summaryrefslogtreecommitdiffstats
path: root/ext/fts3/fts3_aux.c
diff options
context:
space:
mode:
Diffstat (limited to 'ext/fts3/fts3_aux.c')
-rw-r--r--ext/fts3/fts3_aux.c556
1 files changed, 556 insertions, 0 deletions
diff --git a/ext/fts3/fts3_aux.c b/ext/fts3/fts3_aux.c
new file mode 100644
index 0000000..d3b194c
--- /dev/null
+++ b/ext/fts3/fts3_aux.c
@@ -0,0 +1,556 @@
+/*
+** 2011 Jan 27
+**
+** The author disclaims copyright to this source code. In place of
+** a legal notice, here is a blessing:
+**
+** May you do good and not evil.
+** May you find forgiveness for yourself and forgive others.
+** May you share freely, never taking more than you give.
+**
+******************************************************************************
+**
+*/
+#include "fts3Int.h"
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#include <string.h>
+#include <assert.h>
+
+typedef struct Fts3auxTable Fts3auxTable;
+typedef struct Fts3auxCursor Fts3auxCursor;
+
+struct Fts3auxTable {
+ sqlite3_vtab base; /* Base class used by SQLite core */
+ Fts3Table *pFts3Tab;
+};
+
+struct Fts3auxCursor {
+ sqlite3_vtab_cursor base; /* Base class used by SQLite core */
+ Fts3MultiSegReader csr; /* Must be right after "base" */
+ Fts3SegFilter filter;
+ char *zStop;
+ int nStop; /* Byte-length of string zStop */
+ int iLangid; /* Language id to query */
+ int isEof; /* True if cursor is at EOF */
+ sqlite3_int64 iRowid; /* Current rowid */
+
+ int iCol; /* Current value of 'col' column */
+ int nStat; /* Size of aStat[] array */
+ struct Fts3auxColstats {
+ sqlite3_int64 nDoc; /* 'documents' values for current csr row */
+ sqlite3_int64 nOcc; /* 'occurrences' values for current csr row */
+ } *aStat;
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_AUX_SCHEMA \
+ "CREATE TABLE x(term, col, documents, occurrences, languageid HIDDEN)"
+
+/*
+** This function does all the work for both the xConnect and xCreate methods.
+** These tables have no persistent representation of their own, so xConnect
+** and xCreate are identical operations.
+*/
+static int fts3auxConnectMethod(
+ sqlite3 *db, /* Database connection */
+ void *pUnused, /* Unused */
+ int argc, /* Number of elements in argv array */
+ const char * const *argv, /* xCreate/xConnect argument array */
+ sqlite3_vtab **ppVtab, /* OUT: New sqlite3_vtab object */
+ char **pzErr /* OUT: sqlite3_malloc'd error message */
+){
+ char const *zDb; /* Name of database (e.g. "main") */
+ char const *zFts3; /* Name of fts3 table */
+ int nDb; /* Result of strlen(zDb) */
+ int nFts3; /* Result of strlen(zFts3) */
+ sqlite3_int64 nByte; /* Bytes of space to allocate here */
+ int rc; /* value returned by declare_vtab() */
+ Fts3auxTable *p; /* Virtual table object to return */
+
+ UNUSED_PARAMETER(pUnused);
+
+ /* The user should invoke this in one of two forms:
+ **
+ ** CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table);
+ ** CREATE VIRTUAL TABLE xxx USING fts4aux(fts4-table-db, fts4-table);
+ */
+ if( argc!=4 && argc!=5 ) goto bad_args;
+
+ zDb = argv[1];
+ nDb = (int)strlen(zDb);
+ if( argc==5 ){
+ if( nDb==4 && 0==sqlite3_strnicmp("temp", zDb, 4) ){
+ zDb = argv[3];
+ nDb = (int)strlen(zDb);
+ zFts3 = argv[4];
+ }else{
+ goto bad_args;
+ }
+ }else{
+ zFts3 = argv[3];
+ }
+ nFts3 = (int)strlen(zFts3);
+
+ rc = sqlite3_declare_vtab(db, FTS3_AUX_SCHEMA);
+ if( rc!=SQLITE_OK ) return rc;
+
+ nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+ p = (Fts3auxTable *)sqlite3_malloc64(nByte);
+ if( !p ) return SQLITE_NOMEM;
+ memset(p, 0, nByte);
+
+ p->pFts3Tab = (Fts3Table *)&p[1];
+ p->pFts3Tab->zDb = (char *)&p->pFts3Tab[1];
+ p->pFts3Tab->zName = &p->pFts3Tab->zDb[nDb+1];
+ p->pFts3Tab->db = db;
+ p->pFts3Tab->nIndex = 1;
+
+ memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+ memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+ sqlite3Fts3Dequote((char *)p->pFts3Tab->zName);
+
+ *ppVtab = (sqlite3_vtab *)p;
+ return SQLITE_OK;
+
+ bad_args:
+ sqlite3Fts3ErrMsg(pzErr, "invalid arguments to fts4aux constructor");
+ return SQLITE_ERROR;
+}
+
+/*
+** This function does the work for both the xDisconnect and xDestroy methods.
+** These tables have no persistent representation of their own, so xDisconnect
+** and xDestroy are identical operations.
+*/
+static int fts3auxDisconnectMethod(sqlite3_vtab *pVtab){
+ Fts3auxTable *p = (Fts3auxTable *)pVtab;
+ Fts3Table *pFts3 = p->pFts3Tab;
+ int i;
+
+ /* Free any prepared statements held */
+ for(i=0; i<SizeofArray(pFts3->aStmt); i++){
+ sqlite3_finalize(pFts3->aStmt[i]);
+ }
+ sqlite3_free(pFts3->zSegmentsTbl);
+ sqlite3_free(p);
+ return SQLITE_OK;
+}
+
+#define FTS4AUX_EQ_CONSTRAINT 1
+#define FTS4AUX_GE_CONSTRAINT 2
+#define FTS4AUX_LE_CONSTRAINT 4
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3auxBestIndexMethod(
+ sqlite3_vtab *pVTab,
+ sqlite3_index_info *pInfo
+){
+ int i;
+ int iEq = -1;
+ int iGe = -1;
+ int iLe = -1;
+ int iLangid = -1;
+ int iNext = 1; /* Next free argvIndex value */
+
+ UNUSED_PARAMETER(pVTab);
+
+ /* This vtab delivers always results in "ORDER BY term ASC" order. */
+ if( pInfo->nOrderBy==1
+ && pInfo->aOrderBy[0].iColumn==0
+ && pInfo->aOrderBy[0].desc==0
+ ){
+ pInfo->orderByConsumed = 1;
+ }
+
+ /* Search for equality and range constraints on the "term" column.
+ ** And equality constraints on the hidden "languageid" column. */
+ for(i=0; i<pInfo->nConstraint; i++){
+ if( pInfo->aConstraint[i].usable ){
+ int op = pInfo->aConstraint[i].op;
+ int iCol = pInfo->aConstraint[i].iColumn;
+
+ if( iCol==0 ){
+ if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iEq = i;
+ if( op==SQLITE_INDEX_CONSTRAINT_LT ) iLe = i;
+ if( op==SQLITE_INDEX_CONSTRAINT_LE ) iLe = i;
+ if( op==SQLITE_INDEX_CONSTRAINT_GT ) iGe = i;
+ if( op==SQLITE_INDEX_CONSTRAINT_GE ) iGe = i;
+ }
+ if( iCol==4 ){
+ if( op==SQLITE_INDEX_CONSTRAINT_EQ ) iLangid = i;
+ }
+ }
+ }
+
+ if( iEq>=0 ){
+ pInfo->idxNum = FTS4AUX_EQ_CONSTRAINT;
+ pInfo->aConstraintUsage[iEq].argvIndex = iNext++;
+ pInfo->estimatedCost = 5;
+ }else{
+ pInfo->idxNum = 0;
+ pInfo->estimatedCost = 20000;
+ if( iGe>=0 ){
+ pInfo->idxNum += FTS4AUX_GE_CONSTRAINT;
+ pInfo->aConstraintUsage[iGe].argvIndex = iNext++;
+ pInfo->estimatedCost /= 2;
+ }
+ if( iLe>=0 ){
+ pInfo->idxNum += FTS4AUX_LE_CONSTRAINT;
+ pInfo->aConstraintUsage[iLe].argvIndex = iNext++;
+ pInfo->estimatedCost /= 2;
+ }
+ }
+ if( iLangid>=0 ){
+ pInfo->aConstraintUsage[iLangid].argvIndex = iNext++;
+ pInfo->estimatedCost--;
+ }
+
+ return SQLITE_OK;
+}
+
+/*
+** xOpen - Open a cursor.
+*/
+static int fts3auxOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
+ Fts3auxCursor *pCsr; /* Pointer to cursor object to return */
+
+ UNUSED_PARAMETER(pVTab);
+
+ pCsr = (Fts3auxCursor *)sqlite3_malloc(sizeof(Fts3auxCursor));
+ if( !pCsr ) return SQLITE_NOMEM;
+ memset(pCsr, 0, sizeof(Fts3auxCursor));
+
+ *ppCsr = (sqlite3_vtab_cursor *)pCsr;
+ return SQLITE_OK;
+}
+
+/*
+** xClose - Close a cursor.
+*/
+static int fts3auxCloseMethod(sqlite3_vtab_cursor *pCursor){
+ Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+ Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+
+ sqlite3Fts3SegmentsClose(pFts3);
+ sqlite3Fts3SegReaderFinish(&pCsr->csr);
+ sqlite3_free((void *)pCsr->filter.zTerm);
+ sqlite3_free(pCsr->zStop);
+ sqlite3_free(pCsr->aStat);
+ sqlite3_free(pCsr);
+ return SQLITE_OK;
+}
+
+static int fts3auxGrowStatArray(Fts3auxCursor *pCsr, int nSize){
+ if( nSize>pCsr->nStat ){
+ struct Fts3auxColstats *aNew;
+ aNew = (struct Fts3auxColstats *)sqlite3_realloc64(pCsr->aStat,
+ sizeof(struct Fts3auxColstats) * nSize
+ );
+ if( aNew==0 ) return SQLITE_NOMEM;
+ memset(&aNew[pCsr->nStat], 0,
+ sizeof(struct Fts3auxColstats) * (nSize - pCsr->nStat)
+ );
+ pCsr->aStat = aNew;
+ pCsr->nStat = nSize;
+ }
+ return SQLITE_OK;
+}
+
+/*
+** xNext - Advance the cursor to the next row, if any.
+*/
+static int fts3auxNextMethod(sqlite3_vtab_cursor *pCursor){
+ Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+ Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+ int rc;
+
+ /* Increment our pretend rowid value. */
+ pCsr->iRowid++;
+
+ for(pCsr->iCol++; pCsr->iCol<pCsr->nStat; pCsr->iCol++){
+ if( pCsr->aStat[pCsr->iCol].nDoc>0 ) return SQLITE_OK;
+ }
+
+ rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+ if( rc==SQLITE_ROW ){
+ int i = 0;
+ int nDoclist = pCsr->csr.nDoclist;
+ char *aDoclist = pCsr->csr.aDoclist;
+ int iCol;
+
+ int eState = 0;
+
+ if( pCsr->zStop ){
+ int n = (pCsr->nStop<pCsr->csr.nTerm) ? pCsr->nStop : pCsr->csr.nTerm;
+ int mc = memcmp(pCsr->zStop, pCsr->csr.zTerm, n);
+ if( mc<0 || (mc==0 && pCsr->csr.nTerm>pCsr->nStop) ){
+ pCsr->isEof = 1;
+ return SQLITE_OK;
+ }
+ }
+
+ if( fts3auxGrowStatArray(pCsr, 2) ) return SQLITE_NOMEM;
+ memset(pCsr->aStat, 0, sizeof(struct Fts3auxColstats) * pCsr->nStat);
+ iCol = 0;
+ rc = SQLITE_OK;
+
+ while( i<nDoclist ){
+ sqlite3_int64 v = 0;
+
+ i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
+ switch( eState ){
+ /* State 0. In this state the integer just read was a docid. */
+ case 0:
+ pCsr->aStat[0].nDoc++;
+ eState = 1;
+ iCol = 0;
+ break;
+
+ /* State 1. In this state we are expecting either a 1, indicating
+ ** that the following integer will be a column number, or the
+ ** start of a position list for column 0.
+ **
+ ** The only difference between state 1 and state 2 is that if the
+ ** integer encountered in state 1 is not 0 or 1, then we need to
+ ** increment the column 0 "nDoc" count for this term.
+ */
+ case 1:
+ assert( iCol==0 );
+ if( v>1 ){
+ pCsr->aStat[1].nDoc++;
+ }
+ eState = 2;
+ /* fall through */
+
+ case 2:
+ if( v==0 ){ /* 0x00. Next integer will be a docid. */
+ eState = 0;
+ }else if( v==1 ){ /* 0x01. Next integer will be a column number. */
+ eState = 3;
+ }else{ /* 2 or greater. A position. */
+ pCsr->aStat[iCol+1].nOcc++;
+ pCsr->aStat[0].nOcc++;
+ }
+ break;
+
+ /* State 3. The integer just read is a column number. */
+ default: assert( eState==3 );
+ iCol = (int)v;
+ if( iCol<1 ){
+ rc = SQLITE_CORRUPT_VTAB;
+ break;
+ }
+ if( fts3auxGrowStatArray(pCsr, iCol+2) ) return SQLITE_NOMEM;
+ pCsr->aStat[iCol+1].nDoc++;
+ eState = 2;
+ break;
+ }
+ }
+
+ pCsr->iCol = 0;
+ }else{
+ pCsr->isEof = 1;
+ }
+ return rc;
+}
+
+/*
+** xFilter - Initialize a cursor to point at the start of its data.
+*/
+static int fts3auxFilterMethod(
+ sqlite3_vtab_cursor *pCursor, /* The cursor used for this query */
+ int idxNum, /* Strategy index */
+ const char *idxStr, /* Unused */
+ int nVal, /* Number of elements in apVal */
+ sqlite3_value **apVal /* Arguments for the indexing scheme */
+){
+ Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+ Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
+ int rc;
+ int isScan = 0;
+ int iLangVal = 0; /* Language id to query */
+
+ int iEq = -1; /* Index of term=? value in apVal */
+ int iGe = -1; /* Index of term>=? value in apVal */
+ int iLe = -1; /* Index of term<=? value in apVal */
+ int iLangid = -1; /* Index of languageid=? value in apVal */
+ int iNext = 0;
+
+ UNUSED_PARAMETER(nVal);
+ UNUSED_PARAMETER(idxStr);
+
+ assert( idxStr==0 );
+ assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
+ || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
+ || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
+ );
+
+ if( idxNum==FTS4AUX_EQ_CONSTRAINT ){
+ iEq = iNext++;
+ }else{
+ isScan = 1;
+ if( idxNum & FTS4AUX_GE_CONSTRAINT ){
+ iGe = iNext++;
+ }
+ if( idxNum & FTS4AUX_LE_CONSTRAINT ){
+ iLe = iNext++;
+ }
+ }
+ if( iNext<nVal ){
+ iLangid = iNext++;
+ }
+
+ /* In case this cursor is being reused, close and zero it. */
+ testcase(pCsr->filter.zTerm);
+ sqlite3Fts3SegReaderFinish(&pCsr->csr);
+ sqlite3_free((void *)pCsr->filter.zTerm);
+ sqlite3_free(pCsr->aStat);
+ sqlite3_free(pCsr->zStop);
+ memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr);
+
+ pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+ if( isScan ) pCsr->filter.flags |= FTS3_SEGMENT_SCAN;
+
+ if( iEq>=0 || iGe>=0 ){
+ const unsigned char *zStr = sqlite3_value_text(apVal[0]);
+ assert( (iEq==0 && iGe==-1) || (iEq==-1 && iGe==0) );
+ if( zStr ){
+ pCsr->filter.zTerm = sqlite3_mprintf("%s", zStr);
+ if( pCsr->filter.zTerm==0 ) return SQLITE_NOMEM;
+ pCsr->filter.nTerm = (int)strlen(pCsr->filter.zTerm);
+ }
+ }
+
+ if( iLe>=0 ){
+ pCsr->zStop = sqlite3_mprintf("%s", sqlite3_value_text(apVal[iLe]));
+ if( pCsr->zStop==0 ) return SQLITE_NOMEM;
+ pCsr->nStop = (int)strlen(pCsr->zStop);
+ }
+
+ if( iLangid>=0 ){
+ iLangVal = sqlite3_value_int(apVal[iLangid]);
+
+ /* If the user specified a negative value for the languageid, use zero
+ ** instead. This works, as the "languageid=?" constraint will also
+ ** be tested by the VDBE layer. The test will always be false (since
+ ** this module will not return a row with a negative languageid), and
+ ** so the overall query will return zero rows. */
+ if( iLangVal<0 ) iLangVal = 0;
+ }
+ pCsr->iLangid = iLangVal;
+
+ rc = sqlite3Fts3SegReaderCursor(pFts3, iLangVal, 0, FTS3_SEGCURSOR_ALL,
+ pCsr->filter.zTerm, pCsr->filter.nTerm, 0, isScan, &pCsr->csr
+ );
+ if( rc==SQLITE_OK ){
+ rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter);
+ }
+
+ if( rc==SQLITE_OK ) rc = fts3auxNextMethod(pCursor);
+ return rc;
+}
+
+/*
+** xEof - Return true if the cursor is at EOF, or false otherwise.
+*/
+static int fts3auxEofMethod(sqlite3_vtab_cursor *pCursor){
+ Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+ return pCsr->isEof;
+}
+
+/*
+** xColumn - Return a column value.
+*/
+static int fts3auxColumnMethod(
+ sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
+ sqlite3_context *pCtx, /* Context for sqlite3_result_xxx() calls */
+ int iCol /* Index of column to read value from */
+){
+ Fts3auxCursor *p = (Fts3auxCursor *)pCursor;
+
+ assert( p->isEof==0 );
+ switch( iCol ){
+ case 0: /* term */
+ sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+ break;
+
+ case 1: /* col */
+ if( p->iCol ){
+ sqlite3_result_int(pCtx, p->iCol-1);
+ }else{
+ sqlite3_result_text(pCtx, "*", -1, SQLITE_STATIC);
+ }
+ break;
+
+ case 2: /* documents */
+ sqlite3_result_int64(pCtx, p->aStat[p->iCol].nDoc);
+ break;
+
+ case 3: /* occurrences */
+ sqlite3_result_int64(pCtx, p->aStat[p->iCol].nOcc);
+ break;
+
+ default: /* languageid */
+ assert( iCol==4 );
+ sqlite3_result_int(pCtx, p->iLangid);
+ break;
+ }
+
+ return SQLITE_OK;
+}
+
+/*
+** xRowid - Return the current rowid for the cursor.
+*/
+static int fts3auxRowidMethod(
+ sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
+ sqlite_int64 *pRowid /* OUT: Rowid value */
+){
+ Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
+ *pRowid = pCsr->iRowid;
+ return SQLITE_OK;
+}
+
+/*
+** Register the fts3aux module with database connection db. Return SQLITE_OK
+** if successful or an error code if sqlite3_create_module() fails.
+*/
+int sqlite3Fts3InitAux(sqlite3 *db){
+ static const sqlite3_module fts3aux_module = {
+ 0, /* iVersion */
+ fts3auxConnectMethod, /* xCreate */
+ fts3auxConnectMethod, /* xConnect */
+ fts3auxBestIndexMethod, /* xBestIndex */
+ fts3auxDisconnectMethod, /* xDisconnect */
+ fts3auxDisconnectMethod, /* xDestroy */
+ fts3auxOpenMethod, /* xOpen */
+ fts3auxCloseMethod, /* xClose */
+ fts3auxFilterMethod, /* xFilter */
+ fts3auxNextMethod, /* xNext */
+ fts3auxEofMethod, /* xEof */
+ fts3auxColumnMethod, /* xColumn */
+ fts3auxRowidMethod, /* xRowid */
+ 0, /* xUpdate */
+ 0, /* xBegin */
+ 0, /* xSync */
+ 0, /* xCommit */
+ 0, /* xRollback */
+ 0, /* xFindFunction */
+ 0, /* xRename */
+ 0, /* xSavepoint */
+ 0, /* xRelease */
+ 0, /* xRollbackTo */
+ 0 /* xShadowName */
+ };
+ int rc; /* Return code */
+
+ rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
+ return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */