[libcalamares] Add spot-patches to timezone data

- for the purposes of Calamares's nearest-location selection algorithm
  for timezone selection, introduce spot patches: alternate markers
  on the map to indicate "things close to here belong in this timezone".
- hide the implementation detail in the find() methods.
This commit is contained in:
Adriaan de Groot 2020-08-09 00:05:40 +10:00
parent 028d424c73
commit e35992cf0b

View File

@ -183,17 +183,30 @@ loadTZData( RegionVector& regions, ZoneVector& zones, QTextStream& in )
}
}
static void
loadTZData( RegionVector& regions, ZoneVector& zones )
{
QFile file( TZ_DATA_FILE );
if ( file.open( QIODevice::ReadOnly | QIODevice::Text ) )
{
QTextStream in( &file );
loadTZData( regions, zones, in );
}
}
/** @brief Extra, fake, timezones
*
* The timezone locations in zone.tab are not always very useful,
* given Calamares's standard "nearest zone" algorithm: for instance,
* in most locations physically in the country of South Africa,
* Maseru (the capital of Lesotho, and location for timezone Africa/Maseru)
* is closer than Johannesburg (the location for timezone Africa/Johannesburg).
*
* The algorithm picks the wrong place. This is for instance annoying
* when clicking on Cape Town, you get Maseru, and to get Johannesburg
* you need to click somewhere very carefully north of Maserru.
*
* These alternate zones are used to introduce "extra locations"
* into the timezone database, in order to influence the closest-location
* algorithm. Lines are formatted just like in zone.tab: remember the \n
*/
static const char altZones[] =
/* This extra zone is north-east of Karoo National park,
* and means that Western Cape province and a good chunk of
* Northern- and Eastern- Cape provinces get pulled in to Johannesburg.
* Bloemfontein is still closer to Maseru than either correct zone,
* but this is a definite improvement.
*/
"ZA -3230+02259 Africa/Johannesburg\n";
class Private : public QObject
{
@ -201,13 +214,27 @@ class Private : public QObject
public:
RegionVector m_regions;
ZoneVector m_zones;
ZoneVector m_altZones; //< Extra locations for zones
Private()
{
m_regions.reserve( 12 ); // reasonable guess
m_zones.reserve( 452 ); // wc -l /usr/share/zoneinfo/zone.tab
loadTZData( m_regions, m_zones );
// Load the official timezones
{
QFile file( TZ_DATA_FILE );
if ( file.open( QIODevice::ReadOnly | QIODevice::Text ) )
{
QTextStream in( &file );
loadTZData( m_regions, m_zones, in );
}
}
// Load the alternate zones (see documentation at altZones)
{
QTextStream in( altZones );
loadTZData( m_regions, m_altZones, in );
}
std::sort( m_regions.begin(), m_regions.end(), []( const RegionData* lhs, const RegionData* rhs ) {
return lhs->key() < rhs->key();
@ -343,9 +370,9 @@ ZonesModel::find( const QString& region, const QString& zone ) const
}
STATICTEST const TimeZoneData*
find( const ZoneVector& zones, const std::function< double( const TimeZoneData* ) >& distanceFunc )
find( double startingDistance, const ZoneVector& zones, const std::function< double( const TimeZoneData* ) >& distanceFunc )
{
double smallestDistance = 1000000.0;
double smallestDistance = startingDistance;
const TimeZoneData* closest = nullptr;
for ( const auto* zone : zones )
@ -363,7 +390,14 @@ find( const ZoneVector& zones, const std::function< double( const TimeZoneData*
const TimeZoneData*
ZonesModel::find( const std::function< double( const TimeZoneData* ) >& distanceFunc ) const
{
return CalamaresUtils::Locale::find( m_private->m_zones, distanceFunc );
const auto* officialZone = CalamaresUtils::Locale::find( 1000000.0, m_private->m_zones, distanceFunc );
const auto* altZone = CalamaresUtils::Locale::find( distanceFunc( officialZone ), m_private->m_altZones, distanceFunc );
// If nothing was closer than the official zone already was, altZone is
// nullptr; but if there is a spot-patch, then we need to re-find
// the zone by name, since we want to always return pointers into
// m_zones, not into the alternative spots.
return altZone ? find( altZone->region(), altZone->zone() ) : officialZone;
}
const TimeZoneData*