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Merge pull request #3597 from rouault/saveas_overwrite_append

[FEATURE] Vector layer save as: offer file/layer overwriting, new layer creation, feature and field appending
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rouault committed Oct 17, 2016
2 parents 03f08a6 + 34894c6 commit da0ee8b007f742f14dcbf40d930157c2a47379ff
@@ -132,6 +132,43 @@ class QgsVectorFileWriter
virtual QVariant convert( int fieldIdxInLayer, const QVariant& value );
};

/** Edition capability flags
* @note Added in QGIS 3.0 */
enum EditionCapability
{
/** Flag to indicate that a new layer can be added to the dataset */
CanAddNewLayer,

/** Flag to indicate that new features can be added to an existing layer */
CanAppendToExistingLayer ,

/** Flag to indicate that new fields can be added to an existing layer. Imply CanAppendToExistingLayer */
CanAddNewFieldsToExistingLayer,

/** Flag to indicate that an existing layer can be deleted */
CanDeleteLayer
};

typedef QFlags<QgsVectorFileWriter::EditionCapability> EditionCapabilities;

/** Enumeration to describe how to handle existing files
@note Added in QGIS 3.0
*/
enum ActionOnExistingFile
{
/** Create or overwrite file */
CreateOrOverwriteFile,

/** Create or overwrite layer */
CreateOrOverwriteLayer,

/** Append features to existing layer, but do not create new fields */
AppendToLayerNoNewFields,

/** Append features to existing layer, and create new fields if needed */
AppendToLayerAddFields
};

/** Write contents of vector layer to an (OGR supported) vector formt
* @param layer layer to write
* @param fileName file name to write to
@@ -220,6 +257,88 @@ class QgsVectorFileWriter
FieldValueConverter* fieldValueConverter = nullptr
);


/**
* Options to pass to writeAsVectorFormat()
* @note Added in QGIS 3.0
*/
class SaveVectorOptions
{
public:
/** Constructor */
SaveVectorOptions();

/** Destructor */
virtual ~SaveVectorOptions();

/** OGR driver to use */
QString driverName;

/** Layer name. If let empty, it will be derived from the filename */
QString layerName;

/** Action on existing file */
QgsVectorFileWriter::ActionOnExistingFile actionOnExistingFile;

/** Encoding to use */
QString fileEncoding;

/** Transform to reproject exported geometries with, or invalid transform
* for no transformation */
QgsCoordinateTransform ct;

/** Write only selected features of layer */
bool onlySelectedFeatures;

/** List of OGR data source creation options */
QStringList datasourceOptions;

/** List of OGR layer creation options */
QStringList layerOptions;

/** Only write geometries */
bool skipAttributeCreation;

/** Attributes to export (empty means all unless skipAttributeCreation is set) */
QgsAttributeList attributes;

/** Symbology to export */
QgsVectorFileWriter::SymbologyExport symbologyExport;

/** Scale of symbology */
double symbologyScale;

/** If not empty, only features intersecting the extent will be saved */
QgsRectangle filterExtent;

/** Set to a valid geometry type to override the default geometry type for the layer. This parameter
* allows for conversion of geometryless tables to null geometries, etc */
QgsWkbTypes::Type overrideGeometryType;

/** Set to true to force creation of multi* geometries */
bool forceMulti;

/** Set to true to include z dimension in output. This option is only valid if overrideGeometryType is set */
bool includeZ;

/** Field value converter */
QgsVectorFileWriter::FieldValueConverter* fieldValueConverter;
};

/** Writes a layer out to a vector file.
* @param layer source layer to write
* @param fileName file name to write to
* @param options options.
* @param newFilename QString pointer which will contain the new file name created (in case it is different to fileName).
* @param errorMessage pointer to buffer fo error message
* @note added in 3.0
*/
static WriterError writeAsVectorFormat( QgsVectorLayer* layer,
const QString& fileName,
const SaveVectorOptions& options,
QString *newFilename = nullptr,
QString *errorMessage = nullptr );

/** Create a new vector file writer */
QgsVectorFileWriter( const QString& vectorFileName,
const QString& fileEncoding,
@@ -294,6 +413,27 @@ class QgsVectorFileWriter
*/
static QStringList defaultLayerOptions( const QString& driverName );

/**
* Return edition capabilites for an existing dataset name.
* @note added in QGIS 3.0
*/
static EditionCapabilities editionCapabilities( const QString& datasetName );

/**
* Returns whether the target layer already exists.
* @note added in QGIS 3.0
*/
static bool targetLayerExists( const QString& datasetName,
const QString& layerName );

/**
* Returns whether there are among the attributes specified some that do not exist yet in the layer
* @note added in QGIS 3.0
*/
static bool areThereNewFieldsToCreate( const QString& datasetName,
const QString& layerName,
QgsVectorLayer* layer,
const QgsAttributeList& attributes );
protected:
//! @note not available in python bindings
// OGRGeometryH createEmptyGeometry( QgsWkbTypes::Type wkbType );
@@ -302,3 +442,5 @@ class QgsVectorFileWriter

QgsVectorFileWriter( const QgsVectorFileWriter& rh );
};

QFlags<QgsVectorFileWriter::EditionCapability> operator|(QgsVectorFileWriter::EditionCapability f1, QFlags<QgsVectorFileWriter::EditionCapability> f2);

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