/**
* Set the pointer-map entries for all children of page pPage. Also, if pPage contains cells that
* point to overflow pages, set the pointer map entries for the overflow pages as well.
*
* @throws SqlJetException
*/
public void setChildPtrmaps() throws SqlJetException {
int i; /* Counter variable */
int nCell; /* Number of cells in page pPage */
boolean isInitOrig = isInit;
assert (pBt.mutex.held());
try {
initPage();
nCell = this.nCell;
for (i = 0; i < nCell; i++) {
ISqlJetMemoryPointer pCell = findCell(i);
ptrmapPutOvflPtr(pCell);
if (!leaf) {
int childPgno = get4byte(pCell);
pBt.ptrmapPut(childPgno, SqlJetBtreeShared.PTRMAP_BTREE, pgno);
}
}
if (!leaf) {
int childPgno = get4byte(aData, hdrOffset + 8);
pBt.ptrmapPut(childPgno, SqlJetBtreeShared.PTRMAP_BTREE, pgno);
}
} catch (SqlJetException e) {
// set_child_ptrmaps_out:
isInit = isInitOrig;
throw e;
}
}
/** * Free any overflow pages associated with the given Cell. */
public void clearCell(ISqlJetMemoryPointer pCell) throws SqlJetException {
SqlJetBtreeCellInfo info;
int[] ovflPgno = new int[1];
int nOvfl;
int ovflPageSize;
assert (pBt.mutex.held());
info = parseCellPtr(pCell);
if (info.iOverflow == 0) {
return; /* No overflow pages. Return without doing anything */
}
ovflPgno[0] = get4byte(pCell, info.iOverflow);
ovflPageSize = pBt.usableSize - 4;
nOvfl = (info.nPayload - info.nLocal + ovflPageSize - 1) / ovflPageSize;
assert (ovflPgno[0] == 0 || nOvfl > 0);
while (nOvfl-- != 0) {
SqlJetMemPage[] pOvfl = new SqlJetMemPage[1];
if (ovflPgno[0] < 2 || ovflPgno[0] > pBt.pPager.getPageCount()) {
/* 0 is not a legal page number and page 1 cannot be an
** overflow page. Therefore if ovflPgno<2 or past the end of the
** file the database must be corrupt. */
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
}
pBt.getOverflowPage(ovflPgno[0], pOvfl, (nOvfl == 0) ? null : ovflPgno);
pOvfl[0].freePage();
pOvfl[0].pDbPage.unref();
}
}
/**
* If the cell pCell, part of page pPage contains a pointer to an overflow page, insert an entry
* into the pointer-map for the overflow page.
*
* @throws SqlJetException
*/
public void ptrmapPutOvflPtr(ISqlJetMemoryPointer pCell) throws SqlJetException {
assert (pCell != null);
SqlJetBtreeCellInfo info = parseCellPtr(pCell);
assert ((info.nData + (intKey ? 0 : info.nKey)) == info.nPayload);
if ((info.nData + (intKey ? 0 : info.nKey)) > info.nLocal) {
int ovfl = get4byte(pCell, info.iOverflow);
pBt.ptrmapPut(ovfl, SqlJetBtreeShared.PTRMAP_OVERFLOW1, pgno);
}
}
/**
* Initialize the auxiliary information for a disk block.
*
* <p>Return SQLITE_OK on success. If we see that the page does not contain a well-formed database
* page, then return SQLITE_CORRUPT. Note that a return of SQLITE_OK does not guarantee that the
* page is well-formed. It only shows that we failed to detect any corruption.
*/
public void initPage() throws SqlJetException {
assert (pBt != null);
assert (pBt.mutex.held());
assert (pgno == pDbPage.getPageNumber());
assert (this == pDbPage.getExtra());
assert (aData.getBuffer() == pDbPage.getData().getBuffer());
if (!isInit) {
int pc; /* Address of a freeblock within pPage->aData[] */
byte hdr; /* Offset to beginning of page header */
int usableSize; /* Amount of usable space on each page */
int cellOffset; /* Offset from start of page to first cell pointer */
int nFree; /* Number of unused bytes on the page */
int top; /* First byte of the cell content area */
hdr = hdrOffset;
decodeFlags(SqlJetUtility.getUnsignedByte(aData, hdr));
assert (pBt.pageSize >= 512 && pBt.pageSize <= 32768);
maskPage = pBt.pageSize - 1;
nOverflow = 0;
usableSize = pBt.usableSize;
this.cellOffset = cellOffset = hdr + 12 - 4 * (leaf ? 1 : 0);
top = get2byte(aData, hdr + 5);
nCell = get2byte(aData, hdr + 3);
if (nCell > pBt.MX_CELL()) {
/* To many cells for a single page. The page must be corrupt */
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
}
int iCellFirst = cellOffset + 2 * this.nCell;
/* Compute the total free space on the page */
pc = get2byte(aData, hdr + 1);
nFree = SqlJetUtility.getUnsignedByte(aData, hdr + 7) + top; // - (cellOffset + 2 * nCell);
while (pc > 0) {
int next, size;
if (pc > usableSize - 4) {
/* Free block is off the page */
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
}
next = get2byte(aData, pc);
size = get2byte(aData, pc + 2);
if (next > 0 && next <= pc + size + 3) {
/* Free blocks must be in accending order */
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
}
nFree += size;
pc = next;
}
if (nFree > usableSize) {
/* Free space cannot exceed total page size */
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
}
this.nFree = (nFree - iCellFirst);
isInit = true;
}
}
/** Add a page of the database file to the freelist. unref() is NOT called for pPage. */
public void freePage() throws SqlJetException {
SqlJetMemPage pPage1 = pBt.pPage1;
int n, k;
/* Prepare the page for freeing */
assert (pBt.mutex.held());
assert (this.pgno > 1);
this.isInit = false;
/* Increment the free page count on pPage1 */
pPage1.pDbPage.write();
n = get4byte(pPage1.aData, 36);
put4byte(pPage1.aData, 36, n + 1);
if (ISqlJetConfig.SECURE_DELETE) {
/*
* If the SQLITE_SECURE_DELETE compile-time option is enabled, then
* always fully overwrite deleted information with zeros.
*/
pDbPage.write();
memset(aData, (byte) 0, pBt.pageSize);
}
/*
* If the database supports auto-vacuum, write an entry in the
* pointer-map to indicate that the page is free.
*/
if (ISAUTOVACUUM()) {
pBt.ptrmapPut(pgno, SqlJetBtreeShared.PTRMAP_FREEPAGE, 0);
}
if (n == 0) {
/* This is the first free page */
pDbPage.write();
memset(aData, (byte) 0, 8);
put4byte(pPage1.aData, 32, pgno);
TRACE("FREE-PAGE: %d first\n", this.pgno);
} else {
/*
* Other free pages already exist. Retrive the first trunk page* of
* the freelist and find out how many leaves it has.
*/
SqlJetMemPage pTrunk;
pTrunk = pBt.getPage(get4byte(pPage1.aData, 32), false);
k = get4byte(pTrunk.aData, 4);
if (k >= pBt.usableSize / 4 - 8) {
/*
* The trunk is full. Turn the page being freed into a new*
* trunk page with no leaves.** Note that the trunk page is not
* really full until it contains* usableSize/4 - 2 entries, not
* usableSize/4 - 8 entries as we have* coded. But due to a
* coding error in versions of SQLite prior to* 3.6.0, databases
* with freelist trunk pages holding more than* usableSize/4 - 8
* entries will be reported as corrupt. In order* to maintain
* backwards compatibility with older versions of SQLite,* we
* will contain to restrict the number of entries to
* usableSize/4 - 8* for now. At some point in the future (once
* everyone has upgraded* to 3.6.0 or later) we should consider
* fixing the conditional above* to read "usableSize/4-2"
* instead of "usableSize/4-8".
*/
pDbPage.write();
put4byte(aData, pTrunk.pgno);
put4byte(aData, 4, 0);
put4byte(pPage1.aData, 32, pgno);
TRACE("FREE-PAGE: %d new trunk page replacing %d\n", this.pgno, pTrunk.pgno);
} else if (k < 0) {
throw new SqlJetException(SqlJetErrorCode.CORRUPT);
} else {
/* Add the newly freed page as a leaf on the current trunk */
pTrunk.pDbPage.write();
put4byte(pTrunk.aData, 4, k + 1);
put4byte(pTrunk.aData, 8 + k * 4, pgno);
if (ISqlJetConfig.SECURE_DELETE) {
pDbPage.dontWrite();
}
TRACE("FREE-PAGE: %d leaf on trunk page %d\n", this.pgno, pTrunk.pgno);
}
releasePage(pTrunk);
}
}
/**
* Create the byte sequence used to represent a cell on page pPage and write that byte sequence
* into pCell[]. Overflow pages are allocated and filled in as necessary. The calling procedure is
* responsible for making sure sufficient space has been allocated for pCell[].
*
* <p>Note that pCell does not necessary need to point to the pPage->aData area. pCell might point
* to some temporary storage. The cell will be constructed in this temporary area then copied into
* pPage->aData later.
*
* @param pCell Complete text of the cell
* @param pKey The key
* @param nKey The key
* @param pData The data
* @param nData The data
* @param nZero Extra zero bytes to append to pData
* @return cell size
* @throws SqlJetException
*/
public int fillInCell(
ISqlJetMemoryPointer pCell,
ISqlJetMemoryPointer pKey,
long nKey,
ISqlJetMemoryPointer pData,
int nData,
int nZero)
throws SqlJetException {
final SqlJetMemPage pPage = this;
int pnSize = 0;
int nPayload;
ISqlJetMemoryPointer pSrc;
int nSrc, n;
int spaceLeft;
SqlJetMemPage pOvfl = null;
SqlJetMemPage pToRelease = null;
ISqlJetMemoryPointer pPrior;
ISqlJetMemoryPointer pPayload;
SqlJetBtreeShared pBt = pPage.pBt;
int[] pgnoOvfl = {0};
int nHeader;
SqlJetBtreeCellInfo info;
assert (pPage.pBt.mutex.held());
/*
* pPage is not necessarily writeable since pCell might be auxiliary*
* buffer space that is separate from the pPage buffer area
*/
assert (pCell.getBuffer() != pPage.aData.getBuffer() || pPage.pDbPage.isWriteable());
/* Fill in the header. */
nHeader = 0;
if (!pPage.leaf) {
nHeader += 4;
}
if (pPage.hasData) {
nHeader += putVarint(pointer(pCell, nHeader), nData + nZero);
} else {
nData = nZero = 0;
}
nHeader += putVarint(pointer(pCell, nHeader), nKey);
info = pPage.parseCellPtr(pCell);
assert (info.nHeader == nHeader);
assert (info.nKey == nKey);
assert (info.nData == nData + nZero);
/* Fill in the payload */
nPayload = nData + nZero;
if (pPage.intKey) {
pSrc = pData;
nSrc = nData;
nData = 0;
} else {
/* TBD: Perhaps raise SQLITE_CORRUPT if nKey is larger than 31 bits? */
nPayload += (int) nKey;
pSrc = pKey;
nSrc = (int) nKey;
}
pnSize = info.nSize;
spaceLeft = info.nLocal;
pPayload = pointer(pCell, nHeader);
pPrior = pointer(pCell, info.iOverflow);
while (nPayload > 0) {
if (spaceLeft == 0) {
int pgnoPtrmap = pgnoOvfl[0]; /*
* Overflow page pointer-map entry
* page
*/
if (pBt.autoVacuum) {
do {
pgnoOvfl[0]++;
} while (pBt.PTRMAP_ISPAGE(pgnoOvfl[0]) || pgnoOvfl[0] == pBt.PENDING_BYTE_PAGE());
}
try {
pOvfl = pBt.allocatePage(pgnoOvfl, pgnoOvfl[0], false);
/*
* If the database supports auto-vacuum, and the second or
* subsequent* overflow page is being allocated, add an
* entry to the pointer-map* for that page now.** If this is
* the first overflow page, then write a partial entry* to
* the pointer-map. If we write nothing to this pointer-map
* slot,* then the optimistic overflow chain processing in
* clearCell()* may misinterpret the uninitialised values
* and delete the* wrong pages from the database.
*/
if (pBt.autoVacuum) {
byte eType =
(pgnoPtrmap != 0
? SqlJetBtreeShared.PTRMAP_OVERFLOW2
: SqlJetBtreeShared.PTRMAP_OVERFLOW1);
try {
pBt.ptrmapPut(pgnoOvfl[0], eType, pgnoPtrmap);
} catch (SqlJetException e) {
releasePage(pOvfl);
}
}
} catch (SqlJetException e) {
releasePage(pToRelease);
throw e;
}
/*
* If pToRelease is not zero than pPrior points into the data
* area* of pToRelease. Make sure pToRelease is still writeable.
*/
assert (pToRelease == null || pToRelease.pDbPage.isWriteable());
/*
* If pPrior is part of the data area of pPage, then make sure
* pPage* is still writeable
*/
assert (pPrior.getBuffer() != pPage.aData.getBuffer() || pPage.pDbPage.isWriteable());
put4byte(pPrior, pgnoOvfl[0]);
releasePage(pToRelease);
pToRelease = pOvfl;
pPrior = pOvfl.aData;
put4byte(pPrior, 0);
pPayload = pointer(pOvfl.aData, 4);
spaceLeft = pBt.usableSize - 4;
}
n = nPayload;
if (n > spaceLeft) n = spaceLeft;
/*
* If pToRelease is not zero than pPayload points into the data area
* * of pToRelease. Make sure pToRelease is still writeable.
*/
assert (pToRelease == null || pToRelease.pDbPage.isWriteable());
/*
* If pPayload is part of the data area of pPage, then make sure
* pPage* is still writeable
*/
assert (pPayload.getBuffer() != pPage.aData.getBuffer() || pPage.pDbPage.isWriteable());
if (nSrc > 0) {
if (n > nSrc) n = nSrc;
assert (pSrc != null);
memcpy(pPayload, pSrc, n);
} else {
memset(pPayload, (byte) 0, n);
}
nPayload -= n;
movePtr(pPayload, n);
pSrc = pointer(pSrc, n);
nSrc -= n;
spaceLeft -= n;
if (nSrc == 0) {
nSrc = nData;
pSrc = pData;
}
}
releasePage(pToRelease);
return pnSize;
}
