sqlite3/ext/fts5/fts5_test_tok.c

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2023-06-27 18:34:42 +08:00
/*
** 2013 Apr 22
**
** 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 contains code for the "fts5tokenize" virtual table module.
** An fts5tokenize virtual table is created as follows:
**
** CREATE VIRTUAL TABLE <tbl> USING fts5tokenize(
** <tokenizer-name>, <arg-1>, ...
** );
**
** The table created has the following schema:
**
** CREATE TABLE <tbl>(input HIDDEN, token, start, end, position)
**
** When queried, the query must include a WHERE clause of type:
**
** input = <string>
**
** The virtual table module tokenizes this <string>, using the FTS3
** tokenizer specified by the arguments to the CREATE VIRTUAL TABLE
** statement and returns one row for each token in the result. With
** fields set as follows:
**
** input: Always set to a copy of <string>
** token: A token from the input.
** start: Byte offset of the token within the input <string>.
** end: Byte offset of the byte immediately following the end of the
** token within the input string.
** pos: Token offset of token within input.
**
*/
#if defined(SQLITE_TEST) && defined(SQLITE_ENABLE_FTS5)
#include "fts5.h"
#include <string.h>
#include <assert.h>
typedef struct Fts5tokTable Fts5tokTable;
typedef struct Fts5tokCursor Fts5tokCursor;
typedef struct Fts5tokRow Fts5tokRow;
/*
** Virtual table structure.
*/
struct Fts5tokTable {
sqlite3_vtab base; /* Base class used by SQLite core */
fts5_tokenizer tok; /* Tokenizer functions */
Fts5Tokenizer *pTok; /* Tokenizer instance */
};
/*
** A container for a rows values.
*/
struct Fts5tokRow {
char *zToken;
int iStart;
int iEnd;
int iPos;
};
/*
** Virtual table cursor structure.
*/
struct Fts5tokCursor {
sqlite3_vtab_cursor base; /* Base class used by SQLite core */
int iRowid; /* Current 'rowid' value */
char *zInput; /* Input string */
int nRow; /* Number of entries in aRow[] */
Fts5tokRow *aRow; /* Array of rows to return */
};
static void fts5tokDequote(char *z){
char q = z[0];
if( q=='[' || q=='\'' || q=='"' || q=='`' ){
int iIn = 1;
int iOut = 0;
if( q=='[' ) q = ']';
while( z[iIn] ){
if( z[iIn]==q ){
if( z[iIn+1]!=q ){
/* Character iIn was the close quote. */
iIn++;
break;
}else{
/* Character iIn and iIn+1 form an escaped quote character. Skip
** the input cursor past both and copy a single quote character
** to the output buffer. */
iIn += 2;
z[iOut++] = q;
}
}else{
z[iOut++] = z[iIn++];
}
}
z[iOut] = '\0';
}
}
/*
** The second argument, argv[], is an array of pointers to nul-terminated
** strings. This function makes a copy of the array and strings into a
** single block of memory. It then dequotes any of the strings that appear
** to be quoted.
**
** If successful, output parameter *pazDequote is set to point at the
** array of dequoted strings and SQLITE_OK is returned. The caller is
** responsible for eventually calling sqlite3_free() to free the array
** in this case. Or, if an error occurs, an SQLite error code is returned.
** The final value of *pazDequote is undefined in this case.
*/
static int fts5tokDequoteArray(
int argc, /* Number of elements in argv[] */
const char * const *argv, /* Input array */
char ***pazDequote /* Output array */
){
int rc = SQLITE_OK; /* Return code */
if( argc==0 ){
*pazDequote = 0;
}else{
int i;
int nByte = 0;
char **azDequote;
for(i=0; i<argc; i++){
nByte += (int)(strlen(argv[i]) + 1);
}
*pazDequote = azDequote = sqlite3_malloc64(sizeof(char *)*argc + nByte);
if( azDequote==0 ){
rc = SQLITE_NOMEM;
}else{
char *pSpace = (char *)&azDequote[argc];
for(i=0; i<argc; i++){
int n = (int)strlen(argv[i]);
azDequote[i] = pSpace;
memcpy(pSpace, argv[i], n+1);
fts5tokDequote(pSpace);
pSpace += (n+1);
}
}
}
return rc;
}
/*
** Schema of the tokenizer table.
*/
#define FTS3_TOK_SCHEMA "CREATE TABLE x(input HIDDEN, token, start, end, position)"
/*
** 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.
**
** argv[0]: module name
** argv[1]: database name
** argv[2]: table name
** argv[3]: first argument (tokenizer name)
*/
static int fts5tokConnectMethod(
sqlite3 *db, /* Database connection */
void *pCtx, /* Pointer to fts5_api object */
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 */
){
fts5_api *pApi = (fts5_api*)pCtx;
Fts5tokTable *pTab = 0;
int rc;
char **azDequote = 0;
int nDequote = 0;
rc = sqlite3_declare_vtab(db,
"CREATE TABLE x(input HIDDEN, token, start, end, position)"
);
if( rc==SQLITE_OK ){
nDequote = argc-3;
rc = fts5tokDequoteArray(nDequote, &argv[3], &azDequote);
}
if( rc==SQLITE_OK ){
pTab = (Fts5tokTable*)sqlite3_malloc(sizeof(Fts5tokTable));
if( pTab==0 ){
rc = SQLITE_NOMEM;
}else{
memset(pTab, 0, sizeof(Fts5tokTable));
}
}
if( rc==SQLITE_OK ){
void *pTokCtx = 0;
const char *zModule = 0;
if( nDequote>0 ){
zModule = azDequote[0];
}
rc = pApi->xFindTokenizer(pApi, zModule, &pTokCtx, &pTab->tok);
if( rc==SQLITE_OK ){
const char **azArg = (nDequote>1 ? (const char **)&azDequote[1] : 0);
int nArg = nDequote>0 ? nDequote-1 : 0;
rc = pTab->tok.xCreate(pTokCtx, azArg, nArg, &pTab->pTok);
}
}
if( rc!=SQLITE_OK ){
sqlite3_free(pTab);
pTab = 0;
}
*ppVtab = (sqlite3_vtab*)pTab;
sqlite3_free(azDequote);
return rc;
}
/*
** 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 fts5tokDisconnectMethod(sqlite3_vtab *pVtab){
Fts5tokTable *pTab = (Fts5tokTable *)pVtab;
if( pTab->pTok ){
pTab->tok.xDelete(pTab->pTok);
}
sqlite3_free(pTab);
return SQLITE_OK;
}
/*
** xBestIndex - Analyze a WHERE and ORDER BY clause.
*/
static int fts5tokBestIndexMethod(
sqlite3_vtab *pVTab,
sqlite3_index_info *pInfo
){
int i;
for(i=0; i<pInfo->nConstraint; i++){
if( pInfo->aConstraint[i].usable
&& pInfo->aConstraint[i].iColumn==0
&& pInfo->aConstraint[i].op==SQLITE_INDEX_CONSTRAINT_EQ
){
pInfo->idxNum = 1;
pInfo->aConstraintUsage[i].argvIndex = 1;
pInfo->aConstraintUsage[i].omit = 1;
pInfo->estimatedCost = 1;
return SQLITE_OK;
}
}
pInfo->idxNum = 0;
assert( pInfo->estimatedCost>1000000.0 );
return SQLITE_OK;
}
/*
** xOpen - Open a cursor.
*/
static int fts5tokOpenMethod(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCsr){
Fts5tokCursor *pCsr;
pCsr = (Fts5tokCursor *)sqlite3_malloc(sizeof(Fts5tokCursor));
if( pCsr==0 ){
return SQLITE_NOMEM;
}
memset(pCsr, 0, sizeof(Fts5tokCursor));
*ppCsr = (sqlite3_vtab_cursor *)pCsr;
return SQLITE_OK;
}
/*
** Reset the tokenizer cursor passed as the only argument. As if it had
** just been returned by fts5tokOpenMethod().
*/
static void fts5tokResetCursor(Fts5tokCursor *pCsr){
int i;
for(i=0; i<pCsr->nRow; i++){
sqlite3_free(pCsr->aRow[i].zToken);
}
sqlite3_free(pCsr->zInput);
sqlite3_free(pCsr->aRow);
pCsr->zInput = 0;
pCsr->aRow = 0;
pCsr->nRow = 0;
pCsr->iRowid = 0;
}
/*
** xClose - Close a cursor.
*/
static int fts5tokCloseMethod(sqlite3_vtab_cursor *pCursor){
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
fts5tokResetCursor(pCsr);
sqlite3_free(pCsr);
return SQLITE_OK;
}
/*
** xNext - Advance the cursor to the next row, if any.
*/
static int fts5tokNextMethod(sqlite3_vtab_cursor *pCursor){
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
pCsr->iRowid++;
return SQLITE_OK;
}
static int fts5tokCb(
void *pCtx, /* Pointer to Fts5tokCursor */
int tflags, /* Mask of FTS5_TOKEN_* flags */
const char *pToken, /* Pointer to buffer containing token */
int nToken, /* Size of token in bytes */
int iStart, /* Byte offset of token within input text */
int iEnd /* Byte offset of end of token within input text */
){
Fts5tokCursor *pCsr = (Fts5tokCursor*)pCtx;
Fts5tokRow *pRow;
if( (pCsr->nRow & (pCsr->nRow-1))==0 ){
int nNew = pCsr->nRow ? pCsr->nRow*2 : 32;
Fts5tokRow *aNew;
aNew = (Fts5tokRow*)sqlite3_realloc64(pCsr->aRow, nNew*sizeof(Fts5tokRow));
if( aNew==0 ) return SQLITE_NOMEM;
memset(&aNew[pCsr->nRow], 0, sizeof(Fts5tokRow)*(nNew-pCsr->nRow));
pCsr->aRow = aNew;
}
pRow = &pCsr->aRow[pCsr->nRow];
pRow->iStart = iStart;
pRow->iEnd = iEnd;
if( pCsr->nRow ){
pRow->iPos = pRow[-1].iPos + ((tflags & FTS5_TOKEN_COLOCATED) ? 0 : 1);
}
pRow->zToken = sqlite3_malloc(nToken+1);
if( pRow->zToken==0 ) return SQLITE_NOMEM;
memcpy(pRow->zToken, pToken, nToken);
pRow->zToken[nToken] = 0;
pCsr->nRow++;
return SQLITE_OK;
}
/*
** xFilter - Initialize a cursor to point at the start of its data.
*/
static int fts5tokFilterMethod(
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 */
){
int rc = SQLITE_ERROR;
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
Fts5tokTable *pTab = (Fts5tokTable *)(pCursor->pVtab);
fts5tokResetCursor(pCsr);
if( idxNum==1 ){
const char *zByte = (const char *)sqlite3_value_text(apVal[0]);
int nByte = sqlite3_value_bytes(apVal[0]);
pCsr->zInput = sqlite3_malloc(nByte+1);
if( pCsr->zInput==0 ){
rc = SQLITE_NOMEM;
}else{
if( nByte>0 ) memcpy(pCsr->zInput, zByte, nByte);
pCsr->zInput[nByte] = 0;
rc = pTab->tok.xTokenize(
pTab->pTok, (void*)pCsr, 0, zByte, nByte, fts5tokCb
);
}
}
if( rc!=SQLITE_OK ) return rc;
return fts5tokNextMethod(pCursor);
}
/*
** xEof - Return true if the cursor is at EOF, or false otherwise.
*/
static int fts5tokEofMethod(sqlite3_vtab_cursor *pCursor){
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
return (pCsr->iRowid>pCsr->nRow);
}
/*
** xColumn - Return a column value.
*/
static int fts5tokColumnMethod(
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 */
){
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
Fts5tokRow *pRow = &pCsr->aRow[pCsr->iRowid-1];
/* CREATE TABLE x(input, token, start, end, position) */
switch( iCol ){
case 0:
sqlite3_result_text(pCtx, pCsr->zInput, -1, SQLITE_TRANSIENT);
break;
case 1:
sqlite3_result_text(pCtx, pRow->zToken, -1, SQLITE_TRANSIENT);
break;
case 2:
sqlite3_result_int(pCtx, pRow->iStart);
break;
case 3:
sqlite3_result_int(pCtx, pRow->iEnd);
break;
default:
assert( iCol==4 );
sqlite3_result_int(pCtx, pRow->iPos);
break;
}
return SQLITE_OK;
}
/*
** xRowid - Return the current rowid for the cursor.
*/
static int fts5tokRowidMethod(
sqlite3_vtab_cursor *pCursor, /* Cursor to retrieve value from */
sqlite_int64 *pRowid /* OUT: Rowid value */
){
Fts5tokCursor *pCsr = (Fts5tokCursor *)pCursor;
*pRowid = (sqlite3_int64)pCsr->iRowid;
return SQLITE_OK;
}
/*
** Register the fts5tok module with database connection db. Return SQLITE_OK
** if successful or an error code if sqlite3_create_module() fails.
*/
int sqlite3Fts5TestRegisterTok(sqlite3 *db, fts5_api *pApi){
static const sqlite3_module fts5tok_module = {
0, /* iVersion */
fts5tokConnectMethod, /* xCreate */
fts5tokConnectMethod, /* xConnect */
fts5tokBestIndexMethod, /* xBestIndex */
fts5tokDisconnectMethod, /* xDisconnect */
fts5tokDisconnectMethod, /* xDestroy */
fts5tokOpenMethod, /* xOpen */
fts5tokCloseMethod, /* xClose */
fts5tokFilterMethod, /* xFilter */
fts5tokNextMethod, /* xNext */
fts5tokEofMethod, /* xEof */
fts5tokColumnMethod, /* xColumn */
fts5tokRowidMethod, /* 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, "fts5tokenize", &fts5tok_module, (void*)pApi);
return rc;
}
#endif /* defined(SQLITE_TEST) && defined(SQLITE_ENABLE_FTS5) */