ircservices5/databases.h
2019-01-23 09:42:02 +01:00

140 lines
5.2 KiB
C

/* Database structures and declarations.
*
* IRC Services is copyright (c) 1996-2009 Andrew Church.
* E-mail: <achurch@achurch.org>
* Parts written by Andrew Kempe and others.
* This program is free but copyrighted software; see the file GPL.txt for
* details.
*/
#ifndef DATABASE_H
#define DATABASE_H
#ifndef MODULES_H
# include "modules.h"
#endif
/*************************************************************************/
/* Type constants for DBField.type */
typedef enum {
DBTYPE_INT8,
DBTYPE_UINT8,
DBTYPE_INT16,
DBTYPE_UINT16,
DBTYPE_INT32,
DBTYPE_UINT32,
DBTYPE_TIME,
DBTYPE_STRING,
DBTYPE_BUFFER, /* Buffer size in DBField.length */
DBTYPE_PASSWORD,
} DBType;
/* Structure that describes a field of a database table */
typedef struct dbfield_ {
const char *name; /* Field name */
DBType type; /* Field type */
int offset; /* Offset to field from start of structure
* (use standard `offsetof' macro) */
int length; /* Length of DBTYPE_BUFFER fields */
int load_only; /* If nonzero, field is not saved (use for reading
* obsolete fields) */
void (*get)(const void *record, void **value_ret);
/* Function to retrieve the field's value when
* saving; `value_ret' points to a variable of
* the appropriate type (for DBTYPE_STRING, the
* string should be malloc'd if not NULL) */
void (*put)(void *record, const void *value);
/* Function to set the field's value on load;
* `value' points to a variable of the
* appropriate type */
} DBField;
/* Structure that describes a database table */
typedef struct dbtable_ {
const char *name; /* Table name */
DBField *fields; /* Array of fields, terminated with name==NULL */
void *(*newrec)(void);
/* Routine to allocate a new record */
void (*freerec)(void *record);
/* Routine to free an allocated record (that has
* not been inserted into the table) */
void (*insert)(void *record);
/* Routine to insert a record (used when loading,
* returns nonzero for success or 0 for failure) */
void *(*first)(void), *(*next)(void);
/* Routines to iterate through all records (used
* when saving) */
int (*postload)(void);
/* Routine called after all records have been loaded;
* returns nonzero for success or 0 for failure */
} DBTable;
/* Container for module-implemented database functions */
typedef struct dbmodule_ {
/* Load the given table from permanent storage, returning nonzero for
* success, zero for failure. */
int (*load_table)(DBTable *table);
/* Save the given table to permanent storage, returning nonzero for
* success, zero for failure */
int (*save_table)(DBTable *table);
} DBModule;
/*************************************************************************/
/* Macro to return a pointer to a field in a record */
#define DB_FIELDPTR(record,field) ((int8 *)(record) + (field)->offset)
/*************************************************************************/
/* Initialization/cleanup routines. */
extern int database_init(int ac, char **av);
extern void database_cleanup(void);
/* Register a new database table. Returns nonzero on success, zero on
* error. */
#define register_dbtable(table) _register_dbtable((table), THIS_MODULE)
extern int _register_dbtable(DBTable *table, const Module *caller);
/* Unregister a database table. Does nothing if the table was not
* registered in the first place. */
extern void unregister_dbtable(DBTable *table);
/* Save all registered database tables to permanent storage. Returns 1 if
* all tables were successfully saved or no tables are registered, 0 if
* some tables were successfully saved (but some were not), or -1 if no
* tables were successfully saved. */
extern int save_all_dbtables(void);
/* Register a database module. Returns nonzero on success, zero on error.
* On success, all registered tables which have not already been loaded
* will be loaded from permanent storage. Only one database module can be
* registered. */
extern int register_dbmodule(DBModule *module);
/* Unregister a database module. Does nothing if the module was not
* registered in the first place. */
extern void unregister_dbmodule(DBModule *module);
/* Read a value from a database field. The value buffer is assumed to be
* large enough to hold the retrieved value. */
extern void get_dbfield(const void *record, const DBField *field,
void *buffer);
/* Store a value to a database field. */
extern void put_dbfield(void *record, const DBField *field, const void *value);
/*************************************************************************/
#endif /* DATABASE_H */
/*
* Local variables:
* c-file-style: "stroustrup"
* c-file-offsets: ((case-label . *) (statement-case-intro . *))
* indent-tabs-mode: nil
* End:
*
* vim: expandtab shiftwidth=4:
*/