packages/flutter_tools/lib/src/base/file_system.dart

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'dart:io' as dart_io;

import 'package:file/io.dart';
import 'package:file/sync_io.dart';
import 'package:path/path.dart' as path;

export 'package:file/io.dart';
export 'package:file/sync_io.dart';

/// Currently active implmenetation of the file system.
///
/// By default it uses local disk-based implementation. Override this in tests
/// with [MemoryFileSystem].
FileSystem fs = new LocalFileSystem();
SyncFileSystem syncFs = new SyncLocalFileSystem();

typedef String CurrentDirectoryGetter();

final CurrentDirectoryGetter _defaultCurrentDirectoryGetter = () {
  return dart_io.Directory.current.path;
};

/// Points to the current working directory (like `pwd`).
CurrentDirectoryGetter getCurrentDirectory = _defaultCurrentDirectoryGetter;

/// Exits the process with the given [exitCode].
typedef void ExitFunction([int exitCode]);

final ExitFunction _defaultExitFunction = ([int exitCode]) {
  dart_io.exit(exitCode);
};

/// Exits the process.
ExitFunction exit = _defaultExitFunction;

/// Restores [fs] and [syncFs] to the default local disk-based implementation.
void restoreFileSystem() {
  fs = new LocalFileSystem();
  syncFs = new SyncLocalFileSystem();
  getCurrentDirectory = _defaultCurrentDirectoryGetter;
  exit = _defaultExitFunction;
}

/// Uses in-memory replacments for `dart:io` functionality. Useful in tests.
void useInMemoryFileSystem({ cwd: '/', ExitFunction exitFunction }) {
  MemoryFileSystem memFs = new MemoryFileSystem();
  fs = memFs;
  syncFs = new SyncMemoryFileSystem(backedBy: memFs.storage);
  getCurrentDirectory = () => cwd;
  exit = exitFunction ?? ([int exitCode]) {
    throw new Exception('Exited with code $exitCode');
  };
}

/// Create the ancestor directories of a file path if they do not already exist.
void ensureDirectoryExists(String filePath) {
  String dirPath = path.dirname(filePath);

  if (syncFs.type(dirPath) == FileSystemEntityType.DIRECTORY)
    return;
  syncFs.directory(dirPath).create(recursive: true);
}