SQLite

#ifndef LARGEST_INT64
# define LARGEST_INT64  (0xffffffff|(((sqlite3_int64)0x7fffffff)<<32))
#endif
#ifndef SMALLEST_INT64
# define SMALLEST_INT64 (((sqlite3_int64)-1) - LARGEST_INT64)
#endif

/*
** The following is also copied from sqliteInt.h. To facilitate coverage
** testing.
*/
#ifndef ALWAYS
# if defined(SQLITE_COVERAGE_TEST) || defined(SQLITE_MUTATION_TEST)
#  define ALWAYS(X)      (1)
#  define NEVER(X)       (0)
# elif !defined(NDEBUG)
#  define ALWAYS(X)      ((X)?1:(assert(0),0))
#  define NEVER(X)       ((X)?(assert(0),1):0)
# else
#  define ALWAYS(X)      (X)
#  define NEVER(X)       (X)
# endif
#endif

/*
** The swarmvtab module attempts to keep the number of open database files
** at or below this limit. This may not be possible if there are too many
** simultaneous queries.
*/
#define SWARMVTAB_MAX_OPEN 9

    char q = z[0];

    /* Set stack variable q to the close-quote character */
    if( q=='[' || q=='\'' || q=='"' || q=='`' ){
      int iIn = 1;
      int iOut = 0;
      if( q=='[' ) q = ']';  
      while( ALWAYS(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

static sqlite3_stmt *unionPrepare(
  int *pRc,                       /* IN/OUT: Error code */
  sqlite3 *db,                    /* Database handle */
  const char *zSql,               /* SQL statement to prepare */
  char **pzErr                    /* OUT: Error message */
){
  sqlite3_stmt *pRet = 0;
  assert( pzErr );
  if( *pRc==SQLITE_OK ){
    int rc = sqlite3_prepare_v2(db, zSql, -1, &pRet, 0);
    if( rc!=SQLITE_OK ){
      *pzErr = sqlite3_mprintf("sql error: %s", sqlite3_errmsg(db));
      *pRc = rc;
    }
  }
  return pRet;
}

/*
** Call sqlite3_reset() on SQL statement pStmt. If *pRc is set to 
** SQLITE_OK when this function is called, then it is set to the
** value returned by sqlite3_reset() before this function exits.
** In this case, *pzErr may be set to point to an error message
** buffer allocated by sqlite3_malloc().
*/
#if 0
static void unionReset(int *pRc, sqlite3_stmt *pStmt, char **pzErr){
  int rc = sqlite3_reset(pStmt);
  if( *pRc==SQLITE_OK ){
    *pRc = rc;
    if( rc ){
      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(sqlite3_db_handle(pStmt)));
    }
  }
}
#endif

/*
** Call sqlite3_finalize() on SQL statement pStmt. If *pRc is set to 
** SQLITE_OK when this function is called, then it is set to the
** value returned by sqlite3_finalize() before this function exits.
*/
static void unionFinalize(int *pRc, sqlite3_stmt *pStmt, char **pzErr){

}

/*
** This function is a no-op for unionvtab. For swarmvtab, it attempts to
** close open database files until at most nMax are open. An SQLite error
** code is returned if an error occurs, or SQLITE_OK otherwise.
*/
static void unionCloseSources(UnionTab *pTab, int nMax){


  while( pTab->pClosable && pTab->nOpen>nMax ){
    UnionSrc **pp;
    for(pp=&pTab->pClosable; (*pp)->pNextClosable; pp=&(*pp)->pNextClosable);
    assert( (*pp)->db );
    sqlite3_close((*pp)->db);
    (*pp)->db = 0;
    *pp = 0;
    pTab->nOpen--;
  }


}

/*
** xDisconnect method.
*/
static int unionDisconnect(sqlite3_vtab *pVtab){
  if( pVtab ){

  UnionSrc *pSrc,                 /* Source table to test */
  char **pzErr                    /* OUT: Error message */
){
  char *zRet = 0;
  if( *pRc==SQLITE_OK ){
    sqlite3 *db = unionGetDb(pTab, pSrc);
    int rc = unionIsIntkeyTable(db, pSrc, pzErr);

    sqlite3_stmt *pStmt = unionPrepare(&rc, db, 
        "SELECT group_concat(quote(name) || '.' || quote(type)) "
        "FROM pragma_table_info(?, ?)", pzErr
    );
    if( rc==SQLITE_OK ){
      sqlite3_bind_text(pStmt, 1, pSrc->zTab, -1, SQLITE_STATIC);
      sqlite3_bind_text(pStmt, 2, pSrc->zDb, -1, SQLITE_STATIC);
      if( SQLITE_ROW==sqlite3_step(pStmt) ){
        const char *z = (const char*)sqlite3_column_text(pStmt, 0);
        zRet = unionStrdup(&rc, z);
      }
      unionFinalize(&rc, pStmt, pzErr);

*/
static int unionOpenDatabase(UnionTab *pTab, int iSrc, char **pzErr){
  int rc = SQLITE_OK;
  UnionSrc *pSrc = &pTab->aSrc[iSrc];

  assert( pTab->bSwarm && iSrc<pTab->nSrc );
  if( pSrc->db==0 ){
    unionCloseSources(pTab, pTab->nMaxOpen-1);


    rc = sqlite3_open_v2(pSrc->zFile, &pSrc->db, SQLITE_OPEN_READONLY, 0);
    if( rc!=SQLITE_OK ){
      *pzErr = sqlite3_mprintf("%s", sqlite3_errmsg(pSrc->db));
    }else{
      char *z = unionSourceToStr(&rc, pTab, pSrc, pzErr);
      if( rc==SQLITE_OK ){
        if( pTab->zSourceStr==0 ){
          pTab->zSourceStr = z;
        }else{
          if( sqlite3_stricmp(z, pTab->zSourceStr) ){
            *pzErr = sqlite3_mprintf("source table schema mismatch");
            rc = SQLITE_ERROR;
          }
          sqlite3_free(z);
        }
      }
    }

    if( rc==SQLITE_OK ){
      pSrc->pNextClosable = pTab->pClosable;
      pTab->pClosable = pSrc;
      pTab->nOpen++;
    }else{
      sqlite3_close(pSrc->db);
      pSrc->db = 0;

    }
  }

  return rc;
}

    if( pTab->bSwarm ){
      pSrc->nUser--;
      assert( pSrc->nUser>=0 );
      if( pSrc->nUser==0 ){
        pSrc->pNextClosable = pTab->pClosable;
        pTab->pClosable = pSrc;
      }
      unionCloseSources(pTab, pTab->nMaxOpen);
    }
  }
  return rc;
}

/* 
** xConnect/xCreate method.

    rc = unionFinalizeCsrStmt(pCsr);
    if( rc==SQLITE_OK && pTab->bSwarm ){
      pCsr->iTab++;
      if( pCsr->iTab<pTab->nSrc ){
        UnionSrc *pSrc = &pTab->aSrc[pCsr->iTab];
        if( pCsr->iMaxRowid>=pSrc->iMin ){
          /* It is necessary to scan the next table. */

          rc = unionOpenDatabase(pTab, pCsr->iTab, &pTab->base.zErrMsg);

          pCsr->pStmt = unionPreparePrintf(&rc, &pTab->base.zErrMsg, pSrc->db,
              "SELECT rowid, * FROM %Q %s %lld",
              pSrc->zTab,
              (pSrc->iMax>pCsr->iMaxRowid ? "WHERE _rowid_ <=" : "-- "),
              pCsr->iMaxRowid
          );
          if( rc==SQLITE_OK ){
            assert( pCsr->pStmt );

}
do_faultsim_test 1.2 -faults oom* -prep {
} -body {
  execsql { SELECT * FROM uuu }
} -test {
  faultsim_test_result {0 {1 one 2 two 3 three 10 ten 11 eleven 12 twelve 20 twenty 21 twenty-one 22 twenty-two}} 
}

#-------------------------------------------------------------------------
# Error while registering the two vtab modules.
do_faultsim_test 2.0 -faults * -prep {
  catch { db close }
  sqlite3 db :memory:
} -body {
  load_static_extension db unionvtab
} -test {
  faultsim_test_result {0 {}} {1 {initialization of unionvtab failed: }}
}



finish_test