Merge pull request #40750 from elpaso/connections-api-queryresult-model

QgsQueryResultModel
qgis · Jan 14, 2021 · a0d847f · a0d847f
2 parents 4b9f82d + dbef0ea
commit a0d847f
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Showing 21 changed files with 631 additions and 125 deletions.
diff --git a/python/core/auto_generated/qgsabstractdatabaseproviderconnection.sip.in b/python/core/auto_generated/qgsabstractdatabaseproviderconnection.sip.in
@@ -47,41 +47,50 @@ is not supported or cannot be performed without errors.
 
     struct QueryResult
     {
-        SIP_PYOBJECT __repr__();
-%MethodCode
-        QString str = QStringLiteral( "<QgsAbstractDatabaseProviderConnection.QueryResult: %1 rows>" ).arg( sipCpp->rowCount() );
-        sipRes = PyUnicode_FromString( str.toUtf8().constData() );
-%End
 
         QStringList columns() const;
 %Docstring
 Returns the column names
 %End
 
-        QList<QList<QVariant> > rows() const;
+        QList<QList<QVariant> > rows( QgsFeedback *feedback = 0 );
 %Docstring
-Returns the results rows
-%End
-
-        qlonglong rowCount() const;
-%Docstring
-Returns the row count
+Returns the result rows by calling the iterator internally and fetching
+all the rows, an optional ``feedback`` can be used to interrupt the fetching loop.
 
 .. note::
 
-   the value may not be exact or it may be -1 if not known
+   calling this function more than one time is not supported: the second
+   call will always return an empty list.
 %End
 
         bool hasNextRow() const;
 %Docstring
 Returns ``True`` if there are more rows to fetch
+
+.. seealso:: :py:func:`nextRow`
+
+.. seealso:: :py:func:`rewind`
 %End
 
-        QList<QVariant> nextRow();
+        QList<QVariant> nextRow() const;
 %Docstring
 Returns the next result row or an empty row if there are no rows left
+
+.. seealso:: :py:func:`hasNextRow`
+
+.. seealso:: :py:func:`rewind`
+%End
+
+        qlonglong fetchedRowCount( ) const;
+%Docstring
+Returns the number of fetched rows
+
+.. seealso:: :py:func:`rowCount`
 %End
 
+
+        // Python iterator
         QueryResult *__iter__();
 %MethodCode
         sipRes = sipCpp;
@@ -110,7 +119,6 @@ Returns the next result row or an empty row if there are no rows left
 
 
 
-
     };
 
 

diff --git a/python/core/auto_generated/qgsqueryresultmodel.sip.in b/python/core/auto_generated/qgsqueryresultmodel.sip.in
@@ -0,0 +1,60 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsqueryresultmodel.h                                       *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+
+
+
+class QgsQueryResultModel : QAbstractListModel
+{
+%Docstring
+The QgsQueryResultModel class is a model for QgsAbstractDatabaseProviderConnection.QueryResult
+
+.. versionadded:: 3.18
+%End
+
+%TypeHeaderCode
+#include "qgsqueryresultmodel.h"
+%End
+  public:
+
+    QgsQueryResultModel( const QgsAbstractDatabaseProviderConnection::QueryResult &queryResult, QObject *parent = 0 );
+%Docstring
+Constructs a QgsQueryResultModel from a ``queryResult`` with optional ``parent``
+%End
+
+    ~QgsQueryResultModel();
+
+  public:
+
+    virtual int rowCount( const QModelIndex &parent ) const;
+
+    virtual int columnCount( const QModelIndex &parent ) const;
+
+    virtual QVariant data( const QModelIndex &index, int role ) const;
+
+
+  public slots:
+
+    void rowsReady( const QList<QList<QVariant> > &rows );
+%Docstring
+Triggered when ``newRows`` have been fetched and can be added to the model
+%End
+
+};
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/qgsqueryresultmodel.h                                       *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
diff --git a/python/core/core_auto.sip b/python/core/core_auto.sip
@@ -156,6 +156,7 @@
 %Include auto_generated/qgsproxyfeaturesink.sip
 %Include auto_generated/qgsproxyprogresstask.sip
 %Include auto_generated/qgspythonrunner.sip
+%Include auto_generated/qgsqueryresultmodel.sip
 %Include auto_generated/qgsrange.sip
 %Include auto_generated/qgsreadwritecontext.sip
 %Include auto_generated/qgsreadwritelocker.sip

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -397,6 +397,7 @@ set(QGIS_CORE_SRCS
   qgspointxy.cpp
   qgspointlocator.cpp
   qgspointlocatorinittask.cpp
+  qgsqueryresultmodel.cpp
   qgssnappingconfig.cpp
   qgsprojutils.cpp
   qgsproperty.cpp
@@ -1004,6 +1005,7 @@ set(QGIS_CORE_HDRS
   qgsproxyfeaturesink.h
   qgsproxyprogresstask.h
   qgspythonrunner.h
+  qgsqueryresultmodel.h
   qgsrange.h
   qgsreadwritecontext.h
   qgsreadwritelocker.h

diff --git a/src/core/providers/ogr/qgsgeopackageproviderconnection.cpp b/src/core/providers/ogr/qgsgeopackageproviderconnection.cpp
@@ -380,10 +380,6 @@ QgsAbstractDatabaseProviderConnection::QueryResult QgsGeoPackageProviderConnecti
 
       auto iterator = std::make_shared<QgsGeoPackageProviderResultIterator>( std::move( hDS ), ogrLayer );
       QgsAbstractDatabaseProviderConnection::QueryResult results( iterator );
-      // Note: Returns the number of features in the layer. For dynamic databases the count may not be exact.
-      //       If bForce is FALSE, and it would be expensive to establish the feature count a value of -1 may
-      //       be returned indicating that the count isn’t know.
-      results.setRowCount( OGR_L_GetFeatureCount( ogrLayer, 0 /* bForce=false: do not scan the whole layer */ ) );
 
       gdal::ogr_feature_unique_ptr fet;
       if ( fet.reset( OGR_L_GetNextFeature( ogrLayer ) ), fet )
@@ -425,14 +421,14 @@ QgsAbstractDatabaseProviderConnection::QueryResult QgsGeoPackageProviderConnecti
   return QgsAbstractDatabaseProviderConnection::QueryResult();
 }
 
-QVariantList QgsGeoPackageProviderResultIterator::nextRow()
+QVariantList QgsGeoPackageProviderResultIterator::nextRowPrivate()
 {
   const QVariantList currentRow { mNextRow };
-  mNextRow = nextRowPrivate();
+  mNextRow = nextRowInternal();
   return currentRow;
 }
 
-QVariantList QgsGeoPackageProviderResultIterator::nextRowPrivate()
+QVariantList QgsGeoPackageProviderResultIterator::nextRowInternal()
 {
   QVariantList row;
   if ( mHDS && mOgrLayer )
@@ -457,11 +453,17 @@ QVariantList QgsGeoPackageProviderResultIterator::nextRowPrivate()
         }
       }
     }
+    else
+    {
+      // Release the resources
+      GDALDatasetReleaseResultSet( mHDS.get(), mOgrLayer );
+      mHDS.release();
+    }
   }
   return row;
 }
 
-bool QgsGeoPackageProviderResultIterator::hasNextRow() const
+bool QgsGeoPackageProviderResultIterator::hasNextRowPrivate() const
 {
   return ! mNextRow.isEmpty();
 }
@@ -488,5 +490,8 @@ QList<QgsVectorDataProvider::NativeType> QgsGeoPackageProviderConnection::native
 
 QgsGeoPackageProviderResultIterator::~QgsGeoPackageProviderResultIterator()
 {
-  GDALDatasetReleaseResultSet( mHDS.get(), mOgrLayer );
+  if ( mHDS )
+  {
+    GDALDatasetReleaseResultSet( mHDS.get(), mOgrLayer );
+  }
 }
diff --git a/src/core/providers/ogr/qgsgeopackageproviderconnection.h b/src/core/providers/ogr/qgsgeopackageproviderconnection.h
@@ -34,9 +34,6 @@ struct QgsGeoPackageProviderResultIterator: public QgsAbstractDatabaseProviderCo
 
     ~QgsGeoPackageProviderResultIterator();
 
-    QVariantList nextRow() override;
-    bool hasNextRow() const override;
-
     void setFields( const QgsFields &fields );
 
   private:
@@ -46,7 +43,9 @@ struct QgsGeoPackageProviderResultIterator: public QgsAbstractDatabaseProviderCo
     QgsFields mFields;
     QVariantList mNextRow;
 
-    QVariantList nextRowPrivate();
+    QVariantList nextRowPrivate() override;
+    QVariantList nextRowInternal();
+    bool hasNextRowPrivate() const override;
 
 };
 

diff --git a/src/core/qgsabstractdatabaseproviderconnection.cpp b/src/core/qgsabstractdatabaseproviderconnection.cpp
@@ -17,6 +17,8 @@
 #include "qgsvectorlayer.h"
 #include "qgsexception.h"
 #include "qgslogger.h"
+#include "qgsfeedback.h"
+
 #include <QVariant>
 #include <QObject>
 
@@ -435,49 +437,55 @@ void QgsAbstractDatabaseProviderConnection::TableProperty::setSchema( const QStr
 }
 
 
+///@cond PRIVATE
+
 QStringList QgsAbstractDatabaseProviderConnection::QueryResult::columns() const
 {
   return mColumns;
 }
 
-QList<QList<QVariant> > QgsAbstractDatabaseProviderConnection::QueryResult::rows() const
+QList<QList<QVariant> > QgsAbstractDatabaseProviderConnection::QueryResult::rows( QgsFeedback *feedback )
 {
-  // mRowCount might be -1 (unknown)
-  while ( mResultIterator && ( mRowCount < 0 || mRows.count() < mRowCount ) )
+
+  QList<QList<QVariant> > rows;
+
+  while ( mResultIterator &&
+          mResultIterator->hasNextRow() &&
+          ( ! feedback || ! feedback->isCanceled() ) )
   {
     const QVariantList row( mResultIterator->nextRow() );
     if ( row.isEmpty() )
     {
       break;
     }
-    mRows.push_back( row );
+    else
+    {
+      rows.push_back( row );
+    }
   }
-  return mRows;
+  return rows;
 }
 
-QList<QVariant> QgsAbstractDatabaseProviderConnection::QueryResult::nextRow()
+QList<QVariant> QgsAbstractDatabaseProviderConnection::QueryResult::nextRow() const
 {
-  if ( ! mResultIterator && ! mResultIterator->hasNextRow() )
+  if ( ! mResultIterator )
   {
     return QList<QVariant>();
   }
+  return mResultIterator->nextRow();
+}
 
-  const QList<QVariant> row( mResultIterator->nextRow() );
 
-  if ( ! row.isEmpty() )
+qlonglong QgsAbstractDatabaseProviderConnection::QueryResult::fetchedRowCount() const
+{
+  if ( ! mResultIterator )
   {
-    mRows.push_back( row );
+    return 0;
   }
-
-  return row;
+  return mResultIterator->fetchedRowCount();
 }
 
 
-qlonglong QgsAbstractDatabaseProviderConnection::QueryResult::rowCount() const
-{
-  return mRowCount;
-}
-
 bool QgsAbstractDatabaseProviderConnection::QueryResult::hasNextRow() const
 {
   if ( ! mResultIterator )
@@ -487,20 +495,39 @@ bool QgsAbstractDatabaseProviderConnection::QueryResult::hasNextRow() const
   return mResultIterator->hasNextRow();
 }
 
-///@cond PRIVATE
-
 void QgsAbstractDatabaseProviderConnection::QueryResult::appendColumn( const QString &columnName )
 {
   mColumns.push_back( columnName );
 }
 
-void QgsAbstractDatabaseProviderConnection::QueryResult::setRowCount( const qlonglong &rowCount )
-{
-  mRowCount = rowCount;
-}
 
 QgsAbstractDatabaseProviderConnection::QueryResult::QueryResult( std::shared_ptr<QgsAbstractDatabaseProviderConnection::QueryResult::QueryResultIterator> iterator )
   : mResultIterator( iterator )
 {}
 
+
+QVariantList QgsAbstractDatabaseProviderConnection::QueryResult::QueryResultIterator::nextRow()
+{
+  QMutexLocker lock( &mMutex );
+  const QVariantList row { nextRowPrivate() };
+  if ( ! row.isEmpty() )
+  {
+    mFetchedRowCount++;
+  }
+  return row;
+}
+
+bool QgsAbstractDatabaseProviderConnection::QueryResult::QueryResultIterator::hasNextRow() const
+{
+  QMutexLocker lock( &mMutex );
+  return hasNextRowPrivate();
+}
+
+qlonglong QgsAbstractDatabaseProviderConnection::QueryResult::QueryResultIterator::fetchedRowCount()
+{
+  QMutexLocker lock( &mMutex );
+  return mFetchedRowCount;
+}
+
+
 ///@endcond private