cxx_db.cpp

这是国外的resip协议栈

	ret = db->pget(db, unwrap(txnid), key, pkey, value, flags);

	/* The logic here is identical to Db::get - reuse the macro. */
	if (!DB_RETOK_DBGET(ret)) {
		if (ret == ENOMEM && DB_OVERFLOWED_DBT(value))
			DB_ERROR_DBT(env_, "Db::pget", value, error_policy());
		else
			DB_ERROR(env_, "Db::pget", ret, error_policy());
	}

	return (ret);
}

DB_METHOD(put, (DbTxn *txnid, Dbt *key, Dbt *value, u_int32_t flags),
    (db, unwrap(txnid), key, value, flags), DB_RETOK_DBPUT)

DB_DESTRUCTOR(rename,
    (const char *file, const char *database, const char *newname,
    u_int32_t flags),
    (db, file, database, newname, flags), DB_RETOK_STD)

DB_DESTRUCTOR(remove, (const char *file, const char *database, u_int32_t flags),
    (db, file, database, flags), DB_RETOK_STD)

DB_METHOD(truncate, (DbTxn *txnid, u_int32_t *countp, u_int32_t flags),
    (db, unwrap(txnid), countp, flags), DB_RETOK_STD)

DB_METHOD(stat, (DbTxn *txnid, void *sp, u_int32_t flags),
    (db, unwrap(txnid), sp, flags), DB_RETOK_STD)

DB_METHOD(stat_print, (u_int32_t flags), (db, flags), DB_RETOK_STD)

DB_METHOD(sync, (u_int32_t flags), (db, flags), DB_RETOK_STD)

DB_METHOD(upgrade,
    (const char *name, u_int32_t flags), (db, name, flags), DB_RETOK_STD)

////////////////////////////////////////////////////////////////////////
//
// callbacks
//
// *_intercept_c are 'glue' functions that must be declared
// as extern "C" so to be typesafe.  Using a C++ method, even
// a static class method with 'correct' arguments, will not pass
// the test; some picky compilers do not allow mixing of function
// pointers to 'C' functions with function pointers to C++ functions.
//
// One wart with this scheme is that the *_callback_ method pointer
// must be declared public to be accessible by the C intercept.
// It's possible to accomplish the goal without this, and with
// another public transfer method, but it's just too much overhead.
// These callbacks are supposed to be *fast*.
//
// The DBTs we receive in these callbacks from the C layer may be
// manufactured there, but we want to treat them as a Dbts.
// Technically speaking, these DBTs were not constructed as a Dbts,
// but it should be safe to cast them as such given that Dbt is a
// *very* thin extension of the DBT.  That is, Dbt has no additional
// data elements, does not use virtual functions, virtual inheritance,
// multiple inheritance, RTI, or any other language feature that
// causes the structure to grow or be displaced.  Although this may
// sound risky, a design goal of C++ is complete structure
// compatibility with C, and has the philosophy 'if you don't use it,
// you shouldn't incur the overhead'.  If the C/C++ compilers you're
// using on a given machine do not have matching struct layouts, then
// a lot more things will be broken than just this.
//
// The alternative, creating a Dbt here in the callback, and populating
// it from the DBT, is just too slow and cumbersome to be very useful.

// These macros avoid a lot of boilerplate code for callbacks

#define	DB_CALLBACK_C_INTERCEPT(_name, _rettype, _cargspec,		\
    _return, _cxxargs)							\
extern "C" _rettype _db_##_name##_intercept_c _cargspec			\
{									\
	Db *cxxthis;							\
									\
	DB_ASSERT(cthis != NULL);					\
	cxxthis = Db::get_Db(cthis);					\
	DB_ASSERT(cxxthis != NULL);					\
	DB_ASSERT(cxxthis->_name##_callback_ != 0);			\
									\
	_return (*cxxthis->_name##_callback_) _cxxargs;			\
}

#define	DB_SET_CALLBACK(_cxxname, _name, _cxxargspec, _cb)		\
int Db::_cxxname _cxxargspec						\
{									\
	DB *cthis = unwrap(this);					\
									\
	_name##_callback_ = _cb;					\
	return ((*(cthis->_cxxname))(cthis,				\
	    (_cb) ? _db_##_name##_intercept_c : NULL));			\
}

/* associate callback - doesn't quite fit the pattern because of the flags */
DB_CALLBACK_C_INTERCEPT(associate,
    int, (DB *cthis, const DBT *key, const DBT *data, DBT *retval),
    return, (cxxthis, Dbt::get_const_Dbt(key), Dbt::get_const_Dbt(data),
    Dbt::get_Dbt(retval)))

int Db::associate(DbTxn *txn, Db *secondary, int (*callback)(Db *, const Dbt *,
	const Dbt *, Dbt *), u_int32_t flags)
{
	DB *cthis = unwrap(this);

	/* Since the secondary Db is used as the first argument
	 * to the callback, we store the C++ callback on it
	 * rather than on 'this'.
	 */
	secondary->associate_callback_ = callback;
	return ((*(cthis->associate))(cthis, unwrap(txn), unwrap(secondary),
	    (callback) ? _db_associate_intercept_c : NULL, flags));
}

DB_CALLBACK_C_INTERCEPT(feedback,
    void, (DB *cthis, int opcode, int pct),
    /* no return */ (void), (cxxthis, opcode, pct))

DB_SET_CALLBACK(set_feedback, feedback,
    (void (*arg)(Db *cxxthis, int opcode, int pct)), arg)

DB_CALLBACK_C_INTERCEPT(append_recno,
    int, (DB *cthis, DBT *data, db_recno_t recno),
    return, (cxxthis, Dbt::get_Dbt(data), recno))

DB_SET_CALLBACK(set_append_recno, append_recno,
    (int (*arg)(Db *cxxthis, Dbt *data, db_recno_t recno)), arg)

DB_CALLBACK_C_INTERCEPT(bt_compare,
    int, (DB *cthis, const DBT *data1, const DBT *data2),
    return,
    (cxxthis, Dbt::get_const_Dbt(data1), Dbt::get_const_Dbt(data2)))

DB_SET_CALLBACK(set_bt_compare, bt_compare,
    (int (*arg)(Db *cxxthis, const Dbt *data1, const Dbt *data2)), arg)

DB_CALLBACK_C_INTERCEPT(bt_prefix,
    size_t, (DB *cthis, const DBT *data1, const DBT *data2),
    return,
    (cxxthis, Dbt::get_const_Dbt(data1), Dbt::get_const_Dbt(data2)))

DB_SET_CALLBACK(set_bt_prefix, bt_prefix,
    (size_t (*arg)(Db *cxxthis, const Dbt *data1, const Dbt *data2)), arg)

DB_CALLBACK_C_INTERCEPT(dup_compare,
    int, (DB *cthis, const DBT *data1, const DBT *data2),
    return,
    (cxxthis, Dbt::get_const_Dbt(data1), Dbt::get_const_Dbt(data2)))

DB_SET_CALLBACK(set_dup_compare, dup_compare,
    (int (*arg)(Db *cxxthis, const Dbt *data1, const Dbt *data2)), arg)

DB_CALLBACK_C_INTERCEPT(h_hash,
    u_int32_t, (DB *cthis, const void *data, u_int32_t len),
    return, (cxxthis, data, len))

DB_SET_CALLBACK(set_h_hash, h_hash,
    (u_int32_t (*arg)(Db *cxxthis, const void *data, u_int32_t len)), arg)

// This is a 'glue' function declared as extern "C" so it will
// be compatible with picky compilers that do not allow mixing
// of function pointers to 'C' functions with function pointers
// to C++ functions.
//
extern "C"
int _verify_callback_c(void *handle, const void *str_arg)
{
	char *str;
	__DB_STD(ostream) *out;

	str = (char *)str_arg;
	out = (__DB_STD(ostream) *)handle;

	(*out) << str;
	if (out->fail())
		return (EIO);

	return (0);
}

int Db::verify(const char *name, const char *subdb,
	       __DB_STD(ostream) *ostr, u_int32_t flags)
{
	DB *db = unwrap(this);
	int ret;

	if (!db)
		ret = EINVAL;
	else {
		// after a DB->verify (no matter if success or failure),
		// the underlying DB object must not be accessed,
		// so we clean up in advance.
		//
		cleanup();

		ret = __db_verify_internal(db, name, subdb, ostr,
		    _verify_callback_c, flags);
	}

	if (!DB_RETOK_STD(ret))
		DB_ERROR(env_, "Db::verify", ret, error_policy());

	return (ret);
}

DB_METHOD(set_bt_compare, (bt_compare_fcn_type func),
    (db, func), DB_RETOK_STD)
DB_METHOD(set_bt_maxkey, (u_int32_t bt_maxkey),
    (db, bt_maxkey), DB_RETOK_STD)
DB_METHOD(get_bt_minkey, (u_int32_t *bt_minkeyp),
    (db, bt_minkeyp), DB_RETOK_STD)
DB_METHOD(set_bt_minkey, (u_int32_t bt_minkey),
    (db, bt_minkey), DB_RETOK_STD)
DB_METHOD(set_bt_prefix, (bt_prefix_fcn_type func),
    (db, func), DB_RETOK_STD)
DB_METHOD(set_dup_compare, (dup_compare_fcn_type func),
    (db, func), DB_RETOK_STD)
DB_METHOD(get_encrypt_flags, (u_int32_t *flagsp),
    (db, flagsp), DB_RETOK_STD)
DB_METHOD(set_encrypt, (const char *passwd, u_int32_t flags),
    (db, passwd, flags), DB_RETOK_STD)
DB_METHOD_VOID(get_errfile, (FILE **errfilep), (db, errfilep))
DB_METHOD_VOID(set_errfile, (FILE *errfile), (db, errfile))
DB_METHOD_VOID(get_errpfx, (const char **errpfx), (db, errpfx))
DB_METHOD_VOID(set_errpfx, (const char *errpfx), (db, errpfx))
DB_METHOD(get_flags, (u_int32_t *flagsp), (db, flagsp),
    DB_RETOK_STD)
DB_METHOD(set_flags, (u_int32_t flags), (db, flags),
    DB_RETOK_STD)
DB_METHOD(get_h_ffactor, (u_int32_t *h_ffactorp),
    (db, h_ffactorp), DB_RETOK_STD)
DB_METHOD(set_h_ffactor, (u_int32_t h_ffactor),
    (db, h_ffactor), DB_RETOK_STD)
DB_METHOD(set_h_hash, (h_hash_fcn_type func),
    (db, func), DB_RETOK_STD)
DB_METHOD(get_h_nelem, (u_int32_t *h_nelemp),
    (db, h_nelemp), DB_RETOK_STD)
DB_METHOD(set_h_nelem, (u_int32_t h_nelem),
    (db, h_nelem), DB_RETOK_STD)
DB_METHOD(get_lorder, (int *db_lorderp), (db, db_lorderp),
    DB_RETOK_STD)
DB_METHOD(set_lorder, (int db_lorder), (db, db_lorder),
    DB_RETOK_STD)
DB_METHOD_VOID(get_msgfile, (FILE **msgfilep), (db, msgfilep))
DB_METHOD_VOID(set_msgfile, (FILE *msgfile), (db, msgfile))
DB_METHOD(get_pagesize, (u_int32_t *db_pagesizep),
    (db, db_pagesizep), DB_RETOK_STD)
DB_METHOD(set_pagesize, (u_int32_t db_pagesize),
    (db, db_pagesize), DB_RETOK_STD)
DB_METHOD(get_re_delim, (int *re_delimp),
    (db, re_delimp), DB_RETOK_STD)
DB_METHOD(set_re_delim, (int re_delim),
    (db, re_delim), DB_RETOK_STD)
DB_METHOD(get_re_len, (u_int32_t *re_lenp),
    (db, re_lenp), DB_RETOK_STD)
DB_METHOD(set_re_len, (u_int32_t re_len),
    (db, re_len), DB_RETOK_STD)
DB_METHOD(get_re_pad, (int *re_padp),
    (db, re_padp), DB_RETOK_STD)
DB_METHOD(set_re_pad, (int re_pad),
    (db, re_pad), DB_RETOK_STD)
DB_METHOD(get_re_source, (const char **re_source),
    (db, re_source), DB_RETOK_STD)
DB_METHOD(set_re_source, (const char *re_source),
    (db, re_source), DB_RETOK_STD)
DB_METHOD(get_q_extentsize, (u_int32_t *extentsizep),
    (db, extentsizep), DB_RETOK_STD)
DB_METHOD(set_q_extentsize, (u_int32_t extentsize),
    (db, extentsize), DB_RETOK_STD)

DB_METHOD_QUIET(set_alloc, (db_malloc_fcn_type malloc_fcn,
    db_realloc_fcn_type realloc_fcn, db_free_fcn_type free_fcn),
    (db, malloc_fcn, realloc_fcn, free_fcn))

void Db::set_errcall(void (*arg)(const DbEnv *, const char *, const char *))
{
	env_->set_errcall(arg);
}

void Db::set_msgcall(void (*arg)(const DbEnv *, const char *))
{
	env_->set_msgcall(arg);
}

void *Db::get_app_private() const
{
	return unwrapConst(this)->app_private;
}

void Db::set_app_private(void *value)
{
	unwrap(this)->app_private = value;
}

DB_METHOD(get_cachesize, (u_int32_t *gbytesp, u_int32_t *bytesp, int *ncachep),
    (db, gbytesp, bytesp, ncachep), DB_RETOK_STD)
DB_METHOD(set_cachesize, (u_int32_t gbytes, u_int32_t bytes, int ncache),
    (db, gbytes, bytes, ncache), DB_RETOK_STD)

int Db::set_paniccall(void (*callback)(DbEnv *, int))
{
	return (env_->set_paniccall(callback));
}

__DB_STD(ostream) *Db::get_error_stream()
{
	return env_->get_error_stream();
}

void Db::set_error_stream(__DB_STD(ostream) *error_stream)
{
	env_->set_error_stream(error_stream);
}

__DB_STD(ostream) *Db::get_message_stream()
{
	return env_->get_message_stream();
}

void Db::set_message_stream(__DB_STD(ostream) *message_stream)
{
	env_->set_message_stream(message_stream);
}

DB_METHOD_QUIET(get_transactional, (), (db))