cmake-gui: set generator field defaults from environment

Fixes: #20251

Help/release/dev/cmake-gui-env-platform-defaults.rst

@@ -0,0 +1,8 @@
+cmake-gui-env-platform-defaults
+-------------------------------
+
+* :manual:`cmake-gui(1)` now populates its generator selection
+  widget default value from the :envvar:`CMAKE_GENERATOR` environment
+  variable.  Additionally, environment variables
+  :envvar:`CMAKE_GENERATOR_PLATFORM` and :envvar:`CMAKE_GENERATOR_TOOLSET`
+  are used to populate their respective widget defaults.

Source/QtDialog/FirstConfigure.cxx

@@ -10,8 +10,12 @@
 
 #include "Compilers.h"
 
-StartCompilerSetup::StartCompilerSetup(QWidget* p)
+StartCompilerSetup::StartCompilerSetup(QString defaultGeneratorPlatform,
+                                       QString defaultGeneratorToolset,
+                                       QWidget* p)
   : QWizardPage(p)
+  , DefaultGeneratorPlatform(std::move(defaultGeneratorPlatform))
+  , DefaultGeneratorToolset(std::move(defaultGeneratorToolset))
 {
   QVBoxLayout* l = new QVBoxLayout(this);
   l->addWidget(new QLabel(tr("Specify the generator for this project")));
@@ -68,6 +72,10 @@ QFrame* StartCompilerSetup::CreateToolsetWidgets()
   Toolset = new QLineEdit(frame);
   l->addWidget(Toolset);
 
+  // Default to CMAKE_GENERATOR_TOOLSET env var if set
+  if (!DefaultGeneratorToolset.isEmpty()) {
+    this->Toolset->setText(DefaultGeneratorToolset);
+  }
   return frame;
 }
 
@@ -199,6 +207,14 @@ void StartCompilerSetup::onGeneratorChanged(QString const& name)
 
     this->PlatformOptions->addItems(platform_list);
     PlatformFrame->show();
+
+    // Default to generator platform from environment
+    if (!DefaultGeneratorPlatform.isEmpty()) {
+      int platform_index = platforms.indexOf(DefaultGeneratorPlatform);
+      if (platform_index != -1) {
+        this->PlatformOptions->setCurrentIndex(platform_index);
+      }
+    }
   } else {
     PlatformFrame->hide();
   }
@@ -421,8 +437,26 @@ void ToolchainCompilerSetup::setToolchainFile(const QString& t)
 
 FirstConfigure::FirstConfigure()
 {
+  const char* env_generator = std::getenv("CMAKE_GENERATOR");
+  const char* env_generator_platform = nullptr;
+  const char* env_generator_toolset = nullptr;
+  if (env_generator && std::strlen(env_generator)) {
+    mDefaultGenerator = env_generator;
+    env_generator_platform = std::getenv("CMAKE_GENERATOR_PLATFORM");
+    env_generator_toolset = std::getenv("CMAKE_GENERATOR_TOOLSET");
+  }
+
+  if (!env_generator_platform) {
+    env_generator_platform = "";
+  }
+
+  if (!env_generator_toolset) {
+    env_generator_toolset = "";
+  }
+
   // this->setOption(QWizard::HaveFinishButtonOnEarlyPages, true);
-  this->mStartCompilerSetupPage = new StartCompilerSetup(this);
+  this->mStartCompilerSetupPage = new StartCompilerSetup(
+    env_generator_platform, env_generator_toolset, this);
   this->setPage(Start, this->mStartCompilerSetupPage);
   QObject::connect(this->mStartCompilerSetupPage, SIGNAL(selectionChanged()),
                    this, SLOT(restart()));
@@ -504,6 +538,17 @@ void FirstConfigure::loadFromSettings()
   this->mCrossCompilerSetupPage->setIncludeMode(
     settings.value("IncludeMode", 0).toInt());
   settings.endGroup();
+
+  // environment variables take precedence over application settings because...
+  // - they're harder to set
+  // - settings always exist after the program is run once, so the environment
+  //     variables would never be used otherwise
+  // - platform and toolset are populated only from environment variables, so
+  //     this prevents them from being taken from environment, while the
+  //     generator is taken from application settings
+  if (!mDefaultGenerator.isEmpty()) {
+    this->mStartCompilerSetupPage->setCurrentGenerator(mDefaultGenerator);
+  }
 }
 
 void FirstConfigure::saveToSettings()

Source/QtDialog/FirstConfigure.h

@@ -29,7 +29,8 @@ class StartCompilerSetup : public QWizardPage
 {
   Q_OBJECT
 public:
-  StartCompilerSetup(QWidget* p);
+  StartCompilerSetup(QString defaultGeneratorPlatform,
+                     QString defaultGeneratorToolset, QWidget* p);
   ~StartCompilerSetup();
   void setGenerators(std::vector<cmake::GeneratorInfo> const& gens);
   void setCurrentGenerator(const QString& gen);
@@ -64,6 +65,7 @@ protected:
   QStringList GeneratorsSupportingPlatform;
   QMultiMap<QString, QString> GeneratorSupportedPlatforms;
   QMap<QString, QString> GeneratorDefaultPlatform;
+  QString DefaultGeneratorPlatform, DefaultGeneratorToolset;
 
 private:
   QFrame* CreateToolsetWidgets();
@@ -197,6 +199,7 @@ protected:
   NativeCompilerSetup* mNativeCompilerSetupPage;
   CrossCompilerSetup* mCrossCompilerSetupPage;
   ToolchainCompilerSetup* mToolchainCompilerSetupPage;
+  QString mDefaultGenerator;
 };
 
 #endif // FirstConfigure_h