// Copyright 2023 The Emscripten Authors. All rights reserved.

// Emscripten is available under two separate licenses, the MIT license and the

// University of Illinois/NCSA Open Source License. Both these licenses can be

// found in the LICENSE file.

//

// This file contains implementations of emscripten APIs that are compatible

// with WasmFS. These replace APIs in src/library*js, and basically do things

// in a simpler manner for the situation where the FS is in wasm and not JS

// (in particular, these implemenations avoid calling from JS to wasm, and

// dependency issues that arise from that).

//

#include <emscripten.h>

#include <stdio.h>

#include <string>

#include "file.h"

#include "file_table.h"

#include "wasmfs.h"

namespace wasmfs {

// Given an fd, returns the string path that the fd refers to.

// TODO: full error handling

// TODO: maybe make this a public API, as it is useful for debugging

std::string getPath(int fd) {

auto fileTable = wasmfs::wasmFS.getFileTable().locked();

auto openFile = fileTable.getEntry(fd);

if (!openFile) {

return "!";

}

auto curr = openFile->locked().getFile();

std::string result = "";

while (curr != wasmfs::wasmFS.getRootDirectory()) {

auto parent = curr->locked().getParent();

// Check if the parent exists. The parent may not exist if curr was

// unlinked.

if (!parent) {

return "?/" + result;

}

auto parentDir = parent->dynCast<wasmfs::Directory>();

auto name = parentDir->locked().getName(curr);

result = '/' + name + result;

curr = parentDir;

}

return result;

}

} // namespace wasmfs

extern "C" {

char* emscripten_get_preloaded_image_data_from_FILE(FILE* file,

int* w,

int* h) {

auto fd = fileno(file);

if (fd < 0) {

return 0;

}

auto path = wasmfs::getPath(fd);

return emscripten_get_preloaded_image_data(path.c_str(), w, h);

}

} // extern "C"