gecko-dev/db/include/btree.h

345 строки
11 KiB
C

/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995, 1996
* Keith Bostic. All rights reserved.
*/
/*
* Copyright (c) 1990, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Mike Olson.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)btree.h 10.21 (Sleepycat) 5/23/98
*/
/* Forward structure declarations. */
struct __btree; typedef struct __btree BTREE;
struct __cursor; typedef struct __cursor CURSOR;
struct __epg; typedef struct __epg EPG;
struct __rcursor; typedef struct __rcursor RCURSOR;
struct __recno; typedef struct __recno RECNO;
#undef DEFMINKEYPAGE /* Minimum keys per page */
#define DEFMINKEYPAGE (2)
#undef ISINTERNAL /* If an internal page. */
#define ISINTERNAL(p) (TYPE(p) == P_IBTREE || TYPE(p) == P_IRECNO)
#undef ISLEAF /* If a leaf page. */
#define ISLEAF(p) (TYPE(p) == P_LBTREE || TYPE(p) == P_LRECNO)
/* Allocate and discard thread structures. */
#define GETHANDLE(dbp, set_txn, dbpp, ret) { \
if (F_ISSET(dbp, DB_AM_THREAD)) { \
if ((ret = __db_gethandle(dbp, __bam_bdup, dbpp)) != 0) \
return (ret); \
} else \
*dbpp = dbp; \
*dbpp->txn = set_txn; \
}
#define PUTHANDLE(dbp) { \
dbp->txn = NULL; \
if (F_ISSET(dbp, DB_AM_THREAD)) \
__db_puthandle(dbp); \
}
/*
* If doing transactions we have to hold the locks associated with a data item
* from a page for the entire transaction. However, we don't have to hold the
* locks associated with walking the tree. Distinguish between the two so that
* we don't tie up the internal pages of the tree longer than necessary.
*/
#define __BT_LPUT(dbp, lock) \
(F_ISSET((dbp), DB_AM_LOCKING) ? \
lock_put((dbp)->dbenv->lk_info, lock) : 0)
#define __BT_TLPUT(dbp, lock) \
(F_ISSET((dbp), DB_AM_LOCKING) && (dbp)->txn == NULL ? \
lock_put((dbp)->dbenv->lk_info, lock) : 0)
/*
* Flags to __bt_search() and __rec_search().
*
* Note, internal page searches must find the largest record less than key in
* the tree so that descents work. Leaf page searches must find the smallest
* record greater than key so that the returned index is the record's correct
* position for insertion.
*
* The flags parameter to the search routines describes three aspects of the
* search: the type of locking required (including if we're locking a pair of
* pages), the item to return in the presence of duplicates and whether or not
* to return deleted entries. To simplify both the mnemonic representation
* and the code that checks for various cases, we construct a set of bitmasks.
*/
#define S_READ 0x00001 /* Read locks. */
#define S_WRITE 0x00002 /* Write locks. */
#define S_APPEND 0x00040 /* Append to the tree. */
#define S_DELNO 0x00080 /* Don't return deleted items. */
#define S_DUPFIRST 0x00100 /* Return first duplicate. */
#define S_DUPLAST 0x00200 /* Return last duplicate. */
#define S_EXACT 0x00400 /* Exact items only. */
#define S_PARENT 0x00800 /* Lock page pair. */
#define S_STACK 0x01000 /* Need a complete stack. */
#define S_DELETE (S_WRITE | S_DUPFIRST | S_DELNO | S_EXACT | S_STACK)
#define S_FIND (S_READ | S_DUPFIRST | S_DELNO)
#define S_INSERT (S_WRITE | S_DUPLAST | S_STACK)
#define S_KEYFIRST (S_WRITE | S_DUPFIRST | S_STACK)
#define S_KEYLAST (S_WRITE | S_DUPLAST | S_STACK)
#define S_WRPAIR (S_WRITE | S_DUPLAST | S_PARENT)
/*
* If doing insert search (including keyfirst or keylast operations) or a
* split search on behalf of an insert, it's okay to return the entry one
* past the end of the page.
*/
#define PAST_END_OK(f) \
((f) == S_INSERT || \
(f) == S_KEYFIRST || (f) == S_KEYLAST || (f) == S_WRPAIR)
/*
* Flags to __bam_iitem().
*/
#define BI_DELETED 0x01 /* Key/data pair only placeholder. */
#define BI_DOINCR 0x02 /* Increment the record count. */
#define BI_NEWKEY 0x04 /* New key. */
/*
* Various routines pass around page references. A page reference can be a
* pointer to the page or a page number; for either, an indx can designate
* an item on the page.
*/
struct __epg {
PAGE *page; /* The page. */
db_indx_t indx; /* The index on the page. */
DB_LOCK lock; /* The page's lock. */
};
/*
* All cursors are queued from the master DB structure. Convert the user's
* DB reference to the master DB reference. We lock the master DB mutex
* so that we can walk the cursor queue. There's no race in accessing the
* cursors, because if we're modifying a page, we have a write lock on it,
* and therefore no other thread than the current one can have a cursor that
* references the page.
*/
#define CURSOR_SETUP(dbp) { \
(dbp) = (dbp)->master; \
DB_THREAD_LOCK(dbp); \
}
#define CURSOR_TEARDOWN(dbp) \
DB_THREAD_UNLOCK(dbp);
/*
* Btree cursor.
*
* Arguments passed to __bam_ca_replace().
*/
typedef enum {
REPLACE_SETUP,
REPLACE_SUCCESS,
REPLACE_FAILED
} ca_replace_arg;
struct __cursor {
DBC *dbc; /* Enclosing DBC. */
PAGE *page; /* Cursor page. */
db_pgno_t pgno; /* Page. */
db_indx_t indx; /* Page item ref'd by the cursor. */
db_pgno_t dpgno; /* Duplicate page. */
db_indx_t dindx; /* Page item ref'd by the cursor. */
DB_LOCK lock; /* Cursor read lock. */
db_lockmode_t mode; /* Lock mode. */
/*
* If a cursor record is deleted, the key/data pair has to remain on
* the page so that subsequent inserts/deletes don't interrupt the
* cursor progression through the file. This results in interesting
* cases when "standard" operations, e.g., dbp->put() are done in the
* context of "deleted" cursors.
*
* C_DELETED -- The item referenced by the cursor has been "deleted"
* but not physically removed from the page.
* C_REPLACE -- The "deleted" item referenced by a cursor has been
* replaced by a dbp->put(), so the cursor is no longer
* responsible for physical removal from the page.
* C_REPLACE_SETUP --
* We are about to overwrite a "deleted" item, flag any
* cursors referencing it for transition to C_REPLACE
* state.
*/
#define C_DELETED 0x0001
#define C_REPLACE 0x0002
#define C_REPLACE_SETUP 0x0004
/*
* Internal cursor held for DB->get; don't hold locks unless involved
* in a TXN.
*/
#define C_INTERNAL 0x0008
u_int32_t flags;
};
/*
* Recno cursor.
*
* Arguments passed to __ram_ca().
*/
typedef enum {
CA_DELETE,
CA_IAFTER,
CA_IBEFORE
} ca_recno_arg;
struct __rcursor {
DBC *dbc; /* Enclosing DBC. */
db_recno_t recno; /* Current record number. */
/*
* Cursors referencing "deleted" records are positioned between
* two records, and so must be specially adjusted until they are
* moved.
*/
#define CR_DELETED 0x0001 /* Record deleted. */
u_int32_t flags;
};
/*
* We maintain a stack of the pages that we're locking in the tree. Btree's
* (currently) only save two levels of the tree at a time, so the default
* stack is always large enough. Recno trees have to lock the entire tree to
* do inserts/deletes, however. Grow the stack as necessary.
*/
#undef BT_STK_CLR
#define BT_STK_CLR(t) \
((t)->bt_csp = (t)->bt_sp)
#undef BT_STK_ENTER
#define BT_STK_ENTER(t, pagep, page_indx, lock, ret) do { \
if ((ret = \
(t)->bt_csp == (t)->bt_esp ? __bam_stkgrow(t) : 0) == 0) { \
(t)->bt_csp->page = pagep; \
(t)->bt_csp->indx = page_indx; \
(t)->bt_csp->lock = lock; \
} \
} while (0)
#undef BT_STK_PUSH
#define BT_STK_PUSH(t, pagep, page_indx, lock, ret) do { \
BT_STK_ENTER(t, pagep, page_indx, lock, ret); \
++(t)->bt_csp; \
} while (0)
#undef BT_STK_POP
#define BT_STK_POP(t) \
((t)->bt_csp == (t)->bt_stack ? NULL : --(t)->bt_csp)
/*
* The in-memory recno data structure.
*
* !!!
* These fields are ignored as far as multi-threading is concerned. There
* are no transaction semantics associated with backing files, nor is there
* any thread protection.
*/
#undef RECNO_OOB
#define RECNO_OOB 0 /* Illegal record number. */
struct __recno {
int re_delim; /* Variable-length delimiting byte. */
int re_pad; /* Fixed-length padding byte. */
u_int32_t re_len; /* Length for fixed-length records. */
char *re_source; /* Source file name. */
int re_fd; /* Source file descriptor */
db_recno_t re_last; /* Last record number read. */
void *re_cmap; /* Current point in mapped space. */
void *re_smap; /* Start of mapped space. */
void *re_emap; /* End of mapped space. */
size_t re_msize; /* Size of mapped region. */
/* Recno input function. */
int (*re_irec) __P((DB *, db_recno_t));
#define RECNO_EOF 0x0001 /* EOF on backing source file. */
#define RECNO_MODIFIED 0x0002 /* Tree was modified. */
u_int32_t flags;
};
/*
* The in-memory btree data structure.
*/
struct __btree {
/*
* These fields are per-thread and are initialized when the BTREE structure
* is created.
*/
db_pgno_t bt_lpgno; /* Last insert location. */
DBT bt_rkey; /* Returned key. */
DBT bt_rdata; /* Returned data. */
EPG *bt_sp; /* Stack pointer. */
EPG *bt_csp; /* Current stack entry. */
EPG *bt_esp; /* End stack pointer. */
EPG bt_stack[5];
RECNO *bt_recno; /* Private recno structure. */
DB_BTREE_LSTAT lstat; /* Btree local statistics. */
/*
* These fields are copied from the original BTREE structure and never
* change.
*/
db_indx_t bt_maxkey; /* Maximum keys per page. */
db_indx_t bt_minkey; /* Minimum keys per page. */
int (*bt_compare) /* Comparison function. */
__P((const DBT *, const DBT *));
size_t(*bt_prefix) /* Prefix function. */
__P((const DBT *, const DBT *));
db_indx_t bt_ovflsize; /* Maximum key/data on-page size. */
};
#include "btree_auto.h"
#include "btree_ext.h"
#include "db_am.h"
#include "common_ext.h"