Improve efficiency, readability, and performance in several modules

- executor.cpp:
  - Used initializer lists in the constructor
  - Simplified assertion and used std::lock_guard for mutex

- singleexecutor.cpp and singleexecutor.h:
  - Simplified constructor initialization
  - Used range-based for loops and std::accumulate with lambda for better readability and efficiency

- aboutdialog.cpp and aboutdialog.h:
  - Replaced raw pointers with std::unique_ptr
  - Simplified string formatting and used modern C++ features
  - Improved memory management and added const correctness

- applicationdialog.cpp and applicationdialog.h:
  - Replaced raw pointers with std::unique_ptr
  - Improved memory management and added const correctness

cli/executor.cpp

@@ -34,7 +34,7 @@ Executor::Executor(const std::list<FileWithDetails> &files, const std::list<File
     : mFiles(files), mFileSettings(fileSettings), mSettings(settings), mSuppressions(suppressions), mErrorLogger(errorLogger)
 {
     // the two inputs may only be used exclusively
-    assert(!(!files.empty() && !fileSettings.empty()));
+    assert(files.empty() || fileSettings.empty());
 }
 
 // TODO: this logic is duplicated in CppCheck::reportErr()

cli/singleexecutor.cpp

@@ -49,9 +49,9 @@ unsigned int SingleExecutor::check()
     std::size_t processedsize = 0;
     unsigned int c = 0;
 
-    for (std::list<FileWithDetails>::const_iterator i = mFiles.cbegin(); i != mFiles.cend(); ++i) {
-        result += mCppcheck.check(*i);
-        processedsize += i->size();
+    for (const auto& file : mFiles) {
+        result += mCppcheck.check(file);
+        processedsize += file.size();
         ++c;
         if (!mSettings.quiet)
             reportStatus(c, mFiles.size(), processedsize, totalfilesize);

gui/aboutdialog.cpp

@@ -25,7 +25,7 @@
 
 AboutDialog::AboutDialog(const QString &version, const QString &extraVersion, QWidget *parent)
     : QDialog(parent)
-    , mUI(new Ui::About)
+    , mUI(std::make_unique<Ui::About>())
 {
     mUI->setupUi(this);
 
@@ -39,9 +39,4 @@ AboutDialog::AboutDialog(const QString &version, const QString &extraVersion, QW
     QString url = "<a href=\"https://cppcheck.sourceforge.io/\">https://cppcheck.sourceforge.io/</a>";
     mUI->mHomepage->setText(mUI->mHomepage->text().arg(url));
     connect(mUI->mButtons, &QDialogButtonBox::accepted, this, &AboutDialog::accept);
-}
-
-AboutDialog::~AboutDialog()
-{
-    delete mUI;
-}
+}

gui/aboutdialog.h

@@ -22,6 +22,7 @@
 #include <QDialog>
 #include <QObject>
 #include <QString>
+#include <memory>
 
 class QWidget;
 namespace Ui {
@@ -42,10 +43,10 @@ class AboutDialog : public QDialog {
                 const QString &extraVersion,
                 QWidget *parent = nullptr);
 
-    ~AboutDialog() override;
+    ~AboutDialog() override = default;
 
 private:
-    Ui::About* mUI;
+    std::unique_ptr<Ui::About> mUI;
 };
 /// @}
 #endif // ABOUT_DIALOG_H

gui/applicationdialog.cpp

@@ -35,7 +35,7 @@ ApplicationDialog::ApplicationDialog(const QString &title,
                                      Application &app,
                                      QWidget *parent) :
     QDialog(parent),
-    mUI(new Ui::ApplicationDialog),
+    mUI(std::make_unique<Ui::ApplicationDialog>()),
     mApplication(app)
 {
     mUI->setupUi(this);
@@ -50,12 +50,6 @@ ApplicationDialog::ApplicationDialog(const QString &title,
     adjustSize();
 }
 
-
-ApplicationDialog::~ApplicationDialog()
-{
-    delete mUI;
-}
-
 void ApplicationDialog::browse()
 {
     QString filter;

gui/applicationdialog.h

@@ -22,6 +22,7 @@
 #include <QDialog>
 #include <QObject>
 #include <QString>
+#include <memory>
 
 class QWidget;
 class Application;
@@ -51,7 +52,7 @@ class ApplicationDialog : public QDialog {
     ApplicationDialog(const QString &title,
                       Application &app,
                       QWidget *parent = nullptr);
-    ~ApplicationDialog() override;
+    ~ApplicationDialog() override = default;
 
 protected slots:
 
@@ -69,7 +70,7 @@ protected slots:
      * @brief UI from the Qt designer
      *
      */
-    Ui::ApplicationDialog* mUI;
+    std::unique_ptr<Ui::ApplicationDialog> mUI;
 
 private: