src/lib/libwasmfs_jsimpl.js

/**
 * @license
 * Copyright 2022 The Emscripten Authors
 * SPDX-License-Identifier: MIT
 */

addToLibrary({
  // Backend support. wasmFS$backends will contain a mapping of backend IDs to
  // the JS code that implements them. This is the JS side of the JSImpl* class
  // in C++, together with the js_impl calls defined right after it.
  $wasmFS$backends: {},

  _wasmfs_jsimpl_alloc_file: (backend, file) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    return wasmFS$backends[backend].allocFile(file);
  },

  _wasmfs_jsimpl_free_file: (backend, file) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    return wasmFS$backends[backend].freeFile(file);
  },

  _wasmfs_jsimpl_write__i53abi: true,
  _wasmfs_jsimpl_write: (backend, file, buffer, length, offset) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    if (!wasmFS$backends[backend].write) {
      return -{{{ cDefs.EINVAL }}};
    }
    return wasmFS$backends[backend].write(file, buffer, length, offset);
  },

  _wasmfs_jsimpl_read__i53abi: true,
  _wasmfs_jsimpl_read: (backend, file, buffer, length, offset) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    if (!wasmFS$backends[backend].read) {
      return -{{{ cDefs.EINVAL }}};
    }
    return wasmFS$backends[backend].read(file, buffer, length, offset);
  },

  _wasmfs_jsimpl_get_size: (backend, file) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    return wasmFS$backends[backend].getSize(file);
  },

  _wasmfs_jsimpl_set_size__i53abi: true,
  _wasmfs_jsimpl_set_size: (backend, file, size) => {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    return wasmFS$backends[backend].setSize(file, size);
  },

  // ProxiedAsyncJSImpl. Each function receives a function pointer and a
  // parameter. We convert those into a convenient Promise API for the
  // implementors of backends: the hooks we call should return Promises, which
  // we then connect to the calling C++.

  _wasmfs_jsimpl_async_alloc_file__deps: ['emscripten_proxy_finish'],
  _wasmfs_jsimpl_async_alloc_file: async function(ctx, backend, file) {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    await wasmFS$backends[backend].allocFile(file);
    _emscripten_proxy_finish(ctx);
  },

  _wasmfs_jsimpl_async_free_file__deps: ['emscripten_proxy_finish'],
  _wasmfs_jsimpl_async_free_file: async function(ctx, backend, file) {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    await wasmFS$backends[backend].freeFile(file);
    _emscripten_proxy_finish(ctx);
  },

  _wasmfs_jsimpl_async_write__i53abi: true,
  _wasmfs_jsimpl_async_write__deps: ['emscripten_proxy_finish'],
  _wasmfs_jsimpl_async_write: async function(ctx, backend, file, buffer, length, offset, result_p) {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    var result = await wasmFS$backends[backend].write(file, buffer, length, offset);
    {{{ makeSetValue('result_p', 0, 'result', SIZE_TYPE) }}};
    _emscripten_proxy_finish(ctx);
  },

  _wasmfs_jsimpl_async_read__i53abi: true,
  _wasmfs_jsimpl_async_read__deps: ['emscripten_proxy_finish'],
  _wasmfs_jsimpl_async_read: async function(ctx, backend, file, buffer, length, offset, result_p) {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    var result = await wasmFS$backends[backend].read(file, buffer, length, offset);
    {{{ makeSetValue('result_p', 0, 'result', SIZE_TYPE) }}};
    _emscripten_proxy_finish(ctx);
  },

  _wasmfs_jsimpl_async_get_size__deps: ['emscripten_proxy_finish'],
  _wasmfs_jsimpl_async_get_size: async function(ctx, backend, file, size_p) {
#if ASSERTIONS
    assert(wasmFS$backends[backend]);
#endif
    var size = await wasmFS$backends[backend].getSize(file);
    {{{ makeSetValue('size_p', 0, 'size', 'i64') }}};
    _emscripten_proxy_finish(ctx);
  },
});