Add versioning and checksumming to the playlist cache. The new "version 1"

will support saving and restoring of the history and search playlists once
streaming operators are written for those types.

svn path=/trunk/kdemultimedia/juk/; revision=243233

playlistsplitter.cpp

@@ -424,7 +424,7 @@ void PlaylistSplitter::slotAdvancedSearch()
     delete d;
 
     if(r.result == AdvancedSearchDialog::Accepted) {
-	SearchPlaylist *p = new SearchPlaylist(r.search, m_playlistStack, r.playlistName);
+	SearchPlaylist *p = new SearchPlaylist(m_playlistStack, r.search, r.playlistName);
 	setupPlaylist(p, true, "find");
     }
 }
@@ -681,22 +681,82 @@ void PlaylistSplitter::readPlaylists()
     if(!f.open(IO_ReadOnly))
 	return;
 
-    QByteArray data = f.readAll();
-    f.close();
+    QDataStream fs(&f);
+
+    Q_INT32 version;
+    fs >> version;
+
+    switch(version) {
+    case 1:
+    {
+	// Our checksum is only for the values after the version and checksum so
+	// we want to get a byte array with just the checksummed data.
+
+	QByteArray data;
+	Q_UINT16 checksum;
+	fs >> checksum >> data;
+
+	if(checksum != qChecksum(data.data(), data.size()))
+	    return;
 
-    QDataStream s(data, IO_ReadOnly);
+	// Create a new stream just based on the data.
 
-    while(!s.atEnd()) {
-	Playlist *p = new Playlist(m_playlistStack);
-	s >> *p;
+	QDataStream s(data, IO_ReadOnly);
 
-	// check to see if we've alredy loaded this item before continuing
+	while(!s.atEnd()) {
 
-	if(p->fileName().isEmpty() || !m_playlistFiles.insert(p->fileName()))
-	    setupPlaylist(p);
-	else
-	    delete p;
+	    Q_INT32 playlistType;
+	    s >> playlistType;
+
+	    Playlist *p;
+
+	    switch(playlistType) {
+	    case Search:
+		p = new SearchPlaylist(m_playlistStack);
+		break;
+	    case History:
+		p = new HistoryPlaylist(m_playlistStack);
+		break;
+	    default:
+		p = new Playlist(m_playlistStack);
+		s >> *p;
+
+		if(!p->fileName().isEmpty() && m_playlistFiles.insert(p->fileName())) {
+		    delete p;
+		    p = 0;
+		}
+		break;
+	    }
+
+	    if(p)
+		setupPlaylist(p);
+	}
+	break;
     }
+    default:
+    {
+	// Because the original version of the playlist cache did not contain a
+	// version number, we want to revert to the beginning of the file before
+	// reading the data.
+
+	f.reset();
+
+	while(!fs.atEnd()) {
+	    Playlist *p = new Playlist(m_playlistStack);
+	    fs >> *p;
+
+	    // check to see if we've alredy loaded this item before continuing
+
+	    if(p->fileName().isEmpty() || !m_playlistFiles.insert(p->fileName()))
+		setupPlaylist(p);
+	    else
+		delete p;
+	}
+	break;
+    }
+    }
+
+    f.close();
 }
 
 void PlaylistSplitter::savePlaylists()
@@ -713,11 +773,28 @@ void PlaylistSplitter::savePlaylists()
     PlaylistList l = m_playlistBox->playlists();
 
     for(PlaylistList::Iterator it = l.begin(); it != l.end(); it++) {
-	if(*it && *it != m_history)
-	    s << *(*it);
+	if(*it) {
+
+	    // These first two aren't implemented yet.
+
+	    if(*it == m_history) {
+		// s << Q_INT32(History);
+	    }
+	    else if(dynamic_cast<SearchPlaylist *>(*it)) {
+		// s << Q_INT32(Search);
+	    }
+	    else {
+		s << Q_INT32(Normal);
+		s << *(*it);
+	    }
+	}
     }
 
-    f.writeBlock(data);
+    QDataStream fs(&f);
+    fs << Q_INT32(playlistCacheVersion);
+    fs << qChecksum(data.data(), data.size());
+
+    fs << data;
     f.close();
 }
 
@@ -844,7 +921,7 @@ void PlaylistSplitter::slotCreateSearchList(const PlaylistSearch &search,
 					    const QString &searchCategory,
 					    const QString &name)
 {
-    SearchPlaylist *p = new SearchPlaylist(search, m_playlistStack, name);
+    SearchPlaylist *p = new SearchPlaylist(m_playlistStack, search, name);
     m_playlistBox->createSearchItem(p, searchCategory);
     setupPlaylist(p, false, 0);
 }

playlistsplitter.h

@@ -273,6 +273,11 @@ signals:
     void signalSelectedPlaylistCountChanged(int);
 
 private:
+
+    enum PlaylistType { Normal = 0, Search = 1, History = 2 };
+    static const int playlistCacheVersion = 1;
+
+
     /**
      * Returns a PlaylistItemList of the selected PlaylistItems in the top playlist in
      * the QWidgetStack of playlists.

searchplaylist.cpp

@@ -24,7 +24,7 @@
 // public methods
 ////////////////////////////////////////////////////////////////////////////////
 
-SearchPlaylist::SearchPlaylist(const PlaylistSearch &search, QWidget *parent, const QString &name) :
+SearchPlaylist::SearchPlaylist(QWidget *parent, const PlaylistSearch &search, const QString &name) :
     DynamicPlaylist(search.playlists(), parent, name),
     m_search(search)
 {

searchplaylist.h

@@ -25,7 +25,9 @@ class SearchPlaylist : public DynamicPlaylist
 {
     Q_OBJECT
 public:
-    SearchPlaylist(const PlaylistSearch &search, QWidget *parent, const QString &name = QString::null);
+    SearchPlaylist(QWidget *parent,
+		   const PlaylistSearch &search = PlaylistSearch(),
+		   const QString &name = QString::null);
     
 protected:
     /**