1 /****************************************************************************************
2  * Copyright (c) 2014 Ralf Engels <ralf-engels@gmx.de>                                  *
3  *                                                                                      *
4  * This program is free software; you can redistribute it and/or modify it under        *
5  * the terms of the GNU General Public License as published by the Free Software        *
6  * Foundation; either version 2 of the License, or (at your option) any later           *
7  * version.                                                                             *
8  *                                                                                      *
9  * This program is distributed in the hope that it will be useful, but WITHOUT ANY      *
10  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A      *
11  * PARTICULAR PURPOSE. See the GNU General Public License for more details.             *
12  *                                                                                      *
13  * You should have received a copy of the GNU General Public License along with         *
14  * this program.  If not, see <http://www.gnu.org/licenses/>.                           *
15  ****************************************************************************************/
16 
17 #ifndef AMAROK_STORAGEMANAGER_H
18 #define AMAROK_STORAGEMANAGER_H
19 
20 #include "amarok_export.h"
21 
22 #include <QObject>
23 #include <QList>
24 #include <QSharedPointer>
25 #include <QStringList>
26 
27 namespace Plugins {
28     class PluginFactory;
29 }
30 
31 class SqlStorage;
32 
33 /** Class managing the Amarok SqlStorage
34  *
35  *  This singleton class is the main responsible for providing everybody
36  *  with the current SqlStorage.
37  */
38 class AMAROK_EXPORT StorageManager : public QObject
39 {
40     Q_OBJECT
41 
42     public:
43 
44         /** Get THE instance of the storage manager.
45          *
46          * This function will return the storage manager
47          * that returns the sql storage to be used for Amarok.
48          *
49          * In addition to the SqlCollection a lot of other components
50          * use a sql storage to persist data.
51          *
52          */
53         static StorageManager *instance();
54 
55         /** Destroys the instance of the StorageManager.
56          */
57         static void destroy();
58 
59         /**
60             retrieve an interface which allows client-code to store/load data in a relational database.
61             Note: You should never modify the database unless you really really know what you do.
62                    Using the SqlMeta (e.g. SqlRegistry or SqlTrack) is much better.
63             @return Returns a pointer to the amarok wide SqlStorage or
64                     to an internal dummy SqlStorage if that cannot be found.
65                     It never returns a null pointer.
66         */
67         QSharedPointer<SqlStorage> sqlStorage() const;
68 
69         /**
70          * Set the list of current factories
71          *
72          * For every factory that is a CollectionFactory uses it to create new
73          * collections and register with this manager.
74          */
75         void setFactories( const QList<QSharedPointer<Plugins::PluginFactory> > &factories );
76 
77         /** Returns a list of the last sql errors.
78           The list might not include every one error if the number
79           is beyond a sensible limit.
80           */
81         QStringList getLastErrors() const;
82 
83         /** Clears the list of the last errors. */
84         void clearLastErrors();
85 
86     private Q_SLOTS:
87 
88         /** Will be called whenever a factory emits a newStorage signal.
89          *
90          *  The first factory to Q_EMIT this signal will get it's storage
91          *  registered as "the" storage.
92          *
93          *  StorageManager will take ownership of the pointer and free it
94          *  after all other plugins are done.
95          */
96         void slotNewStorage( QSharedPointer<SqlStorage> newStorage );
97 
98         /** Will be called whenever a factory emits a newError signal.
99          *
100          *  The factories will not Q_EMIT the newStorage signal in case
101          *  of initialization problems.
102          *  In order to report their issues they will instead Q_EMIT
103          *  newError with the list of errors.
104          */
105         void slotNewError( const QStringList &errorMessageList );
106 
107     private:
108         static StorageManager* s_instance;
109         StorageManager();
110         ~StorageManager() override;
111 
112         void init();
113 
114 
115         Q_DISABLE_COPY( StorageManager )
116 
117         struct Private;
118         Private * const d;
119 };
120 
121 #endif /* AMAROK_STORAGEMANAGER_H */
122