bt_cursor.c

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							space = *spacep + size;
						}
						break;
					}
					memcpy(dp,
					    (u_int8_t *)pg + HOFFSET(pg), size);
					need_pg = 0;
					space -= size;
					np += size;
				}
				if (first == 0 && keyoff != NULL) {
					*offp-- = keyoff[0];
					*offp-- = keyoff[-1];
				}
				size = bk->len;
				*offp-- = (int32_t)(inp[indx] - HOFFSET(pg)
				    + dp - dbuf + SSZA(BKEYDATA, data));
			}
			*offp-- = size;
			first = 0;
			if (no_dup)
				break;
contin:
			indx++;
			if (opd->dbtype == DB_RECNO)
				cp->recno++;
		} while (indx < NUM_ENT(pg));
		if (no_dup)
			break;
		cp->indx = indx;

	} while (ret == 0);

	/* Return the updated information. */
	*spacep = space;
	*offpp = offp;
	*dpp = np;

	/*
	 * If we ran out of space back up the pointer.
	 * If we did not return any dups or reached the end, close the opd.
	 */
	if (ret == ENOMEM) {
		if (opd->dbtype == DB_RECNO) {
			if (--cp->recno == 0)
				goto close_opd;
		} else if (indx != 0)
			cp->indx--;
		else {
			t_ret = __bam_c_prev(opd);
			if (t_ret == DB_NOTFOUND)
				goto close_opd;
			if (t_ret != 0)
				ret = t_ret;
		}
	} else if (keyoff == NULL && ret == DB_NOTFOUND) {
		cp->indx--;
		if (opd->dbtype == DB_RECNO)
			--cp->recno;
	} else if (indx == 0 || ret == DB_NOTFOUND) {
close_opd:
		opd->c_close(opd);
		((BTREE_CURSOR *)dbc->internal)->opd = NULL;
	}
	if (ret == DB_NOTFOUND)
		ret = 0;

	return (ret);
}

/*
 * __bam_getbothc --
 *	Search for a matching data item on a join.
 */
static int
__bam_getbothc(dbc, data)
	DBC *dbc;
	DBT *data;
{
	BTREE_CURSOR *cp;
	DB *dbp;
	DB_MPOOLFILE *mpf;
	int cmp, exact, ret;

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	cp = (BTREE_CURSOR *)dbc->internal;

	/*
	 * Acquire the current page.  We have at least a read-lock
	 * already.  The caller may have set DB_RMW asking for a
	 * write lock, but upgrading to a write lock has no better
	 * chance of succeeding now instead of later, so don't try.
	 */
	if ((ret = mpf->get(mpf, &cp->pgno, 0, &cp->page)) != 0)
		return (ret);

	/*
	 * An off-page duplicate cursor.  Search the remaining duplicates
	 * for one which matches (do a normal btree search, then verify
	 * that the retrieved record is greater than the original one).
	 */
	if (F_ISSET(dbc, DBC_OPD)) {
		/*
		 * Check to make sure the desired item comes strictly after
		 * the current position;  if it doesn't, return DB_NOTFOUND.
		 */
		if ((ret = __bam_cmp(dbp, data, cp->page, cp->indx,
		    dbp->dup_compare == NULL ? __bam_defcmp : dbp->dup_compare,
		    &cmp)) != 0)
			return (ret);

		if (cmp <= 0)
			return (DB_NOTFOUND);

		/* Discard the current page, we're going to do a full search. */
		if ((ret = mpf->put(mpf, cp->page, 0)) != 0)
			return (ret);
		cp->page = NULL;

		return (__bam_c_search(dbc,
		    PGNO_INVALID, data, DB_GET_BOTH, &exact));
	}

	/*
	 * We're doing a DBC->c_get(DB_GET_BOTHC) and we're already searching
	 * a set of on-page duplicates (either sorted or unsorted).  Continue
	 * a linear search from after the current position.
	 *
	 * (Note that we could have just finished a "set" of one duplicate,
	 * i.e. not a duplicate at all, but the following check will always
	 * return DB_NOTFOUND in this case, which is the desired behavior.)
	 */
	if (cp->indx + P_INDX >= NUM_ENT(cp->page) ||
	    !IS_DUPLICATE(dbc, cp->indx, cp->indx + P_INDX))
		return (DB_NOTFOUND);
	cp->indx += P_INDX;

	return (__bam_getboth_finddatum(dbc, data, DB_GET_BOTH));
}

/*
 * __bam_getboth_finddatum --
 *	Find a matching on-page data item.
 */
static int
__bam_getboth_finddatum(dbc, data, flags)
	DBC *dbc;
	DBT *data;
	u_int32_t flags;
{
	BTREE_CURSOR *cp;
	DB *dbp;
	db_indx_t base, lim, top;
	int cmp, ret;

	dbp = dbc->dbp;
	cp = (BTREE_CURSOR *)dbc->internal;

	/*
	 * Called (sometimes indirectly) from DBC->get to search on-page data
	 * item(s) for a matching value.  If the original flag was DB_GET_BOTH
	 * or DB_GET_BOTH_RANGE, the cursor is set to the first undeleted data
	 * item for the key.  If the original flag was DB_GET_BOTHC, the cursor
	 * argument is set to the first data item we can potentially return.
	 * In both cases, there may or may not be additional duplicate data
	 * items to search.
	 *
	 * If the duplicates are not sorted, do a linear search.
	 */
	if (dbp->dup_compare == NULL) {
		for (;; cp->indx += P_INDX) {
			if (!IS_CUR_DELETED(dbc) &&
			    (ret = __bam_cmp(dbp, data, cp->page,
			    cp->indx + O_INDX, __bam_defcmp, &cmp)) != 0)
				return (ret);
			if (cmp == 0)
				return (0);

			if (cp->indx + P_INDX >= NUM_ENT(cp->page) ||
			    !IS_DUPLICATE(dbc, cp->indx, cp->indx + P_INDX))
				break;
		}
		return (DB_NOTFOUND);
	}

	/*
	 * If the duplicates are sorted, do a binary search.  The reason for
	 * this is that large pages and small key/data pairs result in large
	 * numbers of on-page duplicates before they get pushed off-page.
	 *
	 * Find the top and bottom of the duplicate set.  Binary search
	 * requires at least two items, don't loop if there's only one.
	 */
	for (base = top = cp->indx; top < NUM_ENT(cp->page); top += P_INDX)
		if (!IS_DUPLICATE(dbc, cp->indx, top))
			break;
	if (base == (top - P_INDX)) {
		if  ((ret = __bam_cmp(dbp, data,
		    cp->page, cp->indx + O_INDX, dbp->dup_compare, &cmp)) != 0)
			return (ret);
		return (cmp == 0 ||
		    (cmp < 0 && flags == DB_GET_BOTH_RANGE) ? 0 : DB_NOTFOUND);
	}

	for (lim = (top - base) / (db_indx_t)P_INDX; lim != 0; lim >>= 1) {
		cp->indx = base + ((lim >> 1) * P_INDX);
		if ((ret = __bam_cmp(dbp, data, cp->page,
		    cp->indx + O_INDX, dbp->dup_compare, &cmp)) != 0)
			return (ret);
		if (cmp == 0) {
			/*
			 * XXX
			 * No duplicate duplicates in sorted duplicate sets,
			 * so there can be only one.
			 */
			if (!IS_CUR_DELETED(dbc))
				return (0);
			break;
		}
		if (cmp > 0) {
			base = cp->indx + P_INDX;
			--lim;
		}
	}

	/* No match found; if we're looking for an exact match, we're done. */
	if (flags == DB_GET_BOTH)
		return (DB_NOTFOUND);

	/*
	 * Base is the smallest index greater than the data item, may be zero
	 * or a last + O_INDX index, and may be deleted.  Find an undeleted
	 * item.
	 */
	cp->indx = base;
	while (cp->indx < top && IS_CUR_DELETED(dbc))
		cp->indx += P_INDX;
	return (cp->indx < top ? 0 : DB_NOTFOUND);
}

/*
 * __bam_c_put --
 *	Put using a cursor.
 */
static int
__bam_c_put(dbc, key, data, flags, pgnop)
	DBC *dbc;
	DBT *key, *data;
	u_int32_t flags;
	db_pgno_t *pgnop;
{
	BTREE_CURSOR *cp;
	DB *dbp;
	DBT dbt;
	DB_MPOOLFILE *mpf;
	db_pgno_t root_pgno;
	u_int32_t iiop;
	int cmp, exact, ret, stack;
	void *arg;

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	cp = (BTREE_CURSOR *)dbc->internal;
	root_pgno = cp->root;

split:	ret = stack = 0;
	switch (flags) {
	case DB_AFTER:
	case DB_BEFORE:
	case DB_CURRENT:
		iiop = flags;

		/*
		 * If the Btree has record numbers (and we're not replacing an
		 * existing record), we need a complete stack so that we can
		 * adjust the record counts.  The check for flags == DB_CURRENT
		 * is superfluous but left in for clarity.  (If C_RECNUM is set
		 * we know that flags must be DB_CURRENT, as DB_AFTER/DB_BEFORE
		 * are illegal in a Btree unless it's configured for duplicates
		 * and you cannot configure a Btree for both record renumbering
		 * and duplicates.)
		 */
		if (flags == DB_CURRENT &&
		    F_ISSET(cp, C_RECNUM) && F_ISSET(cp, C_DELETED)) {
			if ((ret = __bam_c_getstack(dbc)) != 0)
				goto err;
			/*
			 * Initialize the cursor from the stack.  Don't take
			 * the page number or page index, they should already
			 * be set.
			 */
			cp->page = cp->csp->page;
			cp->lock = cp->csp->lock;
			cp->lock_mode = cp->csp->lock_mode;

			stack = 1;
			break;
		}

		/* Acquire the current page with a write lock. */
		ACQUIRE_WRITE_LOCK(dbc, ret);
		if (ret != 0)
			goto err;
		if ((ret = mpf->get(mpf, &cp->pgno, 0, &cp->page)) != 0)
			goto err;
		break;
	case DB_KEYFIRST:
	case DB_KEYLAST:
	case DB_NODUPDATA:
		/*
		 * Searching off-page, sorted duplicate tree: do a tree search
		 * for the correct item; __bam_c_search returns the smallest
		 * slot greater than the key, use it.
		 *
		 * See comment below regarding where we can start the search.
		 */
		if (F_ISSET(dbc, DBC_OPD)) {
			if ((ret = __bam_c_search(dbc,
			    F_ISSET(cp, C_RECNUM) ? cp->root : root_pgno,
			    data, flags, &exact)) != 0)
				goto err;
			stack = 1;

			/* Disallow "sorted" duplicate duplicates. */
			if (exact) {
				if (IS_DELETED(dbp, cp->page, cp->indx)) {
					iiop = DB_CURRENT;
					break;
				}
				ret = __db_duperr(dbp, flags);
				goto err;
			}
			iiop = DB_BEFORE;
			break;
		}

		/*
		 * Searching a btree.
		 *
		 * If we've done a split, we can start the search from the
		 * parent of the split page, which __bam_split returned
		 * for us in root_pgno, unless we're in a Btree with record
		 * numbering.  In that case, we'll need the true root page
		 * in order to adjust the record count.
		 */
		if ((ret = __bam_c_search(dbc,
		    F_ISSET(cp, C_RECNUM) ? cp->root : root_pgno, key,
		    flags == DB_KEYFIRST || dbp->dup_compare != NULL ?
		    DB_KEYFIRST : DB_KEYLAST, &exact)) != 0)
			goto err;
		stack = 1;

		/*
		 * If we don't have an exact match, __bam_c_search returned
		 * the smallest slot greater than the key, use it.
		 */
		if (!exact) {
			iiop = DB_KEYFIRST;
			break;
		}

		/*
		 * If duplicates aren't supported, replace the current item.
		 * (If implementing the DB->put function, our caller already
		 * checked the DB_NOOVERWRITE flag.)
		 */
		if (!F_ISSET(dbp, DB_AM_DUP)) {
			iiop = DB_CURRENT;
			break;
		}

		/*
		 * If we find a matching entry, it may be an off-page duplicate
		 * tree.  Return the page number to our caller, we need a new
		 * cursor.
		 */
		if (pgnop != NULL && __bam_isopd(dbc, pgnop))
			goto done;

		/* If the duplicates aren't sorted, move to the right slot. */
		if (dbp->dup_compare == NULL) {
			if (flags == DB_KEYFIRST)
				iiop = DB_BEFORE;
			else
				for (;; cp->indx += P_INDX)
					if (cp->indx + P_INDX >=
					    NUM_ENT(cp->page) ||
					    !IS_DUPLICATE(dbc, cp->indx,
					    cp->indx + P_INDX)) {
						iiop = DB_AFTER;
						break;
					}
			break;
		}

		/*
		 * We know that we're looking at the first of a set of sorted
		 * on-page duplicates.  Walk the list to find the right slot.
		 */
		for (;; cp->indx += P_INDX) {
			if ((ret = __bam_cmp(dbp, data, cp->page,
			    cp->indx + O_INDX, dbp->dup_compare, &cmp)) != 0)
				goto err;
			if (cmp < 0) {
				iiop = DB_BEFORE;
				break;
			}

			/* Disallow "sorted" duplicate duplicates. */
			if (cmp == 0) {
				if (IS_DELETED(dbp, cp->page, cp->indx)) {
					iiop = DB_CURRENT;
					break;
				}
				ret = __db_duperr(dbp, flags);
				goto err;
			}

			if (cp->indx + P_INDX >= NUM_ENT(cp->page) ||
			    P_INP(dbp, ((PAGE *)cp->page))[cp->indx] !=
			    P_INP(dbp, ((PAGE *)cp->page))[cp->indx + P_INDX]) {
				iiop = DB_AFTER;
				break;
			}
		}
		break;
	default:
		ret = __db_unknown_flag(dbp->dbenv, "__bam_c_put", flags);
		goto err;
	}

	switch (ret = __bam_iitem(dbc, key, data, iiop, 0)) {
	case 0:
		break;
	case DB_NEEDSPLIT:
		/*
		 * To split, we need a key for the page.  Either use the key
		 * argument or get a copy of the key from the page.
		 */
		if (flags == DB_AFTER ||
		    flags == DB_BEFORE || flags == DB_CURRENT) {
			memset(&dbt, 0, sizeof(DBT));
			if ((ret = __db_ret(dbp, cp->page, 0, &dbt,
			    &dbc->rkey->data, &dbc->rkey->ulen)) != 0)
				goto err;
			arg = &dbt;
		} else
			arg = F_ISSET(dbc, DBC_OPD) ? data : key;

		/*
		 * Discard any locks and pinned pages (the locks are discarded
		 * even if we're running with transactions, as they lock pages
		 * that we're sorry we ever acquired).  If stack is set and the
		 * cursor entries are valid, they point to the same entries as
		 * the stack, don't free them twice.
		 */
		if (stack)
			ret = __bam_stkrel(dbc, STK_CLRDBC | STK_NOLOCK);
		else
			DISCARD_CUR(dbc, ret);
		if (ret != 0)
			goto err;

		/* Split the tree. */
		if ((ret = __bam_split(dbc, arg, &root_pgno)) != 0)
			return (ret);

		goto split;
	default:
		goto err;
	}

err:
done:	/*
	 * Discard any pages pinned in the tree and their locks, except for
	 * the leaf page.  Note, the leaf page participated in any stack we
	 * acquired, and so we have to adjust the stack as necessary.  If
	 * there was only a single page on the stack, we don't have to free
	 * further stack pages.
	 */
	if (stack && BT_STK_POP(cp) != NULL)
		(void)__bam_stkrel(dbc, 0);

	/*
	 * Regardless of whether we were successful or not, clear the delete
	 * flag.  If we're successful, we either moved the cursor or the item
	 * is no longer deleted.  If we're not successful, then we're just a
	 * copy, no need to have the flag set.
	 */
	F_CLR(cp, C_DELETED);

	return (ret);
}

/*
 * __bam_c_rget --
 *	Return the record number for a cursor.
 *
 * PUBLIC: int __bam_c_rget __P((DBC *, DBT *));
 */
int
__bam_c_rget(dbc, data)
	DBC *dbc;