QGIS/python/plugins/db_manager/db_plugins/vlayers/plugin.py

# -*- coding: utf-8 -*-

"""
/***************************************************************************
Name                 : DB Manager plugin for virtual layers
Date                 : December 2015
copyright            : (C) 2015 by Hugo Mercier
email                : hugo dot mercier at oslandia dot 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.                                   *
 *                                                                         *
 ***************************************************************************/
"""

# this will disable the dbplugin if the connector raise an ImportError
from .connector import VLayerConnector

from qgis.PyQt.QtGui import QIcon
from qgis.core import QgsVectorLayer, QgsProject, QgsVirtualLayerDefinition

from ..plugin import DBPlugin, Database, Table, VectorTable, TableField

from . import resources_rc  # NOQA


def classFactory():
    return VLayerDBPlugin


class VLayerDBPlugin(DBPlugin):

    @classmethod
    def icon(self):
        return QIcon(":/db_manager/vlayers/icon")

    @classmethod
    def typeName(self):
        return 'vlayers'

    @classmethod
    def typeNameString(self):
        return 'Virtual Layers'

    @classmethod
    def providerName(self):
        return 'virtual'

    @classmethod
    def connectionSettingsKey(self):
        return 'vlayers'

    @classmethod
    def connections(self):
        return [VLayerDBPlugin('QGIS layers')]

    def databasesFactory(self, connection, uri):
        return FakeDatabase(connection, uri)

    def database(self):
        return self.db

    # def info( self ):

    def connect(self, parent=None):
        self.connectToUri("qgis")
        return True


class FakeDatabase(Database):

    def __init__(self, connection, uri):
        Database.__init__(self, connection, uri)

    def connectorsFactory(self, uri):
        return VLayerConnector(uri)

    def dataTablesFactory(self, row, db, schema=None):
        return LTable(row, db, schema)

    def vectorTablesFactory(self, row, db, schema=None):
        return LVectorTable(row, db, schema)

    def rasterTablesFactory(self, row, db, schema=None):
        return None

    def info(self):
        from .info_model import LDatabaseInfo
        return LDatabaseInfo(self)

    def sqlResultModel(self, sql, parent):
        from .data_model import LSqlResultModel
        return LSqlResultModel(self, sql, parent)

    def toSqlLayer(self, sql, geomCol, uniqueCol, layerName="QueryLayer", layerType=None, avoidSelectById=False, _filter=""):
        df = QgsVirtualLayerDefinition()
        df.setQuery(sql)
        if uniqueCol is not None:
            uniqueCol = uniqueCol.strip('"').replace('""', '"')
            df.setUid(uniqueCol)
        if geomCol is not None:
            df.setGeometryField(geomCol)
        vl = QgsVectorLayer(df.toString(), layerName, "virtual")
        if _filter:
            vl.setSubsetString(_filter)
        return vl

    def registerDatabaseActions(self, mainWindow):
        return

    def runAction(self, action):
        return

    def uniqueIdFunction(self):
        return None

    def explicitSpatialIndex(self):
        return True

    def spatialIndexClause(self, src_table, src_column, dest_table, dest_column):
        return '"%s"._search_frame_ = "%s"."%s"' % (src_table, dest_table, dest_column)


class LTable(Table):

    def __init__(self, row, db, schema=None):
        Table.__init__(self, db, None)
        self.name, self.isView, self.isSysTable = row

    def tableFieldsFactory(self, row, table):
        return LTableField(row, table)

    def tableDataModel(self, parent):
        from .data_model import LTableDataModel
        return LTableDataModel(self, parent)

    def canBeAddedToCanvas(self):
        return False


class LVectorTable(LTable, VectorTable):

    def __init__(self, row, db, schema=None):
        LTable.__init__(self, row[:-5], db, schema)
        VectorTable.__init__(self, db, schema)
        # SpatiaLite does case-insensitive checks for table names, but the
        # SL provider didn't do the same in Qgis < 1.9, so self.geomTableName
        # stores the table name like stored in the geometry_columns table
        self.geomTableName, self.geomColumn, self.geomType, self.geomDim, self.srid = row[
            -5:]

    def uri(self):
        uri = self.database().uri()
        uri.setDataSource('', self.geomTableName, self.geomColumn)
        return uri

    def hasSpatialIndex(self, geom_column=None):
        return True

    def createSpatialIndex(self, geom_column=None):
        return

    def deleteSpatialIndex(self, geom_column=None):
        return

    def refreshTableEstimatedExtent(self):
        self.extent = self.database().connector.getTableExtent(
            ("id", self.geomTableName), None)

    def runAction(self, action):
        return

    def toMapLayer(self):
        return QgsProject.instance().mapLayer(self.geomTableName)


class LTableField(TableField):

    def __init__(self, row, table):
        TableField.__init__(self, table)
        self.num, self.name, self.dataType, self.notNull, self.default, self.primaryKey = row
        self.hasDefault = self.default