hash_page.c

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

	/* Put the item element on the page. */
	if (type == H_OFFPAGE) {
		off = HOFFSET(p) - dbt->size;
		HOFFSET(p) = inp[n] = off;
		memcpy(P_ENTRY(dbp, p, n), dbt->data, dbt->size);
	} else {
		off = HOFFSET(p) - HKEYDATA_SIZE(dbt->size);
		HOFFSET(p) = inp[n] = off;
		PUT_HKEYDATA(P_ENTRY(dbp, p, n), dbt->data, dbt->size, type);
	}

	/* Adjust page info. */
	NUM_ENT(p) += 1;
}

/*
 * PUBLIC: void __ham_reputpair  __P((DB *, PAGE *,
 * PUBLIC:    u_int32_t, const DBT *, const DBT *));
 *
 * This is a special case to restore a key/data pair to its original
 * location during recovery.  We are guaranteed that the pair fits
 * on the page and is not the last pair on the page (because if it's
 * the last pair, the normal insert works).
 */
void
__ham_reputpair(dbp, p, ndx, key, data)
	DB *dbp;
	PAGE *p;
	u_int32_t ndx;
	const DBT *key, *data;
{
	db_indx_t i, *inp, movebytes, newbytes;
	size_t psize;
	u_int8_t *from;

	psize = dbp->pgsize;
	inp = P_INP(dbp, p);
	/* First shuffle the existing items up on the page.  */
	movebytes = (db_indx_t)(
	    (ndx == 0 ? psize : inp[H_DATAINDEX(ndx - 2)]) - HOFFSET(p));
	newbytes = key->size + data->size;
	from = (u_int8_t *)p + HOFFSET(p);
	memmove(from - newbytes, from, movebytes);

	/*
	 * Adjust the indices and move them up 2 spaces. Note that we
	 * have to check the exit condition inside the loop just in case
	 * we are dealing with index 0 (db_indx_t's are unsigned).
	 */
	for (i = NUM_ENT(p) - 1; ; i-- ) {
		inp[i + 2] = inp[i] - newbytes;
		if (i == H_KEYINDEX(ndx))
			break;
	}

	/* Put the key and data on the page. */
	inp[H_KEYINDEX(ndx)] = (db_indx_t)(
	    (ndx == 0 ? psize : inp[H_DATAINDEX(ndx - 2)]) - key->size);
	inp[H_DATAINDEX(ndx)] = inp[H_KEYINDEX(ndx)] - data->size;
	memcpy(P_ENTRY(dbp, p, H_KEYINDEX(ndx)), key->data, key->size);
	memcpy(P_ENTRY(dbp, p, H_DATAINDEX(ndx)), data->data, data->size);

	/* Adjust page info. */
	HOFFSET(p) -= newbytes;
	NUM_ENT(p) += 2;
}

/*
 * PUBLIC: int __ham_del_pair __P((DBC *, int));
 */
int
__ham_del_pair(dbc, reclaim_page)
	DBC *dbc;
	int reclaim_page;
{
	DB *dbp;
	DBT data_dbt, key_dbt;
	DB_LSN new_lsn, *n_lsn, tmp_lsn;
	DB_MPOOLFILE *mpf;
	HASH_CURSOR *hcp;
	PAGE *n_pagep, *nn_pagep, *p, *p_pagep;
	db_ham_mode op;
	db_indx_t ndx;
	db_pgno_t chg_pgno, pgno, tmp_pgno;
	int ret, t_ret;
	u_int32_t order;

	dbp = dbc->dbp;
	mpf = dbp->mpf;
	hcp = (HASH_CURSOR *)dbc->internal;
	n_pagep = p_pagep = nn_pagep = NULL;
	ndx = hcp->indx;

	if (hcp->page == NULL &&
	    (ret = mpf->get(mpf, &hcp->pgno, DB_MPOOL_CREATE, &hcp->page)) != 0)
		return (ret);
	p = hcp->page;

	/*
	 * We optimize for the normal case which is when neither the key nor
	 * the data are large.  In this case, we write a single log record
	 * and do the delete.  If either is large, we'll call __big_delete
	 * to remove the big item and then update the page to remove the
	 * entry referring to the big item.
	 */
	ret = 0;
	if (HPAGE_PTYPE(H_PAIRKEY(dbp, p, ndx)) == H_OFFPAGE) {
		memcpy(&pgno, HOFFPAGE_PGNO(P_ENTRY(dbp, p, H_KEYINDEX(ndx))),
		    sizeof(db_pgno_t));
		ret = __db_doff(dbc, pgno);
	}

	if (ret == 0)
		switch (HPAGE_PTYPE(H_PAIRDATA(dbp, p, ndx))) {
		case H_OFFPAGE:
			memcpy(&pgno,
			    HOFFPAGE_PGNO(P_ENTRY(dbp, p, H_DATAINDEX(ndx))),
			    sizeof(db_pgno_t));
			ret = __db_doff(dbc, pgno);
			break;
		case H_OFFDUP:
		case H_DUPLICATE:
			/*
			 * If we delete a pair that is/was a duplicate, then
			 * we had better clear the flag so that we update the
			 * cursor appropriately.
			 */
			F_CLR(hcp, H_ISDUP);
			break;
		}

	if (ret)
		return (ret);

	/* Now log the delete off this page. */
	if (DBC_LOGGING(dbc)) {
		key_dbt.data = P_ENTRY(dbp, p, H_KEYINDEX(ndx));
		key_dbt.size = LEN_HITEM(dbp, p, dbp->pgsize, H_KEYINDEX(ndx));
		data_dbt.data = P_ENTRY(dbp, p, H_DATAINDEX(ndx));
		data_dbt.size = LEN_HITEM(dbp, p, dbp->pgsize, H_DATAINDEX(ndx));

		if ((ret = __ham_insdel_log(dbp,
		    dbc->txn, &new_lsn, 0, DELPAIR, PGNO(p), (u_int32_t)ndx,
		    &LSN(p), &key_dbt, &data_dbt)) != 0)
			return (ret);
	} else
		LSN_NOT_LOGGED(new_lsn);

	/* Move lsn onto page. */
	LSN(p) = new_lsn;

	/* Do the delete. */
	__ham_dpair(dbp, p, ndx);

	/*
	 * Mark item deleted so that we don't try to return it, and
	 * so that we update the cursor correctly on the next call
	 * to next.
	 */
	F_SET(hcp, H_DELETED);
	F_CLR(hcp, H_OK);

	/*
	 * Update cursors that are on the page where the delete happend.
	 */
	if ((ret = __ham_c_update(dbc, 0, 0, 0)) != 0)
		return (ret);

	/*
	 * If we are locking, we will not maintain this, because it is
	 * a hot spot.
	 *
	 * XXX
	 * Perhaps we can retain incremental numbers and apply them later.
	 */
	if (!STD_LOCKING(dbc)) {
		--hcp->hdr->nelem;
		if ((ret = __ham_dirty_meta(dbc)) != 0)
			return (ret);
	}

	/*
	 * If we need to reclaim the page, then check if the page is empty.
	 * There are two cases.  If it's empty and it's not the first page
	 * in the bucket (i.e., the bucket page) then we can simply remove
	 * it. If it is the first chain in the bucket, then we need to copy
	 * the second page into it and remove the second page.
	 * If its the only page in the bucket we leave it alone.
	 */
	if (!reclaim_page ||
	    NUM_ENT(p) != 0 ||
	    (PREV_PGNO(p) == PGNO_INVALID && NEXT_PGNO(p) == PGNO_INVALID))
		return (mpf->set(mpf, p, DB_MPOOL_DIRTY));

	if (PREV_PGNO(p) == PGNO_INVALID) {
		/*
		 * First page in chain is empty and we know that there
		 * are more pages in the chain.
		 */
		if ((ret = mpf->get(mpf, &NEXT_PGNO(p), 0, &n_pagep)) != 0)
			return (ret);

		if (NEXT_PGNO(n_pagep) != PGNO_INVALID && (ret =
		    mpf->get(mpf, &NEXT_PGNO(n_pagep), 0, &nn_pagep)) != 0)
			goto err;

		if (DBC_LOGGING(dbc)) {
			key_dbt.data = n_pagep;
			key_dbt.size = dbp->pgsize;
			if ((ret = __ham_copypage_log(dbp,
			    dbc->txn, &new_lsn, 0, PGNO(p),
			    &LSN(p), PGNO(n_pagep), &LSN(n_pagep),
			    NEXT_PGNO(n_pagep),
			    nn_pagep == NULL ? NULL : &LSN(nn_pagep),
			    &key_dbt)) != 0)
				goto err;
		} else
			LSN_NOT_LOGGED(new_lsn);

		/* Move lsn onto page. */
		LSN(p) = new_lsn;	/* Structure assignment. */
		LSN(n_pagep) = new_lsn;
		if (NEXT_PGNO(n_pagep) != PGNO_INVALID)
			LSN(nn_pagep) = new_lsn;

		if (nn_pagep != NULL) {
			PREV_PGNO(nn_pagep) = PGNO(p);
			if ((ret =
			    mpf->put(mpf, nn_pagep, DB_MPOOL_DIRTY)) != 0) {
				nn_pagep = NULL;
				goto err;
			}
		}

		tmp_pgno = PGNO(p);
		tmp_lsn = LSN(p);
		memcpy(p, n_pagep, dbp->pgsize);
		PGNO(p) = tmp_pgno;
		LSN(p) = tmp_lsn;
		PREV_PGNO(p) = PGNO_INVALID;

		/*
		 * Update cursors to reflect the fact that records
		 * on the second page have moved to the first page.
		 */
		if ((ret = __ham_c_delpg(dbc, PGNO(n_pagep),
		    PGNO(p), 0, DB_HAM_DELFIRSTPG, &order)) != 0)
			goto err;

		/*
		 * Update the cursor to reflect its new position.
		 */
		hcp->indx = 0;
		hcp->pgno = PGNO(p);
		hcp->order += order;

		if ((ret = mpf->set(mpf, p, DB_MPOOL_DIRTY)) != 0)
			goto err;
		if ((ret = __db_free(dbc, n_pagep)) != 0) {
			n_pagep = NULL;
			goto err;
		}
	} else {
		if ((ret = mpf->get(mpf, &PREV_PGNO(p), 0, &p_pagep)) != 0)
			goto err;

		if (NEXT_PGNO(p) != PGNO_INVALID) {
			if ((ret =
			    mpf->get(mpf, &NEXT_PGNO(p), 0, &n_pagep)) != 0)
				goto err;
			n_lsn = &LSN(n_pagep);
		} else {
			n_pagep = NULL;
			n_lsn = NULL;
		}

		NEXT_PGNO(p_pagep) = NEXT_PGNO(p);
		if (n_pagep != NULL)
			PREV_PGNO(n_pagep) = PGNO(p_pagep);

		if (DBC_LOGGING(dbc)) {
			if ((ret = __ham_newpage_log(dbp, dbc->txn,
			    &new_lsn, 0, DELOVFL, PREV_PGNO(p), &LSN(p_pagep),
			    PGNO(p), &LSN(p), NEXT_PGNO(p), n_lsn)) != 0)
				goto err;
		} else
			LSN_NOT_LOGGED(new_lsn);

		/* Move lsn onto page. */
		LSN(p_pagep) = new_lsn;	/* Structure assignment. */
		if (n_pagep)
			LSN(n_pagep) = new_lsn;
		LSN(p) = new_lsn;

		if (NEXT_PGNO(p) == PGNO_INVALID) {
			/*
			 * There is no next page; put the cursor on the
			 * previous page as if we'd deleted the last item
			 * on that page, with index after the last valid
			 * entry.
			 *
			 * The deleted flag was set up above.
			 */
			hcp->pgno = PGNO(p_pagep);
			hcp->indx = NUM_ENT(p_pagep);
			op = DB_HAM_DELLASTPG;
		} else {
			/*
			 * There is a next page, so put the cursor at
			 * the beginning of it.
			 */
			hcp->pgno = NEXT_PGNO(p);
			hcp->indx = 0;
			op = DB_HAM_DELMIDPG;
		}

		/*
		 * Since we are about to delete the cursor page and we have
		 * just moved the cursor, we need to make sure that the
		 * old page pointer isn't left hanging around in the cursor.
		 */
		hcp->page = NULL;
		chg_pgno = PGNO(p);
		ret = __db_free(dbc, p);
		if ((t_ret =
		    mpf->put(mpf, p_pagep, DB_MPOOL_DIRTY)) != 0 && ret == 0)
			ret = t_ret;
		if (n_pagep != NULL && (t_ret =
		    mpf->put(mpf, n_pagep, DB_MPOOL_DIRTY)) != 0 && ret == 0)
			ret = t_ret;
		if (ret != 0)
			return (ret);
		if ((ret = __ham_c_delpg(dbc,
		    chg_pgno, hcp->pgno, hcp->indx, op, &order)) != 0)
			return (ret);
		hcp->order += order;
	}
	return (ret);

err:	/* Clean up any pages. */
	if (n_pagep != NULL)
		(void)mpf->put(mpf, n_pagep, 0);
	if (nn_pagep != NULL)
		(void)mpf->put(mpf, nn_pagep, 0);
	if (p_pagep != NULL)
		(void)mpf->put(mpf, p_pagep, 0);
	return (ret);
}

/*
 * __ham_replpair --
 *	Given the key data indicated by the cursor, replace part/all of it
 *	according to the fields in the dbt.
 *
 * PUBLIC: int __ham_replpair __P((DBC *, DBT *, u_int32_t));
 */
int
__ham_replpair(dbc, dbt, make_dup)
	DBC *dbc;
	DBT *dbt;
	u_int32_t make_dup;
{
	DB *dbp;
	DBT old_dbt, tdata, tmp;
	DB_ENV *dbenv;
	DB_LSN	new_lsn;
	HASH_CURSOR *hcp;
	int32_t change;			/* XXX: Possible overflow. */
	u_int32_t dup_flag, len, memsize;
	int beyond_eor, is_big, ret, type;
	u_int8_t *beg, *dest, *end, *hk, *src;
	void *memp;

	/*
	 * Big item replacements are handled in generic code.
	 * Items that fit on the current page fall into 4 classes.
	 * 1. On-page element, same size
	 * 2. On-page element, new is bigger (fits)
	 * 3. On-page element, new is bigger (does not fit)
	 * 4. On-page element, old is bigger
	 * Numbers 1, 2, and 4 are essentially the same (and should
	 * be the common case).  We handle case 3 as a delete and
	 * add.
	 */
	dbp = dbc->dbp;
	dbenv = dbp->dbenv;
	hcp = (HASH_CURSOR *)dbc->internal;

	/*
	 * We need to compute the number of bytes that we are adding or
	 * removing from the entry.  Normally, we can simply substract
	 * the number of bytes we are replacing (dbt->dlen) from the
	 * number of bytes we are inserting (dbt->size).  However, if
	 * we are doing a partial put off the end of a record, then this
	 * formula doesn't work, because we are essentially adding
	 * new bytes.
	 */
	change = dbt->size - dbt->dlen;

	hk = H_PAIRDATA(dbp, hcp->page, hcp->indx);
	is_big = HPAGE_PTYPE(hk) == H_OFFPAGE;

	if (is_big)
		memcpy(&len, HOFFPAGE_TLEN(hk), sizeof(u_int32_t));
	else
		len = LEN_HKEYDATA(dbp, hcp->page,
		    dbp->pgsize, H_DATAINDEX(hcp->indx));

	beyond_eor = dbt->doff + dbt->dlen > len;
	if (beyond_eor)
		change += dbt->doff + dbt->dlen - len;

	if (change > (int32_t)P_FREESPACE(dbp, hcp->page) ||
	    beyond_eor || is_big) {
		/*
		 * Case 3 -- two subcases.
		 * A. This is not really a partial operation, but an overwrite.
		 *    Simple del and add works.
		 * B. This is a partial and we need to construct the data that
		 *    we are really inserting (yuck).
		 * In both cases, we need to grab the key off the page (in
		 * some cases we could do this outside of this routine; for
		 * cleanliness we do it here.  If you happen to be on a big
		 * key, this could be a performance hit).
		 */
		memset(&tmp, 0, sizeof(tmp));
		if ((ret =
		    __db_ret(dbp, hcp->page, H_KEYINDEX(hcp->indx),
		    &tmp, &dbc->rkey->data, &dbc->rkey->ulen)) != 0)
			return (ret);

		/* Preserve duplicate info. */
		dup_flag = F_ISSET(hcp, H_ISDUP);
		if (dbt->doff == 0 && dbt->dlen == len) {
			ret = __ham_del_pair(dbc, 0);
			if (ret == 0)
			    ret = __ham_add_el(dbc,
				&tmp, dbt, dup_flag ? H_DUPLICATE : H_KEYDATA);
		} else {					/* Case B */
			type = HPAGE_PTYPE(hk) != H_OFFPAGE ?
			    HPAGE_PTYPE(hk) : H_KEYDATA;
			memset(&tdata, 0, sizeof(tdata));
			memp = NULL;
			memsize = 0;
			if ((ret = __db_ret(dbp, hcp->page,
			    H_DATAINDEX(hcp->indx), &tdata, &memp, &memsize))
			    != 0)
				goto err;

			/* Now we can delete the item. */
			if ((ret = __ham_del_pair(dbc, 0)) != 0) {
				__os_free(dbenv, memp);
				goto err;
			}

			/* Now shift old data around to make room for new. */
			if (change > 0) {
				if ((ret = __os_realloc(dbenv,
				    tdata.size + change, &tdata.data)) != 0)
					return (ret);
				memp = tdata.data;
				memsize = tdata.size + change;
				memset((u_int8_t *)tdata.data + tdata.size,
				    0, change);
			}