/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1997-2003
 *	Sleepycat Software.  All rights reserved.
 */

#include "db_config.h"

#ifndef lint
static const char revid[] = "$Id: cxx_env.cpp,v 11.96 2003/06/30 19:17:48 mjc Exp $";
#endif /* not lint */

#include <errno.h>
#include <stdio.h>              // needed for set_error_stream
#include <string.h>

#include "db_cxx.h"
#include "dbinc/cxx_int.h"

#include "db_int.h"
#include "dbinc_auto/common_ext.h"

#ifdef HAVE_CXX_STDHEADERS
using std::cerr;
#endif

// Helper macros for simple methods that pass through to the
// underlying C method.  They may return an error or raise an exception.
// These macros expect that input _argspec is an argument
// list element (e.g., "char *arg") and that _arglist is the arguments
// that should be passed through to the C method (e.g., "(dbenv, arg)")
//
#define	DBENV_METHOD_ERR(_name, _argspec, _arglist, _on_err)	  \
int DbEnv::_name _argspec					  \
{								  \
	DB_ENV *dbenv = unwrap(this);				  \
	int ret;						  \
								  \
	if ((ret = dbenv->_name _arglist) != 0)	{		  \
		_on_err;					  \
	}							  \
	return (ret);						  \
}

#define	DBENV_METHOD(_name, _argspec, _arglist)			  \
	DBENV_METHOD_ERR(_name, _argspec, _arglist,		  \
	DB_ERROR(this, "DbEnv::" # _name, ret, error_policy()))

#define	DBENV_METHOD_QUIET(_name, _argspec, _arglist)		  \
int DbEnv::_name _argspec					  \
{								  \
	DB_ENV *dbenv = unwrap(this);				  \
								  \
	return (dbenv->_name _arglist);				  \
}

#define	DBENV_METHOD_VOID(_name, _argspec, _arglist)		  \
void DbEnv::_name _argspec					  \
{								  \
	DB_ENV *dbenv = unwrap(this);				  \
								  \
	dbenv->_name _arglist;					  \
}

// This datatype is needed for picky compilers.
//
extern "C" {
	typedef void (*db_errcall_fcn_type)
		(const char *, char *);
};

// The reason for a static variable is that some structures
// (like Dbts) have no connection to any Db or DbEnv, so when
// errors occur in their methods, we must have some reasonable
// way to determine whether to throw or return errors.
//
// This variable is taken from flags whenever a DbEnv is constructed.
// Normally there is only one DbEnv per program, and even if not,
// there is typically a single policy of throwing or returning.
//
static int last_known_error_policy = ON_ERROR_UNKNOWN;

__DB_OSTREAMCLASS *DbEnv::error_stream_ = 0;

// These 'glue' function are declared as extern "C" so they 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"
void _feedback_intercept_c(DB_ENV *env, int opcode, int pct)
{
	DbEnv::_feedback_intercept(env, opcode, pct);
}

extern "C"
void _paniccall_intercept_c(DB_ENV *env, int errval)
{
	DbEnv::_paniccall_intercept(env, errval);
}

extern "C"
void _stream_error_function_c(const char *prefix, char *message)
{
	DbEnv::_stream_error_function(prefix, message);
}

extern "C"
int _app_dispatch_intercept_c(DB_ENV *env, DBT *dbt,
			    DB_LSN *lsn, db_recops op)
{
	return (DbEnv::_app_dispatch_intercept(env, dbt, lsn, op));
}

extern "C"
int _rep_send_intercept_c(DB_ENV *env, const DBT *cntrl,
			  const DBT *data, const DB_LSN *lsn, int id,
			  u_int32_t flags)
{
	return (DbEnv::_rep_send_intercept(env,
	    cntrl, data, lsn, id, flags));
}

void DbEnv::_feedback_intercept(DB_ENV *env, int opcode, int pct)
{
	if (env == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::feedback_callback", EINVAL, ON_ERROR_UNKNOWN);
		return;
	}
	DbEnv *cxxenv = (DbEnv *)env->api1_internal;
	if (cxxenv == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::feedback_callback", EINVAL, ON_ERROR_UNKNOWN);
		return;
	}
	if (cxxenv->feedback_callback_ == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::feedback_callback", EINVAL, cxxenv->error_policy());
		return;
	}
	(*cxxenv->feedback_callback_)(cxxenv, opcode, pct);
}

void DbEnv::_paniccall_intercept(DB_ENV *env, int errval)
{
	if (env == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::paniccall_callback", EINVAL, ON_ERROR_UNKNOWN);
	}
	DbEnv *cxxenv = (DbEnv *)env->api1_internal;
	if (cxxenv == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::paniccall_callback", EINVAL, ON_ERROR_UNKNOWN);
	}
	if (cxxenv->paniccall_callback_ == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::paniccall_callback", EINVAL,
		    cxxenv->error_policy());
	}
	(*cxxenv->paniccall_callback_)(cxxenv, errval);
}

int DbEnv::_app_dispatch_intercept(DB_ENV *env, DBT *dbt,
				DB_LSN *lsn, db_recops op)
{
	if (env == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::app_dispatch_callback", EINVAL, ON_ERROR_UNKNOWN);
		return (EINVAL);
	}
	DbEnv *cxxenv = (DbEnv *)env->api1_internal;
	if (cxxenv == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::app_dispatch_callback", EINVAL, ON_ERROR_UNKNOWN);
		return (EINVAL);
	}
	if (cxxenv->app_dispatch_callback_ == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
		    "DbEnv::app_dispatch_callback", EINVAL,
		    cxxenv->error_policy());
		return (EINVAL);
	}
	Dbt *cxxdbt = (Dbt *)dbt;
	DbLsn *cxxlsn = (DbLsn *)lsn;
	return ((*cxxenv->app_dispatch_callback_)(cxxenv, cxxdbt, cxxlsn, op));
}

int DbEnv::_rep_send_intercept(DB_ENV *env, const DBT *cntrl,
		const DBT *data, const DB_LSN *lsn, int id, u_int32_t flags)
{
	if (env == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
			"DbEnv::rep_send_callback", EINVAL, ON_ERROR_UNKNOWN);
		return (EINVAL);
	}
	DbEnv *cxxenv = (DbEnv *)env->api1_internal;
	if (cxxenv == 0) {
		DB_ERROR(DbEnv::get_DbEnv(env),
			"DbEnv::rep_send_callback", EINVAL, ON_ERROR_UNKNOWN);
		return (EINVAL);
	}
	const Dbt *cxxcntrl = (const Dbt *)cntrl;
	const DbLsn *cxxlsn = (const DbLsn *)lsn;
	Dbt *cxxdata = (Dbt *)data;
	return ((*cxxenv->rep_send_callback_)(cxxenv,
	    cxxcntrl, cxxdata, cxxlsn, id, flags));
}

// A truism for the DbEnv object is that there is a valid
// DB_ENV handle from the constructor until close().
// After the close, the DB_ENV handle is invalid and
// no operations are permitted on the DbEnv (other than
// destructor).  Leaving the DbEnv handle open and not
// doing a close is generally considered an error.
//
// We used to allow DbEnv objects to be closed and reopened.
// This implied always keeping a valid DB_ENV object, and
// coordinating the open objects between Db/DbEnv turned
// out to be overly complicated.  Now we do not allow this.

DbEnv::DbEnv(u_int32_t flags)
:	imp_(0)
,	construct_error_(0)
,	construct_flags_(flags)
,	app_dispatch_callback_(0)
,	feedback_callback_(0)
,	paniccall_callback_(0)
,	pgin_callback_(0)
,	pgout_callback_(0)
,	rep_send_callback_(0)
{
	if ((construct_error_ = initialize(0)) != 0)
		DB_ERROR(this, "DbEnv::DbEnv", construct_error_,
		    error_policy());
}

DbEnv::DbEnv(DB_ENV *env, u_int32_t flags)
:	imp_(0)
,	construct_error_(0)
,	construct_flags_(flags)
,	app_dispatch_callback_(0)
,	feedback_callback_(0)
,	paniccall_callback_(0)
,	pgin_callback_(0)
,	pgout_callback_(0)
,	rep_send_callback_(0)
{
	if ((construct_error_ = initialize(env)) != 0)
		DB_ERROR(this, "DbEnv::DbEnv", construct_error_,
		    error_policy());
}

// If the DB_ENV handle is still open, we close it.  This is to make stack
// allocation of DbEnv objects easier so that they are cleaned up in the error
// path.  Note that the C layer catches cases where handles are open in the
// environment at close time and reports an error.  Applications should call
// close explicitly in normal (non-exceptional) cases to check the return
// value.
//
DbEnv::~DbEnv()
{
	DB_ENV *env = unwrap(this);

	if (env != NULL) {
		cleanup();
		(void)env->close(env, 0);
	}
}

// called by destructors before the DB_ENV is destroyed.
void DbEnv::cleanup()
{
	DB_ENV *env = unwrap(this);

	if (env != NULL) {
		env->api1_internal = 0;
		imp_ = 0;
	}
}

int DbEnv::close(u_int32_t flags)
{
	int ret;
	DB_ENV *env = unwrap(this);

	// after a close (no matter if success or failure),
	// the underlying DB_ENV object must not be accessed,
	// so we clean up in advance.
	//
	cleanup();

	// It's safe to throw an error after the close,
	// since our error mechanism does not peer into
	// the DB* structures.
	//
	if ((ret = env->close(env, flags)) != 0)
		DB_ERROR(this, "DbEnv::close", ret, error_policy());

	return (ret);
}

DBENV_METHOD(dbremove,
    (DbTxn *txn, const char *name, const char *subdb, u_int32_t flags),
    (dbenv, unwrap(txn), name, subdb, flags))
DBENV_METHOD(dbrename, (DbTxn *txn, const char *name, const char *subdb,
    const char *newname, u_int32_t flags),
    (dbenv, unwrap(txn), name, subdb, newname, flags))

void DbEnv::err(int error, const char *format, ...)
{
	DB_ENV *env = unwrap(this);

	DB_REAL_ERR(env, error, 1, 1, format);
}

// Return a tristate value corresponding to whether we should
// throw exceptions on errors:
//   ON_ERROR_RETURN
//   ON_ERROR_THROW
//   ON_ERROR_UNKNOWN
//
int DbEnv::error_policy()
{
	if ((construct_flags_ & DB_CXX_NO_EXCEPTIONS) != 0) {
		return (ON_ERROR_RETURN);
	}
	else {
		return (ON_ERROR_THROW);
	}
}

void DbEnv::errx(const char *format, ...)
{
	DB_ENV *env = unwrap(this);

	DB_REAL_ERR(env, 0, 0, 1, format);
}

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

DBENV_METHOD(get_home, (const char **homep), (dbenv, homep))
DBENV_METHOD(get_open_flags, (u_int32_t *flagsp), (dbenv, flagsp))
DBENV_METHOD(get_data_dirs, (const char ***dirspp), (dbenv, dirspp))

// used internally during constructor
// to associate an existing DB_ENV with this DbEnv,
// or create a new one.
//
int DbEnv::initialize(DB_ENV *env)
{
	int ret;

	last_known_error_policy = error_policy();

	if (env == 0) {
		// Create a new DB_ENV environment.
		if ((ret = ::db_env_create(&env,
		    construct_flags_ & ~DB_CXX_NO_EXCEPTIONS)) != 0)
			return (ret);
	}
	imp_ = wrap(env);
	env->api1_internal = this;	// for DB_ENV* to DbEnv* conversion
	return (0);
}

// lock methods
DBENV_METHOD(lock_detect, (u_int32_t flags, u_int32_t atype, int *aborted),
    (dbenv, flags, atype, aborted))
DBENV_METHOD_ERR(lock_get,
    (u_int32_t locker, u_int32_t flags, const Dbt *obj,
    db_lockmode_t lock_mode, DbLock *lock),
    (dbenv, locker, flags, obj, lock_mode, &lock->lock_),
    DbEnv::runtime_error_lock_get(this, "DbEnv::lock_get", ret,
				  DB_LOCK_GET, lock_mode, obj, *lock,
				  -1, error_policy()))
DBENV_METHOD(lock_id, (u_int32_t *idp), (dbenv, idp))
DBENV_METHOD(lock_id_free, (u_int32_t id), (dbenv, id))
DBENV_METHOD(lock_put, (DbLock *lock), (dbenv, &lock->lock_))
DBENV_METHOD(lock_stat, (DB_LOCK_STAT **statp, u_int32_t flags),
    (dbenv, statp, flags))
DBENV_METHOD_ERR(lock_vec,
    (u_int32_t locker, u_int32_t flags, DB_LOCKREQ list[],
    int nlist, DB_LOCKREQ **elist_returned),
    (dbenv, locker, flags, list, nlist, elist_returned),
    DbEnv::runtime_error_lock_get(this, "DbEnv::lock_vec", ret,
	(*elist_returned)->op, (*elist_returned)->mode,
	Dbt::get_Dbt((*elist_returned)->obj), DbLock((*elist_returned)->lock),
	(*elist_returned) - list, error_policy()))
// log methods
DBENV_METHOD(log_archive, (char **list[], u_int32_t flags),
    (dbenv, list, flags))

int DbEnv::log_compare(const DbLsn *lsn0, const DbLsn *lsn1)
{
	return (::log_compare(lsn0, lsn1));
}

// The following cast implies that DbLogc can be no larger than DB_LOGC
DBENV_METHOD(log_cursor, (DbLogc **cursorp, u_int32_t flags),
    (dbenv, (DB_LOGC **)cursorp, flags))
DBENV_METHOD(log_file, (DbLsn *lsn, char *namep, size_t len),
    (dbenv, lsn, namep, len))
DBENV_METHOD(log_flush, (const DbLsn *lsn), (dbenv, lsn))
DBENV_METHOD(log_put, (DbLsn *lsn, const Dbt *data, u_int32_t flags),
    (dbenv, lsn, data, flags))
DBENV_METHOD(log_stat, (DB_LOG_STAT **spp, u_int32_t flags),
    (dbenv, spp, flags))

int DbEnv::memp_fcreate(DbMpoolFile **dbmfp, u_int32_t flags)
{
	DB_ENV *env = unwrap(this);
	int ret;
	DB_MPOOLFILE *mpf;

	if (env == NULL)
		ret = EINVAL;
	else
		ret = env->memp_fcreate(env, &mpf, flags);

	if (DB_RETOK_STD(ret)) {
		*dbmfp = new DbMpoolFile();
		(*dbmfp)->imp_ = wrap(mpf);
	} else
		DB_ERROR(this, "DbMpoolFile::f_create", ret, ON_ERROR_UNKNOWN);

	return (ret);
}

DBENV_METHOD(memp_register,
    (int ftype, pgin_fcn_type pgin_fcn, pgout_fcn_type pgout_fcn),
    (dbenv, ftype, pgin_fcn, pgout_fcn))

// memory pool methods
DBENV_METHOD(memp_stat,
    (DB_MPOOL_STAT **gsp, DB_MPOOL_FSTAT ***fsp, u_int32_t flags),
    (dbenv, gsp, fsp, flags))

DBENV_METHOD(memp_sync, (DbLsn *sn), (dbenv, sn))

DBENV_METHOD(memp_trickle, (int pct, int *nwrotep), (dbenv, pct, nwrotep))

// If an error occurred during the constructor, report it now.
// Otherwise, call the underlying DB->open method.
//
int DbEnv::open(const char *db_home, u_int32_t flags, int mode)
{
	int ret;
	DB_ENV *env = unwrap(this);

	if (construct_error_ != 0)
		ret = construct_error_;
	else
		ret = env->open(env, db_home, flags, mode);

	if (!DB_RETOK_STD(ret))
		DB_ERROR(this, "DbEnv::open", ret, error_policy());

	return (ret);
}

int DbEnv::remove(const char *db_home, u_int32_t flags)
{
	int ret;
	DB_ENV *env = unwrap(this);

	// after a remove (no matter if success or failure),
	// the underlying DB_ENV object must not be accessed,
	// so we clean up in advance.
	//
	cleanup();

	if ((ret = env->remove(env, db_home, flags)) != 0)
		DB_ERROR(this, "DbEnv::remove", ret, error_policy());

	return (ret);
}

// Report an error associated with the DbEnv.
// error_policy is one of:
//   ON_ERROR_THROW     throw an error
//   ON_ERROR_RETURN    do nothing here, the caller will return an error
//   ON_ERROR_UNKNOWN   defer the policy to policy saved in DbEnv::DbEnv
//
void DbEnv::runtime_error(DbEnv *env,
    const char *caller, int error, int error_policy)
{
	if (error_policy == ON_ERROR_UNKNOWN)
		error_policy = last_known_error_policy;
	if (error_policy == ON_ERROR_THROW) {
		// Creating and throwing the object in two separate
		// statements seems to be necessary for HP compilers.
		switch (error) {
		case DB_LOCK_DEADLOCK:
			{
				DbDeadlockException dl_except(caller);
				dl_except.set_env(env);
				throw dl_except;
			}
			break;
		case DB_RUNRECOVERY:
			{
				DbRunRecoveryException rr_except(caller);
				rr_except.set_env(env);
				throw rr_except;
			}
			break;
		case DB_LOCK_NOTGRANTED:
			{
				DbLockNotGrantedException lng_except(caller);
				lng_except.set_env(env);
				throw lng_except;
			}
			break;
		default:
			{
				DbException except(caller, error);
				except.set_env(env);
				throw except;
			}
			break;
		}
	}
}

// Like DbEnv::runtime_error, but issue a DbMemoryException
// based on the fact that this Dbt is not large enough.
void DbEnv::runtime_error_dbt(DbEnv *env,
    const char *caller, Dbt *dbt, int error_policy)
{
	if (error_policy == ON_ERROR_UNKNOWN)
		error_policy = last_known_error_policy;
	if (error_policy == ON_ERROR_THROW) {
		// Creating and throwing the object in two separate
		// statements seems to be necessary for HP compilers.
		DbMemoryException except(caller, dbt);
		except.set_env(env);
		throw except;
	}
}

// Like DbEnv::runtime_error, but issue a DbLockNotGrantedException,
// or a regular runtime error.
// call regular runtime_error if it
void DbEnv::runtime_error_lock_get(DbEnv *env,
    const char *caller, int error,
    db_lockop_t op, db_lockmode_t mode, const Dbt *obj,
    DbLock lock, int index, int error_policy)
{
	if (error != DB_LOCK_NOTGRANTED) {
		runtime_error(env, caller, error, error_policy);
		return;
	}

	if (error_policy == ON_ERROR_UNKNOWN)
		error_policy = last_known_error_policy;
	if (error_policy == ON_ERROR_THROW) {
		// Creating and throwing the object in two separate
		// statements seems to be necessary for HP compilers.
		DbLockNotGrantedException except(caller, op, mode,
		    obj, lock, index);
		except.set_env(env);
		throw except;
	}
}

// static method
char *DbEnv::strerror(int error)
{
	return (db_strerror(error));
}

void DbEnv::_stream_error_function(const char *prefix, char *message)
{
	// HP compilers need the extra casts, we don't know why.
	if (error_stream_) {
		if (prefix) {
			(*error_stream_) << prefix << (const char *)": ";
		}
		if (message) {
			(*error_stream_) << (const char *)message;
		}
		(*error_stream_) << (const char *)"\n";
	}
}

// set methods

DBENV_METHOD_VOID(get_errfile, (FILE **errfilep), (dbenv, errfilep))
DBENV_METHOD_VOID(set_errfile, (FILE *errfile), (dbenv, errfile))
DBENV_METHOD_VOID(get_errpfx, (const char **errpfxp), (dbenv, errpfxp))
DBENV_METHOD_VOID(set_errpfx, (const char *errpfx), (dbenv, errpfx))

// We keep these alphabetical by field name,
// for comparison with Java's list.
//
DBENV_METHOD(set_data_dir, (const char *dir), (dbenv, dir))
DBENV_METHOD(get_encrypt_flags, (u_int32_t *flagsp),
    (dbenv, flagsp))
DBENV_METHOD(set_encrypt, (const char *passwd, u_int32_t flags),
    (dbenv, passwd, flags))
DBENV_METHOD(get_lg_bsize, (u_int32_t *bsizep), (dbenv, bsizep))
DBENV_METHOD(set_lg_bsize, (u_int32_t bsize), (dbenv, bsize))
DBENV_METHOD(get_lg_dir, (const char **dirp), (dbenv, dirp))
DBENV_METHOD(set_lg_dir, (const char *dir), (dbenv, dir))
DBENV_METHOD(get_lg_max, (u_int32_t *maxp), (dbenv, maxp))
DBENV_METHOD(set_lg_max, (u_int32_t max), (dbenv, max))
DBENV_METHOD(get_lg_regionmax, (u_int32_t *regionmaxp), (dbenv, regionmaxp))
DBENV_METHOD(set_lg_regionmax, (u_int32_t regionmax), (dbenv, regionmax))
DBENV_METHOD(get_lk_conflicts, (const u_int8_t **lk_conflictsp, int *lk_maxp),
    (dbenv, lk_conflictsp, lk_maxp))
DBENV_METHOD(set_lk_conflicts, (u_int8_t *lk_conflicts, int lk_max),
    (dbenv, lk_conflicts, lk_max))
DBENV_METHOD(get_lk_detect, (u_int32_t *detectp), (dbenv, detectp))
DBENV_METHOD(set_lk_detect, (u_int32_t detect), (dbenv, detect))
DBENV_METHOD(set_lk_max, (u_int32_t max), (dbenv, max))
DBENV_METHOD(get_lk_max_lockers, (u_int32_t *max_lockersp),
    (dbenv, max_lockersp))
DBENV_METHOD(set_lk_max_lockers, (u_int32_t max_lockers), (dbenv, max_lockers))
DBENV_METHOD(get_lk_max_locks, (u_int32_t *max_locksp), (dbenv, max_locksp))
DBENV_METHOD(set_lk_max_locks, (u_int32_t max_locks), (dbenv, max_locks))
DBENV_METHOD(get_lk_max_objects, (u_int32_t *max_objectsp),
    (dbenv, max_objectsp))
DBENV_METHOD(set_lk_max_objects, (u_int32_t max_objects), (dbenv, max_objects))
DBENV_METHOD(get_mp_mmapsize, (size_t *mmapsizep), (dbenv, mmapsizep))
DBENV_METHOD(set_mp_mmapsize, (size_t mmapsize), (dbenv, mmapsize))
DBENV_METHOD(get_tmp_dir, (const char **tmp_dirp), (dbenv, tmp_dirp))
DBENV_METHOD(set_tmp_dir, (const char *tmp_dir), (dbenv, tmp_dir))
DBENV_METHOD(get_tx_max, (u_int32_t *tx_maxp), (dbenv, tx_maxp))
DBENV_METHOD(set_tx_max, (u_int32_t tx_max), (dbenv, tx_max))

DBENV_METHOD_QUIET(set_alloc,
    (db_malloc_fcn_type malloc_fcn, db_realloc_fcn_type realloc_fcn,
    db_free_fcn_type free_fcn),
    (dbenv, malloc_fcn, realloc_fcn, free_fcn))

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

DBENV_METHOD(get_cachesize,
    (u_int32_t *gbytesp, u_int32_t *bytesp, int *ncachep),
    (dbenv, gbytesp, bytesp, ncachep))
DBENV_METHOD(set_cachesize,
    (u_int32_t gbytes, u_int32_t bytes, int ncache),
    (dbenv, gbytes, bytes, ncache))

void DbEnv::set_errcall(void (*arg)(const char *, char *))
{
	DB_ENV *dbenv = unwrap(this);

	// XXX
	// We are casting from a function ptr declared with C++
	// linkage to one (same arg types) declared with C
	// linkage.  It's hard to imagine a pair of C/C++
	// compilers from the same vendor for which this
	// won't work.  Unfortunately, we can't use a
	// intercept function like the others since the
	// function does not have a (DbEnv*) as one of
	// the args.  If this causes trouble, we can pull
	// the same trick we use in Java, namely stuffing
	// a (DbEnv*) pointer into the prefix.  We're
	// avoiding this for the moment because it obfuscates.
	//
	(*(dbenv->set_errcall))(dbenv, (db_errcall_fcn_type)arg);
}

// Note: This actually behaves a bit like a static function,
// since DB_ENV.db_errcall has no information about which
// db_env triggered the call.  A user that has multiple DB_ENVs
// will simply not be able to have different streams for each one.
//
void DbEnv::set_error_stream(__DB_OSTREAMCLASS *stream)
{
	DB_ENV *dbenv = unwrap(this);

	error_stream_ = stream;
	dbenv->set_errcall(dbenv, (stream == 0) ? 0 :
			   _stream_error_function_c);
}

int DbEnv::set_feedback(void (*arg)(DbEnv *, int, int))
{
	DB_ENV *dbenv = unwrap(this);

	feedback_callback_ = arg;

	return ((*(dbenv->set_feedback))(dbenv, _feedback_intercept_c));
}

DBENV_METHOD(get_flags, (u_int32_t *flagsp), (dbenv, flagsp))
DBENV_METHOD(set_flags, (u_int32_t flags, int onoff), (dbenv, flags, onoff))

int DbEnv::set_paniccall(void (*arg)(DbEnv *, int))
{
	DB_ENV *dbenv = unwrap(this);

	paniccall_callback_ = arg;

	return ((*(dbenv->set_paniccall))(dbenv, _paniccall_intercept_c));
}

DBENV_METHOD(set_rpc_server,
    (void *cl, char *host, long tsec, long ssec, u_int32_t flags),
    (dbenv, cl, host, tsec, ssec, flags))
DBENV_METHOD(get_shm_key, (long *shm_keyp), (dbenv, shm_keyp))
DBENV_METHOD(set_shm_key, (long shm_key), (dbenv, shm_key))
// Note: this changes from last_known_error_policy to error_policy()
DBENV_METHOD(get_tas_spins, (u_int32_t *argp), (dbenv, argp))
DBENV_METHOD(set_tas_spins, (u_int32_t arg), (dbenv, arg))

int DbEnv::set_app_dispatch
    (int (*arg)(DbEnv *, Dbt *, DbLsn *, db_recops))
{
	DB_ENV *dbenv = unwrap(this);
	int ret;

	app_dispatch_callback_ = arg;
	if ((ret = (*(dbenv->set_app_dispatch))(dbenv,
	    _app_dispatch_intercept_c)) != 0)
		DB_ERROR(this, "DbEnv::set_app_dispatch", ret, error_policy());

	return (ret);
}

DBENV_METHOD(get_tx_timestamp, (time_t *timestamp), (dbenv, timestamp))
DBENV_METHOD(set_tx_timestamp, (time_t *timestamp), (dbenv, timestamp))
DBENV_METHOD(get_verbose, (u_int32_t which, int *onoffp),
    (dbenv, which, onoffp))
DBENV_METHOD(set_verbose, (u_int32_t which, int onoff), (dbenv, which, onoff))

int DbEnv::txn_begin(DbTxn *pid, DbTxn **tid, u_int32_t flags)
{
	DB_ENV *env = unwrap(this);
	DB_TXN *txn;
	int ret;

	ret = env->txn_begin(env, unwrap(pid), &txn, flags);
	if (DB_RETOK_STD(ret))
		*tid = new DbTxn(txn);
	else
		DB_ERROR(this, "DbEnv::txn_begin", ret, error_policy());

	return (ret);
}

DBENV_METHOD(txn_checkpoint, (u_int32_t kbyte, u_int32_t min, u_int32_t flags),
    (dbenv, kbyte, min, flags))

int DbEnv::txn_recover(DbPreplist *preplist, long count,
    long *retp, u_int32_t flags)
{
	DB_ENV *dbenv = unwrap(this);
	DB_PREPLIST *c_preplist;
	long i;
	int ret;

	/*
	 * We need to allocate some local storage for the
	 * returned preplist, and that requires us to do
	 * our own argument validation.
	 */
	if (count <= 0)
		ret = EINVAL;
	else
		ret = __os_malloc(dbenv, sizeof(DB_PREPLIST) * count,
		    &c_preplist);

	if (ret != 0) {
		DB_ERROR(this, "DbEnv::txn_recover", ret, error_policy());
		return (ret);
	}

	if ((ret =
	    dbenv->txn_recover(dbenv, c_preplist, count, retp, flags)) != 0) {
		__os_free(dbenv, c_preplist);
		DB_ERROR(this, "DbEnv::txn_recover", ret, error_policy());
		return (ret);
	}

	for (i = 0; i < *retp; i++) {
		preplist[i].txn = new DbTxn();
		preplist[i].txn->imp_ = wrap(c_preplist[i].txn);
		memcpy(preplist[i].gid, c_preplist[i].gid,
		    sizeof(preplist[i].gid));
	}

	__os_free(dbenv, c_preplist);

	return (0);
}

DBENV_METHOD(txn_stat, (DB_TXN_STAT **statp, u_int32_t flags),
    (dbenv, statp, flags))

int DbEnv::set_rep_transport(int myid,
    int (*f_send)(DbEnv *, const Dbt *, const Dbt *, const DbLsn *, int,
	          u_int32_t))
{
	DB_ENV *dbenv = unwrap(this);
	int ret;

	rep_send_callback_ = f_send;
	if ((ret = dbenv->set_rep_transport(dbenv,
	    myid, _rep_send_intercept_c)) != 0)
		DB_ERROR(this, "DbEnv::set_rep_transport", ret, error_policy());

	return (ret);
}

DBENV_METHOD(rep_elect,
    (int nsites, int pri, u_int32_t timeout, int *idp),
    (dbenv, nsites, pri, timeout, idp))

int DbEnv::rep_process_message(Dbt *control,
    Dbt *rec, int *idp, DbLsn *ret_lsnp)
{
	DB_ENV *dbenv = unwrap(this);
	int ret;

	ret = dbenv->rep_process_message(dbenv, control, rec, idp, ret_lsnp);
	if (!DB_RETOK_REPPMSG(ret))
		DB_ERROR(this, "DbEnv::rep_process_message", ret,
		    error_policy());

	return (ret);
}

DBENV_METHOD(rep_start,
    (Dbt *cookie, u_int32_t flags),
    (dbenv, (DBT *)cookie, flags))

DBENV_METHOD(rep_stat, (DB_REP_STAT **statp, u_int32_t flags),
    (dbenv, statp, flags))

DBENV_METHOD(get_rep_limit, (u_int32_t *gbytesp, u_int32_t *bytesp),
    (dbenv, gbytesp, bytesp))
DBENV_METHOD(set_rep_limit, (u_int32_t gbytes, u_int32_t bytes),
    (dbenv, gbytes, bytes))

DBENV_METHOD(get_timeout,
    (db_timeout_t *timeoutp, u_int32_t flags),
    (dbenv, timeoutp, flags))
DBENV_METHOD(set_timeout,
    (db_timeout_t timeout, u_int32_t flags),
    (dbenv, timeout, flags))

// static method
char *DbEnv::version(int *major, int *minor, int *patch)
{
	return (db_version(major, minor, patch));
}

// static method
DbEnv *DbEnv::wrap_DB_ENV(DB_ENV *dbenv)
{
	DbEnv *wrapped_env = get_DbEnv(dbenv);
	if (wrapped_env == NULL)
		wrapped_env = new DbEnv(dbenv, 0);
	return wrapped_env;
}
