Partitions: extend getDevices() with minimum size.

This is preparatory work for making the available-space check consistent with
what the partition module will allow for installation. Right now, the check
for available space will allow a mounted drive, even /, to satisfy the check.

src/modules/partition/core/DeviceList.cpp

@@ -105,7 +105,7 @@ operator <<( QDebug& s, QList< Device* >::iterator& it )
     return s;
 }
 
-QList< Device* > getDevices( DeviceType which )
+QList< Device* > getDevices( DeviceType which, qint64 minimumSize )
 {
     bool writableOnly = (which == DeviceType::WritableOnly);
 
@@ -135,6 +135,11 @@ QList< Device* > getDevices( DeviceType which )
             cDebug() << "  .. Removing" << it;
             it = devices.erase( it );
         }
+        else if ( (minimumSize >= 0) && !( (*it)->capacity() > minimumSize ) )
+        {
+            cDebug() << "  .. Removing too-small" << it;
+            it = devices.erase( it );
+        }
         else
             ++it;
 

src/modules/partition/core/DeviceList.h

@@ -36,9 +36,12 @@ enum class DeviceType { All, WritableOnly };
  *      the system, filtering out those that do not meet a criterium.
  *      If set to WritableOnly, only devices which can be overwritten
  *      safely are returned (e.g. RO-media are ignored, as are mounted partitions).
+ * @param minimumSize Can be used to filter devices based on their
+ *      size (in bytes). If non-negative, only devices with a size
+ *      greater than @p minimumSize will be returned.
  * @return a list of Devices meeting this criterium.
  */
-QList< Device* > getDevices( DeviceType which = DeviceType::All );
+QList< Device* > getDevices( DeviceType which = DeviceType::All, qint64 minimumSize = -1 );
 
 }