Merge pull request #32551 from rduivenvoorde/from_epoch

[FEATURE] Add datetime_from_epoch (MSec from epoch) expression function
qgis · Nov 22, 2019 · 63911c1 · 63911c1
2 parents baf3819 + 564f9fb
commit 63911c1
Show file tree

Hide file tree

Showing 3 changed files with 18 additions and 0 deletions.
diff --git a/resources/function_help/json/from_epoch b/resources/function_help/json/from_epoch
@@ -0,0 +1,7 @@
+{
+  "name": "datetime_from_epoch",
+  "type": "function",
+  "description": "Returns a datetime whose date and time are the number of milliseconds, msecs, that have passed since 1970-01-01T00:00:00.000, Coordinated Universal Time (Qt.UTC), and converted to Qt.LocalTime.",
+  "arguments": [ {"arg":"int","description":"number (milliseconds)"} ],
+  "examples": [ { "expression":"datetime_from_epoch(1483225200000)", "returns":"2017-01-01T00:00:00"} ]
+}
diff --git a/src/core/expression/qgsexpressionfunction.cpp b/src/core/expression/qgsexpressionfunction.cpp
@@ -2012,6 +2012,13 @@ static QVariant fcnEpoch( const QVariantList &values, const QgsExpressionContext
   }
 }
 
+static QVariant fcnDateTimeFromEpoch( const QVariantList &values, const QgsExpressionContext *, QgsExpression *parent, const QgsExpressionNodeFunction * )
+{
+  long long millisecs_since_epoch = QgsExpressionUtils::getIntValue( values.at( 0 ), parent );
+  // no sense to check for strange values, as Qt behavior is undefined anyway (see docs)
+  return QVariant( QDateTime::fromMSecsSinceEpoch( millisecs_since_epoch ) );
+}
+
 #define ENSURE_GEOM_TYPE(f, g, geomtype) \
   if ( !(f).hasGeometry() ) \
     return QVariant(); \
@@ -5354,6 +5361,7 @@ const QList<QgsExpressionFunction *> &QgsExpression::Functions()
         << new QgsStaticExpressionFunction( QStringLiteral( "minute" ),  QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "datetime" ) ), fcnMinute, QStringLiteral( "Date and Time" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "second" ),  QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "datetime" ) ), fcnSeconds, QStringLiteral( "Date and Time" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "epoch" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "date" ) ), fcnEpoch, QStringLiteral( "Date and Time" ) )
+        << new QgsStaticExpressionFunction( QStringLiteral( "datetime_from_epoch" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "long" ) ), fcnDateTimeFromEpoch, QStringLiteral( "Date and Time" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "day_of_week" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "date" ) ), fcnDayOfWeek, QStringLiteral( "Date and Time" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "lower" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ), fcnLower, QStringLiteral( "String" ) )
         << new QgsStaticExpressionFunction( QStringLiteral( "upper" ), QgsExpressionFunction::ParameterList() << QgsExpressionFunction::Parameter( QStringLiteral( "string" ) ), fcnUpper, QStringLiteral( "String" ) )

diff --git a/tests/src/core/testqgsexpression.cpp b/tests/src/core/testqgsexpression.cpp
@@ -1293,6 +1293,9 @@ class TestQgsExpression: public QObject
       QTest::newRow( "time - time" ) << "to_time('08:30:00') - to_time('05:15:00')" << false << QVariant( QgsInterval( 3 * 60 * 60 + 15 * 60 ) );
       QTest::newRow( "epoch" ) << "epoch(to_datetime('2017-01-01T00:00:01+00:00'))" << false << QVariant( 1483228801000LL );
       QTest::newRow( "epoch invalid date" ) << "epoch('invalid')" << true << QVariant();
+      // datetime_from_epoch will always return a local datetime, so here we create some circular magic to create a local datetime during test (so test can be ran in every timezone...)
+      QTest::newRow( "datetime_from_epoch" ) << "datetime_from_epoch(epoch(to_datetime('2017-01-01T00:00:01')))" << false << QVariant( QDateTime( QDate( 2017, 1, 1 ), QTime( 0, 0, 1 ), Qt::LocalTime ) );
+      QTest::newRow( "datetime_from_epoch_null" ) << "datetime_from_epoch(NULL)" << false <<  QVariant( QVariant::Invalid );
       QTest::newRow( "date from format" ) << "to_date('June 29, 2019','MMMM d, yyyy')" << false << QVariant( QDate( 2019, 6, 29 ) );
       QTest::newRow( "date from format and language" ) << "to_date('29 juin, 2019','d MMMM, yyyy','fr')" << false << QVariant( QDate( 2019, 6, 29 ) );
       QTest::newRow( "date from format, wrong string" ) << "to_date('wrong.string.here','yyyy.MM.dd')" << true << QVariant();