[libcalamares] Extend packages service API

- convenience method to install a (string) list of packages
  (doesn't do the installation, but adds to GS the list, so
  that the packages module can handle it).

src/libcalamares/packages/Globals.cpp

@@ -12,11 +12,11 @@
 #include "GlobalStorage.h"
 #include "utils/Logger.h"
 
-bool
-CalamaresUtils::Packages::setGSPackageAdditions( Calamares::GlobalStorage* gs,
-                                                 const Calamares::ModuleSystem::InstanceKey& module,
-                                                 const QVariantList& installPackages,
-                                                 const QVariantList& tryInstallPackages )
+static bool
+additions( Calamares::GlobalStorage* gs,
+           const QString& key,
+           const QVariantList& installPackages,
+           const QVariantList& tryInstallPackages )
 {
     static const char PACKAGEOP[] = "packageOperations";
 
@@ -25,8 +25,6 @@ CalamaresUtils::Packages::setGSPackageAdditions( Calamares::GlobalStorage* gs,
     QVariantList packageOperations = gs->contains( PACKAGEOP ) ? gs->value( PACKAGEOP ).toList() : QVariantList();
     cDebug() << "Existing package operations length" << packageOperations.length();
 
-    const QString key = module.toString();
-
     // Clear out existing operations for this module, going backwards:
     // Sometimes we remove an item, and we don't want the index to
     // fall off the end of the list.
@@ -66,3 +64,25 @@ CalamaresUtils::Packages::setGSPackageAdditions( Calamares::GlobalStorage* gs,
     }
     return false;
 }
+
+bool
+CalamaresUtils::Packages::setGSPackageAdditions( Calamares::GlobalStorage* gs,
+                                                 const Calamares::ModuleSystem::InstanceKey& module,
+                                                 const QVariantList& installPackages,
+                                                 const QVariantList& tryInstallPackages )
+{
+    return additions( gs, module.toString(), installPackages, tryInstallPackages );
+}
+
+bool
+CalamaresUtils::Packages::setGSPackageAdditions( Calamares::GlobalStorage* gs,
+                                                 const Calamares::ModuleSystem::InstanceKey& module,
+                                                 const QStringList& installPackages )
+{
+    QVariantList l;
+    for ( const auto& s : installPackages )
+    {
+        l << s;
+    }
+    return additions( gs, module.toString(), l, QVariantList() );
+}

src/libcalamares/packages/Globals.h

@@ -28,6 +28,14 @@ bool setGSPackageAdditions( Calamares::GlobalStorage* gs,
                             const Calamares::ModuleSystem::InstanceKey& module,
                             const QVariantList& installPackages,
                             const QVariantList& tryInstallPackages );
+/** @brief Sets the install-packages GS keys for the given module
+ *
+ * This replaces previously-set install-packages lists. Use this with
+ * plain lists of package names. It does not support try-install.
+ */
+bool setGSPackageAdditions( Calamares::GlobalStorage* gs,
+                            const Calamares::ModuleSystem::InstanceKey& module,
+                            const QStringList& installPackages );
 // void setGSPackageRemovals( const Calamares::ModuleSystem::InstanceKey& key, const QVariantList& removePackages );
 }  // namespace Packages
 }  // namespace CalamaresUtils