Function shell_exec

ThirdParty/sqlite/vtksqlite/shell.c:24363–24508

** Execute a statement or set of statements. Print ** any result rows/columns depending on the current mode ** set via the supplied callback. ** ** This is very similar to SQLite's built-in sqlite3_exec() ** function except it takes a slightly different callback ** and callback data argument. */

** and callback data argument.
*/
static int shell_exec(
  ShellState *pArg,                         /* Pointer to ShellState */
  const char *zSql,                         /* SQL to be evaluated */
  char **pzErrMsg                           /* Error msg written here */
){
  sqlite3_stmt *pStmt = NULL;     /* Statement to execute. */
  int rc = SQLITE_OK;             /* Return Code */
  int rc2;
  const char *zLeftover;          /* Tail of unprocessed SQL */
  sqlite3 *db = pArg->db;

  if( pzErrMsg ){
    *pzErrMsg = NULL;
  }

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( pArg->expert.pExpert ){
    rc = expertHandleSQL(pArg, zSql, pzErrMsg);
    return expertFinish(pArg, (rc!=SQLITE_OK), pzErrMsg);
  }
#endif

  while( zSql[0] && (SQLITE_OK == rc) ){
    static const char *zStmtSql;
    rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zLeftover);
    if( SQLITE_OK != rc ){
      if( pzErrMsg ){
        *pzErrMsg = save_err_msg(db, "in prepare", rc, zSql);
      }
    }else{
      if( !pStmt ){
        /* this happens for a comment or white-space */
        zSql = zLeftover;
        while( IsSpace(zSql[0]) ) zSql++;
        continue;
      }
      zStmtSql = sqlite3_sql(pStmt);
      if( zStmtSql==0 ) zStmtSql = "";
      while( IsSpace(zStmtSql[0]) ) zStmtSql++;

      /* save off the prepared statement handle and reset row count */
      if( pArg ){
        pArg->pStmt = pStmt;
        pArg->cnt = 0;
      }

      /* Show the EXPLAIN QUERY PLAN if .eqp is on */
      if( pArg && pArg->autoEQP && sqlite3_stmt_isexplain(pStmt)==0 ){
        sqlite3_stmt *pExplain;
        int triggerEQP = 0;
        disable_debug_trace_modes();
        sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, -1, &triggerEQP);
        if( pArg->autoEQP>=AUTOEQP_trigger ){
          sqlite3_db_config(db, SQLITE_DBCONFIG_TRIGGER_EQP, 1, 0);
        }
        pExplain = pStmt;
        sqlite3_reset(pExplain);
        rc = sqlite3_stmt_explain(pExplain, 2);