Add support for following links, in VirtualDirectory.

Add support for following links, in VirtualDirectory.

A link must be relative, and not escape the 'root' directory. The
implementation is kept conservative, to increase security.

BUG=
R=sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=24310

[Søren Gjesse, 2013-06-24 08:08:53]

lgtm

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/lib/src/virtu...
File pkg/http_server/lib/src/virtual_directory.dart (right):

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/lib/src/virtu...
pkg/http_server/lib/src/virtual_directory.dart:115: targetPath =
path.append('..').join(targetPath)
Why do you need this additional ..?

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
File pkg/http_server/test/virtual_directory_test.dart (right):

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
pkg/http_server/test/virtual_directory_test.dart:151: return new
HttpClient().get('localhost', server.port, '/dir3/file')
Turn this HttpClient call into a separate functions. Seems like more tests use
this.

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
pkg/http_server/test/virtual_directory_test.dart:187: var link = new
Link('${dir.path}/dir3')
Creating a link to a something that does not exist will not work in Windows.

[Anders Johnsen, 2013-06-24 08:21:16]

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/lib/src/virtu...
File pkg/http_server/lib/src/virtual_directory.dart (right):

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/lib/src/virtu...
pkg/http_server/lib/src/virtual_directory.dart:115: targetPath =
path.append('..').join(targetPath)
On 2013/06/24 08:08:53, Søren Gjesse wrote:
> Why do you need this additional ..?

To 'pop' the link. Changed to use path.directoryPath.join.

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
File pkg/http_server/test/virtual_directory_test.dart (right):

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
pkg/http_server/test/virtual_directory_test.dart:151: return new
HttpClient().get('localhost', server.port, '/dir3/file')
On 2013/06/24 08:08:53, Søren Gjesse wrote:
> Turn this HttpClient call into a separate functions. Seems like more tests use
> this.

I have a follow-up CL doing this.

https://codereview.chromium.org/17582007/diff/1/pkg/http_server/test/virtual_...
pkg/http_server/test/virtual_directory_test.dart:187: var link = new
Link('${dir.path}/dir3')
On 2013/06/24 08:08:53, Søren Gjesse wrote:
> Creating a link to a something that does not exist will not work in Windows.

Done.

[Anders Johnsen, 2013-06-24 08:22:00]

Committed patchset #2 manually as r24310 (presubmit successful).