odbc_backend.h

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/*
 * This program source code file is part of KiCad, a free EDA CAD application.
 *
 * Copyright (C) 2022 Jon Evans <[email protected]>
 * Copyright The KiCad Developers, see AUTHORS.txt for contributors.
 *
 * 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 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
#ifndef KICAD_ODBC_BACKEND_H
#define KICAD_ODBC_BACKEND_H
 
#include <chrono>
#include <cstdint>
#include <functional>
#include <map>
#include <memory>
#include <mutex>
#include <optional>
#include <string>
#include <vector>
 
#include <database/database_backend.h>
 
namespace nanodbc
{
class connection;
}
 

class ODBC_BACKEND : public DATABASE_BACKEND
{
public:
    ODBC_BACKEND( std::string aDsn, std::string aUser, std::string aPass, std::string aConnectionString,
                  long aTimeout );
 
    ~ODBC_BACKEND() override;
 
    bool Connect() override;
 
    void Disconnect() override;
 
    bool IsConnected() const override;
 
    bool ListTables( std::vector<std::string>& aTables ) override;
 
    std::optional<DB_TABLE_INFO> DescribeTable( const std::string& aTable ) override;
 
    bool ListColumns( const std::string& aTable, std::vector<std::string>& aColumns ) override;
 
    bool ReadTable( const DB_TABLE_INFO& aTable, const std::vector<std::string>& aColumns, size_t aMaxRows,
                    std::vector<std::string>& aLabels, const DB_ROW_SINK& aSink ) override;

    std::optional<bool> ReadRow( const DB_TABLE_INFO& aTable, const std::vector<std::string>& aColumns,
                                 const std::string& aKeyColumn, const std::string& aKey,
                                 std::vector<std::string>& aLabels, std::vector<DB_VALUE>& aRow ) override;
 
    std::string GetLastError() const override { return m_lastError; }
 
    DB_FAILURE GetLastFailure() const override { return m_lastFailure; }

    struct DATA_SOURCE
    {
        std::string name;
        std::string driver;
    };

    static std::vector<DATA_SOURCE> ListDataSourceDetails();

    static std::vector<std::string> ListDrivers();

    struct SELECTOR
    {
        enum class KIND
        {
            NONE,
            DSN,
            FILE_DSN,
            DRIVER
        };
 
        KIND        kind = KIND::NONE;
        std::string value; 
    };

    static SELECTOR FirstSelector( const std::string& aConnectionString );

    using DSN_LOOKUP = std::function<std::optional<std::string>( const std::string& )>;

    static bool NeedsDriverLock( const std::string& aDsn, const std::string& aConnectionString,
                                 const DSN_LOOKUP& aLookup );

    static bool IsAccessDriver( const std::string& aDriverName );

    static bool IsAccessFileInUse( const std::string& aLowerMessage );

    static DB_FAILURE ClassifyFailure( const std::string& aState, const std::string& aMessage );

    struct KEY_PARAMETER
    {
        short         type = 0;          
        unsigned long size = 0;          
        short         scale = 0;         
        bool          asInteger = false; 
        int64_t       integerValue = 0;  
    };

    static KEY_PARAMETER DescribeKeyParameter( int aColumnType, long aColumnSize, short aColumnScale,
                                               const std::string& aKey );
 
private:
    bool getQuoteChar();

    bool takeAccessDriverLock( std::unique_lock<std::timed_mutex>& aLock );

    void disconnectLocked();

    std::string quoted( const std::string& aIdentifier ) const;

    std::string escapePattern( const std::string& aName ) const;

    std::string columnList( const std::vector<std::string>& aColumns ) const;
 
    std::unique_ptr<nanodbc::connection> m_conn;
 
    std::string m_dsn;
    std::string m_user;
    std::string m_pass;
    std::string m_connectionString;
 
    bool m_accessDriver = false;

    std::optional<std::chrono::steady_clock::time_point> m_engineDeadline;
 
    std::string m_lastError;
    DB_FAILURE  m_lastFailure = DB_FAILURE::UNKNOWN;

    struct COLUMN_INFO
    {
        int   type = 0;  
        long  size = 0;  
        short scale = 0; 
    };

    std::map<std::string, std::map<std::string, COLUMN_INFO>> m_columnInfo;
 
    long m_timeout;
 
    char m_quoteChar = '"';
 
    std::string m_patternEscape;
};
 
#endif // KICAD_ODBC_BACKEND_H