Fix mock inclusion

Summary:
The 'fs' mock was set up to require 'graceful-fs', which used to delegate to the corresponding mock. After turning off automocking, this no longer necessarily works.
This moves the mock to `fs.js` and makes the mock for graceful-fs require the fs mock via a relative path.

Reviewed By: cpojer

Differential Revision: D5209130

fbshipit-source-id: d468577e09d18382d0b9602ad0964dd880ec2366

Author: davidaurelio

packages/metro-bundler/src/node-haste/__mocks__/fs.js

@@ -8,4 +8,301 @@
  */
 'use strict';
 
-module.exports = require('graceful-fs');
+const {EventEmitter} = require('events');
+const {dirname} = require.requireActual('path');
+const fs = jest.genMockFromModule('fs');
+const path = require('path');
+const stream = require.requireActual('stream');
+
+const noop = () => {};
+
+function asyncCallback(cb) {
+  return function() {
+    setImmediate(() => cb.apply(this, arguments));
+  };
+}
+
+const mtime = {
+  getTime: () => Math.ceil(Math.random() * 10000000),
+};
+
+fs.realpath.mockImplementation((filepath, callback) => {
+  callback = asyncCallback(callback);
+  let node;
+  try {
+    node = getToNode(filepath);
+  } catch (e) {
+    return callback(e);
+  }
+  if (node && typeof node === 'object' && node.SYMLINK != null) {
+    return callback(null, node.SYMLINK);
+  }
+  return callback(null, filepath);
+});
+
+fs.readdirSync.mockImplementation(filepath => Object.keys(getToNode(filepath)));
+
+fs.readdir.mockImplementation((filepath, callback) => {
+  callback = asyncCallback(callback);
+  let node;
+  try {
+    node = getToNode(filepath);
+    if (node && typeof node === 'object' && node.SYMLINK != null) {
+      node = getToNode(node.SYMLINK);
+    }
+  } catch (e) {
+    return callback(e);
+  }
+
+  if (!(node && typeof node === 'object' && node.SYMLINK == null)) {
+    return callback(new Error(filepath + ' is not a directory.'));
+  }
+
+  return callback(null, Object.keys(node));
+});
+
+fs.readFile.mockImplementation(function(filepath, encoding, callback) {
+  callback = asyncCallback(callback);
+  if (arguments.length === 2) {
+    callback = encoding;
+    encoding = null;
+  }
+
+  let node;
+  try {
+    node = getToNode(filepath);
+    // dir check
+    if (node && typeof node === 'object' && node.SYMLINK == null) {
+      callback(new Error('Error readFile a dir: ' + filepath));
+    }
+    if (node == null) {
+      return callback(Error('No such file: ' + filepath));
+    } else {
+      return callback(null, node);
+    }
+  } catch (e) {
+    return callback(e);
+  }
+});
+
+fs.readFileSync.mockImplementation(function(filepath, encoding) {
+  const node = getToNode(filepath);
+  // dir check
+  if (node && typeof node === 'object' && node.SYMLINK == null) {
+    throw new Error('Error readFileSync a dir: ' + filepath);
+  }
+  return node;
+});
+
+function makeStatResult(node) {
+  const isSymlink = node != null && node.SYMLINK != null;
+  return {
+    isBlockDevice: () => false,
+    isCharacterDevice: () => false,
+    isDirectory: () => node != null && typeof node === 'object' && !isSymlink,
+    isFIFO: () => false,
+    isFile: () => node != null && typeof node === 'string',
+    isSocket: () => false,
+    isSymbolicLink: () => isSymlink,
+    mtime,
+  };
+}
+
+function statSync(filepath) {
+  const node = getToNode(filepath);
+  if (node != null && node.SYMLINK) {
+    return statSync(node.SYMLINK);
+  }
+  return makeStatResult(node);
+}
+
+fs.stat.mockImplementation((filepath, callback) => {
+  callback = asyncCallback(callback);
+  let result;
+  try {
+    result = statSync(filepath);
+  } catch (e) {
+    callback(e);
+    return;
+  }
+  callback(null, result);
+});
+
+fs.statSync.mockImplementation(statSync);
+
+function lstatSync(filepath) {
+  const node = getToNode(filepath);
+  return makeStatResult(node);
+}
+
+fs.lstat.mockImplementation((filepath, callback) => {
+  callback = asyncCallback(callback);
+  let result;
+  try {
+    result = lstatSync(filepath);
+  } catch (e) {
+    callback(e);
+    return;
+  }
+  callback(null, result);
+});
+
+fs.lstatSync.mockImplementation(lstatSync);
+
+fs.open.mockImplementation(function(filepath) {
+  const callback = arguments[arguments.length - 1] || noop;
+  let data, error, fd;
+  try {
+    data = getToNode(filepath);
+  } catch (e) {
+    error = e;
+  }
+
+  if (error || data == null) {
+    error = Error(`ENOENT: no such file or directory, open ${filepath}`);
+  }
+  if (data != null) {
+    /* global Buffer: true */
+    fd = {buffer: new Buffer(data, 'utf8'), position: 0};
+  }
+
+  callback(error, fd);
+});
+
+fs.read.mockImplementation((fd, buffer, writeOffset, length, position, callback = noop) => {
+  let bytesWritten;
+  try {
+    if (position == null || position < 0) {
+      ({position} = fd);
+    }
+    bytesWritten = fd.buffer.copy(buffer, writeOffset, position, position + length);
+    fd.position = position + bytesWritten;
+  } catch (e) {
+    callback(Error('invalid argument'));
+    return;
+  }
+  callback(null, bytesWritten, buffer);
+});
+
+fs.close.mockImplementation((fd, callback = noop) => {
+  try {
+    fd.buffer = fs.position = undefined;
+  } catch (e) {
+    callback(Error('invalid argument'));
+    return;
+  }
+  callback(null);
+});
+
+let filesystem;
+
+fs.createReadStream.mockImplementation(filepath => {
+  if (!filepath.startsWith('/')) {
+    throw Error('Cannot open file ' + filepath);
+  }
+
+  const parts = filepath.split('/').slice(1);
+  let file = filesystem;
+
+  for (const part of parts) {
+    file = file[part];
+    if (!file) {
+      break;
+    }
+  }
+
+  if (typeof file !== 'string') {
+    throw Error('Cannot open file ' + filepath);
+  }
+
+  return new stream.Readable({
+    read() {
+      this.push(file, 'utf8');
+      this.push(null);
+    },
+  });
+});
+
+fs.createWriteStream.mockImplementation(file => {
+  let node;
+  try {
+    node = getToNode(dirname(file));
+  } finally {
+    if (typeof node === 'object') {
+      const writeStream = new stream.Writable({
+        write(chunk) {
+          this.__chunks.push(chunk);
+        },
+      });
+      writeStream.__file = file;
+      writeStream.__chunks = [];
+      writeStream.end = jest.fn(writeStream.end);
+      fs.createWriteStream.mock.returned.push(writeStream);
+      return writeStream;
+    } else {
+      throw new Error('Cannot open file ' + file);
+    }
+  }
+});
+fs.createWriteStream.mock.returned = [];
+
+fs.__setMockFilesystem = object => (filesystem = object);
+
+const watcherListByPath = new Map();
+
+fs.watch.mockImplementation((filename, options, listener) => {
+  if (options.recursive) {
+    throw new Error('recursive watch not implemented');
+  }
+  let watcherList = watcherListByPath.get(filename);
+  if (watcherList == null) {
+    watcherList = [];
+    watcherListByPath.set(filename, watcherList);
+  }
+  const fsWatcher = new EventEmitter();
+  fsWatcher.on('change', listener);
+  fsWatcher.close = () => {
+    watcherList.splice(watcherList.indexOf(fsWatcher), 1);
+    fsWatcher.close = () => { throw new Error('FSWatcher is already closed'); };
+  };
+  watcherList.push(fsWatcher);
+});
+
+fs.__triggerWatchEvent = (eventType, filename) => {
+  const directWatchers = watcherListByPath.get(filename) || [];
+  directWatchers.forEach(wtc => wtc.emit('change', eventType));
+  const dirPath = path.dirname(filename);
+  const dirWatchers = watcherListByPath.get(dirPath) || [];
+  dirWatchers.forEach(wtc => wtc.emit('change', eventType, path.relative(dirPath, filename)));
+};
+
+function getToNode(filepath) {
+  // Ignore the drive for Windows paths.
+  if (filepath.match(/^[a-zA-Z]:\\/)) {
+    filepath = filepath.substring(2);
+  }
+
+  if (filepath.endsWith(path.sep)) {
+    filepath = filepath.slice(0, -1);
+  }
+  const parts = filepath.split(/[\/\\]/);
+  if (parts[0] !== '') {
+    throw new Error('Make sure all paths are absolute.');
+  }
+  let node = filesystem;
+  parts.slice(1).forEach(part => {
+    if (node && node.SYMLINK) {
+      node = getToNode(node.SYMLINK);
+    }
+    node = node[part];
+    if (node == null) {
+      const err = new Error('ENOENT: no such file or directory');
+      err.code = 'ENOENT';
+      throw err;
+    }
+  });
+
+  return node;
+}
+
+module.exports = fs;