QofDbiBackendProvider< Type > Class Template Reference

Inheritance diagram for QofDbiBackendProvider< Type >:

Public Member Functions
	QofDbiBackendProvider (const char *name, const char *type)
	QofDbiBackendProvider (QofDbiBackendProvider &)=delete
QofDbiBackendProvider	operator= (QofDbiBackendProvider &)=delete
	QofDbiBackendProvider (QofDbiBackendProvider &&)=delete
QofDbiBackendProvider	operator= (QofDbiBackendProvider &&)=delete
QofBackend *	create_backend (void)
	Return a new, fully initialized backend. More...
bool	type_check (const char *type)
	Distinguish two providers with same access method. More...
template<>
bool	type_check (const char *uri)
	Distinguish two providers with same access method. More...
Public Member Functions inherited from QofBackendProvider
	QofBackendProvider (const char *name, const char *type)
	QofBackendProvider (QofBackendProvider &)=delete
	QofBackendProvider (QofBackendProvider &&)=delete

Additional Inherited Members
Data Fields inherited from QofBackendProvider
const char *	provider_name
	Some arbitrary name given for this particular backend provider.
const char *	access_method
	The access method that this provider provides, for example, file:// http:// postgres:// or sqlite://, but without the :// at the end.

Detailed Description

template<DbType Type>
class QofDbiBackendProvider< Type >

Definition at line 97 of file gnc-backend-dbi.cpp.

Member Function Documentation

create_backend()

template<DbType Type>

QofBackend* QofDbiBackendProvider< Type >::create_backend ( void  )

inlinevirtual

Return a new, fully initialized backend.

If the backend supports configuration, all configuration options should be initialised to usable values here.

Implements QofBackendProvider.

Definition at line 107 of file gnc-backend-dbi.cpp.

    {
        return new GncDbiBackend<Type>(nullptr, nullptr);
    }

type_check() [1/2]

template<DbType Type>

bool QofDbiBackendProvider< Type >::type_check ( const char *  )

inlinevirtual

Distinguish two providers with same access method.

More than 1 backend can be registered under the same access_method, so each one is passed the path to the data (e.g. a file) and should return TRUE only:

1. if the backend recognises the type as one that it can load and write or

2. if the path contains no data but can be used (e.g. a new session).

   Note

   If the backend can cope with more than one type, the backend should not try to store or cache the sub-type for this data. It is sufficient only to return TRUE if any ONE of the supported types match the incoming data. The backend should not assume that returning TRUE will mean that the data will naturally follow.

Implements QofBackendProvider.

Definition at line 111 of file gnc-backend-dbi.cpp.

{ return true; }

type_check() [2/2]

template<>

bool QofDbiBackendProvider< DbType::DBI_SQLITE >::type_check ( const char *  )

virtual

Distinguish two providers with same access method.

More than 1 backend can be registered under the same access_method, so each one is passed the path to the data (e.g. a file) and should return TRUE only:

1. if the backend recognises the type as one that it can load and write or

2. if the path contains no data but can be used (e.g. a new session).

   Note

   If the backend can cope with more than one type, the backend should not try to store or cache the sub-type for this data. It is sufficient only to return TRUE if any ONE of the supported types match the incoming data. The backend should not assume that returning TRUE will mean that the data will naturally follow.

Implements QofBackendProvider.

Definition at line 1030 of file gnc-backend-dbi.cpp.

{
    FILE* f;
    gchar buf[51]{};
    G_GNUC_UNUSED size_t chars_read;
    gint status;
    gchar* filename;

    // BAD if the path is null
    g_return_val_if_fail (uri != nullptr, FALSE);

    filename = gnc_uri_get_path (uri);
    f = g_fopen (filename, "r");
    g_free (filename);

    // OK if the file doesn't exist - new file
    if (f == nullptr)
    {
        PINFO ("doesn't exist (errno=%d) -> DBI", errno);
        return TRUE;
    }

    // OK if file has the correct header
    chars_read = fread (buf, sizeof (buf) - 1, 1, f);
    status = fclose (f);
    if (status < 0)
    {
        PERR ("Error in fclose(): %d\n", errno);
    }
    if (g_str_has_prefix (buf, "SQLite format 3"))
    {
        PINFO ("has SQLite format string -> DBI");
        return TRUE;
    }
    PINFO ("exists, does not have SQLite format string -> not DBI");

    // Otherwise, BAD
    return FALSE;
}

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

• gnc-backend-dbi.cpp