Doxy and new at() method

qgis · Jan 13, 2021 · a717bc7 · a717bc7
1 parent ea72ab9
commit a717bc7
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Showing 7 changed files with 81 additions and 7 deletions.
diff --git a/python/core/auto_generated/qgsabstractdatabaseproviderconnection.sip.in b/python/core/auto_generated/qgsabstractdatabaseproviderconnection.sip.in
@@ -60,7 +60,12 @@ Returns the column names
 
         QList<QList<QVariant> > rows() const;
 %Docstring
-Returns the results rows
+Returns the results rows by calling the iterator internally.
+
+.. note::
+
+   results are cached internally and subsequent calls to this method
+   will return the cached results.
 %End
 
         qlonglong rowCount() const;
@@ -82,6 +87,15 @@ Returns ``True`` if there are more rows to fetch
 Returns the next result row or an empty row if there are no rows left
 %End
 
+        QList<QVariant> at( qlonglong index ) const;
+%Docstring
+Returns the row data at 0-based index ``index``, if index is not valid, an empty list is returned.
+
+.. note::
+
+   this method calls the iterator internally until ``index`` row is retrieved
+%End
+
         QueryResult *__iter__();
 %MethodCode
         sipRes = sipCpp;

diff --git a/python/core/auto_generated/qgsqueryresultmodel.sip.in b/python/core/auto_generated/qgsqueryresultmodel.sip.in
@@ -23,6 +23,9 @@ The QgsQueryResultModel class is a model for QgsAbstractDatabaseProviderConnecti
   public:
 
     QgsQueryResultModel( const QgsAbstractDatabaseProviderConnection::QueryResult &queryResult, QObject *parent = 0 );
+%Docstring
+Constructs a QgsQueryResultModel from a ``queryResult`` with optional ``parent``
+%End
 
   public:
 

diff --git a/src/core/qgsabstractdatabaseproviderconnection.cpp b/src/core/qgsabstractdatabaseproviderconnection.cpp
@@ -472,6 +472,32 @@ QList<QVariant> QgsAbstractDatabaseProviderConnection::QueryResult::nextRow()
   return row;
 }
 
+QList<QVariant> QgsAbstractDatabaseProviderConnection::QueryResult::at( qlonglong index ) const
+{
+  if ( index < 0 )
+    return QList<QVariant>();
+  // Fetch rows until the index
+  if ( index > mRows.count( ) )
+  {
+    while ( mResultIterator && ( mRowCount < 0 || mRows.count() < mRowCount ) && index < mRows.count() )
+    {
+      const QVariantList row { mResultIterator->nextRow() };
+      if ( row.isEmpty() )
+      {
+        break;
+      }
+      mRows.push_back( row );
+    }
+  }
+
+  if ( index >= mRows.count( ) )
+  {
+    return QList<QVariant>();
+  }
+
+  return mRows.at( index );
+}
+
 
 qlonglong QgsAbstractDatabaseProviderConnection::QueryResult::rowCount() const
 {

diff --git a/src/core/qgsabstractdatabaseproviderconnection.h b/src/core/qgsabstractdatabaseproviderconnection.h
@@ -73,6 +73,12 @@ class CORE_EXPORT QgsAbstractDatabaseProviderConnection : public QgsAbstractProv
      * It encapsulates the result rows and a list of the column names.
      * The query result may be empty in case the query returns nothing.
      *
+     * Rows can be retrieved by iterating over the result with hasNextRow() and nextRow()
+     * or by calling rows() that will internally iterate over the results and return
+     * the result list.
+     *
+     * The list of results is cached internally and subsequent calls to rows() or at() return the
+     * cached results.
      *
      * \since QGIS 3.18
      */
@@ -92,7 +98,9 @@ class CORE_EXPORT QgsAbstractDatabaseProviderConnection : public QgsAbstractProv
         QStringList columns() const;
 
         /**
-         * Returns the results rows
+         * Returns the results rows by calling the iterator internally.
+         * \note results are cached internally and subsequent calls to this method
+         * will return the cached results.
          */
         QList<QList<QVariant> > rows() const;
 
@@ -112,6 +120,12 @@ class CORE_EXPORT QgsAbstractDatabaseProviderConnection : public QgsAbstractProv
          */
         QList<QVariant> nextRow();
 
+        /**
+         * Returns the row data at 0-based index \a index, if index is not valid, an empty list is returned.
+         * \note this method calls the iterator internally until \a index row is retrieved
+         */
+        QList<QVariant> at( qlonglong index ) const;
+
 #ifdef SIP_RUN
         QueryResult *__iter__();
         % MethodCode

diff --git a/src/core/qgsqueryresultmodel.cpp b/src/core/qgsqueryresultmodel.cpp
@@ -39,17 +39,19 @@ int QgsQueryResultModel::columnCount( const QModelIndex &parent ) const
 
 QVariant QgsQueryResultModel::data( const QModelIndex &index, int role ) const
 {
-  if ( !index.isValid() )
+  if ( !index.isValid() || index.row() < 0 || index.column() > mQueryResult.columns().count() - 1 )
     return QVariant();
 
-  Q_ASSERT( mQueryResult.rows().count( ) == mRowCount );
-
   if ( index.row() >= mRowCount || index.row() < 0 )
     return QVariant();
 
   if ( role == Qt::DisplayRole )
   {
-    return mQueryResult.rows().at( index.row() );
+    const QList<QVariant> result { mQueryResult.at( index.row() ) };
+    if ( index.column() < result.count( ) )
+    {
+      return result.at( index.column() );
+    }
   }
   return QVariant();
 }

diff --git a/src/core/qgsqueryresultmodel.h b/src/core/qgsqueryresultmodel.h
@@ -34,6 +34,9 @@ class CORE_EXPORT QgsQueryResultModel : public QAbstractListModel
     Q_OBJECT
   public:
 
+    /**
+     * Constructs a QgsQueryResultModel from a \a queryResult with optional \a parent
+     */
     QgsQueryResultModel( const QgsAbstractDatabaseProviderConnection::QueryResult &queryResult, QObject *parent = nullptr );
 
     // QAbstractItemModel interface

diff --git a/tests/src/python/test_qgsqueryresultmodel.py b/tests/src/python/test_qgsqueryresultmodel.py
@@ -20,7 +20,7 @@
     QgsAbstractDatabaseProviderConnection,
 )
 from qgis.testing import unittest, start_app
-from qgis.PyQt.QtCore import QCoreApplication
+from qgis.PyQt.QtCore import QCoreApplication, QVariant, Qt
 
 
 class TestPyQgsQgsQueryResultModel(unittest.TestCase):
@@ -49,10 +49,15 @@ def test_model(self):
         self.assertEqual(model.rowCount(model.index(-1)), 0)
         self.assertTrue(model.canFetchMore(model.index(-1)))
 
+        self.assertEqual(model.data(model.index(0, 0), Qt.DisplayRole), QVariant())
+        self.assertEqual(model.data(model.index(999, 0), Qt.DisplayRole), QVariant())
+
         model.fetchMore(model.index(-1))
         self.assertEqual(model.rowCount(model.index(-1)), 200)
         self.assertTrue(res.hasNextRow())
 
+        self.assertEqual(model.data(model.index(0, 0), Qt.DisplayRole), 1)
+
         # Fetch the rest
         for batch in range(2, 6):
             model.fetchMore(model.index(-1))
@@ -62,6 +67,13 @@ def test_model(self):
         self.assertFalse(res.hasNextRow())
         self.assertFalse(model.canFetchMore(model.index(-1)))
 
+        # Test data
+        for i in range(1000):
+            self.assertEqual(model.data(model.index(i, 0), Qt.DisplayRole), i + 1)
+
+        self.assertEqual(model.data(model.index(1000, 0), Qt.DisplayRole), QVariant())
+        self.assertEqual(model.data(model.index(1, 1), Qt.DisplayRole), QVariant())
+
 
 if __name__ == '__main__':
     unittest.main()