qgsdelimitedtextprovider.h

/***************************************************************************
      qgsdelimitedtextprovider.h  -  Data provider for delimited text
                             -------------------
    begin                : 2004-02-27
    copyright            : (C) 2004 by Gary E.Sherman
    email                : sherman at mrcc.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef QGSDELIMITEDTEXTPROVIDER_H
#define QGSDELIMITEDTEXTPROVIDER_H

#include "qgsvectordataprovider.h"
#include "qgscoordinatereferencesystem.h"
#include "qgsdelimitedtextfile.h"

#include <QStringList>

class QgsFeature;
class QgsField;
class QgsGeometry;
class QgsPoint;
class QFile;
class QTextStream;

class QgsDelimitedTextFeatureIterator;
class QgsExpression;
class QgsSpatialIndex;

/**
\class QgsDelimitedTextProvider
\brief Data provider for delimited text files.
*
* The provider needs to know both the path to the text file and
* the delimiter to use. Since the means to add a layer is fairly
* rigid, we must provide this information encoded in a form that
* the provider can decipher and use.
*
* The uri must defines the file path and the parameters used to
* interpret the contents of the file.
*
* Example uri = "/home/foo/delim.txt?delimiter=|"*
*
* For detailed information on the uri format see the QGSVectorLayer
* documentation.  Note that the interpretation of the URI is split
* between QgsDelimitedTextFile and QgsDelimitedTextProvider.
*

*/
class QgsDelimitedTextProvider : public QgsVectorDataProvider
{
    Q_OBJECT

  public:

    /**
     * Regular expression defining possible prefixes to WKT string,
     * (EWKT srid, Informix SRID)
      */
    static QRegExp WktPrefixRegexp;
    static QRegExp CrdDmsRegexp;

    enum GeomRepresentationType
    {
      GeomNone,
      GeomAsXy,
      GeomAsWkt
    };

    QgsDelimitedTextProvider( QString uri = QString() );

    virtual ~QgsDelimitedTextProvider();

    /* Implementation of functions from QgsVectorDataProvider */

    /**
     * Returns the permanent storage type for this layer as a friendly name.
     */
    virtual QString storageType() const;

    virtual QgsFeatureIterator getFeatures( const QgsFeatureRequest& request );

    /**
     * Get feature type.
     * @return int representing the feature type
     */
    virtual QGis::WkbType geometryType() const;

    /**
     * Number of features in the layer
     * @return long containing number of features
     */
    virtual long featureCount() const;

    /**
     * Return a map of indexes with field names for this layer
     * @return map of fields
     */
    virtual const QgsFields & fields() const;

    /** Returns a bitmask containing the supported capabilities
        Note, some capabilities may change depending on whether
        a spatial filter is active on this provider, so it may
        be prudent to check this value per intended operation.
     */
    virtual int capabilities() const;

    /** Creates a spatial index on the data
     *  @return indexCreated  Returns true if a spatial index is created
     */
    virtual bool createSpatialIndex();

    /* Implementation of functions from QgsDataProvider */

    /** return a provider name

        Essentially just returns the provider key.  Should be used to build file
        dialogs so that providers can be shown with their supported types. Thus
        if more than one provider supports a given format, the user is able to
        select a specific provider to open that file.

        @note

        Instead of being pure virtual, might be better to generalize this
        behavior and presume that none of the sub-classes are going to do
        anything strange with regards to their name or description?
     */
    QString name() const;

    /** return description

        Return a terse string describing what the provider is.

        @note

        Instead of being pure virtual, might be better to generalize this
        behavior and presume that none of the sub-classes are going to do
        anything strange with regards to their name or description?
     */
    QString description() const;

    /**
     * Return the extent for this data layer
     */
    virtual QgsRectangle extent();

    /**
     * Returns true if this is a valid delimited file
     */
    bool isValid();

    virtual QgsCoordinateReferenceSystem crs();
    /**
     * Set the subset string used to create a subset of features in
     * the layer.
     */
    virtual bool setSubsetString( QString subset, bool updateFeatureCount = true );

    /**
     * provider supports setting of subset strings

     */
    virtual bool supportsSubsetString() { return true; }

    /**
     * Returns the subset definition string (typically sql) currently in
     * use by the layer and used by the provider to limit the feature set.
     * Must be overridden in the dataprovider, otherwise returns a null
     * QString.
     */
    virtual QString subsetString()
    {
      return mSubsetString;
    }
    /* new functions */

    /**
     * Check to see if the point is withn the selection
     * rectangle
     * @param x X value of point
     * @param y Y value of point
     * @return True if point is within the rectangle
    */
    bool boundsCheck( double x, double y );


    /**
     * Check to see if a geometry overlaps the selection
     * rectangle
     * @param geom geometry to test against bounds
     * @param y Y value of point
     * @return True if point is within the rectangle
    */
    bool boundsCheck( QgsGeometry *geom );

    /**
     * Try to read field types from CSVT (or equialent xxxT) file.
     * @param filename The name of the file from which to read the field types
     * @param message  Pointer to a string to receive a status message
     * @return A list of field type strings, empty if not found or not valid
     */
    QStringList readCsvtFieldTypes( QString filename, QString *message = 0 );

  private slots:

    void onFileUpdated();

  private:

    static QRegExp WktZMRegexp;
    static QRegExp WktCrdRegexp;

    void scanFile( bool buildIndexes );
    void rescanFile();
    void resetCachedSubset();
    void resetIndexes();
    void clearInvalidLines();
    void recordInvalidLine( QString message );
    void reportErrors( QStringList messages = QStringList(), bool showDialog = true );
    void resetStream();
    bool recordIsEmpty( QStringList &record );
    bool nextFeature( QgsFeature& feature, QgsDelimitedTextFile *file, QgsDelimitedTextFeatureIterator *iterator );
    QgsGeometry* loadGeometryWkt( const QStringList& tokens,  QgsDelimitedTextFeatureIterator *iterator );
    QgsGeometry* loadGeometryXY( const QStringList& tokens,  QgsDelimitedTextFeatureIterator *iterator );
    void fetchAttribute( QgsFeature& feature, int fieldIdx, const QStringList& tokens );
    void setUriParameter( QString parameter, QString value );
    bool setNextFeatureId( qint64 fid ) { return mFile->setNextRecordId(( long ) fid ); }


    QgsGeometry *geomFromWkt( QString &sWkt );
    bool pointFromXY( QString &sX, QString &sY, QgsPoint &point );
    double dmsStringToDouble( const QString &sX, bool *xOk );

    // mLayerValid defines whether the layer has been loaded as a valid layer
    bool mLayerValid;
    // mValid defines whether the layer is currently valid (may differ from
    // mLayerValid if the file has been rewritten)
    bool mValid;

    //! Text file
    QgsDelimitedTextFile *mFile;

    // Fields
    GeomRepresentationType mGeomRep;
    QList<int> attributeColumns;
    QgsFields attributeFields;

    int mFieldCount;  // Note: this includes field count for wkt field
    QString mWktFieldName;
    QString mXFieldName;
    QString mYFieldName;

    int mXFieldIndex;
    int mYFieldIndex;
    int mWktFieldIndex;

    // Handling of WKT types with .. Z, .. M, and .. ZM geometries (ie
    // Z values and/or measures).  mWktZMRegexp is used to test for and
    // remove the Z or M fields, and mWktCrdRegexp is used to remove the
    // extra coordinate values. mWktPrefix regexp is used to clean up
    // prefixes sometimes used for WKT (postgis EWKT, informix SRID)

    bool mWktHasZM;
    bool mWktHasPrefix;

    //! Layer extent
    QgsRectangle mExtent;

    int mGeomType;

    long mNumberFeatures;
    int mSkipLines;
    QString mDecimalPoint;
    bool mXyDms;

    QString mSubsetString;
    QString mCachedSubsetString;
    QgsExpression *mSubsetExpression;
    bool mBuildSubsetIndex;
    QList<quintptr> mSubsetIndex;
    bool mUseSubsetIndex;
    bool mCachedUseSubsetIndex;

    //! Storage for any lines in the file that couldn't be loaded
    int mMaxInvalidLines;
    int mNExtraInvalidLines;
    QStringList mInvalidLines;
    //! Only want to show the invalid lines once to the user
    bool mShowInvalidLines;

    struct wkbPoint
    {
      unsigned char byteOrder;
      quint32 wkbType;
      double x;
      double y;
    };
    wkbPoint mWKBpt;

    // Coordinate reference sytem
    QgsCoordinateReferenceSystem mCrs;

    QGis::WkbType mWkbType;
    QGis::GeometryType mGeometryType;

    // Spatial index
    bool mBuildSpatialIndex;
    bool mUseSpatialIndex;
    bool mCachedUseSpatialIndex;
    QgsSpatialIndex *mSpatialIndex;

    friend class QgsDelimitedTextFeatureIterator;
    QSet< QgsDelimitedTextFeatureIterator* > mActiveIterators;
};

#endif