sdk/lib/io/link.dart - sdk - Git at Google

 // 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.
  *
  */
 @pragma("vm:entry-point")
 abstract class Link implements FileSystemEntity {
   /**
    * Creates a Link object.
    */
   @pragma("vm:entry-point")
   factory Link(String path) {
     final IOOverrides overrides = IOOverrides.current;
     if (overrides == null) {
       return new _Link(path);
     }
     return overrides.createLink(path);
   }

   @pragma("vm:entry-point")
   factory Link.fromRawPath(Uint8List rawPath) {
     // TODO(bkonyi): handle overrides
     return new _Link.fromRawPath(rawPath);
   }

   /**
    * 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 call will create a true symbolic link
    * instead of a Junction. In order to create a symbolic link on Windows, Dart
    * must be run in Administrator mode or the system must have Developer Mode
    * enabled, otherwise a [FileSystemException] will be raised with
    * `ERROR_PRIVILEGE_NOT_HELD` set as the errno when this call is made.
    *
    * 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 call will create a true symbolic link
    * instead of a Junction. In order to create a symbolic link on Windows, Dart
    * must be run in Administrator mode or the system must have Developer Mode
    * enabled, otherwise a [FileSystemException] will be raised with
    * `ERROR_PRIVILEGE_NOT_HELD` set as the errno when this call is made.
    *
    * 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.
    */
   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.
    */
   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 {
   String _path;
   Uint8List _rawPath;

   _Link(String path) {
     ArgumentError.checkNotNull(path, 'path');
     _path = path;
     _rawPath = FileSystemEntity._toUtf8Array(path);
   }

   _Link.fromRawPath(Uint8List rawPath) {
     _rawPath = FileSystemEntity._toNullTerminatedUtf8Array(rawPath);
     _path = FileSystemEntity._toStringFromUtf8Array(rawPath);
   }

   String get path => _path;

   String toString() => "Link: '$path'";

   Future<bool> exists() => FileSystemEntity._isLinkRaw(_rawPath);

   bool existsSync() => FileSystemEntity._isLinkRawSync(_rawPath);

   Link get absolute => new Link.fromRawPath(_rawAbsolutePath);

   Future<Link> create(String target, {bool recursive: false}) {
     var result =
         recursive ? parent.create(recursive: true) : new Future.value(null);
     return result
         .then((_) => _File._dispatchWithNamespace(
             _IOService.fileCreateLink, [null, _rawPath, 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);
     }
     var result = _File._createLink(_Namespace._namespace, _rawPath, target);
     throwIfError(result, "Cannot create link", path);
   }

   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<Link>((_) => create(target));
   }

   Future<Link> _delete({bool recursive: false}) {
     if (recursive) {
       return new Directory.fromRawPath(_rawPath)
           .delete(recursive: true)
           .then((_) => this);
     }
     return _File._dispatchWithNamespace(
         _IOService.fileDeleteLink, [null, _rawPath]).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionFromResponse(response, "Cannot delete link", path);
       }
       return this;
     });
   }

   void _deleteSync({bool recursive: false}) {
     if (recursive) {
       return new Directory.fromRawPath(_rawPath).deleteSync(recursive: true);
     }
     var result = _File._deleteLinkNative(_Namespace._namespace, _rawPath);
     throwIfError(result, "Cannot delete link", path);
   }

   Future<Link> rename(String newPath) {
     return _File._dispatchWithNamespace(
         _IOService.fileRenameLink, [null, _rawPath, 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(_Namespace._namespace, _rawPath, newPath);
     throwIfError(result, "Cannot rename link '$path' to '$newPath'");
     return new Link(newPath);
   }

   Future<String> target() {
     return _File._dispatchWithNamespace(
         _IOService.fileLinkTarget, [null, _rawPath]).then((response) {
       if (_isErrorResponse(response)) {
         throw _exceptionFromResponse(
             response, "Cannot get target of link", path);
       }
       return response;
     });
   }

   String targetSync() {
     var result = _File._linkTarget(_Namespace._namespace, _rawPath);
     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] != _successResponse;
   }

   _exceptionFromResponse(response, String message, String path) {
     assert(_isErrorResponse(response));
     switch (response[_errorResponseErrorType]) {
       case _illegalArgumentResponse:
         return new ArgumentError();
       case _osErrorResponse:
         var err = new OSError(response[_osErrorResponseMessage],
             response[_osErrorResponseErrorCode]);
         return new FileSystemException(message, path, err);
       default:
         return new Exception("Unknown error");
     }
   }
 }
	// 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.
	*
	*/
	@pragma("vm:entry-point")
	abstract class Link implements FileSystemEntity {
	/**
	* Creates a Link object.
	*/
	@pragma("vm:entry-point")
	factory Link(String path) {
	final IOOverrides overrides = IOOverrides.current;
	if (overrides == null) {
	return new _Link(path);
	}
	return overrides.createLink(path);
	}

	@pragma("vm:entry-point")
	factory Link.fromRawPath(Uint8List rawPath) {
	// TODO(bkonyi): handle overrides
	return new _Link.fromRawPath(rawPath);
	}

	/**
	* 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 call will create a true symbolic link
	* instead of a Junction. In order to create a symbolic link on Windows, Dart
	* must be run in Administrator mode or the system must have Developer Mode
	* enabled, otherwise a [FileSystemException] will be raised with
	* `ERROR_PRIVILEGE_NOT_HELD` set as the errno when this call is made.
	*
	* 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 call will create a true symbolic link
	* instead of a Junction. In order to create a symbolic link on Windows, Dart
	* must be run in Administrator mode or the system must have Developer Mode
	* enabled, otherwise a [FileSystemException] will be raised with
	* `ERROR_PRIVILEGE_NOT_HELD` set as the errno when this call is made.
	*
	* 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.
	*/
	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.
	*/
	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 {
	String _path;
	Uint8List _rawPath;

	_Link(String path) {
	ArgumentError.checkNotNull(path, 'path');
	_path = path;
	_rawPath = FileSystemEntity._toUtf8Array(path);
	}

	_Link.fromRawPath(Uint8List rawPath) {
	_rawPath = FileSystemEntity._toNullTerminatedUtf8Array(rawPath);
	_path = FileSystemEntity._toStringFromUtf8Array(rawPath);
	}

	String get path => _path;

	String toString() => "Link: '$path'";

	Future<bool> exists() => FileSystemEntity._isLinkRaw(_rawPath);

	bool existsSync() => FileSystemEntity._isLinkRawSync(_rawPath);

	Link get absolute => new Link.fromRawPath(_rawAbsolutePath);

	Future<Link> create(String target, {bool recursive: false}) {
	var result =
	recursive ? parent.create(recursive: true) : new Future.value(null);
	return result
	.then((_) => _File._dispatchWithNamespace(
	_IOService.fileCreateLink, [null, _rawPath, 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);
	}
	var result = _File._createLink(_Namespace._namespace, _rawPath, target);
	throwIfError(result, "Cannot create link", path);
	}

	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<Link>((_) => create(target));
	}

	Future<Link> _delete({bool recursive: false}) {
	if (recursive) {
	return new Directory.fromRawPath(_rawPath)
	.delete(recursive: true)
	.then((_) => this);
	}
	return _File._dispatchWithNamespace(
	_IOService.fileDeleteLink, [null, _rawPath]).then((response) {
	if (_isErrorResponse(response)) {
	throw _exceptionFromResponse(response, "Cannot delete link", path);
	}
	return this;
	});
	}

	void _deleteSync({bool recursive: false}) {
	if (recursive) {
	return new Directory.fromRawPath(_rawPath).deleteSync(recursive: true);
	}
	var result = _File._deleteLinkNative(_Namespace._namespace, _rawPath);
	throwIfError(result, "Cannot delete link", path);
	}

	Future<Link> rename(String newPath) {
	return _File._dispatchWithNamespace(
	_IOService.fileRenameLink, [null, _rawPath, 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(_Namespace._namespace, _rawPath, newPath);
	throwIfError(result, "Cannot rename link '$path' to '$newPath'");
	return new Link(newPath);
	}

	Future<String> target() {
	return _File._dispatchWithNamespace(
	_IOService.fileLinkTarget, [null, _rawPath]).then((response) {
	if (_isErrorResponse(response)) {
	throw _exceptionFromResponse(
	response, "Cannot get target of link", path);
	}
	return response;
	});
	}

	String targetSync() {
	var result = _File._linkTarget(_Namespace._namespace, _rawPath);
	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] != _successResponse;
	}

	_exceptionFromResponse(response, String message, String path) {
	assert(_isErrorResponse(response));
	switch (response[_errorResponseErrorType]) {
	case _illegalArgumentResponse:
	return new ArgumentError();
	case _osErrorResponse:
	var err = new OSError(response[_osErrorResponseMessage],
	response[_osErrorResponseErrorCode]);
	return new FileSystemException(message, path, err);
	default:
	return new Exception("Unknown error");
	}
	}
	}