cache.
51 void remove(string const & file) const;
53 /// Returns \c true if the file is in the cache.
54 bool inCache(string const & file) const;
56 /** Get the cache item associated with file.
57 * Returns an empty container if there is no such item.
59 * IMPORTANT: whatever uses an image must make a local copy of this
60 * ItemPtr. The boost::shared_ptr<>::use_count() function is
61 * used to ascertain whether or not to remove the item from the cache
62 * when remove(file) is called.
64 * You have been warned!
66 typedef boost::shared_ptr<CacheItem> ItemPtr;
68 ItemPtr const item(string const & file) const;
71 /** Make the c-tor, d-tor private so we can control how many objects
78 /// Use the Pimpl idiom to hide the internals.
80 /// The pointer never changes although *pimpl_'s contents may.
81 boost::scoped_ptr<Impl> const pimpl_;
84 } // namespace graphics
87 #endif // GRAPHICSCACHE_H