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/*-
* Copyright (c) 2014-2020 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
/*
* Helpers for calling a function with a data handle in session->dhandle then restoring afterwards.
*/
#define WT_WITH_DHANDLE(s, d, e) \
do { \
WT_DATA_HANDLE *__saved_dhandle = (s)->dhandle; \
(s)->dhandle = (d); \
e; \
(s)->dhandle = __saved_dhandle; \
} while (0)
#define WT_WITH_BTREE(s, b, e) WT_WITH_DHANDLE(s, (b)->dhandle, e)
/* Call a function without the caller's data handle, restore afterwards. */
#define WT_WITHOUT_DHANDLE(s, e) WT_WITH_DHANDLE(s, NULL, e)
/*
* Call a function with the caller's data handle, restore it afterwards in case it is overwritten.
*/
#define WT_SAVE_DHANDLE(s, e) WT_WITH_DHANDLE(s, (s)->dhandle, e)
/* Check if a handle is inactive. */
#define WT_DHANDLE_INACTIVE(dhandle) \
(F_ISSET(dhandle, WT_DHANDLE_DEAD) || !F_ISSET(dhandle, WT_DHANDLE_EXCLUSIVE | WT_DHANDLE_OPEN))
/* Check if a handle could be reopened. */
#define WT_DHANDLE_CAN_REOPEN(dhandle) \
(!WT_DHANDLE_INACTIVE(dhandle) && F_ISSET(dhandle, WT_DHANDLE_OPEN) && \
!F_ISSET(dhandle, WT_DHANDLE_DROPPED))
/* The metadata cursor's data handle. */
#define WT_SESSION_META_DHANDLE(s) (((WT_CURSOR_BTREE *)((s)->meta_cursor))->dhandle)
#define WT_DHANDLE_ACQUIRE(dhandle) (void)__wt_atomic_add32(&(dhandle)->session_ref, 1)
#define WT_DHANDLE_RELEASE(dhandle) (void)__wt_atomic_sub32(&(dhandle)->session_ref, 1)
#define WT_DHANDLE_NEXT(session, dhandle, head, field) \
do { \
WT_ASSERT(session, F_ISSET(session, WT_SESSION_LOCKED_HANDLE_LIST)); \
if ((dhandle) == NULL) \
(dhandle) = TAILQ_FIRST(head); \
else { \
WT_DHANDLE_RELEASE(dhandle); \
(dhandle) = TAILQ_NEXT(dhandle, field); \
} \
if ((dhandle) != NULL) \
WT_DHANDLE_ACQUIRE(dhandle); \
} while (0)
/*
* WT_DATA_HANDLE --
* A handle for a generic named data source.
*/
struct __wt_data_handle {
WT_RWLOCK rwlock; /* Lock for shared/exclusive ops */
TAILQ_ENTRY(__wt_data_handle) q;
TAILQ_ENTRY(__wt_data_handle) hashq;
const char *name; /* Object name as a URI */
uint64_t name_hash; /* Hash of name */
const char *checkpoint; /* Checkpoint name (or NULL) */
const char **cfg; /* Configuration information */
const char *meta_base; /* Base metadata configuration */
/*
* Sessions holding a connection's data handle will have a non-zero reference count; sessions
* using a connection's data handle will have a non-zero in-use count. Instances of cached
* cursors referencing the data handle appear in session_cache_ref.
*/
uint32_t session_ref; /* Sessions referencing this handle */
int32_t session_inuse; /* Sessions using this handle */
uint32_t excl_ref; /* Refs of handle by excl_session */
uint64_t timeofdeath; /* Use count went to 0 */
WT_SESSION_IMPL *excl_session; /* Session with exclusive use, if any */
WT_DATA_SOURCE *dsrc; /* Data source for this handle */
void *handle; /* Generic handle */
enum { WT_DHANDLE_TYPE_BTREE, WT_DHANDLE_TYPE_TABLE } type;
bool compact_skip; /* If the handle failed to compact */
/*
* Data handles can be closed without holding the schema lock; threads walk the list of open
* handles, operating on them (checkpoint is the best example). To avoid sources disappearing
* underneath checkpoint, lock the data handle when closing it.
*/
WT_SPINLOCK close_lock; /* Lock to close the handle */
/* Data-source statistics */
WT_DSRC_STATS *stats[WT_COUNTER_SLOTS];
WT_DSRC_STATS *stat_array;
/* Flags values over 0xff are reserved for WT_BTREE_* */
/* AUTOMATIC FLAG VALUE GENERATION START */
#define WT_DHANDLE_DEAD 0x01u /* Dead, awaiting discard */
#define WT_DHANDLE_DISCARD 0x02u /* Close on release */
#define WT_DHANDLE_DISCARD_KILL 0x04u /* Mark dead on release */
#define WT_DHANDLE_DROPPED 0x08u /* Handle is dropped */
#define WT_DHANDLE_EXCLUSIVE 0x10u /* Exclusive access */
#define WT_DHANDLE_IS_METADATA 0x20u /* Metadata handle */
#define WT_DHANDLE_LOCK_ONLY 0x40u /* Handle only used as a lock */
#define WT_DHANDLE_OPEN 0x80u /* Handle is open */
/* AUTOMATIC FLAG VALUE GENERATION STOP */
uint32_t flags;
};
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