Fix saving of xml files

Do not save XML config files (profiles.xml, toolchains.xml, etc.)
if the file has not changed.

Change-Id: I5f0dea374b33a05e7c428f4031d53c83d92de595
Reviewed-by: Daniel Teske <daniel.teske@nokia.com>

src/libs/utils/persistentsettings.cpp

@@ -332,10 +332,6 @@ bool PersistentSettingsReader::load(const Utils::FileName &fileName)
     \sa Utils::PersistentSettingsReader
 */
 
-PersistentSettingsWriter::PersistentSettingsWriter()
-{
-}
-
 static void writeVariantValue(QXmlStreamWriter &w, const Context &ctx,
                               const QVariant &variant, const QString &key = QString())
 {
@@ -376,24 +372,33 @@ static void writeVariantValue(QXmlStreamWriter &w, const Context &ctx,
     }
 }
 
+PersistentSettingsWriter::PersistentSettingsWriter(const FileName &fileName, const QString &docType) :
+    m_fileName(fileName), m_docType(docType), m_mustSave(false)
+{ }
+
 void PersistentSettingsWriter::saveValue(const QString &variable, const QVariant &value)
 {
+    if (m_valueMap.contains(variable) && m_valueMap.value(variable) == value)
+        return;
+    m_mustSave = true;
     m_valueMap.insert(variable, value);
 }
 
-bool PersistentSettingsWriter::save(const Utils::FileName &fileName, const QString &docType,
-                                    QWidget *parent) const
+bool PersistentSettingsWriter::save(QWidget *parent) const
 {
+    if (!m_mustSave)
+        return true;
+
     QDir tmp;
-    tmp.mkpath(fileName.toFileInfo().path());
-    Utils::FileSaver saver(fileName.toString(), QIODevice::Text);
+    tmp.mkpath(m_fileName.toFileInfo().path());
+    Utils::FileSaver saver(m_fileName.toString(), QIODevice::Text);
     if (!saver.hasError()) {
         const Context ctx;
         QXmlStreamWriter w(saver.file());
         w.setAutoFormatting(true);
         w.setAutoFormattingIndent(1); // Historical, used to be QDom.
         w.writeStartDocument();
-        w.writeDTD(QLatin1String("<!DOCTYPE ") + docType + QLatin1Char('>'));
+        w.writeDTD(QLatin1String("<!DOCTYPE ") + m_docType + QLatin1Char('>'));
         w.writeComment(QString::fromAscii(" Written by Qt Creator %1, %2. ").
                        arg(QLatin1String(Core::Constants::IDE_VERSION_LONG),
                            QDateTime::currentDateTime().toString(Qt::ISODate)));
@@ -409,6 +414,13 @@ bool PersistentSettingsWriter::save(const Utils::FileName &fileName, const QStri
 
         saver.setResult(&w);
     }
-    return saver.finalize(parent);
+    bool ok = saver.finalize(parent);
+    if (ok)
+        m_mustSave = false;
+    return ok;
 }
+
+FileName PersistentSettingsWriter::fileName() const
+{ return m_fileName; }
+
 } // namespace Utils

src/libs/utils/persistentsettings.h

@@ -59,12 +59,17 @@ private:
 class QTCREATOR_UTILS_EXPORT PersistentSettingsWriter
 {
 public:
-    PersistentSettingsWriter();
+    PersistentSettingsWriter(const FileName &fileName, const QString &docType);
     void saveValue(const QString &variable, const QVariant &value);
-    bool save(const FileName &fileName, const QString &docType, QWidget *parent) const;
+    bool save(QWidget *parent) const;
+
+    Utils::FileName fileName() const;
 
 private:
     QMap<QString, QVariant> m_valueMap;
+    const Utils::FileName m_fileName;
+    const QString m_docType;
+    mutable bool m_mustSave;
 };
 
 } // namespace Utils

src/plugins/android/androidconfigurations.cpp

@@ -182,7 +182,7 @@ AndroidConfig::AndroidConfig()
 
 void AndroidConfig::save(QSettings &settings) const
 {
-    QFileInfo fileInfo(settingsFileName().toFileInfo());
+    QFileInfo fileInfo = settingsFileName().toFileInfo();
     if (fileInfo.exists())
         settings.setValue(changeTimeStamp, fileInfo.lastModified().toMSecsSinceEpoch() / 1000);
 

src/plugins/projectexplorer/devicesupport/devicemanager.cpp

@@ -80,6 +80,8 @@ public:
     QList<IDevice::Ptr> devices;
     QList<IDevice::Ptr> inactiveAutoDetectedDevices;
     QHash<Core::Id, Core::Id> defaultDevices;
+
+    Utils::PersistentSettingsWriter *writer;
 };
 DeviceManager *DeviceManagerPrivate::clonedInstance = 0;
 
@@ -134,10 +136,8 @@ void DeviceManager::copy(const DeviceManager *source, DeviceManager *target, boo
 
 void DeviceManager::save()
 {
-    Utils::PersistentSettingsWriter writer;
-    writer.saveValue(QLatin1String(DeviceManagerKey), toMap());
-    writer.save(settingsFilePath(QLatin1String("/qtcreator/devices.xml")),
-                QLatin1String("QtCreatorDevices"), Core::ICore::mainWindow());
+    d->writer->saveValue(QLatin1String(DeviceManagerKey), toMap());
+    d->writer->save(Core::ICore::mainWindow());
 }
 
 void DeviceManager::load()
@@ -332,6 +332,8 @@ const IDeviceFactory *DeviceManager::restoreFactory(const QVariantMap &map)
 
 DeviceManager::DeviceManager(bool isInstance) : d(new DeviceManagerPrivate)
 {
+    d->writer = new Utils::PersistentSettingsWriter(settingsFilePath(QLatin1String("/qtcreator/devices.xml")),
+                                                    QLatin1String("QtCreatorDevices"));
     if (isInstance) {
         load();
         connect(Core::ICore::instance(), SIGNAL(saveSettingsRequested()), SLOT(save()));
@@ -340,6 +342,7 @@ DeviceManager::DeviceManager(bool isInstance) : d(new DeviceManagerPrivate)
 
 DeviceManager::~DeviceManager()
 {
+    delete d->writer;
     delete d;
 }
 

src/plugins/projectexplorer/devicesupport/devicemanager.h

@@ -35,6 +35,8 @@
 #include <projectexplorer/projectexplorer_export.h>
 #include <utils/fileutils.h>
 
+#include <utils/fileutils.h>
+
 #include <QObject>
 
 namespace ProjectExplorer {

src/plugins/projectexplorer/profilemanager.cpp

@@ -86,14 +86,19 @@ public:
     bool m_initialized;
     QList<ProfileInformation *> m_informationList;
     QList<Profile *> m_profileList;
+    Utils::PersistentSettingsWriter *m_writer;
 };
 
 ProfileManagerPrivate::ProfileManagerPrivate()
-    : m_defaultProfile(0), m_initialized(false)
+    : m_defaultProfile(0), m_initialized(false),
+      m_writer(new Utils::PersistentSettingsWriter(settingsFileName(), QLatin1String("QtCreatorProfiles")))
 { }
 
 ProfileManagerPrivate::~ProfileManagerPrivate()
 {
+    qDeleteAll(m_informationList);
+    qDeleteAll(m_profileList);
+    delete m_writer;
 }
 
 QList<Task> ProfileManagerPrivate::validateProfile(Profile *p) const
@@ -213,8 +218,6 @@ void ProfileManager::restoreProfiles()
 ProfileManager::~ProfileManager()
 {
     // Clean out profile information to avoid calling them during deregistration:
-    qDeleteAll(d->m_informationList);
-    qDeleteAll(d->m_profileList);
     delete d;
     m_instance = 0;
 }
@@ -224,21 +227,20 @@ void ProfileManager::saveProfiles()
     if (!d->m_initialized) // ignore save requests while we are not initialized.
         return;
 
-    PersistentSettingsWriter writer;
-    writer.saveValue(QLatin1String(PROFILE_FILE_VERSION_KEY), 1);
+    d->m_writer->saveValue(QLatin1String(PROFILE_FILE_VERSION_KEY), 1);
 
     int count = 0;
     foreach (Profile *p, profiles()) {
         QVariantMap tmp = p->toMap();
         if (tmp.isEmpty())
             continue;
-        writer.saveValue(QString::fromLatin1(PROFILE_DATA_KEY) + QString::number(count), tmp);
+        d->m_writer->saveValue(QString::fromLatin1(PROFILE_DATA_KEY) + QString::number(count), tmp);
         ++count;
     }
-    writer.saveValue(QLatin1String(PROFILE_COUNT_KEY), count);
-    writer.saveValue(QLatin1String(PROFILE_DEFAULT_KEY),
+    d->m_writer->saveValue(QLatin1String(PROFILE_COUNT_KEY), count);
+    d->m_writer->saveValue(QLatin1String(PROFILE_DEFAULT_KEY),
                      d->m_defaultProfile ? QString::fromLatin1(d->m_defaultProfile->id().name()) : QString());
-    writer.save(settingsFileName(), QLatin1String("QtCreatorProfiles"), Core::ICore::mainWindow());
+    d->m_writer->save(Core::ICore::mainWindow());
 }
 
 bool greaterPriority(ProfileInformation *a, ProfileInformation *b)

src/plugins/projectexplorer/project.cpp

@@ -87,23 +87,28 @@ class ProjectPrivate
 {
 public:
     ProjectPrivate();
+    ~ProjectPrivate();
+
     QList<Target *> m_targets;
     Target *m_activeTarget;
     EditorConfiguration *m_editorConfiguration;
     Core::Context m_projectContext;
     Core::Context m_projectLanguage;
     QVariantMap m_pluginSettings;
+    SettingsAccessor *m_accessor;
 };
 
 ProjectPrivate::ProjectPrivate() :
     m_activeTarget(0),
-    m_editorConfiguration(new EditorConfiguration())
-{
-}
+    m_editorConfiguration(new EditorConfiguration()),
+    m_accessor(0)
+{ }
+
+ProjectPrivate::~ProjectPrivate()
+{ delete m_accessor; }
 
 Project::Project() : d(new ProjectPrivate)
-{
-}
+{ }
 
 Project::~Project()
 {
@@ -281,12 +286,16 @@ Target *Project::restoreTarget(const QVariantMap &data)
 void Project::saveSettings()
 {
     emit aboutToSaveSettings();
-    SettingsAccessor::instance()->saveSettings(this, toMap());
+    if (!d->m_accessor)
+        d->m_accessor = new SettingsAccessor(this);
+    d->m_accessor->saveSettings(toMap());
 }
 
 bool Project::restoreSettings()
 {
-    QVariantMap map(SettingsAccessor::instance()->restoreSettings(this));
+    if (!d->m_accessor)
+        d->m_accessor = new SettingsAccessor(this);
+    QVariantMap map(d->m_accessor->restoreSettings());
     bool ok = fromMap(map);
     if (ok)
         emit settingsLoaded();

src/plugins/projectexplorer/session.cpp

@@ -91,7 +91,8 @@ SessionManager::SessionManager(QObject *parent)
     m_sessionName(QLatin1String("default")),
     m_virginSession(true),
     m_loadingSession(false),
-    m_startupProject(0)
+    m_startupProject(0),
+    m_writer(0)
 {
     connect(ModeManager::instance(), SIGNAL(currentModeChanged(Core::IMode*)),
             this, SLOT(saveActiveMode(Core::IMode*)));
@@ -111,6 +112,7 @@ SessionManager::SessionManager(QObject *parent)
 SessionManager::~SessionManager()
 {
     emit aboutToUnloadSession(m_sessionName);
+    delete m_writer;
 }
 
 
@@ -304,12 +306,15 @@ bool SessionManager::save()
 
     emit aboutToSaveSession();
 
-    PersistentSettingsWriter writer;
+    if (!m_writer || m_writer->fileName() != sessionNameToFileName(m_sessionName)) {
+        delete m_writer;
+        m_writer = new Utils::PersistentSettingsWriter(sessionNameToFileName(m_sessionName),
+                                                       QLatin1String("QtCreatorSession"));
+    }
 
     // save the startup project
-    if (m_startupProject) {
-        writer.saveValue(QLatin1String("StartupProject"), m_startupProject->document()->fileName());
-    }
+    if (m_startupProject)
+        m_writer->saveValue(QLatin1String("StartupProject"), m_startupProject->document()->fileName());
 
     QStringList projectFiles;
     foreach (Project *pro, m_projects)
@@ -321,7 +326,7 @@ bool SessionManager::save()
         if (!projectFiles.contains(failed))
             projectFiles << failed;
 
-    writer.saveValue(QLatin1String("ProjectList"), projectFiles);
+    m_writer->saveValue(QLatin1String("ProjectList"), projectFiles);
 
     QMap<QString, QVariant> depMap;
     QMap<QString, QStringList>::const_iterator i = m_depMap.constBegin();
@@ -334,7 +339,7 @@ bool SessionManager::save()
         depMap.insert(key, values);
         ++i;
     }
-    writer.saveValue(QLatin1String("ProjectDependencies"), QVariant(depMap));
+    m_writer->saveValue(QLatin1String("ProjectDependencies"), QVariant(depMap));
 
     int editorCount = 0;
     QList<Core::IEditor *> editors = ICore::editorManager()->openedEditors();
@@ -343,25 +348,24 @@ bool SessionManager::save()
         if (!editor->isTemporary())
             ++editorCount;
     }
-    writer.saveValue(QLatin1String("OpenEditors"), editorCount);
-    writer.saveValue(QLatin1String("EditorSettings"),
-                     ICore::editorManager()->saveState().toBase64());
+    m_writer->saveValue(QLatin1String("OpenEditors"), editorCount);
+    m_writer->saveValue(QLatin1String("EditorSettings"),
+                        ICore::editorManager()->saveState().toBase64());
 
     QMap<QString, QVariant>::const_iterator it, end;
     end = m_values.constEnd();
     QStringList keys;
     for (it = m_values.constBegin(); it != end; ++it) {
-        writer.saveValue(QLatin1String("value-") + it.key(), it.value());
+        m_writer->saveValue(QLatin1String("value-") + it.key(), it.value());
         keys << it.key();
     }
 
-    writer.saveValue(QLatin1String("valueKeys"), keys);
+    m_writer->saveValue(QLatin1String("valueKeys"), keys);
 
-    Utils::FileName fileName = sessionNameToFileName(m_sessionName);
-    bool result = writer.save(fileName, QLatin1String("QtCreatorSession"), Core::ICore::mainWindow());
+    bool result = m_writer->save(Core::ICore::mainWindow());
     if (!result) {
         QMessageBox::warning(0, tr("Error while saving session"),
-                                tr("Could not save session to file %1").arg(fileName.toUserOutput()));
+                                tr("Could not save session to file %1").arg(m_writer->fileName().toUserOutput()));
     }
 
     if (debug)

src/plugins/projectexplorer/session.h

@@ -176,6 +176,7 @@ private:
     QMap<QString, QStringList> m_depMap;
     QMap<QString, QVariant> m_values;
     QFutureInterface<void> m_future;
+    Utils::PersistentSettingsWriter *m_writer;
 };
 
 } // namespace ProjectExplorer

src/plugins/projectexplorer/settingsaccessor.cpp

@@ -450,20 +450,25 @@ static QVariantMap processHandlerNodes(const HandlerNode &node, const QVariantMa
 // -------------------------------------------------------------------------
 // UserFileAccessor
 // -------------------------------------------------------------------------
-SettingsAccessor::SettingsAccessor() :
+SettingsAccessor::SettingsAccessor(Project *project) :
     m_firstVersion(-1),
     m_lastVersion(-1),
     m_userFileAcessor(QByteArray("qtcUserFileName"),
                       QLatin1String(".user"),
                       QString::fromLocal8Bit(qgetenv("QTC_EXTENSION")),
                       true,
-                      true),
+                      true,
+                      this),
     m_sharedFileAcessor(QByteArray("qtcSharedFileName"),
                         QLatin1String(".shared"),
                         QString::fromLocal8Bit(qgetenv("QTC_SHARED_EXTENSION")),
                         false,
-                        false)
+                        false,
+                        this),
+    m_project(project)
 {
+    QTC_CHECK(m_project);
+
     addVersionHandler(new Version0Handler);
     addVersionHandler(new Version1Handler);
     addVersionHandler(new Version2Handler);
@@ -483,11 +488,8 @@ SettingsAccessor::~SettingsAccessor()
     qDeleteAll(m_handlers);
 }
 
-SettingsAccessor *SettingsAccessor::instance()
-{
-    static SettingsAccessor acessor;
-    return &acessor;
-}
+Project *SettingsAccessor::project() const
+{ return m_project; }
 
 namespace {
 
@@ -589,17 +591,21 @@ void trackUserStickySettings(QVariantMap *userMap, const QVariantMap &sharedMap)
 } // Anonymous
 
 
-QVariantMap SettingsAccessor::restoreSettings(Project *project) const
+QVariantMap SettingsAccessor::restoreSettings() const
 {
-    if (m_lastVersion < 0 || !project)
+    if (m_lastVersion < 0)
         return QVariantMap();
 
     SettingsData settings;
-    if (!m_userFileAcessor.readFile(project, &settings))
+    QString fn = project()->property(m_userFileAcessor.id()).toString();
+    if (fn.isEmpty())
+        fn = project()->document()->fileName() + m_userFileAcessor.suffix();
+    settings.m_fileName = Utils::FileName::fromString(fn);
+    if (!m_userFileAcessor.readFile(&settings))
         settings.clear(); // No user settings, but there can still be shared ones.
 
     if (settings.isValid()) {
-        if (settings.m_version > SettingsAccessor::instance()->m_lastVersion + 1) {
+        if (settings.m_version > m_lastVersion + 1) {
             QMessageBox::information(
                 Core::ICore::mainWindow(),
                 QApplication::translate("ProjectExplorer::SettingsAccessor",
@@ -652,7 +658,7 @@ QVariantMap SettingsAccessor::restoreSettings(Project *project) const
 
     // Time to consider shared settings...
     SettingsData sharedSettings;
-    if (m_sharedFileAcessor.readFile(project, &sharedSettings)) {
+    if (m_sharedFileAcessor.readFile(&sharedSettings)) {
         bool useSharedSettings = true;
         if (sharedSettings.m_version != settings.m_version) {
             int baseFileVersion;
@@ -692,20 +698,20 @@ QVariantMap SettingsAccessor::restoreSettings(Project *project) const
             if (useSharedSettings) {
                 // We now update the user and shared settings so they are compatible.
                 for (int i = sharedSettings.m_version; i < baseFileVersion; ++i)
-                    sharedSettings.m_map = m_handlers.value(i)->update(project, sharedSettings.m_map);
+                    sharedSettings.m_map = m_handlers.value(i)->update(m_project, sharedSettings.m_map);
 
                 if (!settings.isValid()) {
-                    project->setProperty(SHARED_SETTINGS, sharedSettings.m_map);
+                    m_project->setProperty(SHARED_SETTINGS, sharedSettings.m_map);
                     return sharedSettings.m_map;
                 }
                 for (int i = settings.m_version; i < baseFileVersion; ++i)
-                    settings.m_map = m_handlers.value(i)->update(project, settings.m_map);
+                    settings.m_map = m_handlers.value(i)->update(m_project, settings.m_map);
                 settings.m_version = baseFileVersion;
             }
         }
 
         if (useSharedSettings) {
-            project->setProperty(SHARED_SETTINGS, sharedSettings.m_map);
+            m_project->setProperty(SHARED_SETTINGS, sharedSettings.m_map);
             if (!settings.isValid())
                 return sharedSettings.m_map;
 
@@ -718,22 +724,26 @@ QVariantMap SettingsAccessor::restoreSettings(Project *project) const
 
     // Update from the base version to Creator's version.
     for (int i = settings.m_version; i <= m_lastVersion; ++i)
-        settings.m_map = m_handlers.value(i)->update(project, settings.m_map);
+        settings.m_map = m_handlers.value(i)->update(m_project, settings.m_map);
 
     return settings.m_map;
 }
 
-bool SettingsAccessor::saveSettings(const Project *project, const QVariantMap &map) const
+bool SettingsAccessor::saveSettings(const QVariantMap &map) const
 {
-    if (!project || map.isEmpty())
+    if (map.isEmpty())
         return false;
 
     SettingsData settings(map);
-    const QVariant &shared = project->property(SHARED_SETTINGS);
+    QString fn = project()->property(m_userFileAcessor.id()).toString();
+    if (fn.isEmpty())
+        fn = project()->document()->fileName() + m_userFileAcessor.suffix();
+    settings.m_fileName = Utils::FileName::fromString(fn);
+    const QVariant &shared = m_project->property(SHARED_SETTINGS);
     if (shared.isValid())
         trackUserStickySettings(&settings.m_map, shared.toMap());
 
-    return m_userFileAcessor.writeFile(project, &settings);
+    return m_userFileAcessor.writeFile(&settings);
 }
 
 void SettingsAccessor::addVersionHandler(UserFileVersionHandler *handler)
@@ -800,14 +810,21 @@ SettingsAccessor::FileAccessor::FileAccessor(const QByteArray &id,
                                              const QString &defaultSuffix,
                                              const QString &environmentSuffix,
                                              bool envSpecific,
-                                             bool versionStrict)
+                                             bool versionStrict, SettingsAccessor *accessor)
     : m_id(id)
     , m_environmentSpecific(envSpecific)
     , m_versionStrict(versionStrict)
+    , m_accessor(accessor)
+    , m_writer(0)
 {
     assignSuffix(defaultSuffix, environmentSuffix);
 }
 
+SettingsAccessor::FileAccessor::~FileAccessor()
+{
+    delete m_writer;
+}
+
 void SettingsAccessor::FileAccessor::assignSuffix(const QString &defaultSuffix,
                                                   const QString &environmentSuffix)
 {
@@ -820,11 +837,6 @@ void SettingsAccessor::FileAccessor::assignSuffix(const QString &defaultSuffix,
     }
 }
 
-QString SettingsAccessor::FileAccessor::assembleFileName(const Project *project) const
-{
-    return project->document()->fileName() + m_suffix;
-}
-
 bool SettingsAccessor::FileAccessor::findNewestCompatibleSetting(SettingsData *settings) const
 {
     const QString baseFileName = settings->m_fileName.toString();
@@ -833,7 +845,6 @@ bool SettingsAccessor::FileAccessor::findNewestCompatibleSetting(SettingsData *s
     settings->m_version = -1;
 
     PersistentSettingsReader reader;
-    SettingsAccessor *acessor = SettingsAccessor::instance();
 
     QFileInfo fileInfo(baseFileName);
     QStringList fileNameFilter(fileInfo.fileName() + QLatin1String(".*"));
@@ -845,10 +856,10 @@ bool SettingsAccessor::FileAccessor::findNewestCompatibleSetting(SettingsData *s
         const QString &suffix = file.mid(fileInfo.fileName().length() + 1);
         const QString &candidateFileName = baseFileName + QLatin1String(".") + suffix;
         candidates.append(candidateFileName);
-        for (int candidateVersion = acessor->m_lastVersion;
-             candidateVersion >= acessor->m_firstVersion;
+        for (int candidateVersion = m_accessor->m_lastVersion;
+             candidateVersion >= m_accessor->m_firstVersion;
              --candidateVersion) {
-            if (suffix == acessor->m_handlers.value(candidateVersion)->displayUserFileVersion()) {
+            if (suffix == m_accessor->m_handlers.value(candidateVersion)->displayUserFileVersion()) {
                 if (candidateVersion > settings->m_version) {
                     settings->m_version = candidateVersion;
                     settings->m_fileName = Utils::FileName::fromString(candidateFileName);
@@ -876,7 +887,7 @@ bool SettingsAccessor::FileAccessor::findNewestCompatibleSetting(SettingsData *s
         if (reader.load(fn)) {
             settings->m_map = reader.restoreValues();
             int candidateVersion = settings->m_map.value(QLatin1String(VERSION_KEY), 0).toInt();
-            if (candidateVersion == acessor->m_lastVersion + 1) {
+            if (candidateVersion == m_accessor->m_lastVersion + 1) {
                 settings->m_version = candidateVersion;
                 settings->m_fileName = fn;
                 return true;
@@ -890,11 +901,9 @@ bool SettingsAccessor::FileAccessor::findNewestCompatibleSetting(SettingsData *s
     return false;
 }
 
-bool SettingsAccessor::FileAccessor::readFile(Project *project,
-                                             SettingsData *settings) const
+bool SettingsAccessor::FileAccessor::readFile(SettingsData *settings) const
 {
     PersistentSettingsReader reader;
-    settings->m_fileName = Utils::FileName::fromString(assembleFileName(project));
     if (!reader.load(settings->m_fileName))
         return false;
 
@@ -905,43 +914,41 @@ bool SettingsAccessor::FileAccessor::readFile(Project *project,
     if (!m_versionStrict)
         return true;
 
-    if (settings->m_version < SettingsAccessor::instance()->m_firstVersion) {
+    if (settings->m_version < m_accessor->m_firstVersion) {
         qWarning() << "Version" << settings->m_version << "in" << m_suffix << "too old.";
         return false;
     }
 
-    if (settings->m_version > SettingsAccessor::instance()->m_lastVersion + 1) {
+    if (settings->m_version > m_accessor->m_lastVersion + 1) {
         if (!findNewestCompatibleSetting(settings))
             return false;
 
         settings->m_usingBackup = true;
-        project->setProperty(m_id.constData(), settings->m_fileName.toString());
+        m_accessor->project()->setProperty(m_id.constData(), settings->m_fileName.toString());
     }
 
     return true;
 }
 
-bool SettingsAccessor::FileAccessor::writeFile(const Project *project,
-                                              const SettingsData *settings) const
+bool SettingsAccessor::FileAccessor::writeFile(const SettingsData *settings) const
 {
-    PersistentSettingsWriter writer;
+    if (!m_writer || m_writer->fileName() != settings->m_fileName) {
+        delete m_writer;
+        m_writer = new Utils::PersistentSettingsWriter(settings->m_fileName, QLatin1String("QtCreatorProject"));