--- /dev/null
+/*
+** 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.
+**
+******************************************************************************
+**
+*/
+
+#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3)
+
+#include "fts3Int.h"
+#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 */
+
+ Fts3SegFilter filter;
+ Fts3SegReaderCursor csr;
+ int isEof;
+
+ sqlite3_int64 iRowid;
+ sqlite3_int64 nDoc;
+ sqlite3_int64 nOcc;
+};
+
+/*
+** Schema of the terms table.
+*/
+#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, documents, occurrences)"
+
+/*
+** 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) */
+ int nByte; /* Bytes of space to allocate here */
+ int rc; /* value returned by declare_vtab() */
+ Fts3auxTable *p; /* Virtual table object to return */
+
+ /* The user should specify a single argument - the name of an fts3 table. */
+ if( argc!=4 ){
+ *pzErr = sqlite3_mprintf("wrong number of arguments");
+ return SQLITE_ERROR;
+ }
+
+ zDb = argv[1];
+ nDb = strlen(zDb);
+ zFts3 = argv[3];
+ nFts3 = strlen(zFts3);
+
+ rc = sqlite3_declare_vtab(db, FTS3_TERMS_SCHEMA);
+ if( rc!=SQLITE_OK ) return rc;
+
+ nByte = sizeof(Fts3auxTable) + sizeof(Fts3Table) + nDb + nFts3 + 2;
+ p = (Fts3auxTable *)sqlite3_malloc(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;
+
+ memcpy((char *)p->pFts3Tab->zDb, zDb, nDb);
+ memcpy((char *)p->pFts3Tab->zName, zFts3, nFts3);
+
+ *ppVtab = (sqlite3_vtab *)p;
+ return SQLITE_OK;
+}
+
+/*
+** 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;
+}
+
+/*
+** xBestIndex - Analyze a WHERE and ORDER BY clause.
+*/
+static int fts3auxBestIndexMethod(
+ sqlite3_vtab *pVTab,
+ sqlite3_index_info *pInfo
+){
+
+ /* 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;
+ }
+
+ pInfo->estimatedCost = 20000;
+ 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 */
+
+ 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(pCsr);
+ 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;
+
+ rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr);
+ if( rc==SQLITE_ROW ){
+ int i;
+ int isIgnore = 1;
+ int nDoclist = pCsr->csr.nDoclist;
+ char *aDoclist = pCsr->csr.aDoclist;
+
+ /* Now count the number of documents and positions in the doclist
+ ** in pCsr->csr.aDoclist[]. Store the number of documents in pCsr->nDoc
+ ** and the number of occurrences in pCsr->nOcc. */
+ pCsr->nDoc = 0;
+ pCsr->nOcc = 0;
+ i = 0;
+ while( i<nDoclist ){
+ sqlite3_int64 v = 0;
+ i += sqlite3Fts3GetVarint(&aDoclist[i], &v);
+ if( isIgnore ){
+ isIgnore = 0;
+ }else if( v>1 ){
+ pCsr->nOcc++;
+ }else{
+ if( v==0 ) pCsr->nDoc++;
+ isIgnore = 1;
+ }
+ }
+
+ rc = SQLITE_OK;
+ pCsr->iRowid++;
+ }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;
+
+ sqlite3Fts3SegReaderFinish(&pCsr->csr);
+ memset(&pCsr->csr, 0, sizeof(Fts3SegReaderCursor));
+ pCsr->isEof = 0;
+ pCsr->iRowid = 0;
+ pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY;
+
+ rc = sqlite3Fts3SegReaderCursor(pFts3, FTS3_SEGCURSOR_ALL, 0, 0,1,&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 *pContext, /* Context for sqlite3_result_xxx() calls */
+ int iCol /* Index of column to read value from */
+){
+ Fts3auxCursor *p = (Fts3auxCursor *)pCursor;
+
+ assert( p->isEof==0 );
+ if( iCol==0 ){ /* Column "term" */
+ sqlite3_result_text(pContext, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT);
+ }else if( iCol==1 ){ /* Column "documents" */
+ sqlite3_result_int64(pContext, p->nDoc);
+ }else{ /* Column "occurrences" */
+ sqlite3_result_int64(pContext, p->nOcc);
+ }
+
+ 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 */
+ };
+ int rc; /* Return code */
+
+ rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
+ return rc;
+}
+
+#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */
projects / thirdparty / sqlite.git / commitdiff
