/*************************************************************************** copyright : (C) 2002 - 2008 by Scott Wheeler email : wheeler@kde.org ***************************************************************************/ /*************************************************************************** * This library is free software; you can redistribute it and/or modify * * it under the terms of the GNU Lesser General Public License version * * 2.1 as published by the Free Software Foundation. * * * * This library is distributed in the hope that it will be useful, but * * WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * * Lesser General Public License for more details. * * * * You should have received a copy of the GNU Lesser General Public * * License along with this library; if not, write to the Free Software * * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA * * 02110-1301 USA * * * * Alternatively, this file is available under the Mozilla Public * * License Version 1.1. You may obtain a copy of the License at * * http://www.mozilla.org/MPL/ * ***************************************************************************/ #ifndef TAGLIB_FILEREF_H #define TAGLIB_FILEREF_H #include "tfile.h" #include "tstringlist.h" #include "taglib_export.h" #include "audioproperties.h" namespace TagLib { class Tag; //! This class provides a simple abstraction for creating and handling files /*! * FileRef exists to provide a minimal, generic and value-based wrapper around * a File. It is lightweight and implicitly shared, and as such suitable for * pass-by-value use. This hides some of the uglier details of TagLib::File * and the non-generic portions of the concrete file implementations. * * This class is useful in a "simple usage" situation where it is desirable * to be able to get and set some of the tag information that is similar * across file types. * * Also note that it is probably a good idea to plug this into your mime * type system rather than using the constructor that accepts a file name using * the FileTypeResolver. * * \see FileTypeResolver * \see addFileTypeResolver() */ class TAGLIB_EXPORT FileRef { public: //! A class for pluggable file type resolution. /*! * This class is used to add extend TagLib's very basic file name based file * type resolution. * * This can be accomplished with: * * \code * * class MyFileTypeResolver : FileTypeResolver * { * TagLib::File *createFile(TagLib::FileName *fileName, bool, AudioProperties::ReadStyle) const * { * if(someCheckForAnMP3File(fileName)) * return new TagLib::MPEG::File(fileName); * return 0; * } * } * * FileRef::addFileTypeResolver(new MyFileTypeResolver); * * \endcode * * Naturally a less contrived example would be slightly more complex. This * can be used to plug in mime-type detection systems or to add new file types * to TagLib. */ class TAGLIB_EXPORT FileTypeResolver { TAGLIB_IGNORE_MISSING_DESTRUCTOR public: /*! * This method must be overridden to provide an additional file type * resolver. If the resolver is able to determine the file type it should * return a valid File object; if not it should return 0. * * \note The created file is then owned by the FileRef and should not be * deleted. Deletion will happen automatically when the FileRef passes * out of scope. */ virtual File *createFile(FileName fileName, bool readAudioProperties = true, AudioProperties::ReadStyle audioPropertiesStyle = AudioProperties::Average) const = 0; }; /*! * Creates a null FileRef. */ FileRef(); /*! * Create a FileRef from \a fileName. If \a readAudioProperties is true then * the audio properties will be read using \a audioPropertiesStyle. If * \a readAudioProperties is false then \a audioPropertiesStyle will be * ignored. * * Also see the note in the class documentation about why you may not want to * use this method in your application. */ explicit FileRef(FileName fileName, bool readAudioProperties = true, AudioProperties::ReadStyle audioPropertiesStyle = AudioProperties::Average); /*! * Construct a FileRef from an opened \a IOStream. If \a readAudioProperties * is true then the audio properties will be read using \a audioPropertiesStyle. * If \a readAudioProperties is false then \a audioPropertiesStyle will be * ignored. * * Also see the note in the class documentation about why you may not want to * use this method in your application. * * \note TagLib will *not* take ownership of the stream, the caller is * responsible for deleting it after the File object. */ explicit FileRef(IOStream* stream, bool readAudioProperties = true, AudioProperties::ReadStyle audioPropertiesStyle = AudioProperties::Average); /*! * Construct a FileRef using \a file. The FileRef now takes ownership of the * pointer and will delete the File when it passes out of scope. */ explicit FileRef(File *file); /*! * Make a copy of \a ref. */ FileRef(const FileRef &ref); /*! * Destroys this FileRef instance. */ virtual ~FileRef(); /*! * Returns a pointer to represented file's tag. * * \warning This pointer will become invalid when this FileRef and all * copies pass out of scope. * * \warning Do not cast it to any subclasses of Tag. * Use tag returning methods of appropriate subclasses of File instead. * * \see File::tag() */ Tag *tag() const; /*! * Returns the audio properties for this FileRef. If no audio properties * were read then this will returns a null pointer. */ AudioProperties *audioProperties() const; /*! * Returns a pointer to the file represented by this handler class. * * As a general rule this call should be avoided since if you need to work * with file objects directly, you are probably better served instantiating * the File subclasses (i.e. MPEG::File) manually and working with their APIs. * * This handle exists to provide a minimal, generic and value-based * wrapper around a File. Accessing the file directly generally indicates * a moving away from this simplicity (and into things beyond the scope of * FileRef). * * \warning This pointer will become invalid when this FileRef and all * copies pass out of scope. */ File *file() const; /*! * Saves the file. Returns true on success. */ bool save(); /*! * Adds a FileTypeResolver to the list of those used by TagLib. Each * additional FileTypeResolver is added to the front of a list of resolvers * that are tried. If the FileTypeResolver returns zero the next resolver * is tried. * * Returns a pointer to the added resolver (the same one that's passed in -- * this is mostly so that static initializers have something to use for * assignment). * * \see FileTypeResolver */ static const FileTypeResolver *addFileTypeResolver(const FileTypeResolver *resolver); /*! * As is mentioned elsewhere in this class's documentation, the default file * type resolution code provided by TagLib only works by comparing file * extensions. * * This method returns the list of file extensions that are used by default. * * The extensions are all returned in lowercase, though the comparison used * by TagLib for resolution is case-insensitive. * * \note This does not account for any additional file type resolvers that * are plugged in. Also note that this is not intended to replace a proper * mime-type resolution system, but is just here for reference. * * \see FileTypeResolver */ static StringList defaultFileExtensions(); /*! * Returns true if the file (and as such other pointers) are null. */ bool isNull() const; /*! * Assign the file pointed to by \a ref to this FileRef. */ FileRef &operator=(const FileRef &ref); /*! * Exchanges the content of the FileRef by the content of \a ref. */ void swap(FileRef &ref); /*! * Returns true if this FileRef and \a ref point to the same File object. */ bool operator==(const FileRef &ref) const; /*! * Returns true if this FileRef and \a ref do not point to the same File * object. */ bool operator!=(const FileRef &ref) const; /*! * A simple implementation of file type guessing. If \a readAudioProperties * is true then the audio properties will be read using * \a audioPropertiesStyle. If \a readAudioProperties is false then * \a audioPropertiesStyle will be ignored. * * \note You generally shouldn't use this method, but instead the constructor * directly. * * \deprecated */ static File *create(FileName fileName, bool readAudioProperties = true, AudioProperties::ReadStyle audioPropertiesStyle = AudioProperties::Average); private: void parse(FileName fileName, bool readAudioProperties, AudioProperties::ReadStyle audioPropertiesStyle); void parse(IOStream *stream, bool readAudioProperties, AudioProperties::ReadStyle audioPropertiesStyle); class FileRefPrivate; FileRefPrivate *d; }; } // namespace TagLib #endif