Function doAutoDetectRestore

ThirdParty/sqlite/vtksqlite/shell.c:31978–32043

** This function is called after processing each line of SQL in the ** runOneSqlLine() function. Its purpose is to detect scenarios where ** defensive mode should be automatically turned off. Specifically, when ** ** 1. The first line of input is "PRAGMA foreign_keys=OFF;", ** 2. The second line of input is "BEGIN TRANSACTION;", ** 3. The database is empty, and ** 4. The shell is not runni

**    7: Nothing left to do. This function becomes a no-op.
*/
static int doAutoDetectRestore(ShellState *p, const char *zSql){
  int rc = SQLITE_OK;

  if( p->eRestoreState<7 ){
    switch( p->eRestoreState ){
      case 0: {
        const char *zExpect = "PRAGMA foreign_keys=OFF;";
        assert( strlen(zExpect)==24 );
        if( p->bSafeMode==0
         && strlen(zSql)>=24
         && memcmp(zSql, zExpect, 25)==0
        ){
          p->eRestoreState = 1;
        }else{
          p->eRestoreState = 7;
        }
        break;
      };
  
      case 1: {
        int bIsDump = 0;
        const char *zExpect = "BEGIN TRANSACTION;";
        assert( strlen(zExpect)==18 );
        if( memcmp(zSql, zExpect, 19)==0 ){
          /* Now check if the database is empty. */
          const char *zQuery = "SELECT 1 FROM sqlite_schema LIMIT 1";
          sqlite3_stmt *pStmt = 0;
  
          bIsDump = 1;
          shellPrepare(p->db, &rc, zQuery, &pStmt);
          if( rc==SQLITE_OK && sqlite3_step(pStmt)==SQLITE_ROW ){
            bIsDump = 0;
          }
          shellFinalize(&rc, pStmt);
        }
        if( bIsDump && rc==SQLITE_OK ){
          int bDefense = 0;
          int bDqsDdl = 0;
          sqlite3_db_config(p->db, SQLITE_DBCONFIG_DEFENSIVE, -1, &bDefense);
          sqlite3_db_config(p->db, SQLITE_DBCONFIG_DQS_DDL, -1, &bDqsDdl);
          sqlite3_db_config(p->db, SQLITE_DBCONFIG_DEFENSIVE, 0, 0);
          sqlite3_db_config(p->db, SQLITE_DBCONFIG_DQS_DDL, 1, 0);
          p->eRestoreState = (bDefense ? 2 : 0) + (bDqsDdl ? 4 : 0);
        }else{
          p->eRestoreState = 7;
        }
        break;
      }
  
      default: {
        if( sqlite3_get_autocommit(p->db) ){
          if( (p->eRestoreState & 2) ){
            sqlite3_db_config(p->db, SQLITE_DBCONFIG_DEFENSIVE, 1, 0);
          }
          if( (p->eRestoreState & 4) ){
            sqlite3_db_config(p->db, SQLITE_DBCONFIG_DQS_DDL, 0, 0);
          }
          p->eRestoreState = 7;