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/*-
* Copyright (c) 2014-2016 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))
/* The metadata cursor's data handle. */
#define WT_SESSION_META_DHANDLE(s) \
(((WT_CURSOR_BTREE *)((s)->meta_cursor))->btree->dhandle)
/*
* 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;
/*
* Sessions caching 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.
*/
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 */
time_t timeofdeath; /* Use count went to 0 */
WT_SESSION_IMPL *excl_session; /* Session with exclusive use, if any */
uint64_t name_hash; /* Hash of name */
const char *name; /* Object name as a URI */
const char *checkpoint; /* Checkpoint name (or NULL) */
const char **cfg; /* Configuration information */
bool compact_skip; /* If the handle failed to compact */
WT_DATA_SOURCE *dsrc; /* Data source for this handle */
void *handle; /* Generic handle */
/*
* 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_* */
#define WT_DHANDLE_DEAD 0x01 /* Dead, awaiting discard */
#define WT_DHANDLE_DISCARD 0x02 /* Discard on release */
#define WT_DHANDLE_DISCARD_FORCE 0x04 /* Force discard on release */
#define WT_DHANDLE_EXCLUSIVE 0x08 /* Need exclusive access */
#define WT_DHANDLE_IS_METADATA 0x10 /* Metadata handle */
#define WT_DHANDLE_LOCK_ONLY 0x20 /* Handle only used as a lock */
#define WT_DHANDLE_OPEN 0x40 /* Handle is open */
uint32_t flags;
};
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