SQLite

  "    --stmt                  Trace statement execution (SQLITE_TRACE_STMT)",
  "    --profile               Profile statements (SQLITE_TRACE_PROFILE)",
  "    --row                   Trace each row (SQLITE_TRACE_ROW)",
  "    --close                 Trace connection close (SQLITE_TRACE_CLOSE)",
#endif /* SQLITE_OMIT_TRACE */
#ifdef SQLITE_DEBUG
  ".unmodule NAME ...       Unregister virtual table modules",
  "    --allexcept             Unregister everything except those named",
#endif
  ".vfsinfo ?AUX?           Information about the top-level VFS",
  ".vfslist                 List all available VFSes",
  ".vfsname ?AUX?           Print the name of the VFS stack",
  ".width NUM1 NUM2 ...     Set column widths for \"column\" mode",
  "     Negative values right-justify",
};

** Return 1 on error, 2 to exit, and 0 otherwise.
*/
static int do_meta_command(char *zLine, ShellState *p){
  int h = 1;
  int nArg = 0;
  int n, c;
  int rc = 0;
  char *azArg[52];

#ifndef SQLITE_OMIT_VIRTUALTABLE
  if( p->expert.pExpert ){
    expertFinish(p, 1, 0);
  }
#endif

  /* Parse the input line into tokens.
  */
  while( zLine[h] && nArg<ArraySize(azArg)-1 ){
    while( IsSpace(zLine[h]) ){ h++; }
    if( zLine[h]==0 ) break;
    if( zLine[h]=='\'' || zLine[h]=='"' ){
      int delim = zLine[h++];
      azArg[nArg++] = &zLine[h];
      while( zLine[h] && zLine[h]!=delim ){
        if( zLine[h]=='\\' && delim=='"' && zLine[h+1]!=0 ) h++;
        h++;
      }
      if( zLine[h]==delim ){
        zLine[h++] = 0;
      }
      if( delim=='"' ) resolve_backslashes(azArg[nArg-1]);
    }else{
      azArg[nArg++] = &zLine[h];
      while( zLine[h] && !IsSpace(zLine[h]) ){ h++; }
      if( zLine[h] ) zLine[h++] = 0;
      resolve_backslashes(azArg[nArg-1]);
    }
  }
  azArg[nArg] = 0;

  /* Process the input line.
  */
  if( nArg==0 ) return 0; /* no tokens, no error */
  n = strlen30(azArg[0]);
  c = azArg[0][0];
  clearTempFile(p);

    }
  }else
#endif /* !defined(SQLITE_OMIT_TRACE) */

#ifdef SQLITE_DEBUG
  if( c=='u' && strncmp(azArg[0], "unmodule", n)==0 ){
    int ii;
    int lenOpt;
    char *zOpt;
    if( nArg<2 ){
      raw_printf(stderr, "Usage: .unmodule [--allexcept] NAME ...\n");
      rc = 1;
      goto meta_command_exit;
    }
    open_db(p, 0);
    zOpt = azArg[1];
    if( zOpt[0]=='-' && zOpt[1]=='-' && zOpt[2]!=0 ) zOpt++;
    lenOpt = (int)strlen(zOpt);
    if( lenOpt>=3 && strncmp(zOpt, "-allexcept",lenOpt)==0 ){
      assert( azArg[nArg]==0 );
      sqlite3_drop_modules(p->db, nArg>2 ? (const char**)(azArg+2) : 0);
    }else{
      for(ii=1; ii<nArg; ii++){
        sqlite3_create_module(p->db, azArg[ii], 0, 0);
      }
    }
  }else
#endif

#if SQLITE_USER_AUTHENTICATION
  if( c=='u' && strncmp(azArg[0], "user", n)==0 ){
    if( nArg<2 ){

** ^The sqlite3_create_module()
** interface is equivalent to sqlite3_create_module_v2() with a NULL
** destructor.
**
** ^If the third parameter (the pointer to the sqlite3_module object) is
** NULL then no new module is create and any existing modules with the
** same name are dropped.
**
** See also: [sqlite3_drop_modules()]
*/
int sqlite3_create_module(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *p,   /* Methods for the module */
  void *pClientData          /* Client data for xCreate/xConnect */
);
int sqlite3_create_module_v2(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *p,   /* Methods for the module */
  void *pClientData,         /* Client data for xCreate/xConnect */
  void(*xDestroy)(void*)     /* Module destructor function */
);

/*
** CAPI3REF: Remove Unnecessary Virtual Table Implementations
** METHOD: sqlite3
**
** ^The sqlite3_drop_modules(D,L) interface removes all virtual
** table modules from database connection D except those named on list L.
** The L parameter must be either NULL or a pointer to an array of pointers
** to strings where the array is terminated by a single NULL pointer.
** ^If the L parameter is NULL, then all virtual table modules are removed.
**
** See also: [sqlite3_create_module()]
*/
int sqlite3_drop_modules(
  sqlite3 *db,                /* Remove modules from this connection */
  const char **azKeep         /* Except, do not remove the ones named here */
);

/*
** CAPI3REF: Virtual Table Instance Object
** KEYWORDS: sqlite3_vtab
**
** Every [virtual table module] implementation uses a subclass
** of this object to describe a particular instance

  }
#endif

  if( sqlite3TestErrCode(interp, db, rc) ) return TCL_ERROR;
  Tcl_SetResult(interp, (char *)t1ErrorName(rc), 0);
  return TCL_OK;
}

/*
** Usage:  sqlite3_drop_modules DB ?NAME ...?
**
** Invoke the sqlite3_drop_modules(D,L) interface on database
** connection DB, in order to drop all modules except those named in
** the argument.
*/
static int SQLITE_TCLAPI test_drop_modules(
  void *NotUsed,
  Tcl_Interp *interp,    /* The TCL interpreter that invoked this command */
  int argc,              /* Number of arguments */
  char **argv            /* Text of each argument */
){
  int rc;
  sqlite3 *db;

  if( argc!=2 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"", argv[0],
       " DB\"", 0);
    return TCL_ERROR;
  }
  if( getDbPointer(interp, argv[1], &db) ) return TCL_ERROR;
  sqlite3_drop_modules(db, argc>2 ? (const char**)(argv+2) : 0);
  return TCL_OK;
}

/*
** Routines to implement the x_count() aggregate function.
**
** x_count() counts the number of non-null arguments.  But there are
** some twists for testing purposes.
**

#ifndef SQLITE_OMIT_GET_TABLE
     { "sqlite3_get_table_printf",      (Tcl_CmdProc*)test_get_table_printf },
#endif
     { "sqlite3_close",                 (Tcl_CmdProc*)sqlite_test_close     },
     { "sqlite3_close_v2",              (Tcl_CmdProc*)sqlite_test_close_v2  },
     { "sqlite3_create_function",       (Tcl_CmdProc*)test_create_function  },
     { "sqlite3_create_aggregate",      (Tcl_CmdProc*)test_create_aggregate },
     { "sqlite3_drop_modules",          (Tcl_CmdProc*)test_drop_modules     },
     { "sqlite_register_test_function", (Tcl_CmdProc*)test_register_func    },
     { "sqlite_abort",                  (Tcl_CmdProc*)sqlite_abort          },
     { "sqlite_bind",                   (Tcl_CmdProc*)test_bind             },
     { "breakpoint",                    (Tcl_CmdProc*)test_breakpoint       },
     { "sqlite3_key",                   (Tcl_CmdProc*)test_key              },
     { "sqlite3_rekey",                 (Tcl_CmdProc*)test_rekey            },
     { "sqlite_set_magic",              (Tcl_CmdProc*)sqlite_set_magic      },

  void (*xDestroy)(void *)        /* Module destructor function */
){
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
  return createModule(db, zName, pModule, pAux, xDestroy);
}

/*
** External API to drop all virtual-table modules, except those named
** on the azNames list.
*/
int sqlite3_drop_modules(sqlite3 *db, const char** azNames){
  HashElem *pThis, *pNext;
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zName==0 ) return SQLITE_MISUSE_BKPT;
#endif
  for(pThis=sqliteHashFirst(&db->aModule); pThis; pThis=pNext){
    Module *pMod = (Module*)sqliteHashData(pThis);
    pNext = sqliteHashNext(pThis);
    if( azNames ){
      int ii;
      for(ii=0; azNames[ii]!=0 && strcmp(azNames[ii],pMod->zName)!=0; ii++){}
      if( azNames[ii]!=0 ) continue;
    }
    createModule(db, pMod->zName, 0, 0, 0);
  }
  return SQLITE_OK;
}

/*
** Decrement the reference count on a Module object.  Destroy the
** module when the reference count reaches zero.
*/
void sqlite3VtabModuleUnref(sqlite3 *db, Module *pMod){
  assert( pMod->nRefModule>0 );