GncDbiSqlConnection Class Reference

Encapsulate a libdbi dbi_conn connection. More...

#include <gnc-dbisqlconnection.hpp>

Inheritance diagram for GncDbiSqlConnection:

Public Member Functions
	GncDbiSqlConnection (DbType type, QofBackend *qbe, dbi_conn conn, SessionOpenMode mode)
GncSqlResultPtr	execute_select_statement (const GncSqlStatementPtr &) noexcept override
int	execute_nonselect_statement (const GncSqlStatementPtr &) noexcept override
	Returns false if error.
GncSqlStatementPtr	create_statement_from_sql (const std::string &) const noexcept override
bool	does_table_exist (const std::string &) const noexcept override
	Returns true if successful.
bool	begin_transaction () noexcept override
	Returns TRUE if successful, false if error.
bool	rollback_transaction () noexcept override
	Returns TRUE if successful, FALSE if error.
bool	commit_transaction () noexcept override
	Returns TRUE if successful, FALSE if error.
bool	create_table (const std::string &, const ColVec &) const noexcept override
	Returns TRUE if successful, FALSE if error.
bool	create_index (const std::string &, const std::string &, const EntryVec &) const noexcept override
	Returns TRUE if successful, FALSE if error.
bool	add_columns_to_table (const std::string &, const ColVec &) const noexcept override
	Returns TRUE if successful, FALSE if error.
std::string	quote_string (const std::string &) const noexcept override
int	dberror () const noexcept override
	Get the connection error value.
QofBackend *	qbe () const noexcept
dbi_conn	conn () const noexcept
void	set_error (QofBackendError error, unsigned int repeat, bool retry) noexcept override
void	init_error () noexcept
bool	verify () noexcept override
	Check if the dbi connection is valid.
bool	retry_connection (const char *msg) noexcept override
bool	table_operation (TableOpType op) noexcept
	Perform a specified SQL operation on every table in a database.
std::string	add_columns_ddl (const std::string &table_name, const ColVec &info_vec) const noexcept
bool	drop_indexes () noexcept
Public Member Functions inherited from GncSqlConnection
virtual	~GncSqlConnection ()=default
	Returns NULL if error.

Detailed Description

Encapsulate a libdbi dbi_conn connection.

Definition at line 41 of file gnc-dbisqlconnection.hpp.

Constructor & Destructor Documentation

GncDbiSqlConnection()

GncDbiSqlConnection::GncDbiSqlConnection	(	DbType	type,
		QofBackend *	qbe,
		dbi_conn	conn,
		SessionOpenMode	mode
	)

Definition at line 79 of file gnc-dbisqlconnection.cpp.

                                                                               :
    m_qbe{qbe}, m_conn{conn},
    m_provider{type == DbType::DBI_SQLITE ?
            make_dbi_provider<DbType::DBI_SQLITE>() :
            type == DbType::DBI_MYSQL ?
            make_dbi_provider<DbType::DBI_MYSQL>() :
            make_dbi_provider<DbType::DBI_PGSQL>()},
    m_conn_ok{true}, m_last_error{ERR_BACKEND_NO_ERR}, m_error_repeat{0},
    m_retry{false}, m_sql_savepoint{0}, m_readonly{false}
{
    if (mode == SESSION_READ_ONLY)
        m_readonly = true;
    else if (!lock_database(mode == SESSION_BREAK_LOCK))
        throw std::runtime_error("Failed to lock database!");
    if (!check_and_rollback_failed_save())
    {
        unlock_database();
        throw std::runtime_error("A failed safe-save was detected and rolling it back failed.");
    }
}

~GncDbiSqlConnection()

GncDbiSqlConnection::~GncDbiSqlConnection ( )

override

Definition at line 247 of file gnc-dbisqlconnection.cpp.

{
    if (m_conn)
    {
        unlock_database();
        dbi_conn_close(m_conn);
        m_conn = nullptr;
    }
}

Member Function Documentation

add_columns_ddl()

std::string GncDbiSqlConnection::add_columns_ddl ( const std::string &  table_name, const ColVec &  info_vec  ) const

noexcept

Definition at line 756 of file gnc-dbisqlconnection.cpp.

{
    std::string ddl;
 
    ddl += "ALTER TABLE " + table_name;
    for (auto const& info : info_vec)
    {
        if (info != *info_vec.begin())
        {
            ddl += ", ";
        }
        ddl += "ADD COLUMN ";
        m_provider->append_col_def (ddl, info);
    }
    return ddl;
}

add_columns_to_table()

bool GncDbiSqlConnection::add_columns_to_table ( const std::string &  , const ColVec &    ) const

overridevirtualnoexcept

Returns TRUE if successful, FALSE if error.

Implements GncSqlConnection.

Definition at line 518 of file gnc-dbisqlconnection.cpp.

{
    auto ddl = add_columns_ddl(table_name, info_vec);
    if (ddl.empty())
        return false;
 
    DEBUG ("SQL: %s\n", ddl.c_str());
    auto result = dbi_conn_query (m_conn, ddl.c_str());
    auto status = dbi_result_free (result);
    if (status < 0)
    {
        PERR( "Error in dbi_result_free() result\n" );
        qof_backend_set_error(m_qbe, ERR_BACKEND_SERVER_ERR );
    }
 
    return true;
}

begin_transaction()

bool GncDbiSqlConnection::begin_transaction ( )

overridevirtualnoexcept

Returns TRUE if successful, false if error.

Implements GncSqlConnection.

Definition at line 335 of file gnc-dbisqlconnection.cpp.

{
    dbi_result result;
 
    DEBUG ("BEGIN\n");
 
    if (!verify ())
    {
        PERR ("gnc_dbi_verify_conn() failed\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
 
    do
    {
        init_error ();
        if (m_sql_savepoint == 0)
            result = dbi_conn_queryf (m_conn, "BEGIN");
        else
        {
            std::ostringstream savepoint;
            savepoint << "savepoint_" << m_sql_savepoint;
            result = dbi_conn_queryf(m_conn, "SAVEPOINT %s",
                                     savepoint.str().c_str());
        }
    }
    while (m_retry);
 
    if (!result)
    {
        PERR ("BEGIN transaction failed()\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
    if (dbi_result_free (result) < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
    ++m_sql_savepoint;
    return true;
}

commit_transaction()

bool GncDbiSqlConnection::commit_transaction ( )

overridevirtualnoexcept

Returns TRUE if successful, FALSE if error.

Implements GncSqlConnection.

Definition at line 413 of file gnc-dbisqlconnection.cpp.

{
    DEBUG ("COMMIT\n");
    if (m_sql_savepoint == 0) return false;
    dbi_result result;
    if (m_sql_savepoint == 1)
        result = dbi_conn_queryf (m_conn, "COMMIT");
    else
    {
        std::ostringstream savepoint;
        savepoint << "savepoint_" << m_sql_savepoint - 1;
        result = dbi_conn_queryf(m_conn, "RELEASE SAVEPOINT %s",
                                 savepoint.str().c_str());
    }
 
    if (!result)
    {
        PERR ("Error in conn_commit_transaction()\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
 
    if (dbi_result_free (result) < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
    --m_sql_savepoint;
    return true;
}

conn()

dbi_conn GncDbiSqlConnection::conn ( ) const

inlinenoexcept

Definition at line 66 of file gnc-dbisqlconnection.hpp.

{ return m_conn; }

create_index()

bool GncDbiSqlConnection::create_index ( const std::string &  , const std::string &  , const EntryVec &    ) const

overridevirtualnoexcept

Returns TRUE if successful, FALSE if error.

Implements GncSqlConnection.

Definition at line 498 of file gnc-dbisqlconnection.cpp.

{
    auto ddl = create_index_ddl (this, index_name, table_name, col_table);
    if (ddl.empty())
        return false;
    DEBUG ("SQL: %s\n", ddl.c_str());
    auto result = dbi_conn_query (m_conn, ddl.c_str());
    auto status = dbi_result_free (result);
    if (status < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
    }
 
    return true;
}

create_statement_from_sql()

GncSqlStatementPtr GncDbiSqlConnection::create_statement_from_sql ( const std::string &  sql ) const

overridevirtualnoexcept

Implements GncSqlConnection.

Definition at line 321 of file gnc-dbisqlconnection.cpp.

{
    return std::unique_ptr<GncSqlStatement>{new GncDbiSqlStatement (sql)};
}

create_table()

bool GncDbiSqlConnection::create_table ( const std::string &  , const ColVec &    ) const

overridevirtualnoexcept

Returns TRUE if successful, FALSE if error.

Implements GncSqlConnection.

Definition at line 447 of file gnc-dbisqlconnection.cpp.

{
    std::string ddl;
    unsigned int col_num = 0;
 
    ddl += "CREATE TABLE " + table_name + "(";
    for (auto const& info : info_vec)
    {
        if (col_num++ != 0)
        {
            ddl += ", ";
        }
        m_provider->append_col_def (ddl, info);
    }
    ddl += ")";
 
    if (ddl.empty())
        return false;
 
    DEBUG ("SQL: %s\n", ddl.c_str());
    auto result = dbi_conn_query (m_conn, ddl.c_str());
    auto status = dbi_result_free (result);
    if (status < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
    }
 
    return true;
}

dberror()

int GncDbiSqlConnection::dberror ( ) const

inlineoverridevirtualnoexcept

Get the connection error value.

If not 0 will normally be meaningless outside of implementation code.

Implements GncSqlConnection.

Definition at line 63 of file gnc-dbisqlconnection.hpp.

                                          {
        return dbi_conn_error(m_conn, nullptr); }

does_table_exist()

bool GncDbiSqlConnection::does_table_exist ( const std::string &  ) const

overridevirtualnoexcept

Returns true if successful.

Implements GncSqlConnection.

Definition at line 328 of file gnc-dbisqlconnection.cpp.

{
    return ! m_provider->get_table_list(m_conn, table_name).empty();
}

drop_indexes()

bool GncDbiSqlConnection::drop_indexes ( )

noexcept

Definition at line 739 of file gnc-dbisqlconnection.cpp.

{
    auto index_list = m_provider->get_index_list (m_conn);
    for (auto index : index_list)
    {
        const char* errmsg;
        m_provider->drop_index (m_conn, index);
        if (DBI_ERROR_NONE != dbi_conn_error (m_conn, &errmsg))
        {
            PERR("Failed to drop indexes %s", errmsg);
            return false;
        }
    }
    return true;
}

execute_nonselect_statement()

int GncDbiSqlConnection::execute_nonselect_statement ( const GncSqlStatementPtr &  )

overridevirtualnoexcept

Returns false if error.

Implements GncSqlConnection.

Definition at line 284 of file gnc-dbisqlconnection.cpp.

{
    dbi_result result;
 
    DEBUG ("SQL: %s\n", stmt->to_sql());
    do
    {
        init_error ();
        result = dbi_conn_query (m_conn, stmt->to_sql());
    }
    while (m_retry);
    if (result == nullptr && m_last_error)
    {
        PERR ("Error executing SQL %s\n", stmt->to_sql());
        if(m_last_error)
            m_qbe->set_error(m_last_error);
        else
            m_qbe->set_error(ERR_BACKEND_SERVER_ERR);
        return -1;
    }
    if (!result)
        return 0;
    auto num_rows = (gint)dbi_result_get_numrows_affected (result);
    auto status = dbi_result_free (result);
    if (status < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        if(m_last_error)
            m_qbe->set_error(m_last_error);
        else
            m_qbe->set_error(ERR_BACKEND_SERVER_ERR);
    }
    return num_rows;
}

execute_select_statement()

GncSqlResultPtr GncDbiSqlConnection::execute_select_statement ( const GncSqlStatementPtr &  stmt )

overridevirtualnoexcept

Implements GncSqlConnection.

Definition at line 258 of file gnc-dbisqlconnection.cpp.

{
    dbi_result result;
 
    DEBUG ("SQL: %s\n", stmt->to_sql());
    auto locale = gnc_push_locale (LC_NUMERIC, "C");
    do
    {
        init_error ();
        result = dbi_conn_query (m_conn, stmt->to_sql());
    }
    while (m_retry);
    if (result == nullptr)
    {
        PERR ("Error executing SQL %s\n", stmt->to_sql());
        if(m_last_error)
            m_qbe->set_error(m_last_error);
        else
            m_qbe->set_error(ERR_BACKEND_SERVER_ERR);
    }
    gnc_pop_locale (LC_NUMERIC, locale);
    return GncSqlResultPtr(new GncDbiSqlResult (this, result));
}

init_error()

void GncDbiSqlConnection::init_error ( )

inlinenoexcept

Definition at line 74 of file gnc-dbisqlconnection.hpp.

    {
        set_error(ERR_BACKEND_NO_ERR, 0, false);
    }

qbe()

QofBackend * GncDbiSqlConnection::qbe ( ) const

inlinenoexcept

Definition at line 65 of file gnc-dbisqlconnection.hpp.

{ return m_qbe; }

quote_string()

std::string GncDbiSqlConnection::quote_string ( const std::string &  unquoted_str ) const

overridevirtualnoexcept

Implements GncSqlConnection.

Definition at line 539 of file gnc-dbisqlconnection.cpp.

{
    char* quoted_str;
 
    dbi_conn_quote_string_copy (m_conn, unquoted_str.c_str(),
                                &quoted_str);
    if (quoted_str == nullptr)
        return std::string{""};
    std::string retval{quoted_str};
    free(quoted_str);
    return retval;
}

retry_connection()

bool GncDbiSqlConnection::retry_connection ( const char *  msg )

overridevirtualnoexcept

Implements GncSqlConnection.

Definition at line 576 of file gnc-dbisqlconnection.cpp.

{
    while (m_retry && m_error_repeat <= DBI_MAX_CONN_ATTEMPTS)
    {
        m_conn_ok = false;
        if (dbi_conn_connect(m_conn) == 0)
        {
            init_error();
            m_conn_ok = true;
            return true;
        }
#ifdef G_OS_WIN32
        const guint backoff_msecs = 1;
        Sleep (backoff_msecs * 2 << ++m_error_repeat);
#else
        const guint backoff_usecs = 1000;
        usleep (backoff_usecs * 2 << ++m_error_repeat);
#endif
        PINFO ("DBI error: %s - Reconnecting...\n", msg);
 
    }
    PERR ("DBI error: %s - Giving up after %d consecutive attempts.\n", msg,
          DBI_MAX_CONN_ATTEMPTS);
    m_conn_ok = false;
    return false;
}

rollback_transaction()

bool GncDbiSqlConnection::rollback_transaction ( )

overridevirtualnoexcept

Returns TRUE if successful, FALSE if error.

Implements GncSqlConnection.

Definition at line 380 of file gnc-dbisqlconnection.cpp.

{
    DEBUG ("ROLLBACK\n");
    if (m_sql_savepoint == 0) return false;
    dbi_result result;
    if (m_sql_savepoint == 1)
        result = dbi_conn_query (m_conn, "ROLLBACK");
    else
    {
        std::ostringstream savepoint;
        savepoint << "savepoint_" << m_sql_savepoint - 1;
        result = dbi_conn_queryf(m_conn, "ROLLBACK TO SAVEPOINT %s",
                                 savepoint.str().c_str());
    }
    if (!result)
    {
        PERR ("Error in conn_rollback_transaction()\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
 
    if (dbi_result_free (result) < 0)
    {
        PERR ("Error in dbi_result_free() result\n");
        qof_backend_set_error (m_qbe, ERR_BACKEND_SERVER_ERR);
        return false;
    }
 
    --m_sql_savepoint;
    return true;
}

set_error()

void GncDbiSqlConnection::set_error ( QofBackendError  error, unsigned int  repeat, bool  retry  )

inlineoverridevirtualnoexcept

Implements GncSqlConnection.

Definition at line 67 of file gnc-dbisqlconnection.hpp.

    {
        m_last_error = error;
        m_error_repeat = repeat;
        m_retry = retry;
    }

table_operation()

bool GncDbiSqlConnection::table_operation ( TableOpType  op )

noexcept

Perform a specified SQL operation on every table in a database.

Possible operations are:

• drop: to DROP all tables from the database
• empty: to DELETE all records from each table in the database.
• backup: Rename every table from "name" to "name_back"
• drop_backup: DROP the backup tables.
• rollback: DROP the new table "name" and rename "name_back" to "name", restoring the database to its previous state.

The intent of the last two is to be able to move an existing table aside, query its contents with a transformation (in 2.4.x this is already done as the contents are loaded completely when a Qof session is started), save them to a new table according to a new database format, and finally drop the backup table; if there's an error during the process, rollback allows returning the table to its original state.

Parameters

sql_conn	The sql connection (via dbi) to which the transactions will be sent
table_namess	StrVec of tables to operate on.
op	The operation to perform.

Returns

Success (TRUE) or failure.

Definition at line 671 of file gnc-dbisqlconnection.cpp.

{
    auto backup_tables = m_provider->get_table_list(m_conn, "%_back");
    auto all_tables = m_provider->get_table_list(m_conn, "");
    /* No operations on the lock table */
    auto new_end = std::remove(all_tables.begin(), all_tables.end(), lock_table);
    all_tables.erase(new_end, all_tables.end());
    StrVec data_tables;
    data_tables.reserve(all_tables.size() - backup_tables.size());
    std::set_difference(all_tables.begin(), all_tables.end(),
                        backup_tables.begin(), backup_tables.end(),
                        std::back_inserter(data_tables));
    switch(op)
    {
    case backup:
        if (!backup_tables.empty())
        {
            PERR("Unable to backup database, an existing backup is present.");
            qof_backend_set_error(m_qbe, ERR_BACKEND_DATA_CORRUPT);
            return false;
        }
        for (auto table : data_tables)
            if (!rename_table(table, table +"_back"))
                return false; /* Error, trigger rollback. */
        break;
    case drop_backup:
        for (auto table : backup_tables)
        {
            auto data_table = table.substr(0, table.find("_back"));
            if (std::find(data_tables.begin(), data_tables.end(),
                          data_table) != data_tables.end())
                drop_table(table); /* Other table exists, OK. */
            else /* No data table, restore the backup */
                rename_table(table, data_table);
        }
        break;
    case rollback:
        for (auto table : backup_tables)
        {
            auto data_table = table.substr(0, table.find("_back"));
            if (std::find(data_tables.begin(), data_tables.end(),
                          data_table) != data_tables.end())
                drop_table(data_table); /* Other table exists, OK. */
            rename_table(table, data_table);
        }
        break;
    case recover:
        for (auto table : backup_tables)
        {
            auto data_table = table.substr(0, table.find("_back"));
            if (std::find(data_tables.begin(), data_tables.end(),
                          data_table) != data_tables.end())
            {
                if (!merge_tables(data_table, table))
                    return false;
            }
            else
            {
                if (!rename_table(table, data_table))
                    return false;
            }
        }
        break;
    }
   return true;
}

verify()

bool GncDbiSqlConnection::verify ( )

overridevirtualnoexcept

Check if the dbi connection is valid.

If not attempt to re-establish it Returns TRUE if there is a valid connection in the end or FALSE otherwise

Implements GncSqlConnection.

Definition at line 558 of file gnc-dbisqlconnection.cpp.

{
    if (m_conn_ok)
        return true;
 
    /* We attempt to connect only once here. The error function will
     * automatically re-attempt up until DBI_MAX_CONN_ATTEMPTS time to connect
     * if this call fails.  After all these attempts, conn_ok will indicate if
     * there is a valid connection or not.
     */
    init_error ();
    m_conn_ok = true;
    (void)dbi_conn_connect (m_conn);
 
    return m_conn_ok;
}

---

The documentation for this class was generated from the following files:

• gnc-dbisqlconnection.hpp
• gnc-dbisqlconnection.cpp