Add a mechanism for extending the file type resolution in JuK using FileRefs.

This is generally much better thought out than the current method of creating
FileRefs using the native mime system and also allows for extension to additional
file formats.

git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@437382 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

diff --git a/fileref.cpp b/fileref.cpp
index 2da2e71ff2de780ceaf349b4a31a260496b82baf..6c12749d0ffdd0b1aa8ca0e70cc548038e8f4efc 100644 (file)
--- a/fileref.cpp
+++ b/fileref.cpp
@@ -39,8 +39,11 @@ public:
   }
 
   File *file;
+  static List<const FileTypeResolver *> fileTypeResolvers;
 };
 
+List<const FileRef::FileTypeResolver *> FileRef::FileRefPrivate::fileTypeResolvers;
+
 ////////////////////////////////////////////////////////////////////////////////
 // public members
 ////////////////////////////////////////////////////////////////////////////////
@@ -92,6 +95,11 @@ bool FileRef::save()
   return d->file->save();
 }
 
+void FileRef::addFileTypeResolver(const FileTypeResolver *resolver) // static
+{
+  FileRefPrivate::fileTypeResolvers.prepend(resolver);
+}
+
 bool FileRef::isNull() const
 {
   return !d->file || !d->file->isValid();

diff --git a/fileref.h b/fileref.h
index ffa7864fc37723bc00e04db569e09d4cc444bd51..b4e64eea6dc23d6fd9c905ffb42f592687487754 100644 (file)
--- a/fileref.h
+++ b/fileref.h
@@ -43,31 +43,60 @@ namespace TagLib {
    * 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.
+   * type system rather than using the constructor that accepts a file name using
+   * the FileTypeResolver.
    *
-   * For example in KDE this could be done with:
+   * \see FileTypeResolver
+   * \see addFileTypeResolver()
+   */
+
+  class 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
    *
-   * TagLib::FileRef createFileRef( const QString &fileName )
+   * class MyFileTypeResolver : FileTypeResolver
    * {
-   *   KMimeType::Ptr result = KMimeType::findByPath( fileName, 0, true );
-   *
-   *   if( result->name() == "audio/x-mp3" )
-   *     return FileRef( new MPEG::File( QFile::encodeName( fileName ).data() ) );
-   *
-   *   if( result->name() == "application/ogg" )
-   *     return FileRef( new Vorbis::File( QFile::encodeName( fileName ).data() ) );
-   *
-   *   return FileRef( 0 );
+   *   TagLib::File *createFile(const char *fileName)
+   *   {
+   *     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 FileRef
-  {
-  public:
+    class FileTypeResolver
+    {
+    public:
+      /*!
+       * This method must be overriden 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(const char *fileName) = 0;
+    };
 
     FileRef();
 
@@ -139,6 +168,14 @@ namespace TagLib {
      */
     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.
+     */
+    static void addFileTypeResolver(const FileTypeResolver *resolver);
+
     /*!
      * Returns true if the file (and as such other pointers) are null.
      */

diff --git a/tests/toolkit-test.cpp b/tests/toolkit-test.cpp
index aa1042d20fda6a77bd8df246be0cb5a69a178eda..e5b8ae3f0562b6d096be4b41e4515352dcb718e1 100644 (file)
--- a/tests/toolkit-test.cpp
+++ b/tests/toolkit-test.cpp
@@ -233,11 +233,11 @@ void testList()
   List<int> l1;
   List<int> l2;
   List<int> l3;
-  l1.append(1);
   l1.append(2);
   l2.append(3);
   l2.append(4);
   l1.append(l2);
+  l1.prepend(1);
   l3.append(1);
   l3.append(2);
   l3.append(3);

diff --git a/toolkit/tlist.h b/toolkit/tlist.h
index 3ea7a669e0a3e7a52b2227081e80a2e4b482a92c..371543a501f4ebd2eabc771e9dae7aa11bbae2a2 100644 (file)
--- a/toolkit/tlist.h
+++ b/toolkit/tlist.h
@@ -120,6 +120,9 @@ namespace TagLib {
      */
     List<T> &append(const List<T> &l);
 
+    List<T> &prepend(const T &item);
+    List<T> &prepend(const List<T> &l);
+
     /*!
      * Clears the list.  If auto deletion is enabled and this list contains a
      * pointer type the members are also deleted.

diff --git a/toolkit/tlist.tcc b/toolkit/tlist.tcc
index ae3f9a220fd4d550969902493a179805b6cb4156..38a150a80c4f162719d9a896fe5675a5e1c9e5b3 100644 (file)
--- a/toolkit/tlist.tcc
+++ b/toolkit/tlist.tcc
@@ -164,6 +164,22 @@ List<T> &List<T>::append(const List<T> &l)
   return *this;
 }
 
+template <class T>
+List<T> &List<T>::prepend(const T &item)
+{
+  detach();
+  d->list.push_front(item);
+  return *this;
+}
+
+template <class T>
+List<T> &List<T>::prepend(const List<T> &l)
+{
+  detach();
+  d->list.insert(d->list.begin(), l.begin(), l.end());
+  return *this;
+}
+
 template <class T>
 void List<T>::clear()
 {