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C/C++

fts3.c：源码内容

if( aTerm[i].nTerm>nToken ) continue;
if( !aTerm[i].isPrefix && aTerm[i].nTerm<nToken ) continue;
assert( aTerm[i].nTerm<=nToken );
if( memcmp(aTerm[i].pTerm, zToken, aTerm[i].nTerm) ) continue;
if( aTerm[i].iPhrase>1 && (prevMatch & (1<<i))==0 ) continue;
match |= 1<<i;
if( i==nTerm-1 || aTerm[i+1].iPhrase==1 ){
for(j=aTerm[i].iPhrase-1; j>=0; j--){
int k = (iRotor-j) & FTS3_ROTOR_MASK;
snippetAppendMatch(pSnippet, iColumn, i-j, iPos-j,
iRotorBegin[k], iRotorLen[k]);
}
}
}
prevMatch = match<<1;
iRotor++;
}
pTModule->xClose(pTCursor);
}
/*
** Remove entries from the pSnippet structure to account for the NEAR
** operator. When this is called, pSnippet contains the list of token
** offsets produced by treating all NEAR operators as AND operators.
** This function removes any entries that should not be present after
** accounting for the NEAR restriction. For example, if the queried
** document is:
**
** "A B C D E A"
**
** and the query is:
**
** A NEAR/0 E
**
** then when this function is called the Snippet contains token offsets
** 0, 4 and 5. This function removes the "0" entry (because the first A
** is not near enough to an E).
*/
static void trimSnippetOffsetsForNear(Query *pQuery, Snippet *pSnippet){
int ii;
int iDir = 1;
while(iDir>-2) {
assert( iDir==1 || iDir==-1 );
for(ii=0; ii<pSnippet->nMatch; ii++){
int jj;
int nNear;
struct snippetMatch *pMatch = &pSnippet->aMatch[ii];
QueryTerm *pQueryTerm = &pQuery->pTerms[pMatch->iTerm];
if( (pMatch->iTerm+iDir)<0
|| (pMatch->iTerm+iDir)>=pQuery->nTerms
){
continue;
}
nNear = pQueryTerm->nNear;
if( iDir<0 ){
nNear = pQueryTerm[-1].nNear;
}
if( pMatch->iTerm>=0 && nNear ){
int isOk = 0;
int iNextTerm = pMatch->iTerm+iDir;
int iPrevTerm = iNextTerm;
int iEndToken;
int iStartToken;
if( iDir<0 ){
int nPhrase = 1;
iStartToken = pMatch->iToken;
while( (pMatch->iTerm+nPhrase)<pQuery->nTerms
&& pQuery->pTerms[pMatch->iTerm+nPhrase].iPhrase>1
){
nPhrase++;
}
iEndToken = iStartToken + nPhrase - 1;
}else{
iEndToken = pMatch->iToken;
iStartToken = pMatch->iToken+1-pQueryTerm->iPhrase;
}
while( pQuery->pTerms[iNextTerm].iPhrase>1 ){
iNextTerm--;
}
while( (iPrevTerm+1)<pQuery->nTerms &&
pQuery->pTerms[iPrevTerm+1].iPhrase>1
){
iPrevTerm++;
}
for(jj=0; isOk==0 && jj<pSnippet->nMatch; jj++){
struct snippetMatch *p = &pSnippet->aMatch[jj];
if( p->iCol==pMatch->iCol && ((
p->iTerm==iNextTerm &&
p->iToken>iEndToken &&
p->iToken<=iEndToken+nNear
) || (
p->iTerm==iPrevTerm &&
p->iToken<iStartToken &&
p->iToken>=iStartToken-nNear
))){
isOk = 1;
}
}
if( !isOk ){
for(jj=1-pQueryTerm->iPhrase; jj<=0; jj++){
pMatch[jj].iTerm = -1;
}
ii = -1;
iDir = 1;
}
}
}
iDir -= 2;
}
}
/*
** Compute all offsets for the current row of the query.
** If the offsets have already been computed, this routine is a no-op.
*/
static void snippetAllOffsets(fulltext_cursor *p){
int nColumn;
int iColumn, i;
int iFirst, iLast;
fulltext_vtab *pFts;
if( p->snippet.nMatch ) return;
if( p->q.nTerms==0 ) return;
pFts = p->q.pFts;
nColumn = pFts->nColumn;
iColumn = (p->iCursorType - QUERY_FULLTEXT);
if( iColumn<0 || iColumn>=nColumn ){
iFirst = 0;
iLast = nColumn-1;
}else{
iFirst = iColumn;
iLast = iColumn;
}
for(i=iFirst; i<=iLast; i++){
const char *zDoc;
int nDoc;
zDoc = (const char*)sqlite3_column_text(p->pStmt, i+1);
nDoc = sqlite3_column_bytes(p->pStmt, i+1);
snippetOffsetsOfColumn(&p->q, &p->snippet, i, zDoc, nDoc);
}
trimSnippetOffsetsForNear(&p->q, &p->snippet);
}
/*
** Convert the information in the aMatch[] array of the snippet
** into the string zOffset[0..nOffset-1].
*/
static void snippetOffsetText(Snippet *p){
int i;
int cnt = 0;
StringBuffer sb;
char zBuf[200];
if( p->zOffset ) return;
initStringBuffer(&sb);
for(i=0; i<p->nMatch; i++){
struct snippetMatch *pMatch = &p->aMatch[i];
if( pMatch->iTerm>=0 ){
/* If snippetMatch.iTerm is less than 0, then the match was
** discarded as part of processing the NEAR operator (see the
** trimSnippetOffsetsForNear() function for details). Ignore
** it in this case
*/
zBuf[0] = ' ';
sqlite3_snprintf(sizeof(zBuf)-1, &zBuf[cnt>0], "%d %d %d %d",
pMatch->iCol, pMatch->iTerm, pMatch->iStart, pMatch->nByte);
append(&sb, zBuf);
cnt++;
}
}
p->zOffset = stringBufferData(&sb);
p->nOffset = stringBufferLength(&sb);
}
/*
** zDoc[0..nDoc-1] is phrase of text. aMatch[0..nMatch-1] are a set
** of matching words some of which might be in zDoc. zDoc is column
** number iCol.
**
** iBreak is suggested spot in zDoc where we could begin or end an
** excerpt. Return a value similar to iBreak but possibly adjusted
** to be a little left or right so that the break point is better.
*/
static int wordBoundary(
int iBreak, /* The suggested break point */
const char *zDoc, /* Document text */
int nDoc, /* Number of bytes in zDoc[] */
struct snippetMatch *aMatch, /* Matching words */
int nMatch, /* Number of entries in aMatch[] */
int iCol /* The column number for zDoc[] */
){
int i;
if( iBreak<=10 ){
return 0;
}
if( iBreak>=nDoc-10 ){
return nDoc;
}
for(i=0; i<nMatch && aMatch[i].iCol<iCol; i++){}
while( i<nMatch && aMatch[i].iStart+aMatch[i].nByte<iBreak ){ i++; }
if( i<nMatch ){
if( aMatch[i].iStart<iBreak+10 ){
return aMatch[i].iStart;
}
if( i>0 && aMatch[i-1].iStart+aMatch[i-1].nByte>=iBreak ){
return aMatch[i-1].iStart;
}
}
for(i=1; i<=10; i++){
if( safe_isspace(zDoc[iBreak-i]) ){
return iBreak - i + 1;
}
if( safe_isspace(zDoc[iBreak+i]) ){
return iBreak + i + 1;
}
}
return iBreak;
}
/*
** Allowed values for Snippet.aMatch[].snStatus
*/
#define SNIPPET_IGNORE 0 /* It is ok to omit this match from the snippet */
#define SNIPPET_DESIRED 1 /* We want to include this match in the snippet */
/*
** Generate the text of a snippet.
*/
static void snippetText(
fulltext_cursor *pCursor, /* The cursor we need the snippet for */
const char *zStartMark, /* Markup to appear before each match */
const char *zEndMark, /* Markup to appear after each match */
const char *zEllipsis /* Ellipsis mark */
){
int i, j;
struct snippetMatch *aMatch;
int nMatch;
int nDesired;
StringBuffer sb;
int tailCol;
int tailOffset;
int iCol;
int nDoc;
const char *zDoc;
int iStart, iEnd;
int tailEllipsis = 0;
int iMatch;
sqlite3_free(pCursor->snippet.zSnippet);
pCursor->snippet.zSnippet = 0;
aMatch = pCursor->snippet.aMatch;
nMatch = pCursor->snippet.nMatch;
initStringBuffer(&sb);
for(i=0; i<nMatch; i++){
aMatch[i].snStatus = SNIPPET_IGNORE;
}
nDesired = 0;
for(i=0; i<pCursor->q.nTerms; i++){
for(j=0; j<nMatch; j++){
if( aMatch[j].iTerm==i ){
aMatch[j].snStatus = SNIPPET_DESIRED;
nDesired++;
break;
}
}
}
iMatch = 0;
tailCol = -1;
tailOffset = 0;
for(i=0; i<nMatch && nDesired>0; i++){
if( aMatch[i].snStatus!=SNIPPET_DESIRED ) continue;
nDesired--;
iCol = aMatch[i].iCol;
zDoc = (const char*)sqlite3_column_text(pCursor->pStmt, iCol+1);
nDoc = sqlite3_column_bytes(pCursor->pStmt, iCol+1);
iStart = aMatch[i].iStart - 40;
iStart = wordBoundary(iStart, zDoc, nDoc, aMatch, nMatch, iCol);
if( iStart<=10 ){
iStart = 0;
}
if( iCol==tailCol && iStart<=tailOffset+20 ){
iStart = tailOffset;
}
if( (iCol!=tailCol && tailCol>=0) || iStart!=tailOffset ){
trimWhiteSpace(&sb);
appendWhiteSpace(&sb);
append(&sb, zEllipsis);
appendWhiteSpace(&sb);
}
iEnd = aMatch[i].iStart + aMatch[i].nByte + 40;
iEnd = wordBoundary(iEnd, zDoc, nDoc, aMatch, nMatch, iCol);
if( iEnd>=nDoc-10 ){
iEnd = nDoc;
tailEllipsis = 0;
}else{
tailEllipsis = 1;
}
while( iMatch<nMatch && aMatch[iMatch].iCol<iCol ){ iMatch++; }
while( iStart<iEnd ){
while( iMatch<nMatch && aMatch[iMatch].iStart<iStart
&& aMatch[iMatch].iCol<=iCol ){
iMatch++;
}
if( iMatch<nMatch && aMatch[iMatch].iStart<iEnd
&& aMatch[iMatch].iCol==iCol ){
nappend(&sb, &zDoc[iStart], aMatch[iMatch].iStart - iStart);
iStart = aMatch[iMatch].iStart;
append(&sb, zStartMark);
nappend(&sb, &zDoc[iStart], aMatch[iMatch].nByte);
append(&sb, zEndMark);
iStart += aMatch[iMatch].nByte;
for(j=iMatch+1; j<nMatch; j++){
if( aMatch[j].iTerm==aMatch[iMatch].iTerm
&& aMatch[j].snStatus==SNIPPET_DESIRED ){
nDesired--;
aMatch[j].snStatus = SNIPPET_IGNORE;
}
}
}else{
nappend(&sb, &zDoc[iStart], iEnd - iStart);
iStart = iEnd;
}
}
tailCol = iCol;
tailOffset = iEnd;
}
trimWhiteSpace(&sb);
if( tailEllipsis ){
appendWhiteSpace(&sb);
append(&sb, zEllipsis);
}
pCursor->snippet.zSnippet = stringBufferData(&sb);
pCursor->snippet.nSnippet = stringBufferLength(&sb);
}
/*
** Close the cursor. For additional information see the documentation
** on the xClose method of the virtual table interface.
*/
static int fulltextClose(sqlite3_vtab_cursor *pCursor){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
FTSTRACE(("FTS3 Close %pn", c));
sqlite3_finalize(c->pStmt);
queryClear(&c->q);
snippetClear(&c->snippet);
if( c->result.nData!=0 ) dlrDestroy(&c->reader);
dataBufferDestroy(&c->result);
sqlite3_free(c);
return SQLITE_OK;
}
static int fulltextNext(sqlite3_vtab_cursor *pCursor){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
int rc;
FTSTRACE(("FTS3 Next %pn", pCursor));
snippetClear(&c->snippet);
if( c->iCursorType < QUERY_FULLTEXT ){
/* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
rc = sqlite3_step(c->pStmt);
switch( rc ){
case SQLITE_ROW:
c->eof = 0;
return SQLITE_OK;
case SQLITE_DONE:
c->eof = 1;
return SQLITE_OK;
default:
c->eof = 1;
return rc;
}
} else { /* full-text query */
rc = sqlite3_reset(c->pStmt);
if( rc!=SQLITE_OK ) return rc;
if( c->result.nData==0 || dlrAtEnd(&c->reader) ){
c->eof = 1;
return SQLITE_OK;
}
rc = sqlite3_bind_int64(c->pStmt, 1, dlrDocid(&c->reader));
dlrStep(&c->reader);
if( rc!=SQLITE_OK ) return rc;
/* TODO(shess) Handle SQLITE_SCHEMA AND SQLITE_BUSY. */
rc = sqlite3_step(c->pStmt);
if( rc==SQLITE_ROW ){ /* the case we expect */
c->eof = 0;
return SQLITE_OK;
}
/* an error occurred; abort */
return rc==SQLITE_DONE ? SQLITE_ERROR : rc;
}
}
/* TODO(shess) If we pushed LeafReader to the top of the file, or to
** another file, term_select() could be pushed above
** docListOfTerm().
*/
static int termSelect(fulltext_vtab *v, int iColumn,
const char *pTerm, int nTerm, int isPrefix,
DocListType iType, DataBuffer *out);
/* Return a DocList corresponding to the query term *pTerm. If *pTerm
** is the first term of a phrase query, go ahead and evaluate the phrase
** query and return the doclist for the entire phrase query.
**
** The resulting DL_DOCIDS doclist is stored in pResult, which is
** overwritten.
*/
static int docListOfTerm(
fulltext_vtab *v, /* The full text index */
int iColumn, /* column to restrict to. No restriction if >=nColumn */
QueryTerm *pQTerm, /* Term we are looking for, or 1st term of a phrase */
DataBuffer *pResult /* Write the result here */
){
DataBuffer left, right, new;
int i, rc;
/* No phrase search if no position info. */
assert( pQTerm->nPhrase==0 || DL_DEFAULT!=DL_DOCIDS );
/* This code should never be called with buffered updates. */
assert( v->nPendingData<0 );
dataBufferInit(&left, 0);
rc = termSelect(v, iColumn, pQTerm->pTerm, pQTerm->nTerm, pQTerm->isPrefix,
(0<pQTerm->nPhrase ? DL_POSITIONS : DL_DOCIDS), &left);
if( rc ) return rc;
for(i=1; i<=pQTerm->nPhrase && left.nData>0; i++){
/* If this token is connected to the next by a NEAR operator, and
** the next token is the start of a phrase, then set nPhraseRight
** to the number of tokens in the phrase. Otherwise leave it at 1.
*/
int nPhraseRight = 1;
while( (i+nPhraseRight)<=pQTerm->nPhrase
&& pQTerm[i+nPhraseRight].nNear==0
){
nPhraseRight++;
}
dataBufferInit(&right, 0);
rc = termSelect(v, iColumn, pQTerm[i].pTerm, pQTerm[i].nTerm,
pQTerm[i].isPrefix, DL_POSITIONS, &right);
if( rc ){
dataBufferDestroy(&left);
return rc;
}
dataBufferInit(&new, 0);
docListPhraseMerge(left.pData, left.nData, right.pData, right.nData,
pQTerm[i-1].nNear, pQTerm[i-1].iPhrase + nPhraseRight,
((i<pQTerm->nPhrase) ? DL_POSITIONS : DL_DOCIDS),
&new);
dataBufferDestroy(&left);
dataBufferDestroy(&right);
left = new;
}
*pResult = left;
return SQLITE_OK;
}
/* Add a new term pTerm[0..nTerm-1] to the query *q.
*/
static void queryAdd(Query *q, const char *pTerm, int nTerm){
QueryTerm *t;
++q->nTerms;
q->pTerms = sqlite3_realloc(q->pTerms, q->nTerms * sizeof(q->pTerms[0]));
if( q->pTerms==0 ){
q->nTerms = 0;
return;
}
t = &q->pTerms[q->nTerms - 1];
CLEAR(t);
t->pTerm = sqlite3_malloc(nTerm+1);
memcpy(t->pTerm, pTerm, nTerm);
t->pTerm[nTerm] = 0;
t->nTerm = nTerm;
t->isOr = q->nextIsOr;
t->isPrefix = 0;
q->nextIsOr = 0;
t->iColumn = q->nextColumn;
q->nextColumn = q->dfltColumn;
}
/*
** Check to see if the string zToken[0...nToken-1] matches any
** column name in the virtual table. If it does,
** return the zero-indexed column number. If not, return -1.
*/
static int checkColumnSpecifier(
fulltext_vtab *pVtab, /* The virtual table */
const char *zToken, /* Text of the token */
int nToken /* Number of characters in the token */
){
int i;
for(i=0; i<pVtab->nColumn; i++){
if( memcmp(pVtab->azColumn[i], zToken, nToken)==0
&& pVtab->azColumn[i][nToken]==0 ){
return i;
}
}
return -1;
}
/*
** Parse the text at pSegment[0..nSegment-1]. Add additional terms
** to the query being assemblied in pQuery.
**
** inPhrase is true if pSegment[0..nSegement-1] is contained within
** double-quotes. If inPhrase is true, then the first term
** is marked with the number of terms in the phrase less one and
** OR and "-" syntax is ignored. If inPhrase is false, then every
** term found is marked with nPhrase=0 and OR and "-" syntax is significant.
*/
static int tokenizeSegment(
sqlite3_tokenizer *pTokenizer, /* The tokenizer to use */
const char *pSegment, int nSegment, /* Query expression being parsed */
int inPhrase, /* True if within "..." */
Query *pQuery /* Append results here */
){
const sqlite3_tokenizer_module *pModule = pTokenizer->pModule;
sqlite3_tokenizer_cursor *pCursor;
int firstIndex = pQuery->nTerms;
int iCol;
int nTerm = 1;
int rc = pModule->xOpen(pTokenizer, pSegment, nSegment, &pCursor);
if( rc!=SQLITE_OK ) return rc;
pCursor->pTokenizer = pTokenizer;
while( 1 ){
const char *pToken;
int nToken, iBegin, iEnd, iPos;
rc = pModule->xNext(pCursor,
&pToken, &nToken,
&iBegin, &iEnd, &iPos);
if( rc!=SQLITE_OK ) break;
if( !inPhrase &&
pSegment[iEnd]==':' &&
(iCol = checkColumnSpecifier(pQuery->pFts, pToken, nToken))>=0 ){
pQuery->nextColumn = iCol;
continue;
}
if( !inPhrase && pQuery->nTerms>0 && nToken==2
&& pSegment[iBegin+0]=='O'
&& pSegment[iBegin+1]=='R'
){
pQuery->nextIsOr = 1;
continue;
}
if( !inPhrase && pQuery->nTerms>0 && !pQuery->nextIsOr && nToken==4
&& pSegment[iBegin+0]=='N'
&& pSegment[iBegin+1]=='E'
&& pSegment[iBegin+2]=='A'
&& pSegment[iBegin+3]=='R'
){
QueryTerm *pTerm = &pQuery->pTerms[pQuery->nTerms-1];
if( (iBegin+6)<nSegment
&& pSegment[iBegin+4] == '/'
&& pSegment[iBegin+5]>='0' && pSegment[iBegin+5]<='9'
){
pTerm->nNear = (pSegment[iBegin+5] - '0');
nToken += 2;
if( pSegment[iBegin+6]>='0' && pSegment[iBegin+6]<=9 ){
pTerm->nNear = pTerm->nNear * 10 + (pSegment[iBegin+6] - '0');
iEnd++;
}
pModule->xNext(pCursor, &pToken, &nToken, &iBegin, &iEnd, &iPos);
} else {
pTerm->nNear = SQLITE_FTS3_DEFAULT_NEAR_PARAM;
}
pTerm->nNear++;
continue;
}
queryAdd(pQuery, pToken, nToken);
if( !inPhrase && iBegin>0 && pSegment[iBegin-1]=='-' ){
pQuery->pTerms[pQuery->nTerms-1].isNot = 1;
}
if( iEnd<nSegment && pSegment[iEnd]=='*' ){
pQuery->pTerms[pQuery->nTerms-1].isPrefix = 1;
}
pQuery->pTerms[pQuery->nTerms-1].iPhrase = nTerm;
if( inPhrase ){
nTerm++;
}
}
if( inPhrase && pQuery->nTerms>firstIndex ){
pQuery->pTerms[firstIndex].nPhrase = pQuery->nTerms - firstIndex - 1;
}
return pModule->xClose(pCursor);
}
/* Parse a query string, yielding a Query object pQuery.
**
** The calling function will need to queryClear() to clean up
** the dynamically allocated memory held by pQuery.
*/
static int parseQuery(
fulltext_vtab *v, /* The fulltext index */
const char *zInput, /* Input text of the query string */
int nInput, /* Size of the input text */
int dfltColumn, /* Default column of the index to match against */
Query *pQuery /* Write the parse results here. */
){
int iInput, inPhrase = 0;
int ii;
QueryTerm *aTerm;
if( zInput==0 ) nInput = 0;
if( nInput<0 ) nInput = strlen(zInput);
pQuery->nTerms = 0;
pQuery->pTerms = NULL;
pQuery->nextIsOr = 0;
pQuery->nextColumn = dfltColumn;
pQuery->dfltColumn = dfltColumn;
pQuery->pFts = v;
for(iInput=0; iInput<nInput; ++iInput){
int i;
for(i=iInput; i<nInput && zInput[i]!='"'; ++i){}
if( i>iInput ){
tokenizeSegment(v->pTokenizer, zInput+iInput, i-iInput, inPhrase,
pQuery);
}
iInput = i;
if( i<nInput ){
assert( zInput[i]=='"' );
inPhrase = !inPhrase;
}
}
if( inPhrase ){
/* unmatched quote */
queryClear(pQuery);
return SQLITE_ERROR;
}
/* Modify the values of the QueryTerm.nPhrase variables to account for
** the NEAR operator. For the purposes of QueryTerm.nPhrase, phrases
** and tokens connected by the NEAR operator are handled as a single
** phrase. See comments above the QueryTerm structure for details.
*/
aTerm = pQuery->pTerms;
for(ii=0; ii<pQuery->nTerms; ii++){
if( aTerm[ii].nNear || aTerm[ii].nPhrase ){
while (aTerm[ii+aTerm[ii].nPhrase].nNear) {
aTerm[ii].nPhrase += (1 + aTerm[ii+aTerm[ii].nPhrase+1].nPhrase);
}
}
}
return SQLITE_OK;
}
/* TODO(shess) Refactor the code to remove this forward decl. */
static int flushPendingTerms(fulltext_vtab *v);
/* Perform a full-text query using the search expression in
** zInput[0..nInput-1]. Return a list of matching documents
** in pResult.
**
** Queries must match column iColumn. Or if iColumn>=nColumn
** they are allowed to match against any column.
*/
static int fulltextQuery(
fulltext_vtab *v, /* The full text index */
int iColumn, /* Match against this column by default */
const char *zInput, /* The query string */
int nInput, /* Number of bytes in zInput[] */
DataBuffer *pResult, /* Write the result doclist here */
Query *pQuery /* Put parsed query string here */
){
int i, iNext, rc;
DataBuffer left, right, or, new;
int nNot = 0;
QueryTerm *aTerm;
/* TODO(shess) Instead of flushing pendingTerms, we could query for
** the relevant term and merge the doclist into what we receive from
** the database. Wait and see if this is a common issue, first.
**
** A good reason not to flush is to not generate update-related
** error codes from here.
*/
/* Flush any buffered updates before executing the query. */
rc = flushPendingTerms(v);
if( rc!=SQLITE_OK ) return rc;
/* TODO(shess) I think that the queryClear() calls below are not
** necessary, because fulltextClose() already clears the query.
*/
rc = parseQuery(v, zInput, nInput, iColumn, pQuery);
if( rc!=SQLITE_OK ) return rc;
/* Empty or NULL queries return no results. */
if( pQuery->nTerms==0 ){
dataBufferInit(pResult, 0);
return SQLITE_OK;
}
/* Merge AND terms. */
/* TODO(shess) I think we can early-exit if( i>nNot && left.nData==0 ). */
aTerm = pQuery->pTerms;
for(i = 0; i<pQuery->nTerms; i=iNext){
if( aTerm[i].isNot ){
/* Handle all NOT terms in a separate pass */
nNot++;
iNext = i + aTerm[i].nPhrase+1;
continue;
}
iNext = i + aTerm[i].nPhrase + 1;
rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &right);
if( rc ){
if( i!=nNot ) dataBufferDestroy(&left);
queryClear(pQuery);
return rc;
}
while( iNext<pQuery->nTerms && aTerm[iNext].isOr ){
rc = docListOfTerm(v, aTerm[iNext].iColumn, &aTerm[iNext], &or);
iNext += aTerm[iNext].nPhrase + 1;
if( rc ){
if( i!=nNot ) dataBufferDestroy(&left);
dataBufferDestroy(&right);
queryClear(pQuery);
return rc;
}
dataBufferInit(&new, 0);
docListOrMerge(right.pData, right.nData, or.pData, or.nData, &new);
dataBufferDestroy(&right);
dataBufferDestroy(&or);
right = new;
}
if( i==nNot ){ /* first term processed. */
left = right;
}else{
dataBufferInit(&new, 0);
docListAndMerge(left.pData, left.nData, right.pData, right.nData, &new);
dataBufferDestroy(&right);
dataBufferDestroy(&left);
left = new;
}
}
if( nNot==pQuery->nTerms ){
/* We do not yet know how to handle a query of only NOT terms */
return SQLITE_ERROR;
}
/* Do the EXCEPT terms */
for(i=0; i<pQuery->nTerms; i += aTerm[i].nPhrase + 1){
if( !aTerm[i].isNot ) continue;
rc = docListOfTerm(v, aTerm[i].iColumn, &aTerm[i], &right);
if( rc ){
queryClear(pQuery);
dataBufferDestroy(&left);
return rc;
}
dataBufferInit(&new, 0);
docListExceptMerge(left.pData, left.nData, right.pData, right.nData, &new);
dataBufferDestroy(&right);
dataBufferDestroy(&left);
left = new;
}
*pResult = left;
return rc;
}
/*
** This is the xFilter interface for the virtual table. See
** the virtual table xFilter method documentation for additional
** information.
**
** If idxNum==QUERY_GENERIC then do a full table scan against
** the %_content table.
**
** If idxNum==QUERY_DOCID then do a docid lookup for a single entry
** in the %_content table.
**
** If idxNum>=QUERY_FULLTEXT then use the full text index. The
** column on the left-hand side of the MATCH operator is column
** number idxNum-QUERY_FULLTEXT, 0 indexed. argv[0] is the right-hand
** side of the MATCH operator.
*/
/* TODO(shess) Upgrade the cursor initialization and destruction to
** account for fulltextFilter() being called multiple times on the
** same cursor. The current solution is very fragile. Apply fix to
** fts3 as appropriate.
*/
static int fulltextFilter(
sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
int idxNum, const char *idxStr, /* Which indexing scheme to use */
int argc, sqlite3_value **argv /* Arguments for the indexing scheme */
){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
fulltext_vtab *v = cursor_vtab(c);
int rc;
StringBuffer sb;
FTSTRACE(("FTS3 Filter %pn",pCursor));
initStringBuffer(&sb);
append(&sb, "SELECT docid, ");
appendList(&sb, v->nColumn, v->azContentColumn);
append(&sb, " FROM %_content");
if( idxNum!=QUERY_GENERIC ) append(&sb, " WHERE docid = ?");
sqlite3_finalize(c->pStmt);
rc = sql_prepare(v->db, v->zDb, v->zName, &c->pStmt, stringBufferData(&sb));
stringBufferDestroy(&sb);
if( rc!=SQLITE_OK ) return rc;
c->iCursorType = idxNum;
switch( idxNum ){
case QUERY_GENERIC:
break;
case QUERY_DOCID:
rc = sqlite3_bind_int64(c->pStmt, 1, sqlite3_value_int64(argv[0]));
if( rc!=SQLITE_OK ) return rc;
break;
default: /* full-text search */
{
const char *zQuery = (const char *)sqlite3_value_text(argv[0]);
assert( idxNum<=QUERY_FULLTEXT+v->nColumn);
assert( argc==1 );
queryClear(&c->q);
if( c->result.nData!=0 ){
/* This case happens if the same cursor is used repeatedly. */
dlrDestroy(&c->reader);
dataBufferReset(&c->result);
}else{
dataBufferInit(&c->result, 0);
}
rc = fulltextQuery(v, idxNum-QUERY_FULLTEXT, zQuery, -1, &c->result, &c->q);
if( rc!=SQLITE_OK ) return rc;
if( c->result.nData!=0 ){
dlrInit(&c->reader, DL_DOCIDS, c->result.pData, c->result.nData);
}
break;
}
}
return fulltextNext(pCursor);
}
/* This is the xEof method of the virtual table. The SQLite core
** calls this routine to find out if it has reached the end of
** a query's results set.
*/
static int fulltextEof(sqlite3_vtab_cursor *pCursor){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
return c->eof;
}
/* This is the xColumn method of the virtual table. The SQLite
** core calls this method during a query when it needs the value
** of a column from the virtual table. This method needs to use
** one of the sqlite3_result_*() routines to store the requested
** value back in the pContext.
*/
static int fulltextColumn(sqlite3_vtab_cursor *pCursor,
sqlite3_context *pContext, int idxCol){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
fulltext_vtab *v = cursor_vtab(c);
if( idxCol<v->nColumn ){
sqlite3_value *pVal = sqlite3_column_value(c->pStmt, idxCol+1);
sqlite3_result_value(pContext, pVal);
}else if( idxCol==v->nColumn ){
/* The extra column whose name is the same as the table.
** Return a blob which is a pointer to the cursor
*/
sqlite3_result_blob(pContext, &c, sizeof(c), SQLITE_TRANSIENT);
}else if( idxCol==v->nColumn+1 ){
/* The docid column, which is an alias for rowid. */
sqlite3_value *pVal = sqlite3_column_value(c->pStmt, 0);
sqlite3_result_value(pContext, pVal);
}
return SQLITE_OK;
}
/* This is the xRowid method. The SQLite core calls this routine to
** retrieve the rowid for the current row of the result set. fts3
** exposes %_content.docid as the rowid for the virtual table. The
** rowid should be written to *pRowid.
*/
static int fulltextRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
fulltext_cursor *c = (fulltext_cursor *) pCursor;
*pRowid = sqlite3_column_int64(c->pStmt, 0);
return SQLITE_OK;
}
/* Add all terms in [zText] to pendingTerms table. If [iColumn] > 0,
** we also store positions and offsets in the hash table using that
** column number.
*/
static int buildTerms(fulltext_vtab *v, sqlite_int64 iDocid,
const char *zText, int iColumn){
sqlite3_tokenizer *pTokenizer = v->pTokenizer;
sqlite3_tokenizer_cursor *pCursor;
const char *pToken;
int nTokenBytes;
int iStartOffset, iEndOffset, iPosition;
int rc;
rc = pTokenizer->pModule->xOpen(pTokenizer, zText, -1, &pCursor);
if( rc!=SQLITE_OK ) return rc;
pCursor->pTokenizer = pTokenizer;
while( SQLITE_OK==(rc=pTokenizer->pModule->xNext(pCursor,
&pToken, &nTokenBytes,
&iStartOffset, &iEndOffset,
&iPosition)) ){
DLCollector *p;
int nData; /* Size of doclist before our update. */
/* Positions can't be negative; we use -1 as a terminator
* internally. Token can't be NULL or empty. */
if( iPosition<0 || pToken == NULL || nTokenBytes == 0 ){
rc = SQLITE_ERROR;
break;
}
p = fts3HashFind(&v->pendingTerms, pToken, nTokenBytes);
if( p==NULL ){
nData = 0;
p = dlcNew(iDocid, DL_DEFAULT);
fts3HashInsert(&v->pendingTerms, pToken, nTokenBytes, p);
/* Overhead for our hash table entry, the key, and the value. */
v->nPendingData += sizeof(struct fts3HashElem)+sizeof(*p)+nTokenBytes;
}else{
nData = p->b.nData;
if( p->dlw.iPrevDocid!=iDocid ) dlcNext(p, iDocid);
}
if( iColumn>=0 ){
dlcAddPos(p, iColumn, iPosition, iStartOffset, iEndOffset);
}
/* Accumulate data added by dlcNew or dlcNext, and dlcAddPos. */
v->nPendingData += p->b.nData-nData;
}
/* TODO(shess) Check return? Should this be able to cause errors at
** this point? Actually, same question about sqlite3_finalize(),
** though one could argue that failure there means that the data is
** not durable. *ponder*
*/
pTokenizer->pModule->xClose(pCursor);
if( SQLITE_DONE == rc ) return SQLITE_OK;
return rc;
}
/* Add doclists for all terms in [pValues] to pendingTerms table. */
static int insertTerms(fulltext_vtab *v, sqlite_int64 iDocid,
sqlite3_value **pValues){
int i;
for(i = 0; i < v->nColumn ; ++i){
char *zText = (char*)sqlite3_value_text(pValues[i]);
int rc = buildTerms(v, iDocid, zText, i);
if( rc!=SQLITE_OK ) return rc;
}
return SQLITE_OK;
}
/* Add empty doclists for all terms in the given row's content to
** pendingTerms.
*/
static int deleteTerms(fulltext_vtab *v, sqlite_int64 iDocid){
const char **pValues;
int i, rc;
/* TODO(shess) Should we allow such tables at all? */
if( DL_DEFAULT==DL_DOCIDS ) return SQLITE_ERROR;
rc = content_select(v, iDocid, &pValues);
if( rc!=SQLITE_OK ) return rc;
for(i = 0 ; i < v->nColumn; ++i) {
rc = buildTerms(v, iDocid, pValues[i], -1);
if( rc!=SQLITE_OK ) break;
}
freeStringArray(v->nColumn, pValues);
return SQLITE_OK;
}
/* TODO(shess) Refactor the code to remove this forward decl. */
static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid);
/* Insert a row into the %_content table; set *piDocid to be the ID of the
** new row. Add doclists for terms to pendingTerms.
*/
static int index_insert(fulltext_vtab *v, sqlite3_value *pRequestDocid,
sqlite3_value **pValues, sqlite_int64 *piDocid){
int rc;
rc = content_insert(v, pRequestDocid, pValues); /* execute an SQL INSERT */
if( rc!=SQLITE_OK ) return rc;
/* docid column is an alias for rowid. */
*piDocid = sqlite3_last_insert_rowid(v->db);
rc = initPendingTerms(v, *piDocid);
if( rc!=SQLITE_OK ) return rc;
return insertTerms(v, *piDocid, pValues);
}
/* Delete a row from the %_content table; add empty doclists for terms
** to pendingTerms.
*/
static int index_delete(fulltext_vtab *v, sqlite_int64 iRow){
int rc = initPendingTerms(v, iRow);
if( rc!=SQLITE_OK ) return rc;
rc = deleteTerms(v, iRow);
if( rc!=SQLITE_OK ) return rc;
return content_delete(v, iRow); /* execute an SQL DELETE */
}
/* Update a row in the %_content table; add delete doclists to
** pendingTerms for old terms not in the new data, add insert doclists
** to pendingTerms for terms in the new data.
*/
static int index_update(fulltext_vtab *v, sqlite_int64 iRow,
sqlite3_value **pValues){
int rc = initPendingTerms(v, iRow);
if( rc!=SQLITE_OK ) return rc;
/* Generate an empty doclist for each term that previously appeared in this
* row. */
rc = deleteTerms(v, iRow);
if( rc!=SQLITE_OK ) return rc;
rc = content_update(v, pValues, iRow); /* execute an SQL UPDATE */
if( rc!=SQLITE_OK ) return rc;
/* Now add positions for terms which appear in the updated row. */
return insertTerms(v, iRow, pValues);
}
/*******************************************************************/
/* InteriorWriter is used to collect terms and block references into
** interior nodes in %_segments. See commentary at top of file for
** format.
*/
/* How large interior nodes can grow. */
#define INTERIOR_MAX 2048
/* Minimum number of terms per interior node (except the root). This
** prevents large terms from making the tree too skinny - must be >0
** so that the tree always makes progress. Note that the min tree
** fanout will be INTERIOR_MIN_TERMS+1.
*/
#define INTERIOR_MIN_TERMS 7
#if INTERIOR_MIN_TERMS<1
# error INTERIOR_MIN_TERMS must be greater than 0.
#endif
/* ROOT_MAX controls how much data is stored inline in the segment
** directory.
*/
/* TODO(shess) Push ROOT_MAX down to whoever is writing things. It's
** only here so that interiorWriterRootInfo() and leafWriterRootInfo()
** can both see it, but if the caller passed it in, we wouldn't even
** need a define.
*/
#define ROOT_MAX 1024
#if ROOT_MAX<VARINT_MAX*2
# error ROOT_MAX must have enough space for a header.
#endif
/* InteriorBlock stores a linked-list of interior blocks while a lower
** layer is being constructed.
*/
typedef struct InteriorBlock {
DataBuffer term; /* Leftmost term in block's subtree. */
DataBuffer data; /* Accumulated data for the block. */
struct InteriorBlock *next;
} InteriorBlock;
static InteriorBlock *interiorBlockNew(int iHeight, sqlite_int64 iChildBlock,
const char *pTerm, int nTerm){
InteriorBlock *block = sqlite3_malloc(sizeof(InteriorBlock));
char c[VARINT_MAX+VARINT_MAX];
int n;
if( block ){
memset(block, 0, sizeof(*block));
dataBufferInit(&block->term, 0);
dataBufferReplace(&block->term, pTerm, nTerm);
n = fts3PutVarint(c, iHeight);
n += fts3PutVarint(c+n, iChildBlock);
dataBufferInit(&block->data, INTERIOR_MAX);
dataBufferReplace(&block->data, c, n);
}
return block;
}
#ifndef NDEBUG
/* Verify that the data is readable as an interior node. */
static void interiorBlockValidate(InteriorBlock *pBlock){
const char *pData = pBlock->data.pData;
int nData = pBlock->data.nData;
int n, iDummy;
sqlite_int64 iBlockid;
assert( nData>0 );
assert( pData!=0 );
assert( pData+nData>pData );
/* Must lead with height of node as a varint(n), n>0 */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n<nData );
pData += n;
nData -= n;
/* Must contain iBlockid. */
n = fts3GetVarint(pData, &iBlockid);
assert( n>0 );
assert( n<=nData );
pData += n;
nData -= n;
/* Zero or more terms of positive length */
if( nData!=0 ){
/* First term is not delta-encoded. */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0);
assert( n+iDummy<=nData );
pData += n+iDummy;
nData -= n+iDummy;
/* Following terms delta-encoded. */
while( nData!=0 ){
/* Length of shared prefix. */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>=0 );
assert( n<nData );
pData += n;
nData -= n;
/* Length and data of distinct suffix. */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0);
assert( n+iDummy<=nData );
pData += n+iDummy;
nData -= n+iDummy;
}
}
}
#define ASSERT_VALID_INTERIOR_BLOCK(x) interiorBlockValidate(x)
#else
#define ASSERT_VALID_INTERIOR_BLOCK(x) assert( 1 )
#endif
typedef struct InteriorWriter {
int iHeight; /* from 0 at leaves. */
InteriorBlock *first, *last;
struct InteriorWriter *parentWriter;
DataBuffer term; /* Last term written to block "last". */
sqlite_int64 iOpeningChildBlock; /* First child block in block "last". */
#ifndef NDEBUG
sqlite_int64 iLastChildBlock; /* for consistency checks. */
#endif
} InteriorWriter;
/* Initialize an interior node where pTerm[nTerm] marks the leftmost
** term in the tree. iChildBlock is the leftmost child block at the
** next level down the tree.
*/
static void interiorWriterInit(int iHeight, const char *pTerm, int nTerm,
sqlite_int64 iChildBlock,
InteriorWriter *pWriter){
InteriorBlock *block;
assert( iHeight>0 );
CLEAR(pWriter);
pWriter->iHeight = iHeight;
pWriter->iOpeningChildBlock = iChildBlock;
#ifndef NDEBUG
pWriter->iLastChildBlock = iChildBlock;
#endif
block = interiorBlockNew(iHeight, iChildBlock, pTerm, nTerm);
pWriter->last = pWriter->first = block;
ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
dataBufferInit(&pWriter->term, 0);
}
/* Append the child node rooted at iChildBlock to the interior node,
** with pTerm[nTerm] as the leftmost term in iChildBlock's subtree.
*/
static void interiorWriterAppend(InteriorWriter *pWriter,
const char *pTerm, int nTerm,
sqlite_int64 iChildBlock){
char c[VARINT_MAX+VARINT_MAX];
int n, nPrefix = 0;
ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
/* The first term written into an interior node is actually
** associated with the second child added (the first child was added
** in interiorWriterInit, or in the if clause at the bottom of this
** function). That term gets encoded straight up, with nPrefix left
** at 0.
*/
if( pWriter->term.nData==0 ){
n = fts3PutVarint(c, nTerm);
}else{
while( nPrefix<pWriter->term.nData &&
pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
nPrefix++;
}
n = fts3PutVarint(c, nPrefix);
n += fts3PutVarint(c+n, nTerm-nPrefix);
}
#ifndef NDEBUG
pWriter->iLastChildBlock++;
#endif
assert( pWriter->iLastChildBlock==iChildBlock );
/* Overflow to a new block if the new term makes the current block
** too big, and the current block already has enough terms.
*/
if( pWriter->last->data.nData+n+nTerm-nPrefix>INTERIOR_MAX &&
iChildBlock-pWriter->iOpeningChildBlock>INTERIOR_MIN_TERMS ){
pWriter->last->next = interiorBlockNew(pWriter->iHeight, iChildBlock,
pTerm, nTerm);
pWriter->last = pWriter->last->next;
pWriter->iOpeningChildBlock = iChildBlock;
dataBufferReset(&pWriter->term);
}else{
dataBufferAppend2(&pWriter->last->data, c, n,
pTerm+nPrefix, nTerm-nPrefix);
dataBufferReplace(&pWriter->term, pTerm, nTerm);
}
ASSERT_VALID_INTERIOR_BLOCK(pWriter->last);
}
/* Free the space used by pWriter, including the linked-list of
** InteriorBlocks, and parentWriter, if present.
*/
static int interiorWriterDestroy(InteriorWriter *pWriter){
InteriorBlock *block = pWriter->first;
while( block!=NULL ){
InteriorBlock *b = block;
block = block->next;
dataBufferDestroy(&b->term);
dataBufferDestroy(&b->data);
sqlite3_free(b);
}
if( pWriter->parentWriter!=NULL ){
interiorWriterDestroy(pWriter->parentWriter);
sqlite3_free(pWriter->parentWriter);
}
dataBufferDestroy(&pWriter->term);
SCRAMBLE(pWriter);
return SQLITE_OK;
}
/* If pWriter can fit entirely in ROOT_MAX, return it as the root info
** directly, leaving *piEndBlockid unchanged. Otherwise, flush
** pWriter to %_segments, building a new layer of interior nodes, and
** recursively ask for their root into.
*/
static int interiorWriterRootInfo(fulltext_vtab *v, InteriorWriter *pWriter,
char **ppRootInfo, int *pnRootInfo,
sqlite_int64 *piEndBlockid){
InteriorBlock *block = pWriter->first;
sqlite_int64 iBlockid = 0;
int rc;
/* If we can fit the segment inline */
if( block==pWriter->last && block->data.nData<ROOT_MAX ){
*ppRootInfo = block->data.pData;
*pnRootInfo = block->data.nData;
return SQLITE_OK;
}
/* Flush the first block to %_segments, and create a new level of
** interior node.
*/
ASSERT_VALID_INTERIOR_BLOCK(block);
rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
if( rc!=SQLITE_OK ) return rc;
*piEndBlockid = iBlockid;
pWriter->parentWriter = sqlite3_malloc(sizeof(*pWriter->parentWriter));
interiorWriterInit(pWriter->iHeight+1,
block->term.pData, block->term.nData,
iBlockid, pWriter->parentWriter);
/* Flush additional blocks and append to the higher interior
** node.
*/
for(block=block->next; block!=NULL; block=block->next){
ASSERT_VALID_INTERIOR_BLOCK(block);
rc = block_insert(v, block->data.pData, block->data.nData, &iBlockid);
if( rc!=SQLITE_OK ) return rc;
*piEndBlockid = iBlockid;
interiorWriterAppend(pWriter->parentWriter,
block->term.pData, block->term.nData, iBlockid);
}
/* Parent node gets the chance to be the root. */
return interiorWriterRootInfo(v, pWriter->parentWriter,
ppRootInfo, pnRootInfo, piEndBlockid);
}
/****************************************************************/
/* InteriorReader is used to read off the data from an interior node
** (see comment at top of file for the format).
*/
typedef struct InteriorReader {
const char *pData;
int nData;
DataBuffer term; /* previous term, for decoding term delta. */
sqlite_int64 iBlockid;
} InteriorReader;
static void interiorReaderDestroy(InteriorReader *pReader){
dataBufferDestroy(&pReader->term);
SCRAMBLE(pReader);
}
/* TODO(shess) The assertions are great, but what if we're in NDEBUG
** and the blob is empty or otherwise contains suspect data?
*/
static void interiorReaderInit(const char *pData, int nData,
InteriorReader *pReader){
int n, nTerm;
/* Require at least the leading flag byte */
assert( nData>0 );
assert( pData[0]!='' );
CLEAR(pReader);
/* Decode the base blockid, and set the cursor to the first term. */
n = fts3GetVarint(pData+1, &pReader->iBlockid);
assert( 1+n<=nData );
pReader->pData = pData+1+n;
pReader->nData = nData-(1+n);
/* A single-child interior node (such as when a leaf node was too
** large for the segment directory) won't have any terms.
** Otherwise, decode the first term.
*/
if( pReader->nData==0 ){
dataBufferInit(&pReader->term, 0);
}else{
n = fts3GetVarint32(pReader->pData, &nTerm);
dataBufferInit(&pReader->term, nTerm);
dataBufferReplace(&pReader->term, pReader->pData+n, nTerm);
assert( n+nTerm<=pReader->nData );
pReader->pData += n+nTerm;
pReader->nData -= n+nTerm;
}
}
static int interiorReaderAtEnd(InteriorReader *pReader){
return pReader->term.nData==0;
}
static sqlite_int64 interiorReaderCurrentBlockid(InteriorReader *pReader){
return pReader->iBlockid;
}
static int interiorReaderTermBytes(InteriorReader *pReader){
assert( !interiorReaderAtEnd(pReader) );
return pReader->term.nData;
}
static const char *interiorReaderTerm(InteriorReader *pReader){
assert( !interiorReaderAtEnd(pReader) );
return pReader->term.pData;
}
/* Step forward to the next term in the node. */
static void interiorReaderStep(InteriorReader *pReader){
assert( !interiorReaderAtEnd(pReader) );
/* If the last term has been read, signal eof, else construct the
** next term.
*/
if( pReader->nData==0 ){
dataBufferReset(&pReader->term);
}else{
int n, nPrefix, nSuffix;
n = fts3GetVarint32(pReader->pData, &nPrefix);
n += fts3GetVarint32(pReader->pData+n, &nSuffix);
/* Truncate the current term and append suffix data. */
pReader->term.nData = nPrefix;
dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
assert( n+nSuffix<=pReader->nData );
pReader->pData += n+nSuffix;
pReader->nData -= n+nSuffix;
}
pReader->iBlockid++;
}
/* Compare the current term to pTerm[nTerm], returning strcmp-style
** results. If isPrefix, equality means equal through nTerm bytes.
*/
static int interiorReaderTermCmp(InteriorReader *pReader,
const char *pTerm, int nTerm, int isPrefix){
const char *pReaderTerm = interiorReaderTerm(pReader);
int nReaderTerm = interiorReaderTermBytes(pReader);
int c, n = nReaderTerm<nTerm ? nReaderTerm : nTerm;
if( n==0 ){
if( nReaderTerm>0 ) return -1;
if( nTerm>0 ) return 1;
return 0;
}
c = memcmp(pReaderTerm, pTerm, n);
if( c!=0 ) return c;
if( isPrefix && n==nTerm ) return 0;
return nReaderTerm - nTerm;
}
/****************************************************************/
/* LeafWriter is used to collect terms and associated doclist data
** into leaf blocks in %_segments (see top of file for format info).
** Expected usage is:
**
** LeafWriter writer;
** leafWriterInit(0, 0, &writer);
** while( sorted_terms_left_to_process ){
** // data is doclist data for that term.
** rc = leafWriterStep(v, &writer, pTerm, nTerm, pData, nData);
** if( rc!=SQLITE_OK ) goto err;
** }
** rc = leafWriterFinalize(v, &writer);
**err:
** leafWriterDestroy(&writer);
** return rc;
**
** leafWriterStep() may write a collected leaf out to %_segments.
** leafWriterFinalize() finishes writing any buffered data and stores
** a root node in %_segdir. leafWriterDestroy() frees all buffers and
** InteriorWriters allocated as part of writing this segment.
**
** TODO(shess) Document leafWriterStepMerge().
*/
/* Put terms with data this big in their own block. */
#define STANDALONE_MIN 1024
/* Keep leaf blocks below this size. */
#define LEAF_MAX 2048
typedef struct LeafWriter {
int iLevel;
int idx;
sqlite_int64 iStartBlockid; /* needed to create the root info */
sqlite_int64 iEndBlockid; /* when we're done writing. */
DataBuffer term; /* previous encoded term */
DataBuffer data; /* encoding buffer */
/* bytes of first term in the current node which distinguishes that
** term from the last term of the previous node.
*/
int nTermDistinct;
InteriorWriter parentWriter; /* if we overflow */
int has_parent;
} LeafWriter;
static void leafWriterInit(int iLevel, int idx, LeafWriter *pWriter){
CLEAR(pWriter);
pWriter->iLevel = iLevel;
pWriter->idx = idx;
dataBufferInit(&pWriter->term, 32);
/* Start out with a reasonably sized block, though it can grow. */
dataBufferInit(&pWriter->data, LEAF_MAX);
}
#ifndef NDEBUG
/* Verify that the data is readable as a leaf node. */
static void leafNodeValidate(const char *pData, int nData){
int n, iDummy;
if( nData==0 ) return;
assert( nData>0 );
assert( pData!=0 );
assert( pData+nData>pData );
/* Must lead with a varint(0) */
n = fts3GetVarint32(pData, &iDummy);
assert( iDummy==0 );
assert( n>0 );
assert( n<nData );
pData += n;
nData -= n;
/* Leading term length and data must fit in buffer. */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0 );
assert( n+iDummy<nData );
pData += n+iDummy;
nData -= n+iDummy;
/* Leading term's doclist length and data must fit. */
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0 );
assert( n+iDummy<=nData );
ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
pData += n+iDummy;
nData -= n+iDummy;
/* Verify that trailing terms and doclists also are readable. */
while( nData!=0 ){
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>=0 );
assert( n<nData );
pData += n;
nData -= n;
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0 );
assert( n+iDummy<nData );
pData += n+iDummy;
nData -= n+iDummy;
n = fts3GetVarint32(pData, &iDummy);
assert( n>0 );
assert( iDummy>0 );
assert( n+iDummy>0 );
assert( n+iDummy<=nData );
ASSERT_VALID_DOCLIST(DL_DEFAULT, pData+n, iDummy, NULL);
pData += n+iDummy;
nData -= n+iDummy;
}
}
#define ASSERT_VALID_LEAF_NODE(p, n) leafNodeValidate(p, n)
#else
#define ASSERT_VALID_LEAF_NODE(p, n) assert( 1 )
#endif
/* Flush the current leaf node to %_segments, and adding the resulting
** blockid and the starting term to the interior node which will
** contain it.
*/
static int leafWriterInternalFlush(fulltext_vtab *v, LeafWriter *pWriter,
int iData, int nData){
sqlite_int64 iBlockid = 0;
const char *pStartingTerm;
int nStartingTerm, rc, n;
/* Must have the leading varint(0) flag, plus at least some
** valid-looking data.
*/
assert( nData>2 );
assert( iData>=0 );
assert( iData+nData<=pWriter->data.nData );
ASSERT_VALID_LEAF_NODE(pWriter->data.pData+iData, nData);
rc = block_insert(v, pWriter->data.pData+iData, nData, &iBlockid);
if( rc!=SQLITE_OK ) return rc;
assert( iBlockid!=0 );
/* Reconstruct the first term in the leaf for purposes of building
** the interior node.
*/
n = fts3GetVarint32(pWriter->data.pData+iData+1, &nStartingTerm);
pStartingTerm = pWriter->data.pData+iData+1+n;
assert( pWriter->data.nData>iData+1+n+nStartingTerm );
assert( pWriter->nTermDistinct>0 );
assert( pWriter->nTermDistinct<=nStartingTerm );
nStartingTerm = pWriter->nTermDistinct;
if( pWriter->has_parent ){
interiorWriterAppend(&pWriter->parentWriter,
pStartingTerm, nStartingTerm, iBlockid);
}else{
interiorWriterInit(1, pStartingTerm, nStartingTerm, iBlockid,
&pWriter->parentWriter);
pWriter->has_parent = 1;
}
/* Track the span of this segment's leaf nodes. */
if( pWriter->iEndBlockid==0 ){
pWriter->iEndBlockid = pWriter->iStartBlockid = iBlockid;
}else{
pWriter->iEndBlockid++;
assert( iBlockid==pWriter->iEndBlockid );
}
return SQLITE_OK;
}
static int leafWriterFlush(fulltext_vtab *v, LeafWriter *pWriter){
int rc = leafWriterInternalFlush(v, pWriter, 0, pWriter->data.nData);
if( rc!=SQLITE_OK ) return rc;
/* Re-initialize the output buffer. */
dataBufferReset(&pWriter->data);
return SQLITE_OK;
}
/* Fetch the root info for the segment. If the entire leaf fits
** within ROOT_MAX, then it will be returned directly, otherwise it
** will be flushed and the root info will be returned from the
** interior node. *piEndBlockid is set to the blockid of the last
** interior or leaf node written to disk (0 if none are written at
** all).
*/
static int leafWriterRootInfo(fulltext_vtab *v, LeafWriter *pWriter,
char **ppRootInfo, int *pnRootInfo,
sqlite_int64 *piEndBlockid){
/* we can fit the segment entirely inline */
if( !pWriter->has_parent && pWriter->data.nData<ROOT_MAX ){
*ppRootInfo = pWriter->data.pData;
*pnRootInfo = pWriter->data.nData;
*piEndBlockid = 0;
return SQLITE_OK;
}
/* Flush remaining leaf data. */
if( pWriter->data.nData>0 ){
int rc = leafWriterFlush(v, pWriter);
if( rc!=SQLITE_OK ) return rc;
}
/* We must have flushed a leaf at some point. */
assert( pWriter->has_parent );
/* Tenatively set the end leaf blockid as the end blockid. If the
** interior node can be returned inline, this will be the final
** blockid, otherwise it will be overwritten by
** interiorWriterRootInfo().
*/
*piEndBlockid = pWriter->iEndBlockid;
return interiorWriterRootInfo(v, &pWriter->parentWriter,
ppRootInfo, pnRootInfo, piEndBlockid);
}
/* Collect the rootInfo data and store it into the segment directory.
** This has the effect of flushing the segment's leaf data to
** %_segments, and also flushing any interior nodes to %_segments.
*/
static int leafWriterFinalize(fulltext_vtab *v, LeafWriter *pWriter){
sqlite_int64 iEndBlockid;
char *pRootInfo;
int rc, nRootInfo;
rc = leafWriterRootInfo(v, pWriter, &pRootInfo, &nRootInfo, &iEndBlockid);
if( rc!=SQLITE_OK ) return rc;
/* Don't bother storing an entirely empty segment. */
if( iEndBlockid==0 && nRootInfo==0 ) return SQLITE_OK;
return segdir_set(v, pWriter->iLevel, pWriter->idx,
pWriter->iStartBlockid, pWriter->iEndBlockid,
iEndBlockid, pRootInfo, nRootInfo);
}
static void leafWriterDestroy(LeafWriter *pWriter){
if( pWriter->has_parent ) interiorWriterDestroy(&pWriter->parentWriter);
dataBufferDestroy(&pWriter->term);
dataBufferDestroy(&pWriter->data);
}
/* Encode a term into the leafWriter, delta-encoding as appropriate.
** Returns the length of the new term which distinguishes it from the
** previous term, which can be used to set nTermDistinct when a node
** boundary is crossed.
*/
static int leafWriterEncodeTerm(LeafWriter *pWriter,
const char *pTerm, int nTerm){
char c[VARINT_MAX+VARINT_MAX];
int n, nPrefix = 0;
assert( nTerm>0 );
while( nPrefix<pWriter->term.nData &&
pTerm[nPrefix]==pWriter->term.pData[nPrefix] ){
nPrefix++;
/* Failing this implies that the terms weren't in order. */
assert( nPrefix<nTerm );
}
if( pWriter->data.nData==0 ){
/* Encode the node header and leading term as:
** varint(0)
** varint(nTerm)
** char pTerm[nTerm]
*/
n = fts3PutVarint(c, '');
n += fts3PutVarint(c+n, nTerm);
dataBufferAppend2(&pWriter->data, c, n, pTerm, nTerm);
}else{
/* Delta-encode the term as:
** varint(nPrefix)
** varint(nSuffix)
** char pTermSuffix[nSuffix]
*/
n = fts3PutVarint(c, nPrefix);
n += fts3PutVarint(c+n, nTerm-nPrefix);
dataBufferAppend2(&pWriter->data, c, n, pTerm+nPrefix, nTerm-nPrefix);
}
dataBufferReplace(&pWriter->term, pTerm, nTerm);
return nPrefix+1;
}
/* Used to avoid a memmove when a large amount of doclist data is in
** the buffer. This constructs a node and term header before
** iDoclistData and flushes the resulting complete node using
** leafWriterInternalFlush().
*/
static int leafWriterInlineFlush(fulltext_vtab *v, LeafWriter *pWriter,
const char *pTerm, int nTerm,
int iDoclistData){
char c[VARINT_MAX+VARINT_MAX];
int iData, n = fts3PutVarint(c, 0);
n += fts3PutVarint(c+n, nTerm);
/* There should always be room for the header. Even if pTerm shared
** a substantial prefix with the previous term, the entire prefix
** could be constructed from earlier data in the doclist, so there
** should be room.
*/
assert( iDoclistData>=n+nTerm );
iData = iDoclistData-(n+nTerm);
memcpy(pWriter->data.pData+iData, c, n);
memcpy(pWriter->data.pData+iData+n, pTerm, nTerm);
return leafWriterInternalFlush(v, pWriter, iData, pWriter->data.nData-iData);
}
/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
** %_segments.
*/
static int leafWriterStepMerge(fulltext_vtab *v, LeafWriter *pWriter,
const char *pTerm, int nTerm,
DLReader *pReaders, int nReaders){
char c[VARINT_MAX+VARINT_MAX];
int iTermData = pWriter->data.nData, iDoclistData;
int i, nData, n, nActualData, nActual, rc, nTermDistinct;
ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
nTermDistinct = leafWriterEncodeTerm(pWriter, pTerm, nTerm);
/* Remember nTermDistinct if opening a new node. */
if( iTermData==0 ) pWriter->nTermDistinct = nTermDistinct;
iDoclistData = pWriter->data.nData;
/* Estimate the length of the merged doclist so we can leave space
** to encode it.
*/
for(i=0, nData=0; i<nReaders; i++){
nData += dlrAllDataBytes(&pReaders[i]);
}
n = fts3PutVarint(c, nData);
dataBufferAppend(&pWriter->data, c, n);
docListMerge(&pWriter->data, pReaders, nReaders);
ASSERT_VALID_DOCLIST(DL_DEFAULT,
pWriter->data.pData+iDoclistData+n,
pWriter->data.nData-iDoclistData-n, NULL);
/* The actual amount of doclist data at this point could be smaller
** than the length we encoded. Additionally, the space required to
** encode this length could be smaller. For small doclists, this is
** not a big deal, we can just use memmove() to adjust things.
*/
nActualData = pWriter->data.nData-(iDoclistData+n);
nActual = fts3PutVarint(c, nActualData);
assert( nActualData<=nData );
assert( nActual<=n );
/* If the new doclist is big enough for force a standalone leaf
** node, we can immediately flush it inline without doing the
** memmove().
*/
/* TODO(shess) This test matches leafWriterStep(), which does this
** test before it knows the cost to varint-encode the term and
** doclist lengths. At some point, change to
** pWriter->data.nData-iTermData>STANDALONE_MIN.
*/
if( nTerm+nActualData>STANDALONE_MIN ){
/* Push leaf node from before this term. */
if( iTermData>0 ){
rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
if( rc!=SQLITE_OK ) return rc;
pWriter->nTermDistinct = nTermDistinct;
}
/* Fix the encoded doclist length. */
iDoclistData += n - nActual;
memcpy(pWriter->data.pData+iDoclistData, c, nActual);
/* Push the standalone leaf node. */
rc = leafWriterInlineFlush(v, pWriter, pTerm, nTerm, iDoclistData);
if( rc!=SQLITE_OK ) return rc;
/* Leave the node empty. */
dataBufferReset(&pWriter->data);
return rc;
}
/* At this point, we know that the doclist was small, so do the
** memmove if indicated.
*/
if( nActual<n ){
memmove(pWriter->data.pData+iDoclistData+nActual,
pWriter->data.pData+iDoclistData+n,
pWriter->data.nData-(iDoclistData+n));
pWriter->data.nData -= n-nActual;
}
/* Replace written length with actual length. */
memcpy(pWriter->data.pData+iDoclistData, c, nActual);
/* If the node is too large, break things up. */
/* TODO(shess) This test matches leafWriterStep(), which does this
** test before it knows the cost to varint-encode the term and
** doclist lengths. At some point, change to
** pWriter->data.nData>LEAF_MAX.
*/
if( iTermData+nTerm+nActualData>LEAF_MAX ){
/* Flush out the leading data as a node */
rc = leafWriterInternalFlush(v, pWriter, 0, iTermData);
if( rc!=SQLITE_OK ) return rc;
pWriter->nTermDistinct = nTermDistinct;
/* Rebuild header using the current term */
n = fts3PutVarint(pWriter->data.pData, 0);
n += fts3PutVarint(pWriter->data.pData+n, nTerm);
memcpy(pWriter->data.pData+n, pTerm, nTerm);
n += nTerm;
/* There should always be room, because the previous encoding
** included all data necessary to construct the term.
*/
assert( n<iDoclistData );
/* So long as STANDALONE_MIN is half or less of LEAF_MAX, the
** following memcpy() is safe (as opposed to needing a memmove).
*/
assert( 2*STANDALONE_MIN<=LEAF_MAX );
assert( n+pWriter->data.nData-iDoclistData<iDoclistData );
memcpy(pWriter->data.pData+n,
pWriter->data.pData+iDoclistData,
pWriter->data.nData-iDoclistData);
pWriter->data.nData -= iDoclistData-n;
}
ASSERT_VALID_LEAF_NODE(pWriter->data.pData, pWriter->data.nData);
return SQLITE_OK;
}
/* Push pTerm[nTerm] along with the doclist data to the leaf layer of
** %_segments.
*/
/* TODO(shess) Revise writeZeroSegment() so that doclists are
** constructed directly in pWriter->data.
*/
static int leafWriterStep(fulltext_vtab *v, LeafWriter *pWriter,
const char *pTerm, int nTerm,
const char *pData, int nData){
int rc;
DLReader reader;
dlrInit(&reader, DL_DEFAULT, pData, nData);
rc = leafWriterStepMerge(v, pWriter, pTerm, nTerm, &reader, 1);
dlrDestroy(&reader);
return rc;
}
/****************************************************************/
/* LeafReader is used to iterate over an individual leaf node. */
typedef struct LeafReader {
DataBuffer term; /* copy of current term. */
const char *pData; /* data for current term. */
int nData;
} LeafReader;
static void leafReaderDestroy(LeafReader *pReader){
dataBufferDestroy(&pReader->term);
SCRAMBLE(pReader);
}
static int leafReaderAtEnd(LeafReader *pReader){
return pReader->nData<=0;
}
/* Access the current term. */
static int leafReaderTermBytes(LeafReader *pReader){
return pReader->term.nData;
}
static const char *leafReaderTerm(LeafReader *pReader){
assert( pReader->term.nData>0 );
return pReader->term.pData;
}
/* Access the doclist data for the current term. */
static int leafReaderDataBytes(LeafReader *pReader){
int nData;
assert( pReader->term.nData>0 );
fts3GetVarint32(pReader->pData, &nData);
return nData;
}
static const char *leafReaderData(LeafReader *pReader){
int n, nData;
assert( pReader->term.nData>0 );
n = fts3GetVarint32(pReader->pData, &nData);
return pReader->pData+n;
}
static void leafReaderInit(const char *pData, int nData,
LeafReader *pReader){
int nTerm, n;
assert( nData>0 );
assert( pData[0]=='' );
CLEAR(pReader);
/* Read the first term, skipping the header byte. */
n = fts3GetVarint32(pData+1, &nTerm);
dataBufferInit(&pReader->term, nTerm);
dataBufferReplace(&pReader->term, pData+1+n, nTerm);
/* Position after the first term. */
assert( 1+n+nTerm<nData );
pReader->pData = pData+1+n+nTerm;
pReader->nData = nData-1-n-nTerm;
}
/* Step the reader forward to the next term. */
static void leafReaderStep(LeafReader *pReader){
int n, nData, nPrefix, nSuffix;
assert( !leafReaderAtEnd(pReader) );
/* Skip previous entry's data block. */
n = fts3GetVarint32(pReader->pData, &nData);
assert( n+nData<=pReader->nData );
pReader->pData += n+nData;
pReader->nData -= n+nData;
if( !leafReaderAtEnd(pReader) ){
/* Construct the new term using a prefix from the old term plus a
** suffix from the leaf data.
*/
n = fts3GetVarint32(pReader->pData, &nPrefix);
n += fts3GetVarint32(pReader->pData+n, &nSuffix);
assert( n+nSuffix<pReader->nData );
pReader->term.nData = nPrefix;
dataBufferAppend(&pReader->term, pReader->pData+n, nSuffix);
pReader->pData += n+nSuffix;
pReader->nData -= n+nSuffix;
}
}
/* strcmp-style comparison of pReader's current term against pTerm.
** If isPrefix, equality means equal through nTerm bytes.
*/
static int leafReaderTermCmp(LeafReader *pReader,
const char *pTerm, int nTerm, int isPrefix){
int c, n = pReader->term.nData<nTerm ? pReader->term.nData : nTerm;
if( n==0 ){
if( pReader->term.nData>0 ) return -1;
if(nTerm>0 ) return 1;
return 0;
}
c = memcmp(pReader->term.pData, pTerm, n);
if( c!=0 ) return c;
if( isPrefix && n==nTerm ) return 0;
return pReader->term.nData - nTerm;
}
/****************************************************************/
/* LeavesReader wraps LeafReader to allow iterating over the entire
** leaf layer of the tree.
*/
typedef struct LeavesReader {
int idx; /* Index within the segment. */
sqlite3_stmt *pStmt; /* Statement we're streaming leaves from. */
int eof; /* we've seen SQLITE_DONE from pStmt. */
LeafReader leafReader; /* reader for the current leaf. */
DataBuffer rootData; /* root data for inline. */
} LeavesReader;
/* Access the current term. */
static int leavesReaderTermBytes(LeavesReader *pReader){
assert( !pReader->eof );
return leafReaderTermBytes(&pReader->leafReader);
}
static const char *leavesReaderTerm(LeavesReader *pReader){
assert( !pReader->eof );
return leafReaderTerm(&pReader->leafReader);
}
/* Access the doclist data for the current term. */
static int leavesReaderDataBytes(LeavesReader *pReader){
assert( !pReader->eof );
return leafReaderDataBytes(&pReader->leafReader);
}
static const char *leavesReaderData(LeavesReader *pReader){
assert( !pReader->eof );
return leafReaderData(&pReader->leafReader);
}
static int leavesReaderAtEnd(LeavesReader *pReader){
return pReader->eof;
}
/* loadSegmentLeaves() may not read all the way to SQLITE_DONE, thus
** leaving the statement handle open, which locks the table.
*/
/* TODO(shess) This "solution" is not satisfactory. Really, there
** should be check-in function for all statement handles which
** arranges to call sqlite3_reset(). This most likely will require
** modification to control flow all over the place, though, so for now
** just punt.
**
** Note the the current system assumes that segment merges will run to
** completion, which is why this particular probably hasn't arisen in
** this case. Probably a brittle assumption.
*/
static int leavesReaderReset(LeavesReader *pReader){
return sqlite3_reset(pReader->pStmt);
}
static void leavesReaderDestroy(LeavesReader *pReader){
leafReaderDestroy(&pReader->leafReader);
dataBufferDestroy(&pReader->rootData);
SCRAMBLE(pReader);
}
/* Initialize pReader with the given root data (if iStartBlockid==0
** the leaf data was entirely contained in the root), or from the
** stream of blocks between iStartBlockid and iEndBlockid, inclusive.
*/
static int leavesReaderInit(fulltext_vtab *v,
int idx,
sqlite_int64 iStartBlockid,
sqlite_int64 iEndBlockid,
const char *pRootData, int nRootData,
LeavesReader *pReader){
CLEAR(pReader);
pReader->idx = idx;
dataBufferInit(&pReader->rootData, 0);
if( iStartBlockid==0 ){
/* Entire leaf level fit in root data. */
dataBufferReplace(&pReader->rootData, pRootData, nRootData);
leafReaderInit(pReader->rootData.pData, pReader->rootData.nData,
&pReader->leafReader);
}else{
sqlite3_stmt *s;
int rc = sql_get_leaf_statement(v, idx, &s);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_bind_int64(s, 1, iStartBlockid);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_bind_int64(s, 2, iEndBlockid);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_step(s);
if( rc==SQLITE_DONE ){
pReader->eof = 1;
return SQLITE_OK;
}
if( rc!=SQLITE_ROW ) return rc;
pReader->pStmt = s;
leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
sqlite3_column_bytes(pReader->pStmt, 0),
&pReader->leafReader);
}
return SQLITE_OK;
}
/* Step the current leaf forward to the next term. If we reach the
** end of the current leaf, step forward to the next leaf block.
*/
static int leavesReaderStep(fulltext_vtab *v, LeavesReader *pReader){
assert( !leavesReaderAtEnd(pReader) );
leafReaderStep(&pReader->leafReader);
if( leafReaderAtEnd(&pReader->leafReader) ){
int rc;
if( pReader->rootData.pData ){
pReader->eof = 1;
return SQLITE_OK;
}
rc = sqlite3_step(pReader->pStmt);
if( rc!=SQLITE_ROW ){
pReader->eof = 1;
return rc==SQLITE_DONE ? SQLITE_OK : rc;
}
leafReaderDestroy(&pReader->leafReader);
leafReaderInit(sqlite3_column_blob(pReader->pStmt, 0),
sqlite3_column_bytes(pReader->pStmt, 0),
&pReader->leafReader);
}
return SQLITE_OK;
}
/* Order LeavesReaders by their term, ignoring idx. Readers at eof
** always sort to the end.
*/
static int leavesReaderTermCmp(LeavesReader *lr1, LeavesReader *lr2){
if( leavesReaderAtEnd(lr1) ){
if( leavesReaderAtEnd(lr2) ) return 0;
return 1;
}
if( leavesReaderAtEnd(lr2) ) return -1;
return leafReaderTermCmp(&lr1->leafReader,
leavesReaderTerm(lr2), leavesReaderTermBytes(lr2),
0);
}
/* Similar to leavesReaderTermCmp(), with additional ordering by idx
** so that older segments sort before newer segments.
*/
static int leavesReaderCmp(LeavesReader *lr1, LeavesReader *lr2){
int c = leavesReaderTermCmp(lr1, lr2);
if( c!=0 ) return c;
return lr1->idx-lr2->idx;
}
/* Assume that pLr[1]..pLr[nLr] are sorted. Bubble pLr[0] into its
** sorted position.
*/
static void leavesReaderReorder(LeavesReader *pLr, int nLr){
while( nLr>1 && leavesReaderCmp(pLr, pLr+1)>0 ){
LeavesReader tmp = pLr[0];
pLr[0] = pLr[1];
pLr[1] = tmp;
nLr--;
pLr++;
}
}
/* Initializes pReaders with the segments from level iLevel, returning
** the number of segments in *piReaders. Leaves pReaders in sorted
** order.
*/
static int leavesReadersInit(fulltext_vtab *v, int iLevel,
LeavesReader *pReaders, int *piReaders){
sqlite3_stmt *s;
int i, rc = sql_get_statement(v, SEGDIR_SELECT_STMT, &s);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_bind_int(s, 1, iLevel);
if( rc!=SQLITE_OK ) return rc;
i = 0;
while( (rc = sqlite3_step(s))==SQLITE_ROW ){
sqlite_int64 iStart = sqlite3_column_int64(s, 0);
sqlite_int64 iEnd = sqlite3_column_int64(s, 1);
const char *pRootData = sqlite3_column_blob(s, 2);
int nRootData = sqlite3_column_bytes(s, 2);
assert( i<MERGE_COUNT );
rc = leavesReaderInit(v, i, iStart, iEnd, pRootData, nRootData,
&pReaders[i]);
if( rc!=SQLITE_OK ) break;
i++;
}
if( rc!=SQLITE_DONE ){
while( i-->0 ){
leavesReaderDestroy(&pReaders[i]);
}
return rc;
}
*piReaders = i;
/* Leave our results sorted by term, then age. */
while( i-- ){
leavesReaderReorder(pReaders+i, *piReaders-i);
}
return SQLITE_OK;
}
/* Merge doclists from pReaders[nReaders] into a single doclist, which
** is written to pWriter. Assumes pReaders is ordered oldest to
** newest.
*/
/* TODO(shess) Consider putting this inline in segmentMerge(). */
static int leavesReadersMerge(fulltext_vtab *v,
LeavesReader *pReaders, int nReaders,
LeafWriter *pWriter){
DLReader dlReaders[MERGE_COUNT];
const char *pTerm = leavesReaderTerm(pReaders);
int i, nTerm = leavesReaderTermBytes(pReaders);
assert( nReaders<=MERGE_COUNT );
for(i=0; i<nReaders; i++){
dlrInit(&dlReaders[i], DL_DEFAULT,
leavesReaderData(pReaders+i),
leavesReaderDataBytes(pReaders+i));
}
return leafWriterStepMerge(v, pWriter, pTerm, nTerm, dlReaders, nReaders);
}
/* Forward ref due to mutual recursion with segdirNextIndex(). */
static int segmentMerge(fulltext_vtab *v, int iLevel);
/* Put the next available index at iLevel into *pidx. If iLevel
** already has MERGE_COUNT segments, they are merged to a higher
** level to make room.
*/
static int segdirNextIndex(fulltext_vtab *v, int iLevel, int *pidx){
int rc = segdir_max_index(v, iLevel, pidx);
if( rc==SQLITE_DONE ){ /* No segments at iLevel. */
*pidx = 0;
}else if( rc==SQLITE_ROW ){
if( *pidx==(MERGE_COUNT-1) ){
rc = segmentMerge(v, iLevel);
if( rc!=SQLITE_OK ) return rc;
*pidx = 0;
}else{
(*pidx)++;
}
}else{
return rc;
}
return SQLITE_OK;
}
/* Merge MERGE_COUNT segments at iLevel into a new segment at
** iLevel+1. If iLevel+1 is already full of segments, those will be
** merged to make room.
*/
static int segmentMerge(fulltext_vtab *v, int iLevel){
LeafWriter writer;
LeavesReader lrs[MERGE_COUNT];
int i, rc, idx = 0;
/* Determine the next available segment index at the next level,
** merging as necessary.
*/
rc = segdirNextIndex(v, iLevel+1, &idx);
if( rc!=SQLITE_OK ) return rc;
/* TODO(shess) This assumes that we'll always see exactly
** MERGE_COUNT segments to merge at a given level. That will be
** broken if we allow the developer to request preemptive or
** deferred merging.
*/
memset(&lrs, '', sizeof(lrs));
rc = leavesReadersInit(v, iLevel, lrs, &i);
if( rc!=SQLITE_OK ) return rc;
assert( i==MERGE_COUNT );
leafWriterInit(iLevel+1, idx, &writer);
/* Since leavesReaderReorder() pushes readers at eof to the end,
** when the first reader is empty, all will be empty.
*/
while( !leavesReaderAtEnd(lrs) ){
/* Figure out how many readers share their next term. */
for(i=1; i<MERGE_COUNT && !leavesReaderAtEnd(lrs+i); i++){
if( 0!=leavesReaderTermCmp(lrs, lrs+i) ) break;
}
rc = leavesReadersMerge(v, lrs, i, &writer);
if( rc!=SQLITE_OK ) goto err;
/* Step forward those that were merged. */
while( i-->0 ){
rc = leavesReaderStep(v, lrs+i);
if( rc!=SQLITE_OK ) goto err;
/* Reorder by term, then by age. */
leavesReaderReorder(lrs+i, MERGE_COUNT-i);
}
}
for(i=0; i<MERGE_COUNT; i++){
leavesReaderDestroy(&lrs[i]);
}
rc = leafWriterFinalize(v, &writer);
leafWriterDestroy(&writer);
if( rc!=SQLITE_OK ) return rc;
/* Delete the merged segment data. */
return segdir_delete(v, iLevel);
err:
for(i=0; i<MERGE_COUNT; i++){
leavesReaderDestroy(&lrs[i]);
}
leafWriterDestroy(&writer);
return rc;
}
/* Accumulate the union of *acc and *pData into *acc. */
static void docListAccumulateUnion(DataBuffer *acc,
const char *pData, int nData) {
DataBuffer tmp = *acc;
dataBufferInit(acc, tmp.nData+nData);
docListUnion(tmp.pData, tmp.nData, pData, nData, acc);
dataBufferDestroy(&tmp);
}
/* TODO(shess) It might be interesting to explore different merge
** strategies, here. For instance, since this is a sorted merge, we
** could easily merge many doclists in parallel. With some
** comprehension of the storage format, we could merge all of the
** doclists within a leaf node directly from the leaf node's storage.
** It may be worthwhile to merge smaller doclists before larger
** doclists, since they can be traversed more quickly - but the
** results may have less overlap, making them more expensive in a
** different way.
*/
/* Scan pReader for pTerm/nTerm, and merge the term's doclist over
** *out (any doclists with duplicate docids overwrite those in *out).
** Internal function for loadSegmentLeaf().
*/
static int loadSegmentLeavesInt(fulltext_vtab *v, LeavesReader *pReader,
const char *pTerm, int nTerm, int isPrefix,
DataBuffer *out){
/* doclist data is accumulated into pBuffers similar to how one does
** increment in binary arithmetic. If index 0 is empty, the data is
** stored there. If there is data there, it is merged and the
** results carried into position 1, with further merge-and-carry
** until an empty position is found.
*/
DataBuffer *pBuffers = NULL;
int nBuffers = 0, nMaxBuffers = 0, rc;
assert( nTerm>0 );
for(rc=SQLITE_OK; rc==SQLITE_OK && !leavesReaderAtEnd(pReader);
rc=leavesReaderStep(v, pReader)){
/* TODO(shess) Really want leavesReaderTermCmp(), but that name is
** already taken to compare the terms of two LeavesReaders. Think
** on a better name. [Meanwhile, break encapsulation rather than
** use a confusing name.]
*/
int c = leafReaderTermCmp(&pReader->leafReader, pTerm, nTerm, isPrefix);
if( c>0 ) break; /* Past any possible matches. */
if( c==0 ){
const char *pData = leavesReaderData(pReader);
int iBuffer, nData = leavesReaderDataBytes(pReader);
/* Find the first empty buffer. */
for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
if( 0==pBuffers[iBuffer].nData ) break;
}
/* Out of buffers, add an empty one. */
if( iBuffer==nBuffers ){
if( nBuffers==nMaxBuffers ){
DataBuffer *p;
nMaxBuffers += 20;
/* Manual realloc so we can handle NULL appropriately. */
p = sqlite3_malloc(nMaxBuffers*sizeof(*pBuffers));
if( p==NULL ){
rc = SQLITE_NOMEM;
break;
}
if( nBuffers>0 ){
assert(pBuffers!=NULL);
memcpy(p, pBuffers, nBuffers*sizeof(*pBuffers));
sqlite3_free(pBuffers);
}
pBuffers = p;
}
dataBufferInit(&(pBuffers[nBuffers]), 0);
nBuffers++;
}
/* At this point, must have an empty at iBuffer. */
assert(iBuffer<nBuffers && pBuffers[iBuffer].nData==0);
/* If empty was first buffer, no need for merge logic. */
if( iBuffer==0 ){
dataBufferReplace(&(pBuffers[0]), pData, nData);
}else{
/* pAcc is the empty buffer the merged data will end up in. */
DataBuffer *pAcc = &(pBuffers[iBuffer]);
DataBuffer *p = &(pBuffers[0]);
/* Handle position 0 specially to avoid need to prime pAcc
** with pData/nData.
*/
dataBufferSwap(p, pAcc);
docListAccumulateUnion(pAcc, pData, nData);
/* Accumulate remaining doclists into pAcc. */
for(++p; p<pAcc; ++p){
docListAccumulateUnion(pAcc, p->pData, p->nData);
/* dataBufferReset() could allow a large doclist to blow up
** our memory requirements.
*/
if( p->nCapacity<1024 ){
dataBufferReset(p);
}else{
dataBufferDestroy(p);
dataBufferInit(p, 0);
}
}
}
}
}
/* Union all the doclists together into *out. */
/* TODO(shess) What if *out is big? Sigh. */
if( rc==SQLITE_OK && nBuffers>0 ){
int iBuffer;
for(iBuffer=0; iBuffer<nBuffers; ++iBuffer){
if( pBuffers[iBuffer].nData>0 ){
if( out->nData==0 ){
dataBufferSwap(out, &(pBuffers[iBuffer]));
}else{
docListAccumulateUnion(out, pBuffers[iBuffer].pData,
pBuffers[iBuffer].nData);
}
}
}
}
while( nBuffers-- ){
dataBufferDestroy(&(pBuffers[nBuffers]));
}
if( pBuffers!=NULL ) sqlite3_free(pBuffers);
return rc;
}
/* Call loadSegmentLeavesInt() with pData/nData as input. */
static int loadSegmentLeaf(fulltext_vtab *v, const char *pData, int nData,
const char *pTerm, int nTerm, int isPrefix,
DataBuffer *out){
LeavesReader reader;
int rc;
assert( nData>1 );
assert( *pData=='' );
rc = leavesReaderInit(v, 0, 0, 0, pData, nData, &reader);
if( rc!=SQLITE_OK ) return rc;
rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
leavesReaderReset(&reader);
leavesReaderDestroy(&reader);
return rc;
}
/* Call loadSegmentLeavesInt() with the leaf nodes from iStartLeaf to
** iEndLeaf (inclusive) as input, and merge the resulting doclist into
** out.
*/
static int loadSegmentLeaves(fulltext_vtab *v,
sqlite_int64 iStartLeaf, sqlite_int64 iEndLeaf,
const char *pTerm, int nTerm, int isPrefix,
DataBuffer *out){
int rc;
LeavesReader reader;
assert( iStartLeaf<=iEndLeaf );
rc = leavesReaderInit(v, 0, iStartLeaf, iEndLeaf, NULL, 0, &reader);
if( rc!=SQLITE_OK ) return rc;
rc = loadSegmentLeavesInt(v, &reader, pTerm, nTerm, isPrefix, out);
leavesReaderReset(&reader);
leavesReaderDestroy(&reader);
return rc;
}
/* Taking pData/nData as an interior node, find the sequence of child
** nodes which could include pTerm/nTerm/isPrefix. Note that the
** interior node terms logically come between the blocks, so there is
** one more blockid than there are terms (that block contains terms >=
** the last interior-node term).
*/
/* TODO(shess) The calling code may already know that the end child is
** not worth calculating, because the end may be in a later sibling
** node. Consider whether breaking symmetry is worthwhile. I suspect
** it is not worthwhile.
*/
static void getChildrenContaining(const char *pData, int nData,
const char *pTerm, int nTerm, int isPrefix,
sqlite_int64 *piStartChild,
sqlite_int64 *piEndChild){
InteriorReader reader;
assert( nData>1 );
assert( *pData!='' );
interiorReaderInit(pData, nData, &reader);
/* Scan for the first child which could contain pTerm/nTerm. */
while( !interiorReaderAtEnd(&reader) ){
if( interiorReaderTermCmp(&reader, pTerm, nTerm, 0)>0 ) break;
interiorReaderStep(&reader);
}
*piStartChild = interiorReaderCurrentBlockid(&reader);
/* Keep scanning to find a term greater than our term, using prefix
** comparison if indicated. If isPrefix is false, this will be the
** same blockid as the starting block.
*/
while( !interiorReaderAtEnd(&reader) ){
if( interiorReaderTermCmp(&reader, pTerm, nTerm, isPrefix)>0 ) break;
interiorReaderStep(&reader);
}
*piEndChild = interiorReaderCurrentBlockid(&reader);
interiorReaderDestroy(&reader);
/* Children must ascend, and if !prefix, both must be the same. */
assert( *piEndChild>=*piStartChild );
assert( isPrefix || *piStartChild==*piEndChild );
}
/* Read block at iBlockid and pass it with other params to
** getChildrenContaining().
*/
static int loadAndGetChildrenContaining(
fulltext_vtab *v,
sqlite_int64 iBlockid,
const char *pTerm, int nTerm, int isPrefix,
sqlite_int64 *piStartChild, sqlite_int64 *piEndChild
){
sqlite3_stmt *s = NULL;
int rc;
assert( iBlockid!=0 );
assert( pTerm!=NULL );
assert( nTerm!=0 ); /* TODO(shess) Why not allow this? */
assert( piStartChild!=NULL );
assert( piEndChild!=NULL );
rc = sql_get_statement(v, BLOCK_SELECT_STMT, &s);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_bind_int64(s, 1, iBlockid);
if( rc!=SQLITE_OK ) return rc;
rc = sqlite3_step(s);
if( rc==SQLITE_DONE ) return SQLITE_ERROR;
if( rc!=SQLITE_ROW ) return rc;
getChildrenContaining(sqlite3_column_blob(s, 0), sqlite3_column_bytes(s, 0),
pTerm, nTerm, isPrefix, piStartChild, piEndChild);
/* We expect only one row. We must execute another sqlite3_step()
* to complete the iteration; otherwise the table will remain
* locked. */
rc = sqlite3_step(s);
if( rc==SQLITE_ROW ) return SQLITE_ERROR;
if( rc!=SQLITE_DONE ) return rc;
return SQLITE_OK;
}
/* Traverse the tree represented by pData[nData] looking for
** pTerm[nTerm], placing its doclist into *out. This is internal to
** loadSegment() to make error-handling cleaner.
*/
static int loadSegmentInt(fulltext_vtab *v, const char *pData, int nData,
sqlite_int64 iLeavesEnd,
const char *pTerm, int nTerm, int isPrefix,
DataBuffer *out){
/* Special case where root is a leaf. */
if( *pData=='' ){
return loadSegmentLeaf(v, pData, nData, pTerm, nTerm, isPrefix, out);
}else{
int rc;
sqlite_int64 iStartChild, iEndChild;
/* Process pData as an interior node, then loop down the tree
** until we find the set of leaf nodes to scan for the term.
*/
getChildrenContaining(pData, nData, pTerm, nTerm, isPrefix,
&iStartChild, &iEndChild);
while( iStartChild>iLeavesEnd ){
sqlite_int64 iNextStart, iNextEnd;
rc = loadAndGetChildrenContaining(v, iStartChild, pTerm, nTerm, isPrefix,
&iNextStart, &iNextEnd);
if( rc!=SQLITE_OK ) return rc;
/* If we've branched, follow the end branch, too. */
if( iStartChild!=iEndChild ){
sqlite_int64 iDummy;
rc = loadAndGetChildrenContaining(v, iEndChild, pTerm, nTerm, isPrefix,
&iDummy, &iNextEnd);
if( rc!=SQLITE_OK ) return rc;
}
assert( iNextStart<=iNextEnd );
iStartChild = iNextStart;
iEndChild = iNextEnd;
}
assert( iStartChild<=iLeavesEnd );
assert( iEndChild<=iLeavesEnd );
/* Scan through the leaf segments for doclists. */
return loadSegmentLeaves(v, iStartChild, iEndChild,
pTerm, nTerm, isPrefix, out);
}
}
/* Call loadSegmentInt() to collect the doclist for pTerm/nTerm, then
** merge its doclist over *out (any duplicate doclists read from the
** segment rooted at pData will overwrite those in *out).
*/
/* TODO(shess) Consider changing this to determine the depth of the
** leaves using either the first characters of interior nodes (when
** ==1, we're one level above the leaves), or the first character of
** the root (which will describe the height of the tree directly).
** Either feels somewhat tricky to me.
*/
/* TODO(shess) The current merge is likely to be slow for large
** doclists (though it should process from newest/smallest to
** oldest/largest, so it may not be that bad). It might be useful to
** modify things to allow for N-way merging. This could either be
** within a segment, with pairwise merges across segments, or across
** all segments at once.
*/
static int loadSegment(fulltext_vtab *v, const char *pData, int nData,
sqlite_int64 iLeavesEnd,
const char *pTerm, int nTerm, int isPrefix,
DataBuffer *out){
DataBuffer result;
int rc;
assert( nData>1 );
/* This code should never be called with buffered updates. */
assert( v->nPendingData<0 );
dataBufferInit(&result, 0);
rc = loadSegmentInt(v, pData, nData, iLeavesEnd,
pTerm, nTerm, isPrefix, &result);
if( rc==SQLITE_OK && result.nData>0 ){
if( out->nData==0 ){
DataBuffer tmp = *out;
*out = result;
result = tmp;
}else{
DataBuffer merged;
DLReader readers[2];
dlrInit(&readers[0], DL_DEFAULT, out->pData, out->nData);
dlrInit(&readers[1], DL_DEFAULT, result.pData, result.nData);
dataBufferInit(&merged, out->nData+result.nData);
docListMerge(&merged, readers, 2);
dataBufferDestroy(out);
*out = merged;
dlrDestroy(&readers[0]);
dlrDestroy(&readers[1]);
}
}
dataBufferDestroy(&result);
return rc;
}
/* Scan the database and merge together the posting lists for the term
** into *out.
*/
static int termSelect(fulltext_vtab *v, int iColumn,
const char *pTerm, int nTerm, int isPrefix,
DocListType iType, DataBuffer *out){
DataBuffer doclist;
sqlite3_stmt *s;
int rc = sql_get_statement(v, SEGDIR_SELECT_ALL_STMT, &s);
if( rc!=SQLITE_OK ) return rc;
/* This code should never be called with buffered updates. */
assert( v->nPendingData<0 );
dataBufferInit(&doclist, 0);
/* Traverse the segments from oldest to newest so that newer doclist
** elements for given docids overwrite older elements.
*/
while( (rc = sqlite3_step(s))==SQLITE_ROW ){
const char *pData = sqlite3_column_blob(s, 0);
const int nData = sqlite3_column_bytes(s, 0);
const sqlite_int64 iLeavesEnd = sqlite3_column_int64(s, 1);
rc = loadSegment(v, pData, nData, iLeavesEnd, pTerm, nTerm, isPrefix,
&doclist);
if( rc!=SQLITE_OK ) goto err;
}
if( rc==SQLITE_DONE ){
if( doclist.nData!=0 ){
/* TODO(shess) The old term_select_all() code applied the column
** restrict as we merged segments, leading to smaller buffers.
** This is probably worthwhile to bring back, once the new storage
** system is checked in.
*/
if( iColumn==v->nColumn) iColumn = -1;
docListTrim(DL_DEFAULT, doclist.pData, doclist.nData,
iColumn, iType, out);
}
rc = SQLITE_OK;
}
err:
dataBufferDestroy(&doclist);
return rc;
}
/****************************************************************/
/* Used to hold hashtable data for sorting. */
typedef struct TermData {
const char *pTerm;
int nTerm;
DLCollector *pCollector;
} TermData;
/* Orders TermData elements in strcmp fashion ( <0 for less-than, 0
** for equal, >0 for greater-than).
*/
static int termDataCmp(const void *av, const void *bv){
const TermData *a = (const TermData *)av;
const TermData *b = (const TermData *)bv;
int n = a->nTerm<b->nTerm ? a->nTerm : b->nTerm;
int c = memcmp(a->pTerm, b->pTerm, n);
if( c!=0 ) return c;
return a->nTerm-b->nTerm;
}
/* Order pTerms data by term, then write a new level 0 segment using
** LeafWriter.
*/
static int writeZeroSegment(fulltext_vtab *v, fts3Hash *pTerms){
fts3HashElem *e;
int idx, rc, i, n;
TermData *pData;
LeafWriter writer;
DataBuffer dl;
/* Determine the next index at level 0, merging as necessary. */
rc = segdirNextIndex(v, 0, &idx);
if( rc!=SQLITE_OK ) return rc;
n = fts3HashCount(pTerms);
pData = sqlite3_malloc(n*sizeof(TermData));
for(i = 0, e = fts3HashFirst(pTerms); e; i++, e = fts3HashNext(e)){
assert( i<n );
pData[i].pTerm = fts3HashKey(e);
pData[i].nTerm = fts3HashKeysize(e);
pData[i].pCollector = fts3HashData(e);
}
assert( i==n );
/* TODO(shess) Should we allow user-defined collation sequences,
** here? I think we only need that once we support prefix searches.
*/
if( n>1 ) qsort(pData, n, sizeof(*pData), termDataCmp);
/* TODO(shess) Refactor so that we can write directly to the segment
** DataBuffer, as happens for segment merges.
*/
leafWriterInit(0, idx, &writer);
dataBufferInit(&dl, 0);
for(i=0; i<n; i++){
dataBufferReset(&dl);
dlcAddDoclist(pData[i].pCollector, &dl);
rc = leafWriterStep(v, &writer,
pData[i].pTerm, pData[i].nTerm, dl.pData, dl.nData);
if( rc!=SQLITE_OK ) goto err;
}
rc = leafWriterFinalize(v, &writer);
err:
dataBufferDestroy(&dl);
sqlite3_free(pData);
leafWriterDestroy(&writer);
return rc;
}
/* If pendingTerms has data, free it. */
static int clearPendingTerms(fulltext_vtab *v){
if( v->nPendingData>=0 ){
fts3HashElem *e;
for(e=fts3HashFirst(&v->pendingTerms); e; e=fts3HashNext(e)){
dlcDelete(fts3HashData(e));
}
fts3HashClear(&v->pendingTerms);
v->nPendingData = -1;
}
return SQLITE_OK;
}
/* If pendingTerms has data, flush it to a level-zero segment, and
** free it.
*/
static int flushPendingTerms(fulltext_vtab *v){
if( v->nPendingData>=0 ){
int rc = writeZeroSegment(v, &v->pendingTerms);
if( rc==SQLITE_OK ) clearPendingTerms(v);
return rc;
}
return SQLITE_OK;
}
/* If pendingTerms is "too big", or docid is out of order, flush it.
** Regardless, be certain that pendingTerms is initialized for use.
*/
static int initPendingTerms(fulltext_vtab *v, sqlite_int64 iDocid){
/* TODO(shess) Explore whether partially flushing the buffer on
** forced-flush would provide better performance. I suspect that if
** we ordered the doclists by size and flushed the largest until the
** buffer was half empty, that would let the less frequent terms
** generate longer doclists.
*/
if( iDocid<=v->iPrevDocid || v->nPendingData>kPendingThreshold ){
int rc = flushPendingTerms(v);
if( rc!=SQLITE_OK ) return rc;
}
if( v->nPendingData<0 ){
fts3HashInit(&v->pendingTerms, FTS3_HASH_STRING, 1);
v->nPendingData = 0;
}
v->iPrevDocid = iDocid;
return SQLITE_OK;
}
/* This function implements the xUpdate callback; it is the top-level entry
* point for inserting, deleting or updating a row in a full-text table. */
static int fulltextUpdate(sqlite3_vtab *pVtab, int nArg, sqlite3_value **ppArg,
sqlite_int64 *pRowid){
fulltext_vtab *v = (fulltext_vtab *) pVtab;
int rc;
FTSTRACE(("FTS3 Update %pn", pVtab));
if( nArg<2 ){
rc = index_delete(v, sqlite3_value_int64(ppArg[0]));
} else if( sqlite3_value_type(ppArg[0]) != SQLITE_NULL ){
/* An update:
* ppArg[0] = old rowid
* ppArg[1] = new rowid
* ppArg[2..2+v->nColumn-1] = values
* ppArg[2+v->nColumn] = value for magic column (we ignore this)
* ppArg[2+v->nColumn+1] = value for docid
*/
sqlite_int64 rowid = sqlite3_value_int64(ppArg[0]);
if( sqlite3_value_type(ppArg[1]) != SQLITE_INTEGER ||
sqlite3_value_int64(ppArg[1]) != rowid ){
rc = SQLITE_ERROR; /* we don't allow changing the rowid */
}else if( sqlite3_value_type(ppArg[2+v->nColumn+1]) != SQLITE_INTEGER ||
sqlite3_value_int64(ppArg[2+v->nColumn+1]) != rowid ){
rc = SQLITE_ERROR; /* we don't allow changing the docid */
}else{
assert( nArg==2+v->nColumn+2);
rc = index_update(v, rowid, &ppArg[2]);
}
} else {
/* An insert:
* ppArg[1] = requested rowid
* ppArg[2..2+v->nColumn-1] = values
* ppArg[2+v->nColumn] = value for magic column (we ignore this)
* ppArg[2+v->nColumn+1] = value for docid
*/
sqlite3_value *pRequestDocid = ppArg[2+v->nColumn+1];
assert( nArg==2+v->nColumn+2);
if( SQLITE_NULL != sqlite3_value_type(pRequestDocid) &&
SQLITE_NULL != sqlite3_value_type(ppArg[1]) ){
/* TODO(shess) Consider allowing this to work if the values are
** identical. I'm inclined to discourage that usage, though,
** given that both rowid and docid are special columns. Better
** would be to define one or the other as the default winner,
** but should it be fts3-centric (docid) or SQLite-centric
** (rowid)?
*/
rc = SQLITE_ERROR;
}else{
if( SQLITE_NULL == sqlite3_value_type(pRequestDocid) ){
pRequestDocid = ppArg[1];
}
rc = index_insert(v, pRequestDocid, &ppArg[2], pRowid);
}
}
return rc;
}
static int fulltextSync(sqlite3_vtab *pVtab){
FTSTRACE(("FTS3 xSync()n"));
return flushPendingTerms((fulltext_vtab *)pVtab);
}
static int fulltextBegin(sqlite3_vtab *pVtab){
fulltext_vtab *v = (fulltext_vtab *) pVtab;
FTSTRACE(("FTS3 xBegin()n"));
/* Any buffered updates should have been cleared by the previous
** transaction.
*/
assert( v->nPendingData<0 );
return clearPendingTerms(v);
}
static int fulltextCommit(sqlite3_vtab *pVtab){
fulltext_vtab *v = (fulltext_vtab *) pVtab;
FTSTRACE(("FTS3 xCommit()n"));
/* Buffered updates should have been cleared by fulltextSync(). */
assert( v->nPendingData<0 );
return clearPendingTerms(v);
}
static int fulltextRollback(sqlite3_vtab *pVtab){
FTSTRACE(("FTS3 xRollback()n"));
return clearPendingTerms((fulltext_vtab *)pVtab);
}
/*
** Implementation of the snippet() function for FTS3
*/
static void snippetFunc(
sqlite3_context *pContext,
int argc,
sqlite3_value **argv
){
fulltext_cursor *pCursor;
if( argc<1 ) return;
if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
sqlite3_result_error(pContext, "illegal first argument to html_snippet",-1);
}else{
const char *zStart = "<b>";
const char *zEnd = "</b>";
const char *zEllipsis = "<b>...</b>";
memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
if( argc>=2 ){
zStart = (const char*)sqlite3_value_text(argv[1]);
if( argc>=3 ){
zEnd = (const char*)sqlite3_value_text(argv[2]);
if( argc>=4 ){
zEllipsis = (const char*)sqlite3_value_text(argv[3]);
}
}
}
snippetAllOffsets(pCursor);
snippetText(pCursor, zStart, zEnd, zEllipsis);
sqlite3_result_text(pContext, pCursor->snippet.zSnippet,
pCursor->snippet.nSnippet, SQLITE_STATIC);
}
}
/*
** Implementation of the offsets() function for FTS3
*/
static void snippetOffsetsFunc(
sqlite3_context *pContext,
int argc,
sqlite3_value **argv
){
fulltext_cursor *pCursor;
if( argc<1 ) return;
if( sqlite3_value_type(argv[0])!=SQLITE_BLOB ||
sqlite3_value_bytes(argv[0])!=sizeof(pCursor) ){
sqlite3_result_error(pContext, "illegal first argument to offsets",-1);
}else{
memcpy(&pCursor, sqlite3_value_blob(argv[0]), sizeof(pCursor));
snippetAllOffsets(pCursor);
snippetOffsetText(&pCursor->snippet);
sqlite3_result_text(pContext,
pCursor->snippet.zOffset, pCursor->snippet.nOffset,
SQLITE_STATIC);
}
}
/*
** This routine implements the xFindFunction method for the FTS3
** virtual table.
*/
static int fulltextFindFunction(
sqlite3_vtab *pVtab,
int nArg,
const char *zName,
void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
void **ppArg
){
if( strcmp(zName,"snippet")==0 ){
*pxFunc = snippetFunc;
return 1;
}else if( strcmp(zName,"offsets")==0 ){
*pxFunc = snippetOffsetsFunc;
return 1;
}
return 0;
}
/*
** Rename an fts3 table.
*/
static int fulltextRename(
sqlite3_vtab *pVtab,
const char *zName
){
fulltext_vtab *p = (fulltext_vtab *)pVtab;
int rc = SQLITE_NOMEM;
char *zSql = sqlite3_mprintf(
"ALTER TABLE %Q.'%q_content' RENAME TO '%q_content';"
"ALTER TABLE %Q.'%q_segments' RENAME TO '%q_segments';"
"ALTER TABLE %Q.'%q_segdir' RENAME TO '%q_segdir';"
, p->zDb, p->zName, zName
, p->zDb, p->zName, zName
, p->zDb, p->zName, zName
);
if( zSql ){
rc = sqlite3_exec(p->db, zSql, 0, 0, 0);
sqlite3_free(zSql);
}
return rc;
}
static const sqlite3_module fts3Module = {
/* iVersion */ 0,
/* xCreate */ fulltextCreate,
/* xConnect */ fulltextConnect,
/* xBestIndex */ fulltextBestIndex,
/* xDisconnect */ fulltextDisconnect,
/* xDestroy */ fulltextDestroy,
/* xOpen */ fulltextOpen,
/* xClose */ fulltextClose,
/* xFilter */ fulltextFilter,
/* xNext */ fulltextNext,
/* xEof */ fulltextEof,
/* xColumn */ fulltextColumn,
/* xRowid */ fulltextRowid,
/* xUpdate */ fulltextUpdate,
/* xBegin */ fulltextBegin,
/* xSync */ fulltextSync,
/* xCommit */ fulltextCommit,
/* xRollback */ fulltextRollback,
/* xFindFunction */ fulltextFindFunction,
/* xRename */ fulltextRename,
};
static void hashDestroy(void *p){
fts3Hash *pHash = (fts3Hash *)p;
sqlite3Fts3HashClear(pHash);
sqlite3_free(pHash);
}
/*
** The fts3 built-in tokenizers - "simple" and "porter" - are implemented
** in files fts3_tokenizer1.c and fts3_porter.c respectively. The following
** two forward declarations are for functions declared in these files
** used to retrieve the respective implementations.
**
** Calling sqlite3Fts3SimpleTokenizerModule() sets the value pointed
** to by the argument to point a the "simple" tokenizer implementation.
** Function ...PorterTokenizerModule() sets *pModule to point to the
** porter tokenizer/stemmer implementation.
*/
void sqlite3Fts3SimpleTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts3PorterTokenizerModule(sqlite3_tokenizer_module const**ppModule);
void sqlite3Fts3IcuTokenizerModule(sqlite3_tokenizer_module const**ppModule);
int sqlite3Fts3InitHashTable(sqlite3 *, fts3Hash *, const char *);
/*
** Initialise the fts3 extension. If this extension is built as part
** of the sqlite library, then this function is called directly by
** SQLite. If fts3 is built as a dynamically loadable extension, this
** function is called by the sqlite3_extension_init() entry point.
*/
int sqlite3Fts3Init(sqlite3 *db){
int rc = SQLITE_OK;
fts3Hash *pHash = 0;
const sqlite3_tokenizer_module *pSimple = 0;
const sqlite3_tokenizer_module *pPorter = 0;
const sqlite3_tokenizer_module *pIcu = 0;
sqlite3Fts3SimpleTokenizerModule(&pSimple);
sqlite3Fts3PorterTokenizerModule(&pPorter);
#ifdef SQLITE_ENABLE_ICU
sqlite3Fts3IcuTokenizerModule(&pIcu);
#endif
/* Allocate and initialise the hash-table used to store tokenizers. */
pHash = sqlite3_malloc(sizeof(fts3Hash));
if( !pHash ){
rc = SQLITE_NOMEM;
}else{
sqlite3Fts3HashInit(pHash, FTS3_HASH_STRING, 1);
}
/* Load the built-in tokenizers into the hash table */
if( rc==SQLITE_OK ){
if( sqlite3Fts3HashInsert(pHash, "simple", 7, (void *)pSimple)
|| sqlite3Fts3HashInsert(pHash, "porter", 7, (void *)pPorter)
|| (pIcu && sqlite3Fts3HashInsert(pHash, "icu", 4, (void *)pIcu))
){
rc = SQLITE_NOMEM;
}
}
/* Create the virtual table wrapper around the hash-table and overload
** the two scalar functions. If this is successful, register the
** module with sqlite.
*/
if( SQLITE_OK==rc
&& SQLITE_OK==(rc = sqlite3Fts3InitHashTable(db, pHash, "fts3_tokenizer"))
&& SQLITE_OK==(rc = sqlite3_overload_function(db, "snippet", -1))
&& SQLITE_OK==(rc = sqlite3_overload_function(db, "offsets", -1))
){
return sqlite3_create_module_v2(
db, "fts3", &fts3Module, (void *)pHash, hashDestroy
);
}
/* An error has occured. Delete the hash table and return the error code. */
assert( rc!=SQLITE_OK );
if( pHash ){
sqlite3Fts3HashClear(pHash);
sqlite3_free(pHash);
}
return rc;
}
#if !SQLITE_CORE
int sqlite3_extension_init(
sqlite3 *db,
char **pzErrMsg,
const sqlite3_api_routines *pApi
){
SQLITE_EXTENSION_INIT2(pApi)
return sqlite3Fts3Init(db);
}
#endif
#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */