Create QgsPoolPostgresConn for RAII usage.

Wraps acquireConnection() and releaseConnection() from a QgsPostgresConnPool.

This can be used for creating std::shared_ptr<PoolPostgresConn>.

(cherry picked from commit 9c5f35c)

src/providers/postgres/qgspostgresconn.cpp

@@ -29,6 +29,7 @@
 #include "qgssettings.h"
 #include "qgsjsonutils.h"
 #include "qgspostgresstringutils.h"
+#include "qgspostgresconnpool.h"
 
 #include <QApplication>
 #include <QStringList>
@@ -142,6 +143,17 @@ Oid QgsPostgresResult::PQoidValue()
   return ::PQoidValue( mRes );
 }
 
+QgsPoolPostgresConn::QgsPoolPostgresConn( const QString &connInfo )
+  : mPgConn( QgsPostgresConnPool::instance()->acquireConnection( connInfo ) )
+{
+}
+
+QgsPoolPostgresConn::~QgsPoolPostgresConn()
+{
+  if ( mPgConn )
+    QgsPostgresConnPool::instance()->releaseConnection( mPgConn );
+}
+
 
 QMap<QString, QgsPostgresConn *> QgsPostgresConn::sConnectionsRO;
 QMap<QString, QgsPostgresConn *> QgsPostgresConn::sConnectionsRW;

src/providers/postgres/qgspostgresconn.h

@@ -188,6 +188,17 @@ class QgsPostgresResult
 
 };
 
+//! Wraps acquireConnection() and releaseConnection() from a QgsPostgresConnPool.
+// This can be used for creating std::shared_ptr<QgsPoolPostgresConn>.
+class QgsPoolPostgresConn
+{
+    class QgsPostgresConn *mPgConn;
+  public:
+    QgsPoolPostgresConn( const QString &connInfo );
+    ~QgsPoolPostgresConn();
+
+    class QgsPostgresConn *get() const { return mPgConn; }
+};
 
 class QgsPostgresConn : public QObject
 {

src/providers/postgres/qgspostgresproviderconnection.cpp

@@ -198,7 +198,7 @@ QList<QVariantList> QgsPostgresProviderConnection::executeSql( const QString &sq
   return executeSqlPrivate( sql, true, feedback );
 }
 
-QList<QVariantList> QgsPostgresProviderConnection::executeSqlPrivate( const QString &sql, bool resolveTypes, QgsFeedback *feedback, QgsPostgresConn *pgconn ) const
+QList<QVariantList> QgsPostgresProviderConnection::executeSqlPrivate( const QString &sql, bool resolveTypes, QgsFeedback *feedback, std::shared_ptr<QgsPoolPostgresConn> pgconn ) const
 {
   QList<QVariantList> results;
 
@@ -208,9 +208,10 @@ QList<QVariantList> QgsPostgresProviderConnection::executeSqlPrivate( const QStr
     return results;
   }
 
-  const QgsDataSourceUri dsUri { uri() };
-  QgsPostgresConn *conn = pgconn ? pgconn : QgsPostgresConnPool::instance()->acquireConnection( dsUri.connectionInfo( false ) );
-  if ( !conn )
+  if ( ! pgconn )
+    pgconn = std::shared_ptr<QgsPoolPostgresConn>( new QgsPoolPostgresConn( QgsDataSourceUri( uri() ).connectionInfo( false ) ) );
+  QgsPostgresConn *conn = pgconn->get();
+  if ( ! conn )
   {
     throw QgsProviderConnectionException( QObject::tr( "Connection failed: %1" ).arg( uri() ) );
   }
@@ -269,7 +270,7 @@ QList<QVariantList> QgsPostgresProviderConnection::executeSqlPrivate( const QStr
             break;
           }
           const Oid oid { res.PQftype( rowIdx ) };
-          QList<QVariantList> typeRes { executeSqlPrivate( QStringLiteral( "SELECT typname FROM pg_type WHERE oid = %1" ).arg( oid ), false, nullptr, conn ) };
+          QList<QVariantList> typeRes { executeSqlPrivate( QStringLiteral( "SELECT typname FROM pg_type WHERE oid = %1" ).arg( oid ), false, nullptr, pgconn ) };
           // Set the default to string
           QVariant::Type vType { QVariant::Type::String };
           if ( typeRes.size() > 0 && typeRes.first().size() > 0 )
@@ -357,8 +358,6 @@ QList<QVariantList> QgsPostgresProviderConnection::executeSqlPrivate( const QStr
         results.push_back( row );
       }
     }
-    if ( ! pgconn )
-      QgsPostgresConnPool::instance()->releaseConnection( conn );
     if ( ! errCause.isEmpty() )
     {
       throw QgsProviderConnectionException( errCause );

src/providers/postgres/qgspostgresproviderconnection.h

@@ -61,7 +61,7 @@ class QgsPostgresProviderConnection : public QgsAbstractDatabaseProviderConnecti
 
   private:
 
-    QList<QVariantList> executeSqlPrivate( const QString &sql, bool resolveTypes = true, QgsFeedback *feedback = nullptr, class QgsPostgresConn *pgconn = nullptr ) const;
+    QList<QVariantList> executeSqlPrivate( const QString &sql, bool resolveTypes = true, QgsFeedback *feedback = nullptr, std::shared_ptr< class QgsPoolPostgresConn > pgconn = nullptr ) const;
     void setDefaultCapabilities();
     void dropTablePrivate( const QString &schema, const QString &name ) const;
     void renameTablePrivate( const QString &schema, const QString &name, const QString &newName ) const;