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Diffstat (limited to 'ext/fts3/fts3_term.c')
| -rw-r--r-- | ext/fts3/fts3_term.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/ext/fts3/fts3_term.c b/ext/fts3/fts3_term.c new file mode 100644 index 0000000..d3eb690 --- /dev/null +++ b/ext/fts3/fts3_term.c @@ -0,0 +1,369 @@ +/* +** 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. +** +****************************************************************************** +** +** This file is not part of the production FTS code. It is only used for +** testing. It contains a virtual table implementation that provides direct +** access to the full-text index of an FTS table. +*/ + +#include "fts3Int.h" +#if !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) +#ifdef SQLITE_TEST + +#include <string.h> +#include <assert.h> +#include <stdlib.h> + +typedef struct Fts3termTable Fts3termTable; +typedef struct Fts3termCursor Fts3termCursor; + +struct Fts3termTable { + sqlite3_vtab base; /* Base class used by SQLite core */ + int iIndex; /* Index for Fts3Table.aIndex[] */ + Fts3Table *pFts3Tab; +}; + +struct Fts3termCursor { + sqlite3_vtab_cursor base; /* Base class used by SQLite core */ + Fts3MultiSegReader csr; /* Must be right after "base" */ + Fts3SegFilter filter; + + int isEof; /* True if cursor is at EOF */ + char *pNext; + + sqlite3_int64 iRowid; /* Current 'rowid' value */ + sqlite3_int64 iDocid; /* Current 'docid' value */ + int iCol; /* Current 'col' value */ + int iPos; /* Current 'pos' value */ +}; + +/* +** Schema of the terms table. +*/ +#define FTS3_TERMS_SCHEMA "CREATE TABLE x(term, docid, col, pos)" + +/* +** 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 fts3termConnectMethod( + sqlite3 *db, /* Database connection */ + void *pCtx, /* Non-zero for an fts4prefix table */ + 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() */ + Fts3termTable *p; /* Virtual table object to return */ + int iIndex = 0; + + if( argc==5 ){ + iIndex = atoi(argv[4]); + argc--; + } + + /* The user should specify a single argument - the name of an fts3 table. */ + if( argc!=4 ){ + *pzErr = sqlite3_mprintf( + "wrong number of arguments to fts4term constructor" + ); + 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(Fts3termTable) + sizeof(Fts3Table) + nDb + nFts3 + 2; + p = (Fts3termTable *)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; + p->pFts3Tab->nIndex = iIndex+1; + p->iIndex = iIndex; + + 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; +} + +/* +** 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 fts3termDisconnectMethod(sqlite3_vtab *pVtab){ + Fts3termTable *p = (Fts3termTable *)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 fts3termBestIndexMethod( + sqlite3_vtab *pVTab, + sqlite3_index_info *pInfo +){ + UNUSED_PARAMETER(pVTab); + + /* This vtab naturally does "ORDER BY term, docid, col, pos". */ + if( pInfo->nOrderBy ){ + int i; + for(i=0; i<pInfo->nOrderBy; i++){ + if( pInfo->aOrderBy[i].iColumn!=i || pInfo->aOrderBy[i].desc ) break; + } + if( i==pInfo->nOrderBy ){ + pInfo->orderByConsumed = 1; + } + } + + return SQLITE_OK; +} + +/* +** xOpen - Open a cursor. +*/ +static int fts3termOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){ + Fts3termCursor *pCsr; /* Pointer to cursor object to return */ + + UNUSED_PARAMETER(pVTab); + + pCsr = (Fts3termCursor *)sqlite3_malloc(sizeof(Fts3termCursor)); + if( !pCsr ) return SQLITE_NOMEM; + memset(pCsr, 0, sizeof(Fts3termCursor)); + + *ppCsr = (sqlite3_vtab_cursor *)pCsr; + return SQLITE_OK; +} + +/* +** xClose - Close a cursor. +*/ +static int fts3termCloseMethod(sqlite3_vtab_cursor *pCursor){ + Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab; + Fts3termCursor *pCsr = (Fts3termCursor *)pCursor; + + sqlite3Fts3SegmentsClose(pFts3); + sqlite3Fts3SegReaderFinish(&pCsr->csr); + sqlite3_free(pCsr); + return SQLITE_OK; +} + +/* +** xNext - Advance the cursor to the next row, if any. +*/ +static int fts3termNextMethod(sqlite3_vtab_cursor *pCursor){ + Fts3termCursor *pCsr = (Fts3termCursor *)pCursor; + Fts3Table *pFts3 = ((Fts3termTable *)pCursor->pVtab)->pFts3Tab; + int rc; + sqlite3_int64 v; + + /* Increment our pretend rowid value. */ + pCsr->iRowid++; + + /* Advance to the next term in the full-text index. */ + if( pCsr->csr.aDoclist==0 + || pCsr->pNext>=&pCsr->csr.aDoclist[pCsr->csr.nDoclist-1] + ){ + rc = sqlite3Fts3SegReaderStep(pFts3, &pCsr->csr); + if( rc!=SQLITE_ROW ){ + pCsr->isEof = 1; + return rc; + } + + pCsr->iCol = 0; + pCsr->iPos = 0; + pCsr->iDocid = 0; + pCsr->pNext = pCsr->csr.aDoclist; + + /* Read docid */ + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &pCsr->iDocid); + } + + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v); + if( v==0 ){ + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v); + pCsr->iDocid += v; + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v); + pCsr->iCol = 0; + pCsr->iPos = 0; + } + + if( v==1 ){ + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v); + pCsr->iCol += v; + pCsr->iPos = 0; + pCsr->pNext += sqlite3Fts3GetVarint(pCsr->pNext, &v); + } + + pCsr->iPos += (v - 2); + + return SQLITE_OK; +} + +/* +** xFilter - Initialize a cursor to point at the start of its data. +*/ +static int fts3termFilterMethod( + 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 */ +){ + Fts3termCursor *pCsr = (Fts3termCursor *)pCursor; + Fts3termTable *p = (Fts3termTable *)pCursor->pVtab; + Fts3Table *pFts3 = p->pFts3Tab; + int rc; + + UNUSED_PARAMETER(nVal); + UNUSED_PARAMETER(idxNum); + UNUSED_PARAMETER(idxStr); + UNUSED_PARAMETER(apVal); + + assert( idxStr==0 && idxNum==0 ); + + /* In case this cursor is being reused, close and zero it. */ + testcase(pCsr->filter.zTerm); + sqlite3Fts3SegReaderFinish(&pCsr->csr); + memset(&pCsr->csr, 0, ((u8*)&pCsr[1]) - (u8*)&pCsr->csr); + + pCsr->filter.flags = FTS3_SEGMENT_REQUIRE_POS|FTS3_SEGMENT_IGNORE_EMPTY; + pCsr->filter.flags |= FTS3_SEGMENT_SCAN; + + rc = sqlite3Fts3SegReaderCursor(pFts3, p->iIndex, FTS3_SEGCURSOR_ALL, + pCsr->filter.zTerm, pCsr->filter.nTerm, 0, 1, &pCsr->csr + ); + if( rc==SQLITE_OK ){ + rc = sqlite3Fts3SegReaderStart(pFts3, &pCsr->csr, &pCsr->filter); + } + if( rc==SQLITE_OK ){ + rc = fts3termNextMethod(pCursor); + } + return rc; +} + +/* +** xEof - Return true if the cursor is at EOF, or false otherwise. +*/ +static int fts3termEofMethod(sqlite3_vtab_cursor *pCursor){ + Fts3termCursor *pCsr = (Fts3termCursor *)pCursor; + return pCsr->isEof; +} + +/* +** xColumn - Return a column value. +*/ +static int fts3termColumnMethod( + 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 */ +){ + Fts3termCursor *p = (Fts3termCursor *)pCursor; + + assert( iCol>=0 && iCol<=3 ); + switch( iCol ){ + case 0: + sqlite3_result_text(pCtx, p->csr.zTerm, p->csr.nTerm, SQLITE_TRANSIENT); + break; + case 1: + sqlite3_result_int64(pCtx, p->iDocid); + break; + case 2: + sqlite3_result_int64(pCtx, p->iCol); + break; + default: + sqlite3_result_int64(pCtx, p->iPos); + break; + } + + return SQLITE_OK; +} + +/* +** xRowid - Return the current rowid for the cursor. +*/ +static int fts3termRowidMethod( + sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */ + sqlite_int64 *pRowid /* OUT: Rowid value */ +){ + Fts3termCursor *pCsr = (Fts3termCursor *)pCursor; + *pRowid = pCsr->iRowid; + return SQLITE_OK; +} + +/* +** Register the fts3term module with database connection db. Return SQLITE_OK +** if successful or an error code if sqlite3_create_module() fails. +*/ +int sqlite3Fts3InitTerm(sqlite3 *db){ + static const sqlite3_module fts3term_module = { + 0, /* iVersion */ + fts3termConnectMethod, /* xCreate */ + fts3termConnectMethod, /* xConnect */ + fts3termBestIndexMethod, /* xBestIndex */ + fts3termDisconnectMethod, /* xDisconnect */ + fts3termDisconnectMethod, /* xDestroy */ + fts3termOpenMethod, /* xOpen */ + fts3termCloseMethod, /* xClose */ + fts3termFilterMethod, /* xFilter */ + fts3termNextMethod, /* xNext */ + fts3termEofMethod, /* xEof */ + fts3termColumnMethod, /* xColumn */ + fts3termRowidMethod, /* xRowid */ + 0, /* xUpdate */ + 0, /* xBegin */ + 0, /* xSync */ + 0, /* xCommit */ + 0, /* xRollback */ + 0, /* xFindFunction */ + 0 /* xRename */ + }; + int rc; /* Return code */ + + rc = sqlite3_create_module(db, "fts4term", &fts3term_module, 0); + return rc; +} + +#endif +#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */ |