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bbolt
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bbolt/cursor.go

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package bolt
// TODO: #define CURSOR_STACK 32
const (
c_initialized = 0x01 /**< cursor has been initialized and is valid */
c_eof = 0x02 /**< No more data */
c_del = 0x08 /**< last op was a cursor_del */
c_splitting = 0x20 /**< Cursor is in page_split */
c_untrack = 0x40 /**< Un-track cursor when closing */
)
type Cursor struct {
flags int
next *Cursor
backup *Cursor
transaction *Transaction
bucket *Bucket
top int
pages []*page
indices []int /* the index of the node for the page at the same level */
}
// , data []byte, op int
func (c *Cursor) Get(key []byte) ([]byte, error) {
/*
int rc;
int exact = 0;
int (*mfunc)(MDB_cursor *mc, MDB_val *key, MDB_val *data);
switch (op) {
case MDB_GET_CURRENT:
if (!(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
} else {
MDB_page *mp = mc->mc_pg[mc->mc_top];
int nkeys = NUMKEYS(mp);
if (!nkeys || mc->mc_ki[mc->mc_top] >= nkeys) {
mc->mc_ki[mc->mc_top] = nkeys;
rc = MDB_NOTFOUND;
break;
}
rc = MDB_SUCCESS;
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
} else {
MDB_node *leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY(leaf, key);
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (mc->mc_flags & C_DEL)
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_get(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_GET_CURRENT);
} else {
rc = mdb_node_read(mc->mc_txn, leaf, data);
}
}
}
}
break;
case MDB_GET_BOTH:
case MDB_GET_BOTH_RANGE:
if (data == NULL) {
rc = EINVAL;
break;
}
if (mc->mc_xcursor == NULL) {
rc = MDB_INCOMPATIBLE;
break;
}
// FALLTHRU
case MDB_SET:
case MDB_SET_KEY:
case MDB_SET_RANGE:
if (key == NULL) {
rc = EINVAL;
} else {
rc = mdb_cursor_set(mc, key, data, op,
op == MDB_SET_RANGE ? NULL : &exact);
}
break;
case MDB_GET_MULTIPLE:
if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = MDB_INCOMPATIBLE;
break;
}
rc = MDB_SUCCESS;
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) ||
(mc->mc_xcursor->mx_cursor.mc_flags & C_EOF))
break;
goto fetchm;
case MDB_NEXT_MULTIPLE:
if (data == NULL) {
rc = EINVAL;
break;
}
if (!(mc->mc_db->md_flags & MDB_DUPFIXED)) {
rc = MDB_INCOMPATIBLE;
break;
}
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
rc = mdb_cursor_next(mc, key, data, MDB_NEXT_DUP);
if (rc == MDB_SUCCESS) {
if (mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED) {
MDB_cursor *mx;
fetchm:
mx = &mc->mc_xcursor->mx_cursor;
data->mv_size = NUMKEYS(mx->mc_pg[mx->mc_top]) *
mx->mc_db->md_pad;
data->mv_data = METADATA(mx->mc_pg[mx->mc_top]);
mx->mc_ki[mx->mc_top] = NUMKEYS(mx->mc_pg[mx->mc_top])-1;
} else {
rc = MDB_NOTFOUND;
}
}
break;
case MDB_NEXT:
case MDB_NEXT_DUP:
case MDB_NEXT_NODUP:
if (!(mc->mc_flags & C_INITIALIZED))
rc = mdb_cursor_first(mc, key, data);
else
rc = mdb_cursor_next(mc, key, data, op);
break;
case MDB_PREV:
case MDB_PREV_DUP:
case MDB_PREV_NODUP:
if (!(mc->mc_flags & C_INITIALIZED)) {
rc = mdb_cursor_last(mc, key, data);
if (rc)
break;
mc->mc_flags |= C_INITIALIZED;
mc->mc_ki[mc->mc_top]++;
}
rc = mdb_cursor_prev(mc, key, data, op);
break;
case MDB_FIRST:
rc = mdb_cursor_first(mc, key, data);
break;
case MDB_FIRST_DUP:
mfunc = mdb_cursor_first;
mmove:
if (data == NULL || !(mc->mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
if (mc->mc_xcursor == NULL) {
rc = MDB_INCOMPATIBLE;
break;
}
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED)) {
rc = EINVAL;
break;
}
rc = mfunc(&mc->mc_xcursor->mx_cursor, data, NULL);
break;
case MDB_LAST:
rc = mdb_cursor_last(mc, key, data);
break;
case MDB_LAST_DUP:
mfunc = mdb_cursor_last;
goto mmove;
default:
DPRINTF(("unhandled/unimplemented cursor operation %u", op));
rc = EINVAL;
break;
}
if (mc->mc_flags & C_DEL)
mc->mc_flags ^= C_DEL;
return rc;
*/
return nil, nil
}
// page retrieves a page with a given key.
func (c *Cursor) page(key []byte, flags int) (*page, error) {
p := c.pages[c.top]
for {
// Find the page index.
var index indx
if (flags & ps_first) != 0 {
index = 0
} else if (flags & ps_last) != 0 {
index = indx(p.numkeys()) - 1
} else {
node, i, exact := p.find(key, c.transaction.db.pageSize)
if exact {
c.indices[c.top] = i
}
if node == nil {
index = indx(p.numkeys()) - 1
} else {
index = indx(c.indices[c.top])
if !exact {
index -= 1
}
}
}
// Find the node index.
node := p.node(index)
// Traverse to next page.
p = c.transaction.db.page(c.transaction.db.data, int(node.pgno()))
c.indices[c.top] = int(index)
c.push(p)
// TODO:
// if (flags & MDB_PS_MODIFY) {
// if ((rc = mdb_page_touch(mc)) != 0)
// return rc;
// mp = mc->mc_pg[mc->mc_top];
// }
}
// If we ended up with a non-leaf page by the end then something is wrong.
if p.flags&p_leaf == 0 {
return nil, CorruptedError
}
// TODO: mc->mc_flags |= C_INITIALIZED;
// TODO: mc->mc_flags &= ~C_EOF;
return p, nil
}
// pop moves the last page off the cursor's page stack.
func (c *Cursor) pop() {
top := len(c.pages) - 1
c.pages = c.pages[0:c.top]
c.indices = c.indices[0:c.top]
}
// push moves a page onto the top of the cursor's page stack.
func (c *Cursor) push(p *page) {
c.pages = append(c.pages, p)
c.indices = append(c.indices, 0)
c.top = len(c.pages) - 1
}
// currentPage retrieves the last page on the page stack.
func (c *Cursor) currentPage() *page {
top := len(c.pages)
if top > 0 {
return c.pages[top]
}
return nil
}
// branchNode retrieves the branch node pointed to on the current page.
func (c *Cursor) currentBranchNode() *page {
top := len(c.pages)
if top > 0 {
return c.pages[top].branchNode(c.indices[top])
}
return nil
}
// lnode retrieves the leaf node pointed to on the current page.
func (c *Cursor) currentLeafNode() *node {
top := len(c.pages)
if top > 0 {
return c.pages[top].leaf(c.indices[top])
}
return nil
}
// //
// //
// //
// //
// //
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ CONVERTED ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ //
// //
// //
// //
// //
// //
// Set or clear P_KEEP in dirty, non-overflow, non-sub pages watched by txn.
// @param[in] mc A cursor handle for the current operation.
// @param[in] pflags Flags of the pages to update:
// P_DIRTY to set P_KEEP, P_DIRTY|P_KEEP to clear it.
// @param[in] all No shortcuts. Needed except after a full #mdb_page_flush().
// @return 0 on success, non-zero on failure.
func (c *Cursor) xkeep(pflags int, all int) error {
/*
enum { Mask = P_SUBP|P_DIRTY|P_KEEP };
MDB_txn *txn = mc->mc_txn;
MDB_cursor *m3;
MDB_xcursor *mx;
MDB_page *dp, *mp;
MDB_node *leaf;
unsigned i, j;
int rc = MDB_SUCCESS, level;
// Mark pages seen by cursors
if (mc->mc_flags & C_UNTRACK)
mc = NULL; // will find mc in mt_cursors
for (i = txn->mt_numdbs;; mc = txn->mt_cursors[--i]) {
for (; mc; mc=mc->mc_next) {
if (!(mc->mc_flags & C_INITIALIZED))
continue;
for (m3 = mc;; m3 = &mx->mx_cursor) {
mp = NULL;
for (j=0; j<m3->mc_snum; j++) {
mp = m3->mc_pg[j];
if ((mp->mp_flags & Mask) == pflags)
mp->mp_flags ^= P_KEEP;
}
mx = m3->mc_xcursor;
// Proceed to mx if it is at a sub-database
if (! (mx && (mx->mx_cursor.mc_flags & C_INITIALIZED)))
break;
if (! (mp && (mp->mp_flags & P_LEAF)))
break;
leaf = NODEPTR(mp, m3->mc_ki[j-1]);
if (!(leaf->mn_flags & F_SUBDATA))
break;
}
}
if (i == 0)
break;
}
if (all) {
// Mark dirty root pages
for (i=0; i<txn->mt_numdbs; i++) {
if (txn->mt_dbflags[i] & DB_DIRTY) {
pgno_t pgno = txn->mt_dbs[i].md_root;
if (pgno == P_INVALID)
continue;
if ((rc = mdb_page_get(txn, pgno, &dp, &level)) != MDB_SUCCESS)
break;
if ((dp->mp_flags & Mask) == pflags && level <= 1)
dp->mp_flags ^= P_KEEP;
}
}
}
return rc;
*/
return nil
}
// Spill pages from the dirty list back to disk.
// This is intended to prevent running into #MDB_TXN_FULL situations,
// but note that they may still occur in a few cases:
// 1) our estimate of the txn size could be too small. Currently this
// seems unlikely, except with a large number of #MDB_MULTIPLE items.
// 2) child txns may run out of space if their parents dirtied a
// lot of pages and never spilled them. TODO: we probably should do
// a preemptive spill during #mdb_txn_begin() of a child txn, if
// the parent's dirty_room is below a given threshold.
//
// Otherwise, if not using nested txns, it is expected that apps will
// not run into #MDB_TXN_FULL any more. The pages are flushed to disk
// the same way as for a txn commit, e.g. their P_DIRTY flag is cleared.
// If the txn never references them again, they can be left alone.
// If the txn only reads them, they can be used without any fuss.
// If the txn writes them again, they can be dirtied immediately without
// going thru all of the work of #mdb_page_touch(). Such references are
// handled by #mdb_page_unspill().
//
// Also note, we never spill DB root pages, nor pages of active cursors,
// because we'll need these back again soon anyway. And in nested txns,
// we can't spill a page in a child txn if it was already spilled in a
// parent txn. That would alter the parent txns' data even though
// the child hasn't committed yet, and we'd have no way to undo it if
// the child aborted.
//
// @param[in] m0 cursor A cursor handle identifying the transaction and
// database for which we are checking space.
// @param[in] key For a put operation, the key being stored.
// @param[in] data For a put operation, the data being stored.
// @return 0 on success, non-zero on failure.
func (c *Cursor) spill(key []byte, data []byte) error {
/*
MDB_txn *txn = m0->mc_txn;
MDB_page *dp;
MDB_ID2L dl = txn->mt_u.dirty_list;
unsigned int i, j, need;
int rc;
if (m0->mc_flags & C_SUB)
return MDB_SUCCESS;
// Estimate how much space this op will take
i = m0->mc_db->md_depth;
// Named DBs also dirty the main DB
if (m0->mc_dbi > MAIN_DBI)
i += txn->mt_dbs[MAIN_DBI].md_depth;
// For puts, roughly factor in the key+data size
if (key)
i += (LEAFSIZE(key, data) + txn->mt_env->me_psize) / txn->mt_env->me_psize;
i += i; // double it for good measure
need = i;
if (txn->mt_dirty_room > i)
return MDB_SUCCESS;
if (!txn->mt_spill_pgs) {
txn->mt_spill_pgs = mdb_midl_alloc(MDB_IDL_UM_MAX);
if (!txn->mt_spill_pgs)
return ENOMEM;
} else {
// purge deleted slots
MDB_IDL sl = txn->mt_spill_pgs;
unsigned int num = sl[0];
j=0;
for (i=1; i<=num; i++) {
if (!(sl[i] & 1))
sl[++j] = sl[i];
}
sl[0] = j;
}
// Preserve pages which may soon be dirtied again
if ((rc = mdb_pages_xkeep(m0, P_DIRTY, 1)) != MDB_SUCCESS)
goto done;
// Less aggressive spill - we originally spilled the entire dirty list,
// with a few exceptions for cursor pages and DB root pages. But this
// turns out to be a lot of wasted effort because in a large txn many
// of those pages will need to be used again. So now we spill only 1/8th
// of the dirty pages. Testing revealed this to be a good tradeoff,
// better than 1/2, 1/4, or 1/10.
if (need < MDB_IDL_UM_MAX / 8)
need = MDB_IDL_UM_MAX / 8;
// Save the page IDs of all the pages we're flushing
// flush from the tail forward, this saves a lot of shifting later on.
for (i=dl[0].mid; i && need; i--) {
MDB_ID pn = dl[i].mid << 1;
dp = dl[i].mptr;
if (dp->mp_flags & P_KEEP)
continue;
// Can't spill twice, make sure it's not already in a parent's
// spill list.
if (txn->mt_parent) {
MDB_txn *tx2;
for (tx2 = txn->mt_parent; tx2; tx2 = tx2->mt_parent) {
if (tx2->mt_spill_pgs) {
j = mdb_midl_search(tx2->mt_spill_pgs, pn);
if (j <= tx2->mt_spill_pgs[0] && tx2->mt_spill_pgs[j] == pn) {
dp->mp_flags |= P_KEEP;
break;
}
}
}
if (tx2)
continue;
}
if ((rc = mdb_midl_append(&txn->mt_spill_pgs, pn)))
goto done;
need--;
}
mdb_midl_sort(txn->mt_spill_pgs);
// Flush the spilled part of dirty list
if ((rc = mdb_page_flush(txn, i)) != MDB_SUCCESS)
goto done;
// Reset any dirty pages we kept that page_flush didn't see
rc = mdb_pages_xkeep(m0, P_DIRTY|P_KEEP, i);
done:
txn->mt_flags |= rc ? MDB_TXN_ERROR : MDB_TXN_SPILLS;
return rc;
return 0
}
*/
return nil
}
// Copy the used portions of a non-overflow page.
// @param[in] dst page to copy into
// @param[in] src page to copy from
// @param[in] psize size of a page
func (p *page) copyTo(dst *page, size int) {
/*
enum { Align = sizeof(pgno_t) };
indx_t upper = src->mp_upper, lower = src->mp_lower, unused = upper-lower;
// If page isn't full, just copy the used portion. Adjust
// alignment so memcpy may copy words instead of bytes.
if ((unused &= -Align) && !IS_LEAF2(src)) {
upper &= -Align;
memcpy(dst, src, (lower + (Align-1)) & -Align);
memcpy((pgno_t *)((char *)dst+upper), (pgno_t *)((char *)src+upper),
psize - upper);
} else {
memcpy(dst, src, psize - unused);
}
*/
}
// Touch a page: make it dirty and re-insert into tree with updated pgno.
// @param[in] mc cursor pointing to the page to be touched
// @return 0 on success, non-zero on failure.
func (c *Cursor) page_touch() int {
/*
MDB_page *mp = mc->mc_pg[mc->mc_top], *np;
MDB_txn *txn = mc->mc_txn;
MDB_cursor *m2, *m3;
pgno_t pgno;
int rc;
if (!F_ISSET(mp->mp_flags, P_DIRTY)) {
if (txn->mt_flags & MDB_TXN_SPILLS) {
np = NULL;
rc = mdb_page_unspill(txn, mp, &np);
if (rc)
goto fail;
if (np)
goto done;
}
if ((rc = mdb_midl_need(&txn->mt_free_pgs, 1)) ||
(rc = mdb_page_alloc(mc, 1, &np)))
goto fail;
pgno = np->mp_pgno;
DPRINTF(("touched db %d page %"Z"u -> %"Z"u", DDBI(mc),
mp->mp_pgno, pgno));
mdb_cassert(mc, mp->mp_pgno != pgno);
mdb_midl_xappend(txn->mt_free_pgs, mp->mp_pgno);
// Update the parent page, if any, to point to the new page
if (mc->mc_top) {
MDB_page *parent = mc->mc_pg[mc->mc_top-1];
MDB_node *node = NODEPTR(parent, mc->mc_ki[mc->mc_top-1]);
SETPGNO(node, pgno);
} else {
mc->mc_db->md_root = pgno;
}
} else if (txn->mt_parent && !IS_SUBP(mp)) {
MDB_ID2 mid, *dl = txn->mt_u.dirty_list;
pgno = mp->mp_pgno;
// If txn has a parent, make sure the page is in our
// dirty list.
if (dl[0].mid) {
unsigned x = mdb_mid2l_search(dl, pgno);
if (x <= dl[0].mid && dl[x].mid == pgno) {
if (mp != dl[x].mptr) { // bad cursor?
mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
txn->mt_flags |= MDB_TXN_ERROR;
return MDB_CORRUPTED;
}
return 0;
}
}
mdb_cassert(mc, dl[0].mid < MDB_IDL_UM_MAX);
// No - copy it
np = mdb_page_malloc(txn, 1);
if (!np)
return ENOMEM;
mid.mid = pgno;
mid.mptr = np;
rc = mdb_mid2l_insert(dl, &mid);
mdb_cassert(mc, rc == 0);
} else {
return 0;
}
mdb_page_copy(np, mp, txn->mt_env->me_psize);
np->mp_pgno = pgno;
np->mp_flags |= P_DIRTY;
done:
// Adjust cursors pointing to mp
mc->mc_pg[mc->mc_top] = np;
m2 = txn->mt_cursors[mc->mc_dbi];
if (mc->mc_flags & C_SUB) {
for (; m2; m2=m2->mc_next) {
m3 = &m2->mc_xcursor->mx_cursor;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[mc->mc_top] == mp)
m3->mc_pg[mc->mc_top] = np;
}
} else {
for (; m2; m2=m2->mc_next) {
if (m2->mc_snum < mc->mc_snum) continue;
if (m2->mc_pg[mc->mc_top] == mp) {
m2->mc_pg[mc->mc_top] = np;
if ((mc->mc_db->md_flags & MDB_DUPSORT) &&
m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
{
MDB_node *leaf = NODEPTR(np, mc->mc_ki[mc->mc_top]);
if (!(leaf->mn_flags & F_SUBDATA))
m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
}
}
}
}
return 0;
fail:
txn->mt_flags |= MDB_TXN_ERROR;
return rc;
*/
return 0
}
// Search for the lowest key under the current branch page.
// This just bypasses a NUMKEYS check in the current page
// before calling mdb_page_search_root(), because the callers
// are all in situations where the current page is known to
// be underfilled.
func (c *Cursor) searchLowest() error {
/*
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_node *node = NODEPTR(mp, 0);
int rc;
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(node), &mp, NULL)) != 0)
return rc;
mc->mc_ki[mc->mc_top] = 0;
if ((rc = mdb_cursor_push(mc, mp)))
return rc;
return mdb_page_search_root(mc, NULL, MDB_PS_FIRST);
*/
return nil
}
func (c *Cursor) freeOverflowPage(p *page) error {
/*
MDB_txn *txn = mc->mc_txn;
pgno_t pg = mp->mp_pgno;
unsigned x = 0, ovpages = mp->mp_pages;
MDB_env *env = txn->mt_env;
MDB_IDL sl = txn->mt_spill_pgs;
MDB_ID pn = pg << 1;
int rc;
DPRINTF(("free ov page %"Z"u (%d)", pg, ovpages));
// If the page is dirty or on the spill list we just acquired it,
// so we should give it back to our current free list, if any.
// Otherwise put it onto the list of pages we freed in this txn.
//
// Won't create me_pghead: me_pglast must be inited along with it.
// Unsupported in nested txns: They would need to hide the page
// range in ancestor txns' dirty and spilled lists.
if (env->me_pghead &&
!txn->mt_parent &&
((mp->mp_flags & P_DIRTY) ||
(sl && (x = mdb_midl_search(sl, pn)) <= sl[0] && sl[x] == pn)))
{
unsigned i, j;
pgno_t *mop;
MDB_ID2 *dl, ix, iy;
rc = mdb_midl_need(&env->me_pghead, ovpages);
if (rc)
return rc;
if (!(mp->mp_flags & P_DIRTY)) {
// This page is no longer spilled
if (x == sl[0])
sl[0]--;
else
sl[x] |= 1;
goto release;
}
// Remove from dirty list
dl = txn->mt_u.dirty_list;
x = dl[0].mid--;
for (ix = dl[x]; ix.mptr != mp; ix = iy) {
if (x > 1) {
x--;
iy = dl[x];
dl[x] = ix;
} else {
mdb_cassert(mc, x > 1);
j = ++(dl[0].mid);
dl[j] = ix; // Unsorted. OK when MDB_TXN_ERROR.
txn->mt_flags |= MDB_TXN_ERROR;
return MDB_CORRUPTED;
}
}
if (!(env->me_flags & MDB_WRITEMAP))
mdb_dpage_free(env, mp);
release:
// Insert in me_pghead
mop = env->me_pghead;
j = mop[0] + ovpages;
for (i = mop[0]; i && mop[i] < pg; i--)
mop[j--] = mop[i];
while (j>i)
mop[j--] = pg++;
mop[0] += ovpages;
} else {
rc = mdb_midl_append_range(&txn->mt_free_pgs, pg, ovpages);
if (rc)
return rc;
}
mc->mc_db->md_overflow_pages -= ovpages;
return 0;
*/
return nil
}
// Find a sibling for a page.
// Replaces the page at the top of the cursor's stack with the
// specified sibling, if one exists.
// @param[in] mc The cursor for this operation.
// @param[in] move_right Non-zero if the right sibling is requested,
// otherwise the left sibling.
// @return 0 on success, non-zero on failure.
func (c *Cursor) sibling(moveRight bool) error {
/*
int rc;
MDB_node *indx;
MDB_page *mp;
if (mc->mc_snum < 2) {
return MDB_NOTFOUND; // root has no siblings
}
mdb_cursor_pop(mc);
DPRINTF(("parent page is page %"Z"u, index %u",
mc->mc_pg[mc->mc_top]->mp_pgno, mc->mc_ki[mc->mc_top]));
if (move_right ? (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mc->mc_pg[mc->mc_top]))
: (mc->mc_ki[mc->mc_top] == 0)) {
DPRINTF(("no more keys left, moving to %s sibling",
move_right ? "right" : "left"));
if ((rc = mdb_cursor_sibling(mc, move_right)) != MDB_SUCCESS) {
// undo cursor_pop before returning
mc->mc_top++;
mc->mc_snum++;
return rc;
}
} else {
if (move_right)
mc->mc_ki[mc->mc_top]++;
else
mc->mc_ki[mc->mc_top]--;
DPRINTF(("just moving to %s index key %u",
move_right ? "right" : "left", mc->mc_ki[mc->mc_top]));
}
mdb_cassert(mc, IS_BRANCH(mc->mc_pg[mc->mc_top]));
indx = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if ((rc = mdb_page_get(mc->mc_txn, NODEPGNO(indx), &mp, NULL)) != 0) {
// mc will be inconsistent if caller does mc_snum++ as above
mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
return rc;
}
mdb_cursor_push(mc, mp);
if (!move_right)
mc->mc_ki[mc->mc_top] = NUMKEYS(mp)-1;
return MDB_SUCCESS;
*/
return nil
}
// Move the cursor to the next data item.
func (c *Cursor) Next(key []byte, data []byte, op int) error {
/*
MDB_page *mp;
MDB_node *leaf;
int rc;
if (mc->mc_flags & C_EOF) {
return MDB_NOTFOUND;
}
mdb_cassert(mc, mc->mc_flags & C_INITIALIZED);
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_NEXT || op == MDB_NEXT_DUP) {
rc = mdb_cursor_next(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_NEXT);
if (op != MDB_NEXT || rc != MDB_NOTFOUND) {
if (rc == MDB_SUCCESS)
MDB_GET_KEY(leaf, key);
return rc;
}
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (op == MDB_NEXT_DUP)
return MDB_NOTFOUND;
}
}
DPRINTF(("cursor_next: top page is %"Z"u in cursor %p",
mdb_dbg_pgno(mp), (void *) mc));
if (mc->mc_flags & C_DEL)
goto skip;
if (mc->mc_ki[mc->mc_top] + 1u >= NUMKEYS(mp)) {
DPUTS("=====> move to next sibling page");
if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS) {
mc->mc_flags |= C_EOF;
return rc;
}
mp = mc->mc_pg[mc->mc_top];
DPRINTF(("next page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
} else
mc->mc_ki[mc->mc_top]++;
skip:
DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
*/
return nil
}
// Move the cursor to the previous data item.
func (c *Cursor) prev(key []byte, data []byte, op int) error {
/*
MDB_page *mp;
MDB_node *leaf;
int rc;
mdb_cassert(mc, mc->mc_flags & C_INITIALIZED);
mp = mc->mc_pg[mc->mc_top];
if (mc->mc_db->md_flags & MDB_DUPSORT) {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_PREV || op == MDB_PREV_DUP) {
rc = mdb_cursor_prev(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_PREV);
if (op != MDB_PREV || rc != MDB_NOTFOUND) {
if (rc == MDB_SUCCESS)
MDB_GET_KEY(leaf, key);
return rc;
}
} else {
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (op == MDB_PREV_DUP)
return MDB_NOTFOUND;
}
}
}
DPRINTF(("cursor_prev: top page is %"Z"u in cursor %p",
mdb_dbg_pgno(mp), (void *) mc));
if (mc->mc_ki[mc->mc_top] == 0) {
DPUTS("=====> move to prev sibling page");
if ((rc = mdb_cursor_sibling(mc, 0)) != MDB_SUCCESS) {
return rc;
}
mp = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_top] = NUMKEYS(mp) - 1;
DPRINTF(("prev page is %"Z"u, key index %u", mp->mp_pgno, mc->mc_ki[mc->mc_top]));
} else
mc->mc_ki[mc->mc_top]--;
mc->mc_flags &= ~C_EOF;
DPRINTF(("==> cursor points to page %"Z"u with %u keys, key index %u",
mdb_dbg_pgno(mp), NUMKEYS(mp), mc->mc_ki[mc->mc_top]));
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
*/
return nil
}
// Set the cursor on a specific data item.
// (bool return is whether it is exact).
func (c *Cursor) set(key []byte, data []byte, op int) (error, bool) {
/*
int rc;
MDB_page *mp;
MDB_node *leaf = NULL;
DKBUF;
if (key->mv_size == 0)
return MDB_BAD_VALSIZE;
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
// See if we're already on the right page
if (mc->mc_flags & C_INITIALIZED) {
MDB_val nodekey;
mp = mc->mc_pg[mc->mc_top];
if (!NUMKEYS(mp)) {
mc->mc_ki[mc->mc_top] = 0;
return MDB_NOTFOUND;
}
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_size = mc->mc_db->md_pad;
nodekey.mv_data = LEAF2KEY(mp, 0, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, 0);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
// Probably happens rarely, but first node on the page
// was the one we wanted.
mc->mc_ki[mc->mc_top] = 0;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc > 0) {
unsigned int i;
unsigned int nkeys = NUMKEYS(mp);
if (nkeys > 1) {
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
nkeys-1, nodekey.mv_size);
} else {
leaf = NODEPTR(mp, nkeys-1);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
// last node was the one we wanted
mc->mc_ki[mc->mc_top] = nkeys-1;
if (exactp)
*exactp = 1;
goto set1;
}
if (rc < 0) {
if (mc->mc_ki[mc->mc_top] < NUMKEYS(mp)) {
// This is definitely the right page, skip search_page
if (mp->mp_flags & P_LEAF2) {
nodekey.mv_data = LEAF2KEY(mp,
mc->mc_ki[mc->mc_top], nodekey.mv_size);
} else {
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
MDB_GET_KEY2(leaf, nodekey);
}
rc = mc->mc_dbx->md_cmp(key, &nodekey);
if (rc == 0) {
// current node was the one we wanted
if (exactp)
*exactp = 1;
goto set1;
}
}
rc = 0;
goto set2;
}
}
// If any parents have right-sibs, search.
// Otherwise, there's nothing further.
for (i=0; i<mc->mc_top; i++)
if (mc->mc_ki[i] <
NUMKEYS(mc->mc_pg[i])-1)
break;
if (i == mc->mc_top) {
// There are no other pages
mc->mc_ki[mc->mc_top] = nkeys;
return MDB_NOTFOUND;
}
}
if (!mc->mc_top) {
// There are no other pages
mc->mc_ki[mc->mc_top] = 0;
if (op == MDB_SET_RANGE) {
rc = 0;
goto set1;
} else
return MDB_NOTFOUND;
}
}
rc = mdb_page_search(mc, key, 0);
if (rc != MDB_SUCCESS)
return rc;
mp = mc->mc_pg[mc->mc_top];
mdb_cassert(mc, IS_LEAF(mp));
set2:
leaf = mdb_node_search(mc, key, exactp);
if (exactp != NULL && !*exactp) {
// MDB_SET specified and not an exact match.
return MDB_NOTFOUND;
}
if (leaf == NULL) {
DPUTS("===> inexact leaf not found, goto sibling");
if ((rc = mdb_cursor_sibling(mc, 1)) != MDB_SUCCESS)
return rc; // no entries matched
mp = mc->mc_pg[mc->mc_top];
mdb_cassert(mc, IS_LEAF(mp));
leaf = NODEPTR(mp, 0);
}
set1:
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
if (IS_LEAF2(mp)) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (op == MDB_SET || op == MDB_SET_KEY || op == MDB_SET_RANGE) {
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
} else {
int ex2, *ex2p;
if (op == MDB_GET_BOTH) {
ex2p = &ex2;
ex2 = 0;
} else {
ex2p = NULL;
}
rc = mdb_cursor_set(&mc->mc_xcursor->mx_cursor, data, NULL, MDB_SET_RANGE, ex2p);
if (rc != MDB_SUCCESS)
return rc;
}
} else if (op == MDB_GET_BOTH || op == MDB_GET_BOTH_RANGE) {
MDB_val d2;
if ((rc = mdb_node_read(mc->mc_txn, leaf, &d2)) != MDB_SUCCESS)
return rc;
rc = mc->mc_dbx->md_dcmp(data, &d2);
if (rc) {
if (op == MDB_GET_BOTH || rc > 0)
return MDB_NOTFOUND;
rc = 0;
*data = d2;
}
} else {
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
// The key already matches in all other cases
if (op == MDB_SET_RANGE || op == MDB_SET_KEY)
MDB_GET_KEY(leaf, key);
DPRINTF(("==> cursor placed on key [%s]", DKEY(key)));
return rc;
*/
return nil, false
}
// Move the cursor to the first item in the database.
func (c *Cursor) first(key []byte, data []byte) error {
/*
int rc;
MDB_node *leaf;
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
if (rc != MDB_SUCCESS)
return rc;
}
mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
leaf = NODEPTR(mc->mc_pg[mc->mc_top], 0);
mc->mc_flags |= C_INITIALIZED;
mc->mc_flags &= ~C_EOF;
mc->mc_ki[mc->mc_top] = 0;
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], 0, key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
*/
return nil
}
// Move the cursor to the last item in the database.
func (c *Cursor) last() ([]byte, []byte) {
/*
int rc;
MDB_node *leaf;
if (mc->mc_xcursor)
mc->mc_xcursor->mx_cursor.mc_flags &= ~(C_INITIALIZED|C_EOF);
if (!(mc->mc_flags & C_EOF)) {
if (!(mc->mc_flags & C_INITIALIZED) || mc->mc_top) {
rc = mdb_page_search(mc, NULL, MDB_PS_LAST);
if (rc != MDB_SUCCESS)
return rc;
}
mdb_cassert(mc, IS_LEAF(mc->mc_pg[mc->mc_top]));
}
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]) - 1;
mc->mc_flags |= C_INITIALIZED|C_EOF;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (IS_LEAF2(mc->mc_pg[mc->mc_top])) {
key->mv_size = mc->mc_db->md_pad;
key->mv_data = LEAF2KEY(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top], key->mv_size);
return MDB_SUCCESS;
}
if (data) {
if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
mdb_xcursor_init1(mc, leaf);
rc = mdb_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
if (rc)
return rc;
} else {
if ((rc = mdb_node_read(mc->mc_txn, leaf, data)) != MDB_SUCCESS)
return rc;
}
}
MDB_GET_KEY(leaf, key);
return MDB_SUCCESS;
*/
return nil, nil
}
// Touch all the pages in the cursor stack. Set mc_top.
// Makes sure all the pages are writable, before attempting a write operation.
// @param[in] mc The cursor to operate on.
func (c *Cursor) touch() error {
/*
int rc = MDB_SUCCESS;
if (mc->mc_dbi > MAIN_DBI && !(*mc->mc_dbflag & DB_DIRTY)) {
MDB_cursor mc2;
MDB_xcursor mcx;
mdb_cursor_init(&mc2, mc->mc_txn, MAIN_DBI, &mcx);
rc = mdb_page_search(&mc2, &mc->mc_dbx->md_name, MDB_PS_MODIFY);
if (rc)
return rc;
*mc->mc_dbflag |= DB_DIRTY;
}
mc->mc_top = 0;
if (mc->mc_snum) {
do {
rc = mdb_page_touch(mc);
} while (!rc && ++(mc->mc_top) < mc->mc_snum);
mc->mc_top = mc->mc_snum-1;
}
return rc;
}
*/
return nil
}
func (c *Cursor) Del(flags int) error {
/*
MDB_node *leaf;
MDB_page *mp;
int rc;
if (mc->mc_txn->mt_flags & (MDB_TXN_RDONLY|MDB_TXN_ERROR))
return (mc->mc_txn->mt_flags & MDB_TXN_RDONLY) ? EACCES : MDB_BAD_TXN;
if (!(mc->mc_flags & C_INITIALIZED))
return EINVAL;
if (mc->mc_ki[mc->mc_top] >= NUMKEYS(mc->mc_pg[mc->mc_top]))
return MDB_NOTFOUND;
if (!(flags & MDB_NOSPILL) && (rc = mdb_page_spill(mc, NULL, NULL)))
return rc;
rc = mdb_cursor_touch(mc);
if (rc)
return rc;
mp = mc->mc_pg[mc->mc_top];
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (!IS_LEAF2(mp) && F_ISSET(leaf->mn_flags, F_DUPDATA)) {
if (!(flags & MDB_NODUPDATA)) {
if (!F_ISSET(leaf->mn_flags, F_SUBDATA)) {
mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
}
rc = mdb_cursor_del(&mc->mc_xcursor->mx_cursor, MDB_NOSPILL);
// If sub-DB still has entries, we're done
if (mc->mc_xcursor->mx_db.md_entries) {
if (leaf->mn_flags & F_SUBDATA) {
// update subDB info
void *db = NODEDATA(leaf);
memcpy(db, &mc->mc_xcursor->mx_db, sizeof(MDB_db));
} else {
MDB_cursor *m2;
// shrink fake page
mdb_node_shrink(mp, mc->mc_ki[mc->mc_top]);
leaf = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
mc->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
// fix other sub-DB cursors pointed at this fake page
for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
if (m2->mc_pg[mc->mc_top] == mp &&
m2->mc_ki[mc->mc_top] == mc->mc_ki[mc->mc_top])
m2->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(leaf);
}
}
mc->mc_db->md_entries--;
mc->mc_flags |= C_DEL;
return rc;
}
// otherwise fall thru and delete the sub-DB
}
if (leaf->mn_flags & F_SUBDATA) {
// add all the child DB's pages to the free list
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc == MDB_SUCCESS) {
mc->mc_db->md_entries -=
mc->mc_xcursor->mx_db.md_entries;
}
}
}
return mdb_cursor_del0(mc, leaf);
*/
return nil
}
// Add a node to the page pointed to by the cursor.
// @param[in] mc The cursor for this operation.
// @param[in] indx The index on the page where the new node should be added.
// @param[in] key The key for the new node.
// @param[in] data The data for the new node, if any.
// @param[in] pgno The page number, if adding a branch node.
// @param[in] flags Flags for the node.
// @return 0 on success, non-zero on failure. Possible errors are:
// <ul>
// <li>ENOMEM - failed to allocate overflow pages for the node.
// <li>MDB_PAGE_FULL - there is insufficient room in the page. This error
// should never happen since all callers already calculate the
// page's free space before calling this function.
// </ul>
func (c *Cursor) addNode(index int, key []byte, data []byte, pgno int, flags int) error {
/*
unsigned int i;
size_t node_size = NODESIZE;
ssize_t room;
indx_t ofs;
MDB_node *node;
MDB_page *mp = mc->mc_pg[mc->mc_top];
MDB_page *ofp = NULL; // overflow page
DKBUF;
mdb_cassert(mc, mp->mp_upper >= mp->mp_lower);
DPRINTF(("add to %s %spage %"Z"u index %i, data size %"Z"u key size %"Z"u [%s]",
IS_LEAF(mp) ? "leaf" : "branch",
IS_SUBP(mp) ? "sub-" : "",
mdb_dbg_pgno(mp), indx, data ? data->mv_size : 0,
key ? key->mv_size : 0, key ? DKEY(key) : "null"));
if (IS_LEAF2(mp)) {
// Move higher keys up one slot.
int ksize = mc->mc_db->md_pad, dif;
char *ptr = LEAF2KEY(mp, indx, ksize);
dif = NUMKEYS(mp) - indx;
if (dif > 0)
memmove(ptr+ksize, ptr, dif*ksize);
// insert new key
memcpy(ptr, key->mv_data, ksize);
// Just using these for counting
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
return MDB_SUCCESS;
}
room = (ssize_t)SIZELEFT(mp) - (ssize_t)sizeof(indx_t);
if (key != NULL)
node_size += key->mv_size;
if (IS_LEAF(mp)) {
mdb_cassert(mc, data);
if (F_ISSET(flags, F_BIGDATA)) {
// Data already on overflow page.
node_size += sizeof(pgno_t);
} else if (node_size + data->mv_size > mc->mc_txn->mt_env->me_nodemax) {
int ovpages = OVPAGES(data->mv_size, mc->mc_txn->mt_env->me_psize);
int rc;
// Put data on overflow page.
DPRINTF(("data size is %"Z"u, node would be %"Z"u, put data on overflow page",
data->mv_size, node_size+data->mv_size));
node_size = EVEN(node_size + sizeof(pgno_t));
if ((ssize_t)node_size > room)
goto full;
if ((rc = mdb_page_new(mc, P_OVERFLOW, ovpages, &ofp)))
return rc;
DPRINTF(("allocated overflow page %"Z"u", ofp->mp_pgno));
flags |= F_BIGDATA;
goto update;
} else {
node_size += data->mv_size;
}
}
node_size = EVEN(node_size);
if ((ssize_t)node_size > room)
goto full;
update:
// Move higher pointers up one slot.
for (i = NUMKEYS(mp); i > indx; i--)
mp->mp_ptrs[i] = mp->mp_ptrs[i - 1];
// Adjust free space offsets.
ofs = mp->mp_upper - node_size;
mdb_cassert(mc, ofs >= mp->mp_lower + sizeof(indx_t));
mp->mp_ptrs[indx] = ofs;
mp->mp_upper = ofs;
mp->mp_lower += sizeof(indx_t);
// Write the node data.
node = NODEPTR(mp, indx);
node->mn_ksize = (key == NULL) ? 0 : key->mv_size;
node->mn_flags = flags;
if (IS_LEAF(mp))
SETDSZ(node,data->mv_size);
else
SETPGNO(node,pgno);
if (key)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
if (IS_LEAF(mp)) {
mdb_cassert(mc, key);
if (ofp == NULL) {
if (F_ISSET(flags, F_BIGDATA))
memcpy(node->mn_data + key->mv_size, data->mv_data,
sizeof(pgno_t));
else if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = node->mn_data + key->mv_size;
else
memcpy(node->mn_data + key->mv_size, data->mv_data,
data->mv_size);
} else {
memcpy(node->mn_data + key->mv_size, &ofp->mp_pgno,
sizeof(pgno_t));
if (F_ISSET(flags, MDB_RESERVE))
data->mv_data = METADATA(ofp);
else
memcpy(METADATA(ofp), data->mv_data, data->mv_size);
}
}
return MDB_SUCCESS;
full:
DPRINTF(("not enough room in page %"Z"u, got %u ptrs",
mdb_dbg_pgno(mp), NUMKEYS(mp)));
DPRINTF(("upper-lower = %u - %u = %"Z"d", mp->mp_upper,mp->mp_lower,room));
DPRINTF(("node size = %"Z"u", node_size));
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
return MDB_PAGE_FULL;
*/
return nil
}
// Delete the specified node from a page.
// @param[in] mp The page to operate on.
// @param[in] indx The index of the node to delete.
// @param[in] ksize The size of a node. Only used if the page is
// part of a #MDB_DUPFIXED database.
func (c *Cursor) deleteNode(ksize int) {
/*
MDB_page *mp = mc->mc_pg[mc->mc_top];
indx_t indx = mc->mc_ki[mc->mc_top];
unsigned int sz;
indx_t i, j, numkeys, ptr;
MDB_node *node;
char *base;
DPRINTF(("delete node %u on %s page %"Z"u", indx,
IS_LEAF(mp) ? "leaf" : "branch", mdb_dbg_pgno(mp)));
numkeys = NUMKEYS(mp);
mdb_cassert(mc, indx < numkeys);
if (IS_LEAF2(mp)) {
int x = numkeys - 1 - indx;
base = LEAF2KEY(mp, indx, ksize);
if (x)
memmove(base, base + ksize, x * ksize);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += ksize - sizeof(indx_t);
return;
}
node = NODEPTR(mp, indx);
sz = NODESIZE + node->mn_ksize;
if (IS_LEAF(mp)) {
if (F_ISSET(node->mn_flags, F_BIGDATA))
sz += sizeof(pgno_t);
else
sz += NODEDSZ(node);
}
sz = EVEN(sz);
ptr = mp->mp_ptrs[indx];
for (i = j = 0; i < numkeys; i++) {
if (i != indx) {
mp->mp_ptrs[j] = mp->mp_ptrs[i];
if (mp->mp_ptrs[i] < ptr)
mp->mp_ptrs[j] += sz;
j++;
}
}
base = (char *)mp + mp->mp_upper;
memmove(base + sz, base, ptr - mp->mp_upper);
mp->mp_lower -= sizeof(indx_t);
mp->mp_upper += sz;
*/
}
// Final setup of a sorted-dups cursor.
// Sets up the fields that depend on the data from the main cursor.
// @param[in] mc The main cursor whose sorted-dups cursor is to be initialized.
// @param[in] node The data containing the #MDB_db record for the
// sorted-dup database.
func (c *Cursor) xcursor_init1(n *node) {
/*
MDB_xcursor *mx = mc->mc_xcursor;
if (node->mn_flags & F_SUBDATA) {
memcpy(&mx->mx_db, NODEDATA(node), sizeof(MDB_db));
mx->mx_cursor.mc_pg[0] = 0;
mx->mx_cursor.mc_snum = 0;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags = C_SUB;
} else {
MDB_page *fp = NODEDATA(node);
mx->mx_db.md_pad = mc->mc_pg[mc->mc_top]->mp_pad;
mx->mx_db.md_flags = 0;
mx->mx_db.md_depth = 1;
mx->mx_db.md_branch_pages = 0;
mx->mx_db.md_leaf_pages = 1;
mx->mx_db.md_overflow_pages = 0;
mx->mx_db.md_entries = NUMKEYS(fp);
COPY_PGNO(mx->mx_db.md_root, fp->mp_pgno);
mx->mx_cursor.mc_snum = 1;
mx->mx_cursor.mc_top = 0;
mx->mx_cursor.mc_flags = C_INITIALIZED|C_SUB;
mx->mx_cursor.mc_pg[0] = fp;
mx->mx_cursor.mc_ki[0] = 0;
if (mc->mc_db->md_flags & MDB_DUPFIXED) {
mx->mx_db.md_flags = MDB_DUPFIXED;
mx->mx_db.md_pad = fp->mp_pad;
if (mc->mc_db->md_flags & MDB_INTEGERDUP)
mx->mx_db.md_flags |= MDB_INTEGERKEY;
}
}
DPRINTF(("Sub-db -%u root page %"Z"u", mx->mx_cursor.mc_dbi,
mx->mx_db.md_root));
mx->mx_dbflag = DB_VALID|DB_DIRTY; // DB_DIRTY guides mdb_cursor_touch
#if UINT_MAX < SIZE_MAX
if (mx->mx_dbx.md_cmp == mdb_cmp_int && mx->mx_db.md_pad == sizeof(size_t))
#ifdef MISALIGNED_OK
mx->mx_dbx.md_cmp = mdb_cmp_long;
#else
mx->mx_dbx.md_cmp = mdb_cmp_cint;
#endif
#endif
*/
}
// Return the count of duplicate data items for the current key.
func (c *Cursor) count() (int, error) {
/*
MDB_node *leaf;
if (mc == NULL || countp == NULL)
return EINVAL;
if (mc->mc_xcursor == NULL)
return MDB_INCOMPATIBLE;
leaf = NODEPTR(mc->mc_pg[mc->mc_top], mc->mc_ki[mc->mc_top]);
if (!F_ISSET(leaf->mn_flags, F_DUPDATA)) {
*countp = 1;
} else {
if (!(mc->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
return EINVAL;
*countp = mc->mc_xcursor->mx_db.md_entries;
}
return MDB_SUCCESS;
*/
return 0, nil
}
func (c *Cursor) Close() {
/*
if (mc && !mc->mc_backup) {
// remove from txn, if tracked
if ((mc->mc_flags & C_UNTRACK) && mc->mc_txn->mt_cursors) {
MDB_cursor **prev = &mc->mc_txn->mt_cursors[mc->mc_dbi];
while (*prev && *prev != mc) prev = &(*prev)->mc_next;
if (*prev == mc)
*prev = mc->mc_next;
}
free(mc);
}
*/
}
func (c *Cursor) Transaction() *Transaction {
return c.transaction
}
func (c *Cursor) Bucket() *Bucket {
return c.bucket
}
// Replace the key for a branch node with a new key.
// @param[in] mc Cursor pointing to the node to operate on.
// @param[in] key The new key to use.
// @return 0 on success, non-zero on failure.
func (c *Cursor) updateKey(key []byte) error {
/*
MDB_page *mp;
MDB_node *node;
char *base;
size_t len;
int delta, ksize, oksize;
indx_t ptr, i, numkeys, indx;
DKBUF;
indx = mc->mc_ki[mc->mc_top];
mp = mc->mc_pg[mc->mc_top];
node = NODEPTR(mp, indx);
ptr = mp->mp_ptrs[indx];
#if MDB_DEBUG
{
MDB_val k2;
char kbuf2[DKBUF_MAXKEYSIZE*2+1];
k2.mv_data = NODEKEY(node);
k2.mv_size = node->mn_ksize;
DPRINTF(("update key %u (ofs %u) [%s] to [%s] on page %"Z"u",
indx, ptr,
mdb_dkey(&k2, kbuf2),
DKEY(key),
mp->mp_pgno));
}
#endif
// Sizes must be 2-byte aligned.
ksize = EVEN(key->mv_size);
oksize = EVEN(node->mn_ksize);
delta = ksize - oksize;
// Shift node contents if EVEN(key length) changed.
if (delta) {
if (delta > 0 && SIZELEFT(mp) < delta) {
pgno_t pgno;
// not enough space left, do a delete and split
DPRINTF(("Not enough room, delta = %d, splitting...", delta));
pgno = NODEPGNO(node);
mdb_node_del(mc, 0);
return mdb_page_split(mc, key, NULL, pgno, MDB_SPLIT_REPLACE);
}
numkeys = NUMKEYS(mp);
for (i = 0; i < numkeys; i++) {
if (mp->mp_ptrs[i] <= ptr)
mp->mp_ptrs[i] -= delta;
}
base = (char *)mp + mp->mp_upper;
len = ptr - mp->mp_upper + NODESIZE;
memmove(base - delta, base, len);
mp->mp_upper -= delta;
node = NODEPTR(mp, indx);
}
// But even if no shift was needed, update ksize
if (node->mn_ksize != key->mv_size)
node->mn_ksize = key->mv_size;
if (key->mv_size)
memcpy(NODEKEY(node), key->mv_data, key->mv_size);
return MDB_SUCCESS;
*/
return nil
}
// Move a node from csrc to cdst.
func (c *Cursor) moveNodeTo(dst *Cursor) error {
/*
MDB_node *srcnode;
MDB_val key, data;
pgno_t srcpg;
MDB_cursor mn;
int rc;
unsigned short flags;
DKBUF;
// Mark src and dst as dirty.
if ((rc = mdb_page_touch(csrc)) ||
(rc = mdb_page_touch(cdst)))
return rc;
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top], key.mv_size);
data.mv_size = 0;
data.mv_data = NULL;
srcpg = 0;
flags = 0;
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], csrc->mc_ki[csrc->mc_top]);
mdb_cassert(csrc, !((size_t)srcnode & 1));
srcpg = NODEPGNO(srcnode);
flags = srcnode->mn_flags;
if (csrc->mc_ki[csrc->mc_top] == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
// must find the lowest key below src
mdb_page_search_lowest(csrc);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
csrc->mc_snum = snum--;
csrc->mc_top = snum;
} else {
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top]) && cdst->mc_ki[cdst->mc_top] == 0) {
unsigned int snum = cdst->mc_snum;
MDB_node *s2;
MDB_val bkey;
// must find the lowest key below dst
mdb_page_search_lowest(cdst);
if (IS_LEAF2(cdst->mc_pg[cdst->mc_top])) {
bkey.mv_size = cdst->mc_db->md_pad;
bkey.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, bkey.mv_size);
} else {
s2 = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
bkey.mv_size = NODEKSZ(s2);
bkey.mv_data = NODEKEY(s2);
}
cdst->mc_snum = snum--;
cdst->mc_top = snum;
mdb_cursor_copy(cdst, &mn);
mn.mc_ki[snum] = 0;
rc = mdb_update_key(&mn, &bkey);
if (rc)
return rc;
}
DPRINTF(("moving %s node %u [%s] on page %"Z"u to node %u on page %"Z"u",
IS_LEAF(csrc->mc_pg[csrc->mc_top]) ? "leaf" : "branch",
csrc->mc_ki[csrc->mc_top],
DKEY(&key),
csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_ki[cdst->mc_top], cdst->mc_pg[cdst->mc_top]->mp_pgno));
// Add the node to the destination page.
rc = mdb_node_add(cdst, cdst->mc_ki[cdst->mc_top], &key, &data, srcpg, flags);
if (rc != MDB_SUCCESS)
return rc;
// Delete the node from the source page.
mdb_node_del(csrc, key.mv_size);
{
// Adjust other cursors pointing to mp
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
MDB_page *mp = csrc->mc_pg[csrc->mc_top];
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == csrc) continue;
if (m3->mc_pg[csrc->mc_top] == mp && m3->mc_ki[csrc->mc_top] ==
csrc->mc_ki[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = cdst->mc_pg[cdst->mc_top];
m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
}
}
}
// Update the parent separators.
if (csrc->mc_ki[csrc->mc_top] == 0) {
if (csrc->mc_ki[csrc->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF(("update separator for source page %"Z"u to [%s]",
csrc->mc_pg[csrc->mc_top]->mp_pgno, DKEY(&key)));
mdb_cursor_copy(csrc, &mn);
mn.mc_snum--;
mn.mc_top--;
if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
MDB_val nullkey;
indx_t ix = csrc->mc_ki[csrc->mc_top];
nullkey.mv_size = 0;
csrc->mc_ki[csrc->mc_top] = 0;
rc = mdb_update_key(csrc, &nullkey);
csrc->mc_ki[csrc->mc_top] = ix;
mdb_cassert(csrc, rc == MDB_SUCCESS);
}
}
if (cdst->mc_ki[cdst->mc_top] == 0) {
if (cdst->mc_ki[cdst->mc_top-1] != 0) {
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_data = LEAF2KEY(cdst->mc_pg[cdst->mc_top], 0, key.mv_size);
} else {
srcnode = NODEPTR(cdst->mc_pg[cdst->mc_top], 0);
key.mv_size = NODEKSZ(srcnode);
key.mv_data = NODEKEY(srcnode);
}
DPRINTF(("update separator for destination page %"Z"u to [%s]",
cdst->mc_pg[cdst->mc_top]->mp_pgno, DKEY(&key)));
mdb_cursor_copy(cdst, &mn);
mn.mc_snum--;
mn.mc_top--;
if ((rc = mdb_update_key(&mn, &key)) != MDB_SUCCESS)
return rc;
}
if (IS_BRANCH(cdst->mc_pg[cdst->mc_top])) {
MDB_val nullkey;
indx_t ix = cdst->mc_ki[cdst->mc_top];
nullkey.mv_size = 0;
cdst->mc_ki[cdst->mc_top] = 0;
rc = mdb_update_key(cdst, &nullkey);
cdst->mc_ki[cdst->mc_top] = ix;
mdb_cassert(csrc, rc == MDB_SUCCESS);
}
}
return MDB_SUCCESS;
*/
return nil
}
// Merge one page into another.
// The nodes from the page pointed to by \b csrc will
// be copied to the page pointed to by \b cdst and then
// the \b csrc page will be freed.
// @param[in] csrc Cursor pointing to the source page.
// @param[in] cdst Cursor pointing to the destination page.
func (c *Cursor) mergePage(dst *Cursor) error {
/*
int rc;
indx_t i, j;
MDB_node *srcnode;
MDB_val key, data;
unsigned nkeys;
DPRINTF(("merging page %"Z"u into %"Z"u", csrc->mc_pg[csrc->mc_top]->mp_pgno,
cdst->mc_pg[cdst->mc_top]->mp_pgno));
mdb_cassert(csrc, csrc->mc_snum > 1); // can't merge root page
mdb_cassert(csrc, cdst->mc_snum > 1);
// Mark dst as dirty.
if ((rc = mdb_page_touch(cdst)))
return rc;
// Move all nodes from src to dst.
j = nkeys = NUMKEYS(cdst->mc_pg[cdst->mc_top]);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = METADATA(csrc->mc_pg[csrc->mc_top]);
for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
rc = mdb_node_add(cdst, j, &key, NULL, 0, 0);
if (rc != MDB_SUCCESS)
return rc;
key.mv_data = (char *)key.mv_data + key.mv_size;
}
} else {
for (i = 0; i < NUMKEYS(csrc->mc_pg[csrc->mc_top]); i++, j++) {
srcnode = NODEPTR(csrc->mc_pg[csrc->mc_top], i);
if (i == 0 && IS_BRANCH(csrc->mc_pg[csrc->mc_top])) {
unsigned int snum = csrc->mc_snum;
MDB_node *s2;
// must find the lowest key below src
mdb_page_search_lowest(csrc);
if (IS_LEAF2(csrc->mc_pg[csrc->mc_top])) {
key.mv_size = csrc->mc_db->md_pad;
key.mv_data = LEAF2KEY(csrc->mc_pg[csrc->mc_top], 0, key.mv_size);
} else {
s2 = NODEPTR(csrc->mc_pg[csrc->mc_top], 0);
key.mv_size = NODEKSZ(s2);
key.mv_data = NODEKEY(s2);
}
csrc->mc_snum = snum--;
csrc->mc_top = snum;
} else {
key.mv_size = srcnode->mn_ksize;
key.mv_data = NODEKEY(srcnode);
}
data.mv_size = NODEDSZ(srcnode);
data.mv_data = NODEDATA(srcnode);
rc = mdb_node_add(cdst, j, &key, &data, NODEPGNO(srcnode), srcnode->mn_flags);
if (rc != MDB_SUCCESS)
return rc;
}
}
DPRINTF(("dst page %"Z"u now has %u keys (%.1f%% filled)",
cdst->mc_pg[cdst->mc_top]->mp_pgno, NUMKEYS(cdst->mc_pg[cdst->mc_top]),
(float)PAGEFILL(cdst->mc_txn->mt_env, cdst->mc_pg[cdst->mc_top]) / 10));
// Unlink the src page from parent and add to free list.
csrc->mc_top--;
mdb_node_del(csrc, 0);
if (csrc->mc_ki[csrc->mc_top] == 0) {
key.mv_size = 0;
rc = mdb_update_key(csrc, &key);
if (rc) {
csrc->mc_top++;
return rc;
}
}
csrc->mc_top++;
rc = mdb_midl_append(&csrc->mc_txn->mt_free_pgs,
csrc->mc_pg[csrc->mc_top]->mp_pgno);
if (rc)
return rc;
if (IS_LEAF(csrc->mc_pg[csrc->mc_top]))
csrc->mc_db->md_leaf_pages--;
else
csrc->mc_db->md_branch_pages--;
{
// Adjust other cursors pointing to mp
MDB_cursor *m2, *m3;
MDB_dbi dbi = csrc->mc_dbi;
MDB_page *mp = cdst->mc_pg[cdst->mc_top];
for (m2 = csrc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (csrc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == csrc) continue;
if (m3->mc_snum < csrc->mc_snum) continue;
if (m3->mc_pg[csrc->mc_top] == csrc->mc_pg[csrc->mc_top]) {
m3->mc_pg[csrc->mc_top] = mp;
m3->mc_ki[csrc->mc_top] += nkeys;
}
}
}
mdb_cursor_pop(csrc);
return mdb_rebalance(csrc);
*/
return nil
}
// Copy the contents of a cursor.
// @param[in] csrc The cursor to copy from.
// @param[out] cdst The cursor to copy to.
func (c *Cursor) copyTo(dst *Cursor) {
/*
unsigned int i;
cdst->mc_txn = csrc->mc_txn;
cdst->mc_dbi = csrc->mc_dbi;
cdst->mc_db = csrc->mc_db;
cdst->mc_dbx = csrc->mc_dbx;
cdst->mc_snum = csrc->mc_snum;
cdst->mc_top = csrc->mc_top;
cdst->mc_flags = csrc->mc_flags;
for (i=0; i<csrc->mc_snum; i++) {
cdst->mc_pg[i] = csrc->mc_pg[i];
cdst->mc_ki[i] = csrc->mc_ki[i];
}
*/
}
// Rebalance the tree after a delete operation.
// @param[in] mc Cursor pointing to the page where rebalancing
// should begin.
// @return 0 on success, non-zero on failure.
func (c *Cursor) rebalance() error {
/*
MDB_node *node;
int rc;
unsigned int ptop, minkeys;
MDB_cursor mn;
minkeys = 1 + (IS_BRANCH(mc->mc_pg[mc->mc_top]));
DPRINTF(("rebalancing %s page %"Z"u (has %u keys, %.1f%% full)",
IS_LEAF(mc->mc_pg[mc->mc_top]) ? "leaf" : "branch",
mdb_dbg_pgno(mc->mc_pg[mc->mc_top]), NUMKEYS(mc->mc_pg[mc->mc_top]),
(float)PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) / 10));
if (PAGEFILL(mc->mc_txn->mt_env, mc->mc_pg[mc->mc_top]) >= FILL_THRESHOLD &&
NUMKEYS(mc->mc_pg[mc->mc_top]) >= minkeys) {
DPRINTF(("no need to rebalance page %"Z"u, above fill threshold",
mdb_dbg_pgno(mc->mc_pg[mc->mc_top])));
return MDB_SUCCESS;
}
if (mc->mc_snum < 2) {
MDB_page *mp = mc->mc_pg[0];
if (IS_SUBP(mp)) {
DPUTS("Can't rebalance a subpage, ignoring");
return MDB_SUCCESS;
}
if (NUMKEYS(mp) == 0) {
DPUTS("tree is completely empty");
mc->mc_db->md_root = P_INVALID;
mc->mc_db->md_depth = 0;
mc->mc_db->md_leaf_pages = 0;
rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
if (rc)
return rc;
// Adjust cursors pointing to mp
mc->mc_snum = 0;
mc->mc_top = 0;
mc->mc_flags &= ~C_INITIALIZED;
{
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[0] == mp) {
m3->mc_snum = 0;
m3->mc_top = 0;
m3->mc_flags &= ~C_INITIALIZED;
}
}
}
} else if (IS_BRANCH(mp) && NUMKEYS(mp) == 1) {
DPUTS("collapsing root page!");
rc = mdb_midl_append(&mc->mc_txn->mt_free_pgs, mp->mp_pgno);
if (rc)
return rc;
mc->mc_db->md_root = NODEPGNO(NODEPTR(mp, 0));
rc = mdb_page_get(mc->mc_txn,mc->mc_db->md_root,&mc->mc_pg[0],NULL);
if (rc)
return rc;
mc->mc_db->md_depth--;
mc->mc_db->md_branch_pages--;
mc->mc_ki[0] = mc->mc_ki[1];
{
// Adjust other cursors pointing to mp
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc || m3->mc_snum < mc->mc_snum) continue;
if (m3->mc_pg[0] == mp) {
int i;
m3->mc_snum--;
m3->mc_top--;
for (i=0; i<m3->mc_snum; i++) {
m3->mc_pg[i] = m3->mc_pg[i+1];
m3->mc_ki[i] = m3->mc_ki[i+1];
}
}
}
}
} else
DPUTS("root page doesn't need rebalancing");
return MDB_SUCCESS;
}
// The parent (branch page) must have at least 2 pointers,
// otherwise the tree is invalid.
ptop = mc->mc_top-1;
mdb_cassert(mc, NUMKEYS(mc->mc_pg[ptop]) > 1);
// Leaf page fill factor is below the threshold.
// Try to move keys from left or right neighbor, or
// merge with a neighbor page.
// Find neighbors.
mdb_cursor_copy(mc, &mn);
mn.mc_xcursor = NULL;
if (mc->mc_ki[ptop] == 0) {
// We're the leftmost leaf in our parent.
DPUTS("reading right neighbor");
mn.mc_ki[ptop]++;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
if (rc)
return rc;
mn.mc_ki[mn.mc_top] = 0;
mc->mc_ki[mc->mc_top] = NUMKEYS(mc->mc_pg[mc->mc_top]);
} else {
// There is at least one neighbor to the left.
DPUTS("reading left neighbor");
mn.mc_ki[ptop]--;
node = NODEPTR(mc->mc_pg[ptop], mn.mc_ki[ptop]);
rc = mdb_page_get(mc->mc_txn,NODEPGNO(node),&mn.mc_pg[mn.mc_top],NULL);
if (rc)
return rc;
mn.mc_ki[mn.mc_top] = NUMKEYS(mn.mc_pg[mn.mc_top]) - 1;
mc->mc_ki[mc->mc_top] = 0;
}
DPRINTF(("found neighbor page %"Z"u (%u keys, %.1f%% full)",
mn.mc_pg[mn.mc_top]->mp_pgno, NUMKEYS(mn.mc_pg[mn.mc_top]),
(float)PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) / 10));
// If the neighbor page is above threshold and has enough keys,
// move one key from it. Otherwise we should try to merge them.
// (A branch page must never have less than 2 keys.)
minkeys = 1 + (IS_BRANCH(mn.mc_pg[mn.mc_top]));
if (PAGEFILL(mc->mc_txn->mt_env, mn.mc_pg[mn.mc_top]) >= FILL_THRESHOLD && NUMKEYS(mn.mc_pg[mn.mc_top]) > minkeys)
return mdb_node_move(&mn, mc);
else {
if (mc->mc_ki[ptop] == 0)
rc = mdb_page_merge(&mn, mc);
else {
mn.mc_ki[mn.mc_top] += mc->mc_ki[mn.mc_top] + 1;
rc = mdb_page_merge(mc, &mn);
mdb_cursor_copy(&mn, mc);
}
mc->mc_flags &= ~(C_INITIALIZED|C_EOF);
}
return rc;
*/
return nil
}
// Complete a delete operation started by #mdb_cursor_del().
func (c *Cursor) del0(leaf *node) error {
/*
int rc;
MDB_page *mp;
indx_t ki;
unsigned int nkeys;
mp = mc->mc_pg[mc->mc_top];
ki = mc->mc_ki[mc->mc_top];
// add overflow pages to free list
if (!IS_LEAF2(mp) && F_ISSET(leaf->mn_flags, F_BIGDATA)) {
MDB_page *omp;
pgno_t pg;
memcpy(&pg, NODEDATA(leaf), sizeof(pg));
if ((rc = mdb_page_get(mc->mc_txn, pg, &omp, NULL)) ||
(rc = mdb_ovpage_free(mc, omp)))
return rc;
}
mdb_node_del(mc, mc->mc_db->md_pad);
mc->mc_db->md_entries--;
rc = mdb_rebalance(mc);
if (rc != MDB_SUCCESS)
mc->mc_txn->mt_flags |= MDB_TXN_ERROR;
else {
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
mp = mc->mc_pg[mc->mc_top];
nkeys = NUMKEYS(mp);
// if mc points past last node in page, find next sibling
if (mc->mc_ki[mc->mc_top] >= nkeys)
mdb_cursor_sibling(mc, 1);
// Adjust other cursors pointing to mp
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
m3 = (mc->mc_flags & C_SUB) ? &m2->mc_xcursor->mx_cursor : m2;
if (! (m2->mc_flags & m3->mc_flags & C_INITIALIZED))
continue;
if (m3 == mc || m3->mc_snum < mc->mc_snum)
continue;
if (m3->mc_pg[mc->mc_top] == mp) {
if (m3->mc_ki[mc->mc_top] >= ki) {
m3->mc_flags |= C_DEL;
if (m3->mc_ki[mc->mc_top] > ki)
m3->mc_ki[mc->mc_top]--;
}
if (m3->mc_ki[mc->mc_top] >= nkeys)
mdb_cursor_sibling(m3, 1);
}
}
mc->mc_flags |= C_DEL;
}
return rc;
*/
return nil
}
// Split a page and insert a new node.
// @param[in,out] mc Cursor pointing to the page and desired insertion index.
// The cursor will be updated to point to the actual page and index where
// the node got inserted after the split.
// @param[in] newkey The key for the newly inserted node.
// @param[in] newdata The data for the newly inserted node.
// @param[in] newpgno The page number, if the new node is a branch node.
// @param[in] nflags The #NODE_ADD_FLAGS for the new node.
// @return 0 on success, non-zero on failure.
func (c *Cursor) splitPage(newKey []byte, newData []byte, newpgno int, nflags int) error {
/*
unsigned int flags;
int rc = MDB_SUCCESS, new_root = 0, did_split = 0;
indx_t newindx;
pgno_t pgno = 0;
int i, j, split_indx, nkeys, pmax;
MDB_env *env = mc->mc_txn->mt_env;
MDB_node *node;
MDB_val sepkey, rkey, xdata, *rdata = &xdata;
MDB_page *copy = NULL;
MDB_page *mp, *rp, *pp;
int ptop;
MDB_cursor mn;
DKBUF;
mp = mc->mc_pg[mc->mc_top];
newindx = mc->mc_ki[mc->mc_top];
nkeys = NUMKEYS(mp);
DPRINTF(("-----> splitting %s page %"Z"u and adding [%s] at index %i/%i",
IS_LEAF(mp) ? "leaf" : "branch", mp->mp_pgno,
DKEY(newkey), mc->mc_ki[mc->mc_top], nkeys));
// Create a right sibling.
if ((rc = mdb_page_new(mc, mp->mp_flags, 1, &rp)))
return rc;
DPRINTF(("new right sibling: page %"Z"u", rp->mp_pgno));
if (mc->mc_snum < 2) {
if ((rc = mdb_page_new(mc, P_BRANCH, 1, &pp)))
return rc;
// shift current top to make room for new parent
mc->mc_pg[1] = mc->mc_pg[0];
mc->mc_ki[1] = mc->mc_ki[0];
mc->mc_pg[0] = pp;
mc->mc_ki[0] = 0;
mc->mc_db->md_root = pp->mp_pgno;
DPRINTF(("root split! new root = %"Z"u", pp->mp_pgno));
mc->mc_db->md_depth++;
new_root = 1;
// Add left (implicit) pointer.
if ((rc = mdb_node_add(mc, 0, NULL, NULL, mp->mp_pgno, 0)) != MDB_SUCCESS) {
// undo the pre-push
mc->mc_pg[0] = mc->mc_pg[1];
mc->mc_ki[0] = mc->mc_ki[1];
mc->mc_db->md_root = mp->mp_pgno;
mc->mc_db->md_depth--;
return rc;
}
mc->mc_snum = 2;
mc->mc_top = 1;
ptop = 0;
} else {
ptop = mc->mc_top-1;
DPRINTF(("parent branch page is %"Z"u", mc->mc_pg[ptop]->mp_pgno));
}
mc->mc_flags |= C_SPLITTING;
mdb_cursor_copy(mc, &mn);
mn.mc_pg[mn.mc_top] = rp;
mn.mc_ki[ptop] = mc->mc_ki[ptop]+1;
if (nflags & MDB_APPEND) {
mn.mc_ki[mn.mc_top] = 0;
sepkey = *newkey;
split_indx = newindx;
nkeys = 0;
} else {
split_indx = (nkeys+1) / 2;
if (IS_LEAF2(rp)) {
char *split, *ins;
int x;
unsigned int lsize, rsize, ksize;
// Move half of the keys to the right sibling
copy = NULL;
x = mc->mc_ki[mc->mc_top] - split_indx;
ksize = mc->mc_db->md_pad;
split = LEAF2KEY(mp, split_indx, ksize);
rsize = (nkeys - split_indx) * ksize;
lsize = (nkeys - split_indx) * sizeof(indx_t);
mp->mp_lower -= lsize;
rp->mp_lower += lsize;
mp->mp_upper += rsize - lsize;
rp->mp_upper -= rsize - lsize;
sepkey.mv_size = ksize;
if (newindx == split_indx) {
sepkey.mv_data = newkey->mv_data;
} else {
sepkey.mv_data = split;
}
if (x<0) {
ins = LEAF2KEY(mp, mc->mc_ki[mc->mc_top], ksize);
memcpy(rp->mp_ptrs, split, rsize);
sepkey.mv_data = rp->mp_ptrs;
memmove(ins+ksize, ins, (split_indx - mc->mc_ki[mc->mc_top]) * ksize);
memcpy(ins, newkey->mv_data, ksize);
mp->mp_lower += sizeof(indx_t);
mp->mp_upper -= ksize - sizeof(indx_t);
} else {
if (x)
memcpy(rp->mp_ptrs, split, x * ksize);
ins = LEAF2KEY(rp, x, ksize);
memcpy(ins, newkey->mv_data, ksize);
memcpy(ins+ksize, split + x * ksize, rsize - x * ksize);
rp->mp_lower += sizeof(indx_t);
rp->mp_upper -= ksize - sizeof(indx_t);
mc->mc_ki[mc->mc_top] = x;
mc->mc_pg[mc->mc_top] = rp;
}
} else {
int psize, nsize, k;
// Maximum free space in an empty page
pmax = env->me_psize - PAGEHDRSZ;
if (IS_LEAF(mp))
nsize = mdb_leaf_size(env, newkey, newdata);
else
nsize = mdb_branch_size(env, newkey);
nsize = EVEN(nsize);
// grab a page to hold a temporary copy
copy = mdb_page_malloc(mc->mc_txn, 1);
if (copy == NULL)
return ENOMEM;
copy->mp_pgno = mp->mp_pgno;
copy->mp_flags = mp->mp_flags;
copy->mp_lower = PAGEHDRSZ;
copy->mp_upper = env->me_psize;
// prepare to insert
for (i=0, j=0; i<nkeys; i++) {
if (i == newindx) {
copy->mp_ptrs[j++] = 0;
}
copy->mp_ptrs[j++] = mp->mp_ptrs[i];
}
// When items are relatively large the split point needs
// to be checked, because being off-by-one will make the
// difference between success or failure in mdb_node_add.
//
// It's also relevant if a page happens to be laid out
// such that one half of its nodes are all "small" and
// the other half of its nodes are "large." If the new
// item is also "large" and falls on the half with
// "large" nodes, it also may not fit.
//
// As a final tweak, if the new item goes on the last
// spot on the page (and thus, onto the new page), bias
// the split so the new page is emptier than the old page.
// This yields better packing during sequential inserts.
if (nkeys < 20 || nsize > pmax/16 || newindx >= nkeys) {
// Find split point
psize = 0;
if (newindx <= split_indx || newindx >= nkeys) {
i = 0; j = 1;
k = newindx >= nkeys ? nkeys : split_indx+2;
} else {
i = nkeys; j = -1;
k = split_indx-1;
}
for (; i!=k; i+=j) {
if (i == newindx) {
psize += nsize;
node = NULL;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[i]);
psize += NODESIZE + NODEKSZ(node) + sizeof(indx_t);
if (IS_LEAF(mp)) {
if (F_ISSET(node->mn_flags, F_BIGDATA))
psize += sizeof(pgno_t);
else
psize += NODEDSZ(node);
}
psize = EVEN(psize);
}
if (psize > pmax || i == k-j) {
split_indx = i + (j<0);
break;
}
}
}
if (split_indx == newindx) {
sepkey.mv_size = newkey->mv_size;
sepkey.mv_data = newkey->mv_data;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[split_indx]);
sepkey.mv_size = node->mn_ksize;
sepkey.mv_data = NODEKEY(node);
}
}
}
DPRINTF(("separator is %d [%s]", split_indx, DKEY(&sepkey)));
// Copy separator key to the parent.
if (SIZELEFT(mn.mc_pg[ptop]) < mdb_branch_size(env, &sepkey)) {
mn.mc_snum--;
mn.mc_top--;
did_split = 1;
rc = mdb_page_split(&mn, &sepkey, NULL, rp->mp_pgno, 0);
// root split?
if (mn.mc_snum == mc->mc_snum) {
mc->mc_pg[mc->mc_snum] = mc->mc_pg[mc->mc_top];
mc->mc_ki[mc->mc_snum] = mc->mc_ki[mc->mc_top];
mc->mc_pg[mc->mc_top] = mc->mc_pg[ptop];
mc->mc_ki[mc->mc_top] = mc->mc_ki[ptop];
mc->mc_snum++;
mc->mc_top++;
ptop++;
}
// Right page might now have changed parent.
// Check if left page also changed parent.
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
mc->mc_pg[ptop] = mn.mc_pg[ptop];
mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
}
} else {
mn.mc_top--;
rc = mdb_node_add(&mn, mn.mc_ki[ptop], &sepkey, NULL, rp->mp_pgno, 0);
mn.mc_top++;
}
mc->mc_flags ^= C_SPLITTING;
if (rc != MDB_SUCCESS) {
return rc;
}
if (nflags & MDB_APPEND) {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[mc->mc_top] = 0;
rc = mdb_node_add(mc, 0, newkey, newdata, newpgno, nflags);
if (rc)
return rc;
for (i=0; i<mc->mc_top; i++)
mc->mc_ki[i] = mn.mc_ki[i];
} else if (!IS_LEAF2(mp)) {
// Move nodes
mc->mc_pg[mc->mc_top] = rp;
i = split_indx;
j = 0;
do {
if (i == newindx) {
rkey.mv_data = newkey->mv_data;
rkey.mv_size = newkey->mv_size;
if (IS_LEAF(mp)) {
rdata = newdata;
} else
pgno = newpgno;
flags = nflags;
// Update index for the new key.
mc->mc_ki[mc->mc_top] = j;
} else {
node = (MDB_node *)((char *)mp + copy->mp_ptrs[i]);
rkey.mv_data = NODEKEY(node);
rkey.mv_size = node->mn_ksize;
if (IS_LEAF(mp)) {
xdata.mv_data = NODEDATA(node);
xdata.mv_size = NODEDSZ(node);
rdata = &xdata;
} else
pgno = NODEPGNO(node);
flags = node->mn_flags;
}
if (!IS_LEAF(mp) && j == 0) {
// First branch index doesn't need key data.
rkey.mv_size = 0;
}
rc = mdb_node_add(mc, j, &rkey, rdata, pgno, flags);
if (rc) {
// return tmp page to freelist
mdb_page_free(env, copy);
return rc;
}
if (i == nkeys) {
i = 0;
j = 0;
mc->mc_pg[mc->mc_top] = copy;
} else {
i++;
j++;
}
} while (i != split_indx);
nkeys = NUMKEYS(copy);
for (i=0; i<nkeys; i++)
mp->mp_ptrs[i] = copy->mp_ptrs[i];
mp->mp_lower = copy->mp_lower;
mp->mp_upper = copy->mp_upper;
memcpy(NODEPTR(mp, nkeys-1), NODEPTR(copy, nkeys-1),
env->me_psize - copy->mp_upper);
// reset back to original page
if (newindx < split_indx) {
mc->mc_pg[mc->mc_top] = mp;
if (nflags & MDB_RESERVE) {
node = NODEPTR(mp, mc->mc_ki[mc->mc_top]);
if (!(node->mn_flags & F_BIGDATA))
newdata->mv_data = NODEDATA(node);
}
} else {
mc->mc_pg[mc->mc_top] = rp;
mc->mc_ki[ptop]++;
// Make sure mc_ki is still valid.
if (mn.mc_pg[ptop] != mc->mc_pg[ptop] &&
mc->mc_ki[ptop] >= NUMKEYS(mc->mc_pg[ptop])) {
for (i=0; i<ptop; i++) {
mc->mc_pg[i] = mn.mc_pg[i];
mc->mc_ki[i] = mn.mc_ki[i];
}
mc->mc_pg[ptop] = mn.mc_pg[ptop];
mc->mc_ki[ptop] = mn.mc_ki[ptop] - 1;
}
}
// return tmp page to freelist
mdb_page_free(env, copy);
}
{
// Adjust other cursors pointing to mp
MDB_cursor *m2, *m3;
MDB_dbi dbi = mc->mc_dbi;
int fixup = NUMKEYS(mp);
for (m2 = mc->mc_txn->mt_cursors[dbi]; m2; m2=m2->mc_next) {
if (mc->mc_flags & C_SUB)
m3 = &m2->mc_xcursor->mx_cursor;
else
m3 = m2;
if (m3 == mc)
continue;
if (!(m2->mc_flags & m3->mc_flags & C_INITIALIZED))
continue;
if (m3->mc_flags & C_SPLITTING)
continue;
if (new_root) {
int k;
// root split
for (k=m3->mc_top; k>=0; k--) {
m3->mc_ki[k+1] = m3->mc_ki[k];
m3->mc_pg[k+1] = m3->mc_pg[k];
}
if (m3->mc_ki[0] >= split_indx) {
m3->mc_ki[0] = 1;
} else {
m3->mc_ki[0] = 0;
}
m3->mc_pg[0] = mc->mc_pg[0];
m3->mc_snum++;
m3->mc_top++;
}
if (m3->mc_top >= mc->mc_top && m3->mc_pg[mc->mc_top] == mp) {
if (m3->mc_ki[mc->mc_top] >= newindx && !(nflags & MDB_SPLIT_REPLACE))
m3->mc_ki[mc->mc_top]++;
if (m3->mc_ki[mc->mc_top] >= fixup) {
m3->mc_pg[mc->mc_top] = rp;
m3->mc_ki[mc->mc_top] -= fixup;
m3->mc_ki[ptop] = mn.mc_ki[ptop];
}
} else if (!did_split && m3->mc_top >= ptop && m3->mc_pg[ptop] == mc->mc_pg[ptop] &&
m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
m3->mc_ki[ptop]++;
}
}
}
DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));
return rc;
*/
return nil
}
// Add all the DB's pages to the free list.
// @param[in] mc Cursor on the DB to free.
// @param[in] subs non-Zero to check for sub-DBs in this DB.
// @return 0 on success, non-zero on failure.
func (c *Cursor) drop0(subs int) error {
/*
int rc;
rc = mdb_page_search(mc, NULL, MDB_PS_FIRST);
if (rc == MDB_SUCCESS) {
MDB_txn *txn = mc->mc_txn;
MDB_node *ni;
MDB_cursor mx;
unsigned int i;
// LEAF2 pages have no nodes, cannot have sub-DBs
if (IS_LEAF2(mc->mc_pg[mc->mc_top]))
mdb_cursor_pop(mc);
mdb_cursor_copy(mc, &mx);
while (mc->mc_snum > 0) {
MDB_page *mp = mc->mc_pg[mc->mc_top];
unsigned n = NUMKEYS(mp);
if (IS_LEAF(mp)) {
for (i=0; i<n; i++) {
ni = NODEPTR(mp, i);
if (ni->mn_flags & F_BIGDATA) {
MDB_page *omp;
pgno_t pg;
memcpy(&pg, NODEDATA(ni), sizeof(pg));
rc = mdb_page_get(txn, pg, &omp, NULL);
if (rc != 0)
return rc;
mdb_cassert(mc, IS_OVERFLOW(omp));
rc = mdb_midl_append_range(&txn->mt_free_pgs,
pg, omp->mp_pages);
if (rc)
return rc;
} else if (subs && (ni->mn_flags & F_SUBDATA)) {
mdb_xcursor_init1(mc, ni);
rc = mdb_drop0(&mc->mc_xcursor->mx_cursor, 0);
if (rc)
return rc;
}
}
} else {
if ((rc = mdb_midl_need(&txn->mt_free_pgs, n)) != 0)
return rc;
for (i=0; i<n; i++) {
pgno_t pg;
ni = NODEPTR(mp, i);
pg = NODEPGNO(ni);
// free it
mdb_midl_xappend(txn->mt_free_pgs, pg);
}
}
if (!mc->mc_top)
break;
mc->mc_ki[mc->mc_top] = i;
rc = mdb_cursor_sibling(mc, 1);
if (rc) {
// no more siblings, go back to beginning
// of previous level.
mdb_cursor_pop(mc);
mc->mc_ki[0] = 0;
for (i=1; i<mc->mc_snum; i++) {
mc->mc_ki[i] = 0;
mc->mc_pg[i] = mx.mc_pg[i];
}
}
}
// free it
rc = mdb_midl_append(&txn->mt_free_pgs, mc->mc_db->md_root);
} else if (rc == MDB_NOTFOUND) {
rc = MDB_SUCCESS;
}
return rc;
*/
return nil
}
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