sqlite/ext/wasm/x-sync-async.js

/*
  2022-09-17

  The author disclaims copyright to this source code.  In place of a
  legal notice, here is a blessing:

  *   May you do good and not evil.
  *   May you find forgiveness for yourself and forgive others.
  *   May you share freely, never taking more than you give.

  ***********************************************************************

  A testing ground for the OPFS VFS.

  Summary of how this works:

  This file uses the sqlite3.StructBinder-created struct wrappers for
  sqlite3_vfs, sqlite3_io_methods, ans sqlite3_file to set up a
  conventional sqlite3_vfs (except that it's implemented in JS). The
  methods which require OPFS APIs use a separate worker (hereafter called the
  OPFS worker) to access that functionality. This worker and that one
  use SharedArrayBuffer.
*/
'use strict';
const tryOpfsVfs = function(sqlite3){
  const toss = function(...args){throw new Error(args.join(' '))};
  const logPrefix = "OPFS tester:";
  const log = (...args)=>{
    console.log(logPrefix,...args);
  };
  const warn =  (...args)=>{
    console.warn(logPrefix,...args);
  };
  const error =  (...args)=>{
    console.error(logPrefix,...args);
  };
  log("tryOpfsVfs()");
  const capi = sqlite3.capi;
  const pVfs = capi.sqlite3_vfs_find("opfs") || toss("Unexpectedly missing 'opfs' VFS.");
  const oVfs = capi.sqlite3_vfs.instanceForPointer(pVfs);
  log("OPFS VFS:",pVfs, oVfs);
  log("Done!");
}/*tryOpfsVfs()*/;

importScripts('sqlite3.js');
self.sqlite3InitModule().then((EmscriptenModule)=>{
  EmscriptenModule.sqlite3.installOpfsVfs()
    .then((sqlite3)=>tryOpfsVfs(sqlite3))
    .catch((e)=>{
      console.error("Error initializing OPFS VFS:",e);
      throw e;
    });
});