Avoid passing QSqlDatabase by mutable reference

...otherwise someone would be able to replace the implicitly shared
instance behind it!

21 files changed, 31 insertions, 41 deletions

diff --git a/src/library/dao/analysisdao.cpp b/src/library/dao/analysisdao.cpp
index da200545c0..6072ec0da5 100644
--- a/src/library/dao/analysisdao.cpp
+++ b/src/library/dao/analysisdao.cpp
@@ -17,7 +17,7 @@ const QString AnalysisDao::s_analysisTableName = "track_analysis";
 // CPU time so I think we should stick with the default. rryan 4/3/2012
 const int kCompressionLevel = -1;
 
-AnalysisDao::AnalysisDao(QSqlDatabase& database, UserSettingsPointer pConfig)
+AnalysisDao::AnalysisDao(const QSqlDatabase& database, UserSettingsPointer pConfig)
         : m_pConfig(pConfig),
           m_db(database) {
     QDir storagePath = getAnalysisStoragePath();
diff --git a/src/library/dao/analysisdao.h b/src/library/dao/analysisdao.h
index 24e11e957c..0130a5a699 100644
--- a/src/library/dao/analysisdao.h
+++ b/src/library/dao/analysisdao.h
@@ -31,7 +31,7 @@ class AnalysisDao : public DAO {
         QByteArray data;
     };
 
-    AnalysisDao(QSqlDatabase& database, UserSettingsPointer pConfig);
+    AnalysisDao(const QSqlDatabase& database, UserSettingsPointer pConfig);
     virtual ~AnalysisDao();
 
     virtual void initialize();
diff --git a/src/library/dao/cuedao.cpp b/src/library/dao/cuedao.cpp
index d45f28cd32..d3d4c74b00 100644
--- a/src/library/dao/cuedao.cpp
+++ b/src/library/dao/cuedao.cpp
@@ -12,7 +12,7 @@
 #include "util/assert.h"
 #include "util/performancetimer.h"
 
-CueDAO::CueDAO(QSqlDatabase& database)
+CueDAO::CueDAO(const QSqlDatabase& database)
         : m_database(database) {
 }
 
diff --git a/src/library/dao/cuedao.h b/src/library/dao/cuedao.h
index e9326185e5..3642721b53 100644
--- a/src/library/dao/cuedao.h
+++ b/src/library/dao/cuedao.h
@@ -16,7 +16,7 @@ class Cue;
 
 class CueDAO : public DAO {
   public:
-    CueDAO(QSqlDatabase& database);
+    explicit CueDAO(const QSqlDatabase& database);
     virtual ~CueDAO();
     void setDatabase(QSqlDatabase& database) { m_database = database; }
 
@@ -34,7 +34,7 @@ class CueDAO : public DAO {
   private:
     CuePointer cueFromRow(const QSqlQuery& query) const;
 
-    QSqlDatabase& m_database;
+    QSqlDatabase m_database;
     mutable QMap<int, CuePointer> m_cues;
 };
 
diff --git a/src/library/dao/directorydao.cpp b/src/library/dao/directorydao.cpp
index 11d5965247..a4f93fa5f4 100644
--- a/src/library/dao/directorydao.cpp
+++ b/src/library/dao/directorydao.cpp
@@ -11,7 +11,7 @@
 #include "util/db/sqllikewildcardescaper.h"
 
 
-DirectoryDAO::DirectoryDAO(QSqlDatabase& database)
+DirectoryDAO::DirectoryDAO(const QSqlDatabase& database)
             : m_database(database) {
 }
 
diff --git a/src/library/dao/directorydao.h b/src/library/dao/directorydao.h
index fc9b49c325..7ee081dc06 100644
--- a/src/library/dao/directorydao.h
+++ b/src/library/dao/directorydao.h
@@ -16,7 +16,7 @@ enum ReturnCodes {
 class DirectoryDAO : public DAO {
   public:
 
-    DirectoryDAO(QSqlDatabase& database);
+    explicit DirectoryDAO(const QSqlDatabase& database);
     virtual ~DirectoryDAO();
 
     void initialize();
@@ -28,7 +28,7 @@ class DirectoryDAO : public DAO {
 
   private:
     bool isChildDir(QString testDir, QString dirStr);
-    QSqlDatabase& m_database;
+    QSqlDatabase m_database;
 };
 
 #endif //DIRECTORYDAO_H
diff --git a/src/library/dao/libraryhashdao.cpp b/src/library/dao/libraryhashdao.cpp
index 63ff28476d..bc35144313 100644
--- a/src/library/dao/libraryhashdao.cpp
+++ b/src/library/dao/libraryhashdao.cpp
@@ -8,7 +8,7 @@
 #include "libraryhashdao.h"
 #include "library/queryutil.h"
 
-LibraryHashDAO::LibraryHashDAO(QSqlDatabase& database)
+LibraryHashDAO::LibraryHashDAO(const QSqlDatabase& database)
         : m_database(database) {
 
 }
diff --git a/src/library/dao/libraryhashdao.h b/src/library/dao/libraryhashdao.h
index 148ee22f4c..f108665054 100644
--- a/src/library/dao/libraryhashdao.h
+++ b/src/library/dao/libraryhashdao.h
@@ -10,7 +10,7 @@
 
 class LibraryHashDAO : public DAO {
   public:
-    LibraryHashDAO(QSqlDatabase& database);
+    explicit LibraryHashDAO(const QSqlDatabase& database);
     virtual ~LibraryHashDAO();
 
     void setDatabase(QSqlDatabase& database) { m_database = database; };
@@ -30,7 +30,7 @@ class LibraryHashDAO : public DAO {
     QStringList getDeletedDirectories();
 
   private:
-    QSqlDatabase& m_database;
+    QSqlDatabase m_database;
 };
 
 #endif //LIBRARYHASHDAO_H
diff --git a/src/library/dao/playlistdao.cpp b/src/library/dao/playlistdao.cpp
index 7a5476adb2..182c652e8e 100644
--- a/src/library/dao/playlistdao.cpp
+++ b/src/library/dao/playlistdao.cpp
@@ -8,7 +8,7 @@
 #include "library/autodj/autodjprocessor.h"
 #include "util/math.h"
 
-PlaylistDAO::PlaylistDAO(QSqlDatabase& database)
+PlaylistDAO::PlaylistDAO(const QSqlDatabase& database)
         : m_database(database),
           m_pAutoDJProcessor(nullptr) {
 }
diff --git a/src/library/dao/playlistdao.h b/src/library/dao/playlistdao.h
index 578a0ebc78..c190d9ca62 100644
--- a/src/library/dao/playlistdao.h
+++ b/src/library/dao/playlistdao.h
@@ -46,7 +46,7 @@ class PlaylistDAO : public QObject, public virtual DAO {
         REPLACE,
     };
 
-    PlaylistDAO(QSqlDatabase& database);
+    explicit PlaylistDAO(const QSqlDatabase& database);
     virtual ~PlaylistDAO();
 
     void initialize();
@@ -140,7 +140,7 @@ class PlaylistDAO : public QObject, public virtual DAO {
                                  int* pTrackDistance);
     void populatePlaylistMembershipCache();
 
-    QSqlDatabase& m_database;
+    QSqlDatabase m_database;
     QMultiHash<TrackId, int> m_playlistsTrackIsIn;
     AutoDJProcessor* m_pAutoDJProcessor;
     DISALLOW_COPY_AND_ASSIGN(PlaylistDAO);
diff --git a/src/library/dao/settingsdao.cpp b/src/library/dao/settingsdao.cpp
index 08c5496721..1c8cf4d47d 100644
--- a/src/library/dao/settingsdao.cpp
+++ b/src/library/dao/settingsdao.cpp
@@ -3,7 +3,7 @@
 
 #include "library/dao/settingsdao.h"
 
-SettingsDAO::SettingsDAO(QSqlDatabase& db)
+SettingsDAO::SettingsDAO(const QSqlDatabase& db)
         : m_db(db) {
 }
 
diff --git a/src/library/dao/settingsdao.h b/src/library/dao/settingsdao.h
index 9cf5bad12b..8cd2882af0 100644
--- a/src/library/dao/settingsdao.h
+++ b/src/library/dao/settingsdao.h
@@ -14,7 +14,7 @@
 // All library-specific preferences go in the library settings table
 class SettingsDAO : public QObject {
   public:
-    SettingsDAO(QSqlDatabase &db);
+    SettingsDAO(const QSqlDatabase& db);
     virtual ~SettingsDAO();
 
     virtual void initialize();
diff --git a/src/library/dao/trackdao.cpp b/src/library/dao/trackdao.cpp
index 5bc3473c7b..18d4d38ef8 100644
--- a/src/library/dao/trackdao.cpp
+++ b/src/library/dao/trackdao.cpp
@@ -68,7 +68,7 @@ RecentTrackCacheItem::~RecentTrackCacheItem() {
 // expensive.
 const int kRecentTracksCacheSize = 5;
 
-TrackDAO::TrackDAO(QSqlDatabase& database,
+TrackDAO::TrackDAO(const QSqlDatabase& database,
                    CueDAO& cueDao,
                    PlaylistDAO& playlistDao,
                    AnalysisDao& analysisDao,
diff --git a/src/library/dao/trackdao.h b/src/library/dao/trackdao.h
index 7fb097ff95..807ed35c4d 100644
--- a/src/library/dao/trackdao.h
+++ b/src/library/dao/trackdao.h
@@ -54,11 +54,12 @@ class TrackDAO : public QObject, public virtual DAO {
   public:
     // The 'config object' is necessary because users decide ID3 tags get
     // synchronized on track metadata change
-    TrackDAO(QSqlDatabase& database, CueDAO& cueDao,
-             PlaylistDAO& playlistDao,
-             AnalysisDao& analysisDao,
-             LibraryHashDAO& libraryHashDao,
-             UserSettingsPointer pConfig);
+    TrackDAO(const QSqlDatabase& database,
+            CueDAO& cueDao,
+            PlaylistDAO& playlistDao,
+            AnalysisDao& analysisDao,
+            LibraryHashDAO& libraryHashDao,
+            UserSettingsPointer pConfig);
     virtual ~TrackDAO();
 
     void finish();
diff --git a/src/library/queryutil.h b/src/library/queryutil.h
index a0742ac83b..bcc10b8b98 100644
--- a/src/library/queryutil.h
+++ b/src/library/queryutil.h
@@ -10,7 +10,7 @@
 
 class ScopedTransaction {
   public:
-    explicit ScopedTransaction(QSqlDatabase& database) :
+    explicit ScopedTransaction(const QSqlDatabase& database) :
             m_database(database),
             m_active(false) {
         if (!transaction()) {
@@ -62,7 +62,7 @@ class ScopedTransaction {
         return result;
     }
   private:
-    QSqlDatabase& m_database;
+    QSqlDatabase m_database;
     bool m_active;
 };
 
diff --git a/src/library/schemamanager.cpp b/src/library/schemamanager.cpp
index 057bfe3be1..685953e943 100644
--- a/src/library/schemamanager.cpp
+++ b/src/library/schemamanager.cpp
@@ -14,7 +14,7 @@ const QString SchemaManager::SETTINGS_MINCOMPATIBLE_STRING = "mixxx.schema.min_c
 // static
 SchemaManager::Result SchemaManager::upgradeToSchemaVersion(
         const QString& schemaFilename,
-        QSqlDatabase& db, const int targetVersion) {
+        const QSqlDatabase& db, const int targetVersion) {
     SettingsDAO settings(db);
     int currentVersion = getCurrentSchemaVersion(settings);
     VERIFY_OR_DEBUG_ASSERT(currentVersion >= 0) {
diff --git a/src/library/schemamanager.h b/src/library/schemamanager.h
index 3997a6c95b..a79bc8620c 100644
--- a/src/library/schemamanager.h
+++ b/src/library/schemamanager.h
@@ -19,7 +19,7 @@ class SchemaManager {
     };
 
     static Result upgradeToSchemaVersion(const QString& schemaFilename,
-                                         QSqlDatabase& db, const int targetVersion);
+                                         const QSqlDatabase& db, const int targetVersion);
 
     static const QString SETTINGS_VERSION_STRING;
     static const QString SETTINGS_MINCOMPATIBLE_STRING;
diff --git a/src/library/trackcollection.cpp b/src/library/trackcollection.cpp
index 0a5fd9f232..f54ec4b688 100644
--- a/src/library/trackcollection.cpp
+++ b/src/library/trackcollection.cpp
@@ -38,7 +38,7 @@ TrackCollection::~TrackCollection() {
 }
 
 bool TrackCollection::checkForTables() {
-    if (!m_dbConnection) {
+    if (!m_dbConnection.database().isOpen()) {
         QMessageBox::critical(0, tr("Cannot open database"),
                             tr("Unable to establish a database connection.\n"
                                 "Mixxx requires QT with SQLite support. Please read "
diff --git a/src/library/trackcollection.h b/src/library/trackcollection.h
index 903421dcf5..209f38e003 100644
--- a/src/library/trackcollection.h
+++ b/src/library/trackcollection.h
@@ -38,7 +38,7 @@ class TrackCollection : public QObject {
 
     void resetLibaryCancellation();
 
-    QSqlDatabase& database() {
+    QSqlDatabase database() {
         return m_dbConnection.database();
     }
 
diff --git a/src/util/db/dbconnection.cpp b/src/util/db/dbconnection.cpp
index 295c10d8f0..60fb3c0a3a 100644
--- a/src/util/db/dbconnection.cpp
+++ b/src/util/db/dbconnection.cpp
@@ -201,7 +201,6 @@ DbConnection::DbConnection(const QString& dirPath)
         qWarning() << "Failed to open database connection:"
             << *this
             << m_database.lastError();
-        DEBUG_ASSERT(!*this); // failure
         return; // early exit
     }
 
@@ -216,7 +215,6 @@ DbConnection::DbConnection(const QString& dirPath)
         VERIFY_OR_DEBUG_ASSERT(handle != nullptr) {
             qWarning() << "Could not get sqlite3 handle";
             m_database.close();
-            DEBUG_ASSERT(!*this); // failure
             return; // early exit
         }
 
@@ -253,9 +251,6 @@ DbConnection::DbConnection(const QString& dirPath)
         VERIFY_OR_DEBUG_ASSERT(result == SQLITE_OK) {
             qWarning() << "Failed to install like 3 function:" << result;
         }
-
-        DEBUG_ASSERT(*this); // success
-        return; // early exit
     } else {
         qWarning() << "localecompare requires a SQLite3 database driver, found:"
                    << v.typeName();
@@ -264,7 +259,7 @@ DbConnection::DbConnection(const QString& dirPath)
 }
 
 DbConnection::~DbConnection() {
-    VERIFY_OR_DEBUG_ASSERT(*this) {
+    VERIFY_OR_DEBUG_ASSERT(m_database.isOpen()) {
         qWarning()
             << "Database connection has already been closed:"
             << *this;
@@ -278,12 +273,10 @@ DbConnection::~DbConnection() {
             << "Rolled back open transaction before closing database connection:"
             << *this;
     }
-    DEBUG_ASSERT(*this);
     qDebug()
         << "Closing database connection:"
         << *this;
     m_database.close();
-    DEBUG_ASSERT(!*this);
 }
 
 QDebug operator<<(QDebug debug, const DbConnection& dbConnection) {
diff --git a/src/util/db/dbconnection.h b/src/util/db/dbconnection.h
index ee320a460a..8820bb7fa1 100644
--- a/src/util/db/dbconnection.h
+++ b/src/util/db/dbconnection.h
@@ -12,11 +12,7 @@ class DbConnection final {
         const QString& dirPath);
     ~DbConnection();
 
-    operator bool() const {
-        return m_database.isOpen();
-    }
-
-    QSqlDatabase& database() {
+    QSqlDatabase database() const {
         return m_database;
     }