Migrate dart2js stubs for dart:io

tool/input_sdk/lib/io/link.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of dart.io;
+
+/**
+ * [Link] objects are references to filesystem links.
+ *
+ */
+abstract class Link implements FileSystemEntity {
+  /**
+   * Creates a Link object.
+   */
+  factory Link(String path) => new _Link(path);
+
+  /**
+   * Creates a [Link] object.
+   *
+   * If [path] is a relative path, it will be interpreted relative to the
+   * current working directory (see [Directory.current]), when used.
+   *
+   * If [path] is an absolute path, it will be immune to changes to the
+   * current working directory.
+   */
+  factory Link.fromUri(Uri uri) => new Link(uri.toFilePath());
+
+  /**
+   * Creates a symbolic link. Returns a [:Future<Link>:] that completes with
+   * the link when it has been created. If the link exists,
+   * the future will complete with an error.
+   *
+   * If [recursive] is false, the default, the link is created
+   * only if all directories in its path exist.
+   * If [recursive] is true, all non-existing path
+   * components are created. The directories in the path of [target] are
+   * not affected, unless they are also in [path].
+   *
+   * On the Windows platform, this will only work with directories, and the
+   * target directory must exist. The link will be created as a Junction.
+   * Only absolute links will be created, and relative paths to the target
+   * will be converted to absolute paths by joining them with the path of the
+   * directory the link is contained in.
+   *
+   * On other platforms, the posix symlink() call is used to make a symbolic
+   * link containing the string [target].  If [target] is a relative path,
+   * it will be interpreted relative to the directory containing the link.
+   */
+  Future<Link> create(String target, {bool recursive: false});
+
+  /**
+   * Synchronously create the link. Calling [createSync] on an existing link
+   * will throw an exception.
+   *
+   * If [recursive] is false, the default, the link is created only if all
+   * directories in its path exist. If [recursive] is true, all
+   * non-existing path components are created. The directories in
+   * the path of [target] are not affected, unless they are also in [path].
+   *
+   * On the Windows platform, this will only work with directories, and the
+   * target directory must exist. The link will be created as a Junction.
+   * Only absolute links will be created, and relative paths to the target
+   * will be converted to absolute paths.
+   *
+   * On other platforms, the posix symlink() call is used to make a symbolic
+   * link containing the string [target].  If [target] is a relative path,
+   * it will be interpreted relative to the directory containing the link.
+   */
+  void createSync(String target, {bool recursive: false});
+
+  /**
+   * Synchronously updates the link. Calling [updateSync] on a non-existing link
+   * will throw an exception.
+   *
+   * On the Windows platform, this will only work with directories, and the
+   * target directory must exist.
+   */
+  void updateSync(String target);
+
+  /**
+   * Updates the link. Returns a [:Future<Link>:] that completes with the
+   * link when it has been updated.  Calling [update] on a non-existing link
+   * will complete its returned future with an exception.
+   *
+   * On the Windows platform, this will only work with directories, and the
+   * target directory must exist.
+   */
+  Future<Link> update(String target);
+
+  Future<String> resolveSymbolicLinks();
+
+  String resolveSymbolicLinksSync();
+
+  /**
+   * Renames this link. Returns a `Future<Link>` that completes
+   * with a [Link] instance for the renamed link.
+   *
+   * If [newPath] identifies an existing link, that link is
+   * replaced. If [newPath] identifies an existing file or directory,
+   * the operation fails and the future completes with an exception.
+   */
+  Future<Link> rename(String newPath);
+
+   /**
+   * Synchronously renames this link. Returns a [Link]
+   * instance for the renamed link.
+   *
+   * If [newPath] identifies an existing link, that link is
+   * replaced. If [newPath] identifies an existing file or directory
+   * the operation fails and an exception is thrown.
+   */
+  Link renameSync(String newPath);
+
+  /**
+   * Returns a [Link] instance whose path is the absolute path to [this].
+   *
+   * The absolute path is computed by prefixing
+   * a relative path with the current working directory, and returning
+   * an absolute path unchanged.
+   */
+  Link get absolute;
+
+  /**
+   * Gets the target of the link. Returns a future that completes with
+   * the path to the target.
+   *
+   * If the returned target is a relative path, it is relative to the
+   * directory containing the link.
+   *
+   * If the link does not exist, or is not a link, the future completes with
+   * a FileSystemException.
+   */
+  Future<String> target();
+
+  /**
+   * Synchronously gets the target of the link. Returns the path to the target.
+   *
+   * If the returned target is a relative path, it is relative to the
+   * directory containing the link.
+   *
+   * If the link does not exist, or is not a link, throws a FileSystemException.
+   */
+  String targetSync();
+}
+
+
+class _Link extends FileSystemEntity implements Link {
+  final String path;
+
+  _Link(this.path) {
+    if (path is! String) {
+      throw new ArgumentError('${Error.safeToString(path)} '
+                              'is not a String');
+    }
+  }
+
+  String toString() => "Link: '$path'";
+
+  Future<bool> exists() => FileSystemEntity.isLink(path);
+
+  bool existsSync() => FileSystemEntity.isLinkSync(path);
+
+  Link get absolute => new Link(_absolutePath);
+
+  Future<FileStat> stat() => FileStat.stat(path);
+
+  FileStat statSync() => FileStat.statSync(path);
+
+  Future<Link> create(String target, {bool recursive: false}) {
+    if (Platform.isWindows) {
+      target = _makeWindowsLinkTarget(target);
+    }
+    var result = recursive ? parent.create(recursive: true)
+                           : new Future.value(null);
+    return result
+      .then((_) => _IOService._dispatch(_FILE_CREATE_LINK, [path, target]))
+      .then((response) {
+        if (_isErrorResponse(response)) {
+          throw _exceptionFromResponse(
+              response, "Cannot create link to target '$target'", path);
+        }
+        return this;
+      });
+  }
+
+  void createSync(String target, {bool recursive: false}) {
+    if (recursive) {
+      parent.createSync(recursive: true);
+    }
+    if (Platform.isWindows) {
+      target = _makeWindowsLinkTarget(target);
+    }
+    var result = _File._createLink(path, target);
+    throwIfError(result, "Cannot create link", path);
+  }
+
+  // Put target into the form "\??\C:\my\target\dir".
+  String _makeWindowsLinkTarget(String target) {
+    Uri base = new Uri.file('${Directory.current.path}\\');
+    Uri link = new Uri.file(path);
+    Uri destination = new Uri.file(target);
+    String result = base.resolveUri(link).resolveUri(destination).toFilePath();
+    if (result.length > 3 && result[1] == ':' && result[2] == '\\') {
+      return '\\??\\$result';
+    } else {
+      throw new FileSystemException(
+          'Target $result of Link.create on Windows cannot be converted' +
+          ' to start with a drive letter.  Unexpected error.');
+    }
+  }
+
+  void updateSync(String target) {
+    // TODO(12414): Replace with atomic update, where supported by platform.
+    // Atomically changing a link can be done by creating the new link, with
+    // a different name, and using the rename() posix call to move it to
+    // the old name atomically.
+    deleteSync();
+    createSync(target);
+  }
+
+  Future<Link> update(String target) {
+    // TODO(12414): Replace with atomic update, where supported by platform.
+    // Atomically changing a link can be done by creating the new link, with
+    // a different name, and using the rename() posix call to move it to
+    // the old name atomically.
+    return delete().then((_) => create(target));
+  }
+
+  Future<Link> _delete({bool recursive: false}) {
+    if (recursive) {
+      return new Directory(path).delete(recursive: true).then((_) => this);
+    }
+    return _IOService._dispatch(_FILE_DELETE_LINK, [path]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(response, "Cannot delete link", path);
+      }
+      return this;
+    });
+  }
+
+  void _deleteSync({bool recursive: false}) {
+    if (recursive) {
+      return new Directory(path).deleteSync(recursive: true);
+    }
+    var result = _File._deleteLinkNative(path);
+    throwIfError(result, "Cannot delete link", path);
+  }
+
+  Future<Link> rename(String newPath) {
+    return _IOService._dispatch(_FILE_RENAME_LINK, [path, newPath])
+        .then((response) {
+          if (_isErrorResponse(response)) {
+            throw _exceptionFromResponse(
+                response, "Cannot rename link to '$newPath'", path);
+          }
+          return new Link(newPath);
+        });
+  }
+
+  Link renameSync(String newPath) {
+    var result = _File._renameLink(path, newPath);
+    throwIfError(result, "Cannot rename link '$path' to '$newPath'");
+    return new Link(newPath);
+  }
+
+  Future<String> target() {
+    return _IOService._dispatch(_FILE_LINK_TARGET, [path]).then((response) {
+      if (_isErrorResponse(response)) {
+        throw _exceptionFromResponse(
+            response, "Cannot get target of link", path);
+      }
+      return response;
+    });
+  }
+
+  String targetSync() {
+    var result = _File._linkTarget(path);
+    throwIfError(result, "Cannot read link", path);
+    return result;
+  }
+
+  static throwIfError(Object result, String msg, [String path = ""]) {
+    if (result is OSError) {
+      throw new FileSystemException(msg, path, result);
+    }
+  }
+
+  bool _isErrorResponse(response) {
+    return response is List && response[0] != _SUCCESS_RESPONSE;
+  }
+
+  _exceptionFromResponse(response, String message, String path) {
+    assert(_isErrorResponse(response));
+    switch (response[_ERROR_RESPONSE_ERROR_TYPE]) {
+      case _ILLEGAL_ARGUMENT_RESPONSE:
+        return new ArgumentError();
+      case _OSERROR_RESPONSE:
+        var err = new OSError(response[_OSERROR_RESPONSE_MESSAGE],
+                              response[_OSERROR_RESPONSE_ERROR_CODE]);
+        return new FileSystemException(message, path, err);
+      default:
+        return new Exception("Unknown error");
+    }
+  }
+}