SQLite

static void setOneColumnName(Vdbe *v, const char *z){
  setAllColumnNames(v, 1, &z);
}

/*
** Generate code to return a single integer value.
*/
static void returnSingleInt(Parse *pParse, const char *zLabel, i64 value){
  Vdbe *v = sqlite3GetVdbe(pParse);
  int nMem = ++pParse->nMem;
  i64 *pI64 = sqlite3DbMallocRaw(pParse->db, sizeof(value));
  if( pI64 ){
    memcpy(pI64, &value, sizeof(value));
  }










  sqlite3VdbeAddOp4(v, OP_Int64, 0, nMem, 0, (char*)pI64, P4_INT64);
  setOneColumnName(v, zLabel);
  sqlite3VdbeAddOp2(v, OP_ResultRow, nMem, 1);

}


/*
** Set the safety_level and pager flags for pager iDb.  Or if iDb<0
** set these values for all pagers.
*/

  aFcntl[0] = 0;
  aFcntl[1] = zLeft;
  aFcntl[2] = zRight;
  aFcntl[3] = 0;
  db->busyHandler.nBusy = 0;
  rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_PRAGMA, (void*)aFcntl);
  if( rc==SQLITE_OK ){
    if( aFcntl[0] ){
      int nMem = ++pParse->nMem;
      sqlite3VdbeAddOp4(v, OP_String8, 0, nMem, 0, aFcntl[0], 0);
      setOneColumnName(v, "result");
      sqlite3VdbeAddOp2(v, OP_ResultRow, nMem, 1);
      sqlite3_free(aFcntl[0]);
    }
    goto pragma_out;
  }
  if( rc!=SQLITE_NOTFOUND ){
    if( aFcntl[0] ){
      sqlite3ErrorMsg(pParse, "%s", aFcntl[0]);
      sqlite3_free(aFcntl[0]);
    }

  ** the database has not yet been created.
  */
  case PragTyp_PAGE_SIZE: {
    Btree *pBt = pDb->pBt;
    assert( pBt!=0 );
    if( !zRight ){
      int size = ALWAYS(pBt) ? sqlite3BtreeGetPageSize(pBt) : 0;
      returnSingleInt(pParse, "page_size", size);
    }else{
      /* Malloc may fail when setting the page-size, as there is an internal
      ** buffer that the pager module resizes using sqlite3_realloc().
      */
      db->nextPagesize = sqlite3Atoi(zRight);
      if( SQLITE_NOMEM==sqlite3BtreeSetPageSize(pBt, db->nextPagesize,-1,0) ){
        db->mallocFailed = 1;

    if( pId2->n==0 && b>=0 ){
      int ii;
      for(ii=0; ii<db->nDb; ii++){
        sqlite3BtreeSecureDelete(db->aDb[ii].pBt, b);
      }
    }
    b = sqlite3BtreeSecureDelete(pBt, b);
    returnSingleInt(pParse, "secure_delete", b);
    break;
  }

  /*
  **  PRAGMA [database.]max_page_count
  **  PRAGMA [database.]max_page_count=N
  **

    }

    assert( eMode==PAGER_LOCKINGMODE_NORMAL
            || eMode==PAGER_LOCKINGMODE_EXCLUSIVE );
    if( eMode==PAGER_LOCKINGMODE_EXCLUSIVE ){
      zRet = "exclusive";
    }
    setOneColumnName(v, "locking_mode");
    sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, zRet, 0);
    sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
    break;
  }

  /*
  **  PRAGMA [database.]journal_mode
  **  PRAGMA [database.]journal_mode =
  **                      (delete|persist|off|truncate|memory|wal|off)

    Pager *pPager = sqlite3BtreePager(pDb->pBt);
    i64 iLimit = -2;
    if( zRight ){
      sqlite3DecOrHexToI64(zRight, &iLimit);
      if( iLimit<-1 ) iLimit = -1;
    }
    iLimit = sqlite3PagerJournalSizeLimit(pPager, iLimit);
    returnSingleInt(pParse, "journal_size_limit", iLimit);
    break;
  }

#endif /* SQLITE_OMIT_PAGER_PRAGMAS */

  /*
  **  PRAGMA [database.]auto_vacuum
  **  PRAGMA [database.]auto_vacuum=N
  **
  ** Get or set the value of the database 'auto-vacuum' parameter.
  ** The value is one of:  0 NONE 1 FULL 2 INCREMENTAL
  */
#ifndef SQLITE_OMIT_AUTOVACUUM
  case PragTyp_AUTO_VACUUM: {
    Btree *pBt = pDb->pBt;
    assert( pBt!=0 );
    if( !zRight ){
      returnSingleInt(pParse, "auto_vacuum", sqlite3BtreeGetAutoVacuum(pBt));
    }else{
      int eAuto = getAutoVacuum(zRight);
      assert( eAuto>=0 && eAuto<=2 );
      db->nextAutovac = (u8)eAuto;
      /* Call SetAutoVacuum() to set initialize the internal auto and
      ** incr-vacuum flags. This is required in case this connection
      ** creates the database file. It is important that it is created

  ** number of pages is adjusted so that the cache uses -N kibibytes
  ** of memory.
  */
  case PragTyp_CACHE_SIZE: {
    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
    if( !zRight ){
      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
      returnSingleInt(pParse, "cache_size", pDb->pSchema->cache_size);
    }else{
      int size = sqlite3Atoi(zRight);
      pDb->pSchema->cache_size = size;
      sqlite3BtreeSetCacheSize(pDb->pBt, pDb->pSchema->cache_size);
      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
    }
    break;

    sz = -1;
    rc = sqlite3_file_control(db, zDb, SQLITE_FCNTL_MMAP_SIZE, &sz);
#else
    sz = 0;
    rc = SQLITE_OK;
#endif
    if( rc==SQLITE_OK ){
      returnSingleInt(pParse, "mmap_size", sz);
    }else if( rc!=SQLITE_NOTFOUND ){
      pParse->nErr++;
      pParse->rc = rc;
    }
    break;
  }

  /*
  **   PRAGMA temp_store
  **   PRAGMA temp_store = "default"|"memory"|"file"
  **
  ** Return or set the local value of the temp_store flag.  Changing
  ** the local value does not make changes to the disk file and the default
  ** value will be restored the next time the database is opened.
  **
  ** Note that it is possible for the library compile-time options to
  ** override this setting
  */
  case PragTyp_TEMP_STORE: {
    if( !zRight ){
      returnSingleInt(pParse, "temp_store", db->temp_store);
    }else{
      changeTempStorage(pParse, zRight);
    }
    break;
  }

  /*
  **   PRAGMA temp_store_directory
  **   PRAGMA temp_store_directory = ""|"directory_name"
  **
  ** Return or set the local value of the temp_store_directory flag.  Changing
  ** the value sets a specific directory to be used for temporary files.
  ** Setting to a null string reverts to the default temporary directory search.
  ** If temporary directory is changed, then invalidateTempStorage.
  **
  */
  case PragTyp_TEMP_STORE_DIRECTORY: {
    if( !zRight ){
      if( sqlite3_temp_directory ){
        setOneColumnName(v, "temp_store_diretory");
        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, sqlite3_temp_directory, 0);
        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
      }
    }else{
#ifndef SQLITE_OMIT_WSD
      if( zRight[0] ){
        int res;
        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
        if( rc!=SQLITE_OK || res==0 ){
          sqlite3ErrorMsg(pParse, "not a writable directory");

  ** a relative path will probably be based on the current directory for the
  ** process.  Database file specified with an absolute path are not impacted
  ** by this setting, regardless of its value.
  **
  */
  case PragTyp_DATA_STORE_DIRECTORY: {
    if( !zRight ){
      if( sqlite3_data_directory ){
        setOneColumnName(v, "data_store_directory");
        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, sqlite3_data_directory, 0);
        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
      }
    }else{
#ifndef SQLITE_OMIT_WSD
      if( zRight[0] ){
        int res;
        rc = sqlite3OsAccess(db->pVfs, zRight, SQLITE_ACCESS_READWRITE, &res);
        if( rc!=SQLITE_OK || res==0 ){
          sqlite3ErrorMsg(pParse, "not a writable directory");

  case PragTyp_LOCK_PROXY_FILE: {
    if( !zRight ){
      Pager *pPager = sqlite3BtreePager(pDb->pBt);
      char *proxy_file_path = NULL;
      sqlite3_file *pFile = sqlite3PagerFile(pPager);
      sqlite3OsFileControlHint(pFile, SQLITE_GET_LOCKPROXYFILE, 
                           &proxy_file_path);
      
      if( proxy_file_path ){
        setOneColumnName(v, "lock_proxy_file");
        sqlite3VdbeAddOp4(v, OP_String8, 0, 1, 0, proxy_file_path, 0);
        sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
      }
    }else{
      Pager *pPager = sqlite3BtreePager(pDb->pBt);
      sqlite3_file *pFile = sqlite3PagerFile(pPager);
      int res;
      if( zRight[0] ){
        res=sqlite3OsFileControl(pFile, SQLITE_SET_LOCKPROXYFILE, 
                                     zRight);

  ** Return or set the local value of the synchronous flag.  Changing
  ** the local value does not make changes to the disk file and the
  ** default value will be restored the next time the database is
  ** opened.
  */
  case PragTyp_SYNCHRONOUS: {
    if( !zRight ){
      returnSingleInt(pParse, "synchronous", pDb->safety_level-1);
    }else{
      if( !db->autoCommit ){
        sqlite3ErrorMsg(pParse, 
            "Safety level may not be changed inside a transaction");
      }else{
        int iLevel = (getSafetyLevel(zRight,0,1)+1) & PAGER_SYNCHRONOUS_MASK;
        if( iLevel==0 ) iLevel = 1;
        pDb->safety_level = iLevel;
        setAllPagerFlags(db);
      }
    }
    break;
  }
#endif /* SQLITE_OMIT_PAGER_PRAGMAS */

#ifndef SQLITE_OMIT_FLAG_PRAGMAS
  case PragTyp_FLAG: {
    if( zRight==0 ){
      returnSingleInt(pParse, pPragma->zName, (db->flags & pPragma->iArg)!=0 );
    }else{
      int mask = pPragma->iArg;    /* Mask of bits to set or clear. */
      if( db->autoCommit==0 ){
        /* Foreign key support may not be enabled or disabled while not
        ** in auto-commit mode.  */
        mask &= ~(SQLITE_ForeignKeys);
      }

      { "UTF-16",   0                  }, /* SQLITE_UTF16NATIVE */
      { "UTF16",    0                  }, /* SQLITE_UTF16NATIVE */
      { 0, 0 }
    };
    const struct EncName *pEnc;
    if( !zRight ){    /* "PRAGMA encoding" */
      if( sqlite3ReadSchema(pParse) ) goto pragma_out;
      setOneColumnName(v, "encoding");
      sqlite3VdbeAddOp2(v, OP_String8, 0, 1);
      assert( encnames[SQLITE_UTF8].enc==SQLITE_UTF8 );
      assert( encnames[SQLITE_UTF16LE].enc==SQLITE_UTF16LE );
      assert( encnames[SQLITE_UTF16BE].enc==SQLITE_UTF16BE );
      sqlite3VdbeChangeP4(v, -1, encnames[ENC(pParse->db)].zName, P4_STATIC);
      sqlite3VdbeAddOp2(v, OP_ResultRow, 1, 1);
    }else{                        /* "PRAGMA encoding = XXX" */
      /* Only change the value of sqlite.enc if the database handle is not
      ** initialized. If the main database exists, the new sqlite.enc value
      ** will be overwritten when the schema is next loaded. If it does not
      ** already exists, it will be created to use the new encoding value.
      */
      if( 

  ** after accumulating N frames in the log. Or query for the current value
  ** of N.
  */
  case PragTyp_WAL_AUTOCHECKPOINT: {
    if( zRight ){
      sqlite3_wal_autocheckpoint(db, sqlite3Atoi(zRight));
    }
    returnSingleInt(pParse, "wal_autocheckpoint", 
       db->xWalCallback==sqlite3WalDefaultHook ? 
           SQLITE_PTR_TO_INT(db->pWalArg) : 0);
  }
  break;
#endif

  /*

  ** disables the timeout.
  */
  /*case PragTyp_BUSY_TIMEOUT*/ default: {
    assert( pPragma->ePragTyp==PragTyp_BUSY_TIMEOUT );
    if( zRight ){
      sqlite3_busy_timeout(db, sqlite3Atoi(zRight));
    }
    returnSingleInt(pParse, "timeout",  db->busyTimeout);
    break;
  }

  /*
  **   PRAGMA soft_heap_limit
  **   PRAGMA soft_heap_limit = N
  **
  ** IMPLEMENTATION-OF: R-26343-45930 This pragma invokes the
  ** sqlite3_soft_heap_limit64() interface with the argument N, if N is
  ** specified and is a non-negative integer.
  ** IMPLEMENTATION-OF: R-64451-07163 The soft_heap_limit pragma always
  ** returns the same integer that would be returned by the
  ** sqlite3_soft_heap_limit64(-1) C-language function.
  */
  case PragTyp_SOFT_HEAP_LIMIT: {
    sqlite3_int64 N;
    if( zRight && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK ){
      sqlite3_soft_heap_limit64(N);
    }
    returnSingleInt(pParse, "soft_heap_limit",  sqlite3_soft_heap_limit64(-1));
    break;
  }

  /*
  **   PRAGMA threads
  **   PRAGMA threads = N
  **
  ** Configure the maximum number of worker threads.  Return the new
  ** maximum, which might be less than requested.
  */
  case PragTyp_THREADS: {
    sqlite3_int64 N;
    if( zRight
     && sqlite3DecOrHexToI64(zRight, &N)==SQLITE_OK
     && N>=0
    ){
      sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, (int)(N&0x7fffffff));
    }
    returnSingleInt(pParse, "threads",
                    sqlite3_limit(db, SQLITE_LIMIT_WORKER_THREADS, -1));
    break;
  }

#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
  /*
  ** Report the current state of file logs for all databases

){
  int addr = sqlite3VdbeAddOp3(p, op, p1, p2, p3);
  sqlite3VdbeChangeP4(p, addr, zP4, p4type);
  return addr;
}

/*
** Add an opcode that includes the p4 value with a P4_INT64 type.

*/
int sqlite3VdbeAddOp4Dup8(
  Vdbe *p,            /* Add the opcode to this VM */
  int op,             /* The new opcode */
  int p1,             /* The P1 operand */
  int p2,             /* The P2 operand */
  int p3,             /* The P3 operand */