Wizards: Support using #pragma once instead of include guards

Allow users to choose #pragma once instead of #ifndef include guards in
generated header files.

Fixes: QTCREATORBUG-12166
Change-Id: I3ba41c7570beb9c5958e174b5581fcc25855050f
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Filip Bucek <fbucek@atlas.cz>

3 files changed, 12 insertions, 3 deletions

diff --git a/src/plugins/designer/cpp/formclasswizarddialog.cpp b/src/plugins/designer/cpp/formclasswizarddialog.cpp
index 95b099b4c4..66956b99a7 100644
--- a/src/plugins/designer/cpp/formclasswizarddialog.cpp
+++ b/src/plugins/designer/cpp/formclasswizarddialog.cpp
@@ -26,6 +26,7 @@
 #include "formclasswizarddialog.h"
 #include "formclasswizardpage.h"
 #include "formclasswizardparameters.h"
+#include <cpptools/abstracteditorsupport.h>
 #include <designer/formtemplatewizardpage.h>
 #include <qtsupport/codegenerator.h>
 
@@ -88,6 +89,7 @@ FormClassWizardParameters FormClassWizardDialog::parameters() const
     m_classPage->getParameters(&rc);
     // Name the ui class in the Ui namespace after the class specified
     rc.uiTemplate = QtSupport::CodeGenerator::changeUiClassName(m_rawFormTemplate, rc.className);
+    rc.usePragmaOnce = CppTools::AbstractEditorSupport::usePragmaOnce();
     return rc;
 }
 
diff --git a/src/plugins/designer/cpp/formclasswizardparameters.h b/src/plugins/designer/cpp/formclasswizardparameters.h
index 7aa25f5cb3..1396c9052c 100644
--- a/src/plugins/designer/cpp/formclasswizardparameters.h
+++ b/src/plugins/designer/cpp/formclasswizardparameters.h
@@ -43,6 +43,7 @@ public:
     QString sourceFile;
     QString headerFile;
     QString uiFile;
+    bool usePragmaOnce = false;
 };
 } // namespace Designer
 
diff --git a/src/plugins/designer/qtdesignerformclasscodegenerator.cpp b/src/plugins/designer/qtdesignerformclasscodegenerator.cpp
index 7ad455e159..2584ff7de1 100644
--- a/src/plugins/designer/qtdesignerformclasscodegenerator.cpp
+++ b/src/plugins/designer/qtdesignerformclasscodegenerator.cpp
@@ -104,8 +104,12 @@ bool QtDesignerFormClassCodeGenerator::generateCpp(const FormClassWizardParamete
 
     // 1) Header file
     QTextStream headerStr(header);
-    headerStr << headerLicense << "#ifndef " << guard
-              << "\n#define " <<  guard << '\n' << '\n';
+    headerStr << headerLicense;
+
+    if (parameters.usePragmaOnce)
+        headerStr << "#pragma once\n\n";
+    else
+        headerStr << "#ifndef " << guard << "\n#define " << guard << "\n\n";
 
     // Include 'ui_'
     if (generationParameters.embedding != QtSupport::CodeGenSettings::PointerAggregatedUiClass) {
@@ -165,7 +169,9 @@ bool QtDesignerFormClassCodeGenerator::generateCpp(const FormClassWizardParamete
     }
     headerStr << namespaceIndent << "};\n\n";
     Utils::writeClosingNameSpaces(namespaceList, QString(), headerStr);
-    headerStr << "#endif // "<<  guard << '\n';
+
+    if (!parameters.usePragmaOnce)
+        headerStr << "#endif // " << guard << '\n';
 
     // 2) Source file
     QTextStream sourceStr(source);