810 lines
22 KiB
C
810 lines
22 KiB
C
/*
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** 2019-04-17
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**
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** The author disclaims copyright to this source code. In place of
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** a legal notice, here is a blessing:
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**
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** May you do good and not evil.
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** May you find forgiveness for yourself and forgive others.
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** May you share freely, never taking more than you give.
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**
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******************************************************************************
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**
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** This file contains an implementation of two eponymous virtual tables,
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** "sqlite_dbdata" and "sqlite_dbptr". Both modules require that the
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** "sqlite_dbpage" eponymous virtual table be available.
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**
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** SQLITE_DBDATA:
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** sqlite_dbdata is used to extract data directly from a database b-tree
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** page and its associated overflow pages, bypassing the b-tree layer.
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** The table schema is equivalent to:
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**
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** CREATE TABLE sqlite_dbdata(
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** pgno INTEGER,
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** cell INTEGER,
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** field INTEGER,
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** value ANY,
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** schema TEXT HIDDEN
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** );
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**
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** IMPORTANT: THE VIRTUAL TABLE SCHEMA ABOVE IS SUBJECT TO CHANGE. IN THE
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** FUTURE NEW NON-HIDDEN COLUMNS MAY BE ADDED BETWEEN "value" AND
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** "schema".
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**
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** Each page of the database is inspected. If it cannot be interpreted as
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** a b-tree page, or if it is a b-tree page containing 0 entries, the
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** sqlite_dbdata table contains no rows for that page. Otherwise, the
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** table contains one row for each field in the record associated with
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** each cell on the page. For intkey b-trees, the key value is stored in
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** field -1.
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**
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** For example, for the database:
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**
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** CREATE TABLE t1(a, b); -- root page is page 2
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** INSERT INTO t1(rowid, a, b) VALUES(5, 'v', 'five');
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** INSERT INTO t1(rowid, a, b) VALUES(10, 'x', 'ten');
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**
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** the sqlite_dbdata table contains, as well as from entries related to
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** page 1, content equivalent to:
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**
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** INSERT INTO sqlite_dbdata(pgno, cell, field, value) VALUES
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** (2, 0, -1, 5 ),
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** (2, 0, 0, 'v' ),
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** (2, 0, 1, 'five'),
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** (2, 1, -1, 10 ),
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** (2, 1, 0, 'x' ),
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** (2, 1, 1, 'ten' );
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**
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** If database corruption is encountered, this module does not report an
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** error. Instead, it attempts to extract as much data as possible and
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** ignores the corruption.
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**
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** SQLITE_DBPTR:
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** The sqlite_dbptr table has the following schema:
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**
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** CREATE TABLE sqlite_dbptr(
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** pgno INTEGER,
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** child INTEGER,
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** schema TEXT HIDDEN
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** );
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**
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** It contains one entry for each b-tree pointer between a parent and
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** child page in the database.
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*/
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#if !defined(SQLITEINT_H)
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#include "sqlite3ext.h"
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typedef unsigned char u8;
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#endif
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SQLITE_EXTENSION_INIT1
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#include <string.h>
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#include <assert.h>
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typedef struct DbdataTable DbdataTable;
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typedef struct DbdataCursor DbdataCursor;
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/* Cursor object */
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struct DbdataCursor {
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sqlite3_vtab_cursor base; /* Base class. Must be first */
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sqlite3_stmt *pStmt; /* For fetching database pages */
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int iPgno; /* Current page number */
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u8 *aPage; /* Buffer containing page */
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int nPage; /* Size of aPage[] in bytes */
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int nCell; /* Number of cells on aPage[] */
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int iCell; /* Current cell number */
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int bOnePage; /* True to stop after one page */
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int szDb;
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sqlite3_int64 iRowid;
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/* Only for the sqlite_dbdata table */
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u8 *pRec; /* Buffer containing current record */
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int nRec; /* Size of pRec[] in bytes */
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int nHdr; /* Size of header in bytes */
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int iField; /* Current field number */
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u8 *pHdrPtr;
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u8 *pPtr;
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sqlite3_int64 iIntkey; /* Integer key value */
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};
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/* Table object */
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struct DbdataTable {
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sqlite3_vtab base; /* Base class. Must be first */
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sqlite3 *db; /* The database connection */
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sqlite3_stmt *pStmt; /* For fetching database pages */
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int bPtr; /* True for sqlite3_dbptr table */
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};
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/* Column and schema definitions for sqlite_dbdata */
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#define DBDATA_COLUMN_PGNO 0
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#define DBDATA_COLUMN_CELL 1
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#define DBDATA_COLUMN_FIELD 2
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#define DBDATA_COLUMN_VALUE 3
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#define DBDATA_COLUMN_SCHEMA 4
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#define DBDATA_SCHEMA \
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"CREATE TABLE x(" \
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" pgno INTEGER," \
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" cell INTEGER," \
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" field INTEGER," \
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" value ANY," \
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" schema TEXT HIDDEN" \
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")"
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/* Column and schema definitions for sqlite_dbptr */
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#define DBPTR_COLUMN_PGNO 0
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#define DBPTR_COLUMN_CHILD 1
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#define DBPTR_COLUMN_SCHEMA 2
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#define DBPTR_SCHEMA \
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"CREATE TABLE x(" \
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" pgno INTEGER," \
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" child INTEGER," \
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" schema TEXT HIDDEN" \
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")"
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/*
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** Connect to an sqlite_dbdata (pAux==0) or sqlite_dbptr (pAux!=0) virtual
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** table.
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*/
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static int dbdataConnect(
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sqlite3 *db,
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void *pAux,
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int argc, const char *const*argv,
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sqlite3_vtab **ppVtab,
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char **pzErr
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){
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DbdataTable *pTab = 0;
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int rc = sqlite3_declare_vtab(db, pAux ? DBPTR_SCHEMA : DBDATA_SCHEMA);
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if( rc==SQLITE_OK ){
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pTab = (DbdataTable*)sqlite3_malloc64(sizeof(DbdataTable));
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if( pTab==0 ){
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rc = SQLITE_NOMEM;
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}else{
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memset(pTab, 0, sizeof(DbdataTable));
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pTab->db = db;
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pTab->bPtr = (pAux!=0);
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}
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}
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*ppVtab = (sqlite3_vtab*)pTab;
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return rc;
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}
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/*
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** Disconnect from or destroy a sqlite_dbdata or sqlite_dbptr virtual table.
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*/
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static int dbdataDisconnect(sqlite3_vtab *pVtab){
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DbdataTable *pTab = (DbdataTable*)pVtab;
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if( pTab ){
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sqlite3_finalize(pTab->pStmt);
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sqlite3_free(pVtab);
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}
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return SQLITE_OK;
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}
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/*
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** This function interprets two types of constraints:
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**
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** schema=?
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** pgno=?
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**
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** If neither are present, idxNum is set to 0. If schema=? is present,
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** the 0x01 bit in idxNum is set. If pgno=? is present, the 0x02 bit
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** in idxNum is set.
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**
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** If both parameters are present, schema is in position 0 and pgno in
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** position 1.
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*/
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static int dbdataBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdx){
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DbdataTable *pTab = (DbdataTable*)tab;
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int i;
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int iSchema = -1;
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int iPgno = -1;
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int colSchema = (pTab->bPtr ? DBPTR_COLUMN_SCHEMA : DBDATA_COLUMN_SCHEMA);
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for(i=0; i<pIdx->nConstraint; i++){
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struct sqlite3_index_constraint *p = &pIdx->aConstraint[i];
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if( p->op==SQLITE_INDEX_CONSTRAINT_EQ ){
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if( p->iColumn==colSchema ){
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if( p->usable==0 ) return SQLITE_CONSTRAINT;
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iSchema = i;
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}
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if( p->iColumn==DBDATA_COLUMN_PGNO && p->usable ){
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iPgno = i;
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}
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}
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}
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if( iSchema>=0 ){
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pIdx->aConstraintUsage[iSchema].argvIndex = 1;
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pIdx->aConstraintUsage[iSchema].omit = 1;
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}
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if( iPgno>=0 ){
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pIdx->aConstraintUsage[iPgno].argvIndex = 1 + (iSchema>=0);
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pIdx->aConstraintUsage[iPgno].omit = 1;
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pIdx->estimatedCost = 100;
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pIdx->estimatedRows = 50;
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if( pTab->bPtr==0 && pIdx->nOrderBy && pIdx->aOrderBy[0].desc==0 ){
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int iCol = pIdx->aOrderBy[0].iColumn;
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if( pIdx->nOrderBy==1 ){
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pIdx->orderByConsumed = (iCol==0 || iCol==1);
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}else if( pIdx->nOrderBy==2 && pIdx->aOrderBy[1].desc==0 && iCol==0 ){
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pIdx->orderByConsumed = (pIdx->aOrderBy[1].iColumn==1);
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}
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}
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}else{
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pIdx->estimatedCost = 100000000;
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pIdx->estimatedRows = 1000000000;
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}
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pIdx->idxNum = (iSchema>=0 ? 0x01 : 0x00) | (iPgno>=0 ? 0x02 : 0x00);
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return SQLITE_OK;
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}
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/*
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** Open a new sqlite_dbdata or sqlite_dbptr cursor.
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*/
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static int dbdataOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
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DbdataCursor *pCsr;
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pCsr = (DbdataCursor*)sqlite3_malloc64(sizeof(DbdataCursor));
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if( pCsr==0 ){
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return SQLITE_NOMEM;
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}else{
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memset(pCsr, 0, sizeof(DbdataCursor));
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pCsr->base.pVtab = pVTab;
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}
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*ppCursor = (sqlite3_vtab_cursor *)pCsr;
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return SQLITE_OK;
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}
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/*
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** Restore a cursor object to the state it was in when first allocated
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** by dbdataOpen().
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*/
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static void dbdataResetCursor(DbdataCursor *pCsr){
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DbdataTable *pTab = (DbdataTable*)(pCsr->base.pVtab);
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if( pTab->pStmt==0 ){
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pTab->pStmt = pCsr->pStmt;
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}else{
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sqlite3_finalize(pCsr->pStmt);
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}
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pCsr->pStmt = 0;
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pCsr->iPgno = 1;
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pCsr->iCell = 0;
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pCsr->iField = 0;
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pCsr->bOnePage = 0;
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}
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/*
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** Close an sqlite_dbdata or sqlite_dbptr cursor.
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*/
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static int dbdataClose(sqlite3_vtab_cursor *pCursor){
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DbdataCursor *pCsr = (DbdataCursor*)pCursor;
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dbdataResetCursor(pCsr);
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sqlite3_free(pCsr);
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return SQLITE_OK;
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}
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/*
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** Utility methods to decode 16 and 32-bit big-endian unsigned integers.
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*/
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static unsigned int get_uint16(unsigned char *a){
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return (a[0]<<8)|a[1];
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}
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static unsigned int get_uint32(unsigned char *a){
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return (a[0]<<24)|(a[1]<<16)|(a[2]<<8)|a[3];
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}
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/*
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** Load page pgno from the database via the sqlite_dbpage virtual table.
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** If successful, set (*ppPage) to point to a buffer containing the page
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** data, (*pnPage) to the size of that buffer in bytes and return
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** SQLITE_OK. In this case it is the responsibility of the caller to
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** eventually free the buffer using sqlite3_free().
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**
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** Or, if an error occurs, set both (*ppPage) and (*pnPage) to 0 and
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** return an SQLite error code.
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*/
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static int dbdataLoadPage(
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DbdataCursor *pCsr, /* Cursor object */
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unsigned int pgno, /* Page number of page to load */
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u8 **ppPage, /* OUT: pointer to page buffer */
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int *pnPage /* OUT: Size of (*ppPage) in bytes */
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){
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int rc2;
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int rc = SQLITE_OK;
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sqlite3_stmt *pStmt = pCsr->pStmt;
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*ppPage = 0;
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*pnPage = 0;
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sqlite3_bind_int64(pStmt, 2, pgno);
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if( SQLITE_ROW==sqlite3_step(pStmt) ){
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int nCopy = sqlite3_column_bytes(pStmt, 0);
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if( nCopy>0 ){
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u8 *pPage;
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pPage = (u8*)sqlite3_malloc64(nCopy);
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if( pPage==0 ){
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rc = SQLITE_NOMEM;
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}else{
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const u8 *pCopy = sqlite3_column_blob(pStmt, 0);
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memcpy(pPage, pCopy, nCopy);
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}
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*ppPage = pPage;
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*pnPage = nCopy;
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}
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}
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rc2 = sqlite3_reset(pStmt);
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if( rc==SQLITE_OK ) rc = rc2;
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return rc;
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}
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/*
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** Read a varint. Put the value in *pVal and return the number of bytes.
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*/
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static int dbdataGetVarint(const u8 *z, sqlite3_int64 *pVal){
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sqlite3_int64 v = 0;
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int i;
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for(i=0; i<8; i++){
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v = (v<<7) + (z[i]&0x7f);
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if( (z[i]&0x80)==0 ){ *pVal = v; return i+1; }
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}
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v = (v<<8) + (z[i]&0xff);
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*pVal = v;
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return 9;
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}
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/*
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** Return the number of bytes of space used by an SQLite value of type
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** eType.
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*/
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static int dbdataValueBytes(int eType){
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switch( eType ){
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case 0: case 8: case 9:
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case 10: case 11:
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return 0;
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case 1:
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return 1;
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case 2:
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return 2;
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case 3:
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return 3;
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case 4:
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return 4;
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case 5:
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return 6;
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case 6:
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case 7:
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return 8;
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default:
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if( eType>0 ){
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return ((eType-12) / 2);
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}
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return 0;
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}
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}
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/*
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** Load a value of type eType from buffer pData and use it to set the
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** result of context object pCtx.
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*/
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static void dbdataValue(
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sqlite3_context *pCtx,
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int eType,
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u8 *pData,
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int nData
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){
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if( eType>=0 && dbdataValueBytes(eType)<=nData ){
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switch( eType ){
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case 0:
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case 10:
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case 11:
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sqlite3_result_null(pCtx);
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break;
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case 8:
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sqlite3_result_int(pCtx, 0);
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break;
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case 9:
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sqlite3_result_int(pCtx, 1);
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break;
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case 1: case 2: case 3: case 4: case 5: case 6: case 7: {
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sqlite3_uint64 v = (signed char)pData[0];
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pData++;
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switch( eType ){
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case 7:
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case 6: v = (v<<16) + (pData[0]<<8) + pData[1]; pData += 2;
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case 5: v = (v<<16) + (pData[0]<<8) + pData[1]; pData += 2;
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case 4: v = (v<<8) + pData[0]; pData++;
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case 3: v = (v<<8) + pData[0]; pData++;
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case 2: v = (v<<8) + pData[0]; pData++;
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}
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if( eType==7 ){
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double r;
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memcpy(&r, &v, sizeof(r));
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sqlite3_result_double(pCtx, r);
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}else{
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sqlite3_result_int64(pCtx, (sqlite3_int64)v);
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}
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break;
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}
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default: {
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int n = ((eType-12) / 2);
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if( eType % 2 ){
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sqlite3_result_text(pCtx, (const char*)pData, n, SQLITE_TRANSIENT);
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}else{
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sqlite3_result_blob(pCtx, pData, n, SQLITE_TRANSIENT);
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}
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}
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}
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}
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}
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/*
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** Move an sqlite_dbdata or sqlite_dbptr cursor to the next entry.
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*/
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static int dbdataNext(sqlite3_vtab_cursor *pCursor){
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DbdataCursor *pCsr = (DbdataCursor*)pCursor;
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DbdataTable *pTab = (DbdataTable*)pCursor->pVtab;
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pCsr->iRowid++;
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while( 1 ){
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int rc;
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int iOff = (pCsr->iPgno==1 ? 100 : 0);
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if( pCsr->aPage==0 ){
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while( 1 ){
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if( pCsr->bOnePage==0 && pCsr->iPgno>pCsr->szDb ) return SQLITE_OK;
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rc = dbdataLoadPage(pCsr, pCsr->iPgno, &pCsr->aPage, &pCsr->nPage);
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if( rc!=SQLITE_OK ) return rc;
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if( pCsr->aPage ) break;
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pCsr->iPgno++;
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}
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pCsr->iCell = pTab->bPtr ? -2 : 0;
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pCsr->nCell = get_uint16(&pCsr->aPage[iOff+3]);
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}
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if( pTab->bPtr ){
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if( pCsr->aPage[iOff]!=0x02 && pCsr->aPage[iOff]!=0x05 ){
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pCsr->iCell = pCsr->nCell;
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}
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pCsr->iCell++;
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if( pCsr->iCell>=pCsr->nCell ){
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sqlite3_free(pCsr->aPage);
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pCsr->aPage = 0;
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if( pCsr->bOnePage ) return SQLITE_OK;
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pCsr->iPgno++;
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}else{
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return SQLITE_OK;
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}
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}else{
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/* If there is no record loaded, load it now. */
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if( pCsr->pRec==0 ){
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int bHasRowid = 0;
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int nPointer = 0;
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sqlite3_int64 nPayload = 0;
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sqlite3_int64 nHdr = 0;
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int iHdr;
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int U, X;
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int nLocal;
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switch( pCsr->aPage[iOff] ){
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case 0x02:
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nPointer = 4;
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break;
|
|
case 0x0a:
|
|
break;
|
|
case 0x0d:
|
|
bHasRowid = 1;
|
|
break;
|
|
default:
|
|
/* This is not a b-tree page with records on it. Continue. */
|
|
pCsr->iCell = pCsr->nCell;
|
|
break;
|
|
}
|
|
|
|
if( pCsr->iCell>=pCsr->nCell ){
|
|
sqlite3_free(pCsr->aPage);
|
|
pCsr->aPage = 0;
|
|
if( pCsr->bOnePage ) return SQLITE_OK;
|
|
pCsr->iPgno++;
|
|
continue;
|
|
}
|
|
|
|
iOff += 8 + nPointer + pCsr->iCell*2;
|
|
iOff = get_uint16(&pCsr->aPage[iOff]);
|
|
|
|
/* For an interior node cell, skip past the child-page number */
|
|
iOff += nPointer;
|
|
|
|
/* Load the "byte of payload including overflow" field */
|
|
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &nPayload);
|
|
|
|
/* If this is a leaf intkey cell, load the rowid */
|
|
if( bHasRowid ){
|
|
iOff += dbdataGetVarint(&pCsr->aPage[iOff], &pCsr->iIntkey);
|
|
}
|
|
|
|
/* Allocate space for payload */
|
|
pCsr->pRec = (u8*)sqlite3_malloc64(nPayload);
|
|
if( pCsr->pRec==0 ) return SQLITE_NOMEM;
|
|
pCsr->nRec = nPayload;
|
|
|
|
U = pCsr->nPage;
|
|
if( bHasRowid ){
|
|
X = U-35;
|
|
}else{
|
|
X = ((U-12)*64/255)-23;
|
|
}
|
|
if( nPayload<=X ){
|
|
nLocal = nPayload;
|
|
}else{
|
|
int M, K;
|
|
M = ((U-12)*32/255)-23;
|
|
K = M+((nPayload-M)%(U-4));
|
|
if( K<=X ){
|
|
nLocal = K;
|
|
}else{
|
|
nLocal = M;
|
|
}
|
|
}
|
|
|
|
/* Load the nLocal bytes of payload */
|
|
memcpy(pCsr->pRec, &pCsr->aPage[iOff], nLocal);
|
|
iOff += nLocal;
|
|
|
|
/* Load content from overflow pages */
|
|
if( nPayload>nLocal ){
|
|
sqlite3_int64 nRem = nPayload - nLocal;
|
|
unsigned int pgnoOvfl = get_uint32(&pCsr->aPage[iOff]);
|
|
while( nRem>0 ){
|
|
u8 *aOvfl = 0;
|
|
int nOvfl = 0;
|
|
int nCopy;
|
|
rc = dbdataLoadPage(pCsr, pgnoOvfl, &aOvfl, &nOvfl);
|
|
assert( rc!=SQLITE_OK || nOvfl==pCsr->nPage );
|
|
if( rc!=SQLITE_OK ) return rc;
|
|
|
|
nCopy = U-4;
|
|
if( nCopy>nRem ) nCopy = nRem;
|
|
memcpy(&pCsr->pRec[nPayload-nRem], &aOvfl[4], nCopy);
|
|
nRem -= nCopy;
|
|
|
|
pgnoOvfl = get_uint32(aOvfl);
|
|
sqlite3_free(aOvfl);
|
|
}
|
|
}
|
|
|
|
iHdr = dbdataGetVarint(pCsr->pRec, &nHdr);
|
|
pCsr->nHdr = nHdr;
|
|
pCsr->pHdrPtr = &pCsr->pRec[iHdr];
|
|
pCsr->pPtr = &pCsr->pRec[pCsr->nHdr];
|
|
pCsr->iField = (bHasRowid ? -1 : 0);
|
|
}else{
|
|
pCsr->iField++;
|
|
if( pCsr->iField>0 ){
|
|
sqlite3_int64 iType;
|
|
pCsr->pHdrPtr += dbdataGetVarint(pCsr->pHdrPtr, &iType);
|
|
pCsr->pPtr += dbdataValueBytes(iType);
|
|
}
|
|
}
|
|
|
|
if( pCsr->iField<0 || pCsr->pHdrPtr<&pCsr->pRec[pCsr->nHdr] ){
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/* Advance to the next cell. The next iteration of the loop will load
|
|
** the record and so on. */
|
|
sqlite3_free(pCsr->pRec);
|
|
pCsr->pRec = 0;
|
|
pCsr->iCell++;
|
|
}
|
|
}
|
|
|
|
assert( !"can't get here" );
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Return true if the cursor is at EOF.
|
|
*/
|
|
static int dbdataEof(sqlite3_vtab_cursor *pCursor){
|
|
DbdataCursor *pCsr = (DbdataCursor*)pCursor;
|
|
return pCsr->aPage==0;
|
|
}
|
|
|
|
/*
|
|
** Determine the size in pages of database zSchema (where zSchema is
|
|
** "main", "temp" or the name of an attached database) and set
|
|
** pCsr->szDb accordingly. If successful, return SQLITE_OK. Otherwise,
|
|
** an SQLite error code.
|
|
*/
|
|
static int dbdataDbsize(DbdataCursor *pCsr, const char *zSchema){
|
|
DbdataTable *pTab = (DbdataTable*)pCsr->base.pVtab;
|
|
char *zSql = 0;
|
|
int rc, rc2;
|
|
sqlite3_stmt *pStmt = 0;
|
|
|
|
zSql = sqlite3_mprintf("PRAGMA %Q.page_count", zSchema);
|
|
if( zSql==0 ) return SQLITE_NOMEM;
|
|
rc = sqlite3_prepare_v2(pTab->db, zSql, -1, &pStmt, 0);
|
|
sqlite3_free(zSql);
|
|
if( rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW ){
|
|
pCsr->szDb = sqlite3_column_int(pStmt, 0);
|
|
}
|
|
rc2 = sqlite3_finalize(pStmt);
|
|
if( rc==SQLITE_OK ) rc = rc2;
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** xFilter method for sqlite_dbdata and sqlite_dbptr.
|
|
*/
|
|
static int dbdataFilter(
|
|
sqlite3_vtab_cursor *pCursor,
|
|
int idxNum, const char *idxStr,
|
|
int argc, sqlite3_value **argv
|
|
){
|
|
DbdataCursor *pCsr = (DbdataCursor*)pCursor;
|
|
DbdataTable *pTab = (DbdataTable*)pCursor->pVtab;
|
|
int rc = SQLITE_OK;
|
|
const char *zSchema = "main";
|
|
|
|
dbdataResetCursor(pCsr);
|
|
assert( pCsr->iPgno==1 );
|
|
if( idxNum & 0x01 ){
|
|
zSchema = (const char*)sqlite3_value_text(argv[0]);
|
|
}
|
|
if( idxNum & 0x02 ){
|
|
pCsr->iPgno = sqlite3_value_int(argv[(idxNum & 0x01)]);
|
|
pCsr->bOnePage = 1;
|
|
}else{
|
|
pCsr->nPage = dbdataDbsize(pCsr, zSchema);
|
|
rc = dbdataDbsize(pCsr, zSchema);
|
|
}
|
|
|
|
if( rc==SQLITE_OK ){
|
|
if( pTab->pStmt ){
|
|
pCsr->pStmt = pTab->pStmt;
|
|
pTab->pStmt = 0;
|
|
}else{
|
|
rc = sqlite3_prepare_v2(pTab->db,
|
|
"SELECT data FROM sqlite_dbpage(?) WHERE pgno=?", -1,
|
|
&pCsr->pStmt, 0
|
|
);
|
|
}
|
|
}
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3_bind_text(pCsr->pStmt, 1, zSchema, -1, SQLITE_TRANSIENT);
|
|
}else{
|
|
pTab->base.zErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pTab->db));
|
|
}
|
|
if( rc==SQLITE_OK ){
|
|
rc = dbdataNext(pCursor);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
** Return a column for the sqlite_dbdata or sqlite_dbptr table.
|
|
*/
|
|
static int dbdataColumn(
|
|
sqlite3_vtab_cursor *pCursor,
|
|
sqlite3_context *ctx,
|
|
int i
|
|
){
|
|
DbdataCursor *pCsr = (DbdataCursor*)pCursor;
|
|
DbdataTable *pTab = (DbdataTable*)pCursor->pVtab;
|
|
if( pTab->bPtr ){
|
|
switch( i ){
|
|
case DBPTR_COLUMN_PGNO:
|
|
sqlite3_result_int64(ctx, pCsr->iPgno);
|
|
break;
|
|
case DBPTR_COLUMN_CHILD: {
|
|
int iOff = pCsr->iPgno==1 ? 100 : 0;
|
|
if( pCsr->iCell<0 ){
|
|
iOff += 8;
|
|
}else{
|
|
iOff += 12 + pCsr->iCell*2;
|
|
iOff = get_uint16(&pCsr->aPage[iOff]);
|
|
}
|
|
sqlite3_result_int64(ctx, get_uint32(&pCsr->aPage[iOff]));
|
|
break;
|
|
}
|
|
}
|
|
}else{
|
|
switch( i ){
|
|
case DBDATA_COLUMN_PGNO:
|
|
sqlite3_result_int64(ctx, pCsr->iPgno);
|
|
break;
|
|
case DBDATA_COLUMN_CELL:
|
|
sqlite3_result_int(ctx, pCsr->iCell);
|
|
break;
|
|
case DBDATA_COLUMN_FIELD:
|
|
sqlite3_result_int(ctx, pCsr->iField);
|
|
break;
|
|
case DBDATA_COLUMN_VALUE: {
|
|
if( pCsr->iField<0 ){
|
|
sqlite3_result_int64(ctx, pCsr->iIntkey);
|
|
}else{
|
|
sqlite3_int64 iType;
|
|
dbdataGetVarint(pCsr->pHdrPtr, &iType);
|
|
dbdataValue(
|
|
ctx, iType, pCsr->pPtr, &pCsr->pRec[pCsr->nRec] - pCsr->pPtr
|
|
);
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
/*
|
|
** Return the rowid for an sqlite_dbdata or sqlite_dptr table.
|
|
*/
|
|
static int dbdataRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
|
|
DbdataCursor *pCsr = (DbdataCursor*)pCursor;
|
|
*pRowid = pCsr->iRowid;
|
|
return SQLITE_OK;
|
|
}
|
|
|
|
|
|
/*
|
|
** Invoke this routine to register the "sqlite_dbdata" virtual table module
|
|
*/
|
|
static int sqlite3DbdataRegister(sqlite3 *db){
|
|
static sqlite3_module dbdata_module = {
|
|
0, /* iVersion */
|
|
0, /* xCreate */
|
|
dbdataConnect, /* xConnect */
|
|
dbdataBestIndex, /* xBestIndex */
|
|
dbdataDisconnect, /* xDisconnect */
|
|
0, /* xDestroy */
|
|
dbdataOpen, /* xOpen - open a cursor */
|
|
dbdataClose, /* xClose - close a cursor */
|
|
dbdataFilter, /* xFilter - configure scan constraints */
|
|
dbdataNext, /* xNext - advance a cursor */
|
|
dbdataEof, /* xEof - check for end of scan */
|
|
dbdataColumn, /* xColumn - read data */
|
|
dbdataRowid, /* xRowid - read data */
|
|
0, /* xUpdate */
|
|
0, /* xBegin */
|
|
0, /* xSync */
|
|
0, /* xCommit */
|
|
0, /* xRollback */
|
|
0, /* xFindMethod */
|
|
0, /* xRename */
|
|
0, /* xSavepoint */
|
|
0, /* xRelease */
|
|
0, /* xRollbackTo */
|
|
0 /* xShadowName */
|
|
};
|
|
|
|
int rc = sqlite3_create_module(db, "sqlite_dbdata", &dbdata_module, 0);
|
|
if( rc==SQLITE_OK ){
|
|
rc = sqlite3_create_module(db, "sqlite_dbptr", &dbdata_module, (void*)1);
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
#ifdef _WIN32
|
|
__declspec(dllexport)
|
|
#endif
|
|
int sqlite3_dbdata_init(
|
|
sqlite3 *db,
|
|
char **pzErrMsg,
|
|
const sqlite3_api_routines *pApi
|
|
){
|
|
SQLITE_EXTENSION_INIT2(pApi);
|
|
return sqlite3DbdataRegister(db);
|
|
}
|