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git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@2936 c8812cc2-4d05-0410-92ff-de0c093fc19c
128 lines
3.5 KiB
C++
128 lines
3.5 KiB
C++
/***************************************************************************
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qgspostgrescountthread.h - Multithreaded PostgreSQL layer count
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retrieval
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-------------------
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begin : Feb 1, 2005
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copyright : (C) 2005 by Brendan Morley
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email : morb at ozemail dot com dot au
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***************************************************************************/
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/***************************************************************************
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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***************************************************************************/
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/* $Id$ */
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#ifndef QGSPOSTGRESCOUNTTHREAD_H
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#define QGSPOSTGRESCOUNTTHREAD_H
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extern "C"
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{
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#include <libpq-fe.h>
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}
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#include <qthread.h>
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/*!
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* \brief A thread to retrieve the exact number of items in a PostgreSQL/PostGIS table.
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\author Brendan Morley
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\date March 2005
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This QThread is designed to take the parsed PostgreSQL connection parameters from
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a parent QgsPostgresProvider, and select the full PostgreSQL count(*) of the specified table.
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Upon completion, this thread expects to be able to post an event back to the parent
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QgsPostgresProvider. This parent should take this event as a notification that the
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exact count is now available for the parent to copy into whereever it keeps its
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layer count.
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The parent is also responsible for notifying any GUI items that use the count.
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Events are used instead of Qt signals/slots as events can be received asynchronously,
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which makes for better mutlithreading behaviour and less opportunity for programmer mishap.
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*/
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class QgsPostgresCountThread : public QThread
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{
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public:
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/*
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* BM
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* The idea behind this one is to retrieve the extents asynchronously
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*
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*/
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virtual void run();
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void setConnInfo( QString s );
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void setTableName( QString s );
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void setSqlWhereClause( QString s );
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void setGeometryColumn( QString s );
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// Feed this the object (e.g. Map Layer) for which you want to update the extents.
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//void setCallback( QgsPostgresProvider& o )
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void setCallback( QObject* o )
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{
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callbackObject = o;
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}
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// signals:
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// Presumably this reimplements the equivalent in QgsPostgresProvider > QgsVectorLayer
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/** This is used to send a request that any mapcanvas using this layer update its extents */
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// void recalculateExtents();
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private:
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/**
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* Connection pointer
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*/
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PGconn *connection;
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/**
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*
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*/
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QString connInfo;
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/**
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* Name of the table with no schema
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*/
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QString tableName;
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/**
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* SQL statement used to limit the features retreived
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*/
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QString sqlWhereClause;
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/**
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* Name of the geometry column in the table
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*/
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QString geometryColumn;
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/**
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* Pointer to the object to call back when the extents have been calculated.
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* It is a void pointer to avoid a circular reference back to QgsPostgresProvider
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*/
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QObject* callbackObject;
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/**
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* Integer that contains the row count (including non-geometry rows) of the layer
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*/
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long numberFeatures;
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};
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#endif
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