SettingsAccessor: Remember last saved state

Remember last saved data and do not save it again if nothing had
changed.

Change-Id: I093859ff5edc8d1d6e7b17ecd97985ca6fb0e579
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/utils/persistentsettings.cpp

@@ -443,6 +443,12 @@ bool PersistentSettingsWriter::save(const QVariantMap &data, QWidget *parent) co
 FileName PersistentSettingsWriter::fileName() const
 { return m_fileName; }
 
+//** * @brief Set contents of file (e.g. from data read from it). */
+void PersistentSettingsWriter::setContents(const QVariantMap &data)
+{
+    m_savedData = data;
+}
+
 bool PersistentSettingsWriter::write(const QVariantMap &data, QString *errorString) const
 {
     QDir tmp;
@@ -472,10 +478,12 @@ bool PersistentSettingsWriter::write(const QVariantMap &data, QString *errorStri
         saver.setResult(&w);
     }
     bool ok = saver.finalize();
-    if (ok)
+    if (ok) {
         m_savedData = data;
-    else if (errorString)
+    } else if (errorString) {
+        m_savedData.clear();
         *errorString = saver.errorString();
+    }
 
     return ok;
 }

src/libs/utils/persistentsettings.h

@@ -61,6 +61,8 @@ public:
 
     FileName fileName() const;
 
+    void setContents(const QVariantMap &data);
+
 private:
     bool write(const QVariantMap &data, QString *errorString) const;
 

src/libs/utils/settingsaccessor.cpp

@@ -82,6 +82,7 @@ QVariantMap SettingsAccessor::restoreSettings(QWidget *parent) const
     QTC_ASSERT(!m_baseFilePath.isEmpty(), return QVariantMap());
 
     const RestoreData result = readData(m_baseFilePath, parent);
+
     const ProceedInfo pi = result.hasIssue() ? reportIssues(result.issue.value(), result.path, parent) : ProceedInfo::Continue;
     return pi == ProceedInfo::DiscardAndContinue ? QVariantMap() : result.data;
 }
@@ -92,6 +93,7 @@ QVariantMap SettingsAccessor::restoreSettings(QWidget *parent) const
 bool SettingsAccessor::saveSettings(const QVariantMap &data, QWidget *parent) const
 {
     const optional<Issue> result = writeData(m_baseFilePath, data, parent);
+
     const ProceedInfo pi = result ? reportIssues(result.value(), m_baseFilePath, parent) : ProceedInfo::Continue;
     return pi == ProceedInfo::Continue;
 }
@@ -132,7 +134,14 @@ SettingsAccessor::RestoreData SettingsAccessor::readFile(const FileName &path) c
                                  .arg(path.toUserOutput()), Issue::Type::ERROR));
     }
 
-    return RestoreData(path, reader.restoreValues());
+    const QVariantMap data = reader.restoreValues();
+    if (path == m_baseFilePath) {
+        if (!m_writer)
+            m_writer = std::make_unique<PersistentSettingsWriter>(m_baseFilePath, docType);
+        m_writer->setContents(data);
+    }
+
+    return RestoreData(path, data);
 }
 
 /*!