[libcalamares] Emphasise that GeoIP::Handler::get() is synchronous

- prep-work for also having an async API

src/libcalamares/geoip/GeoIPTests.cpp

@@ -222,7 +222,7 @@ synchronous_get( const char* urlstring )
         auto tz = GeoIP##t( selector ).processReply( synchronous_get( url ) ); \
         qDebug() << tz; \
         QCOMPARE( default_tz, tz ); \
-        auto tz2 = CalamaresUtils::GeoIP::Handler( ""#t, url, selector ).query(); \
+        auto tz2 = CalamaresUtils::GeoIP::Handler( ""#t, url, selector ).get(); \
         qDebug() << tz2; \
         QCOMPARE( default_tz, tz2 ); \
     }

src/libcalamares/geoip/Handler.cpp

@@ -29,26 +29,29 @@
 #include <QNetworkRequest>
 #include <QNetworkReply>
 
+#include <memory>
+
 namespace CalamaresUtils::GeoIP
 {
 
 Handler::Handler()
-    : m_interface( nullptr )
+    : m_type( Type::None )
 {
 }
 
 Handler::Handler( const QString& implementation, const QString& url, const QString& selector )
-    : m_interface( nullptr )
+    : m_type( Type::None )
     , m_url( url )
 {
     if ( implementation.compare( "json", Qt::CaseInsensitive ) == 0 )
     {
-        m_interface = new GeoIPJSON( selector );
+
+        m_type = Type::JSON;
     }
 #if defined(QT_XML_LIB)
     else if ( implementation.compare( "xml", Qt::CaseInsensitive ) == 0 )
     {
-        m_interface = new GeoIPXML( selector );
+        m_type = Type::XML;
     }
 #endif
     else
@@ -59,13 +62,6 @@ Handler::Handler( const QString& implementation, const QString& url, const QStri
 
 Handler::~Handler()
 {
-    delete m_interface;
-}
-
-bool
-Handler::isValid() const
-{
-    return m_interface;
 }
 
 static QByteArray
@@ -84,14 +80,44 @@ synchronous_get( const QString& urlstring )
     return reply->readAll();
 }
 
+static std::unique_ptr< Interface >
+create_interface( Handler::Type t, const QString& selector )
+{
+    switch( t )
+    {
+        case Handler::Type::None:
+            return nullptr;
+        case Handler::Type::JSON:
+            return std::make_unique< GeoIPJSON >( selector );
+        case Handler::Type::XML:
+#if defined(QT_XML_LIB)
+            return std::make_unique< GeoIPXML >( selector );
+#else
+            return nullptr;
+#endif
+        default:  // there are no others
+            return nullptr;
+    }
+}
 
 RegionZonePair
-Handler::query() const
+Handler::get() const
 {
     if ( !isValid() )
         return RegionZonePair();
 
-    return m_interface->processReply( synchronous_get( m_url ) );
+    const auto interface = create_interface( m_type, m_selector );
+    if ( !interface )
+        return RegionZonePair();
+
+    return interface->processReply( synchronous_get( m_url ) );
+}
+
+/*
+QFuture< RegionZonePair >
+Handler::query() const
+{
 }
+*/
 
 }  // namespace

src/libcalamares/geoip/Handler.h

@@ -21,6 +21,7 @@
 
 #include "Interface.h"
 
+#include <QtConcurrent/QtConcurrentRun>
 #include <QString>
 #include <QVariantMap>
 
@@ -31,13 +32,21 @@ namespace CalamaresUtils::GeoIP
 /** @brief Handle one complete GeoIP lookup.
  *
  * This class handles one complete GeoIP lookup. Create it with
- * suitable configuration values, then call lookup(). This is a
+ * suitable configuration values, then call get(). This is a
  * synchronous API and will return an invalid zone pair on
- * error or if the configuration is not understood/
+ * error or if the configuration is not understood. For an
+ * async API, use query().
  */
 class DLLEXPORT Handler
 {
 public:
+    enum class Type
+    {
+        None,
+        JSON,
+        XML
+    } ;
+
     /** @brief An unconfigured handler; this always returns errors. */
     Handler();
     /** @brief A handler for a specific GeoIP source.
@@ -63,13 +72,27 @@ public:
 
     ~Handler();
 
-    RegionZonePair query() const;
+    /** @brief Synchronously get the GeoIP result.
+     *
+     * If the Handler is valid, then do the actual fetching and interpretation
+     * of data and return the result. An invalid Handler will return an
+     * invalid (empty) result.
+     */
+    RegionZonePair get() const;
+
+    /** @brief Asynchronously get the GeoIP result.
+     *
+     * See get() for the return value.
+     */
+    QFuture< RegionZonePair > query() const;
 
-    bool isValid() const;
+    bool isValid() const { return m_type != Type::None; }
+    Type type() const { return m_type; }
 
 private:
-    Interface* m_interface;
+    Type m_type;
     const QString m_url;
+    const QString m_selector;
 };
 
 }  // namespace