lsup_rdf/include/environment.h

/** @file environment.h
 *
 * @brief Handle LSUP environment initialization and teardown.
 *
 * #LSUP_init() should be called before performing any other interaction with
 * this library.
 *
 * #LSUP_done() is called automatically on program exit (`atexit`).
 */

#ifndef _LSUP_ENVIRONMENT_H
#define _LSUP_ENVIRONMENT_H


#include "term.h"

#if 0
/*
 * TODO Deprecating all non-default environments. All is needed is a NSMap
 * which can be created separately for in-memory graphs.
 */
#include "store_mdb.h"


/*
 * Data types.
 */

/** @brief Environment structure containing global LSUP variables.
 *
 * Multiple environments may be opened within one program. One environment,
 * the default one, is always opened when calling #LSUP_init(), before
 * performing any operation with the library.
 *
 * The namespace map is used by all volatile (not LSUP_STORE_PERM) stores
 * associated with the environment.
 */
typedef struct env_t {
    LSUP_Buffer *       default_ctx;            ///> Default context URI.
    LSUP_NSMap *        nsm;                    ///> Namespace prefix map.
} LSUP_Env;


/** @brief Default environment that gets created with #LSUP_init().
 */
extern LSUP_Env *LSUP_default_env;


/** @brief Initialize default context and MDB environments.
 *
 * The ramdisk data will persist after the application is shut down, but they
 * will be wiped clean the next time this function is called.
 */
LSUP_Env *
LSUP_env_new (const char *default_ctx, const LSUP_NSMap *nsmap);
#endif

extern LSUP_NSMap *LSUP_default_nsm; /// Default namespace prefix map.
extern LSUP_Term *LSUP_default_ctx; /// Default context.
extern LSUP_Buffer *LSUP_default_ctx_buf; /// Serialized default context.


/** @brief Initialize the default environment.
 *
 * This must be called before using the library.
 *
 * The default environment is cleaned up automatically on exit.
 *
 * This environment should suit most cases, unless an application needs to use
 * multiple environments and call #LSUP_env_init with specific handles. Such
 * other environment(s) must be freed up manually with #LSUP_env_done().
 */
LSUP_rc
LSUP_init (void);


/** @brief Whether the environment is already initialized.
 *
 * @TODO Check if the default NS was inserted; this would be slower but more
 * accurate.
 */
inline bool
LSUP_is_init (void)
{ return LSUP_term_cache != NULL; }


#if 0
/** @brief Close an environment.
 *
 * This only needs to be done for non-default environments. The environment
 * handle is not freed.
 */
void
LSUP_env_free (LSUP_Env *env);
#endif 

/** @brief Close the default environment.
 *
 * This is called by atexit(). If called before then, subsequent calls have
 * no effect.
 */
void
LSUP_done (void);


/** TODO
 */
LSUP_rc
LSUP_env_put_id (const uint32_t key, const char *data);


/** TODO
 */
const char *
LSUP_env_get_id (const uint32_t key);

#endif /* _LSUP_ENVIRONMENT_H */