Redo r113722 - Add Pass(), which implements move semantics, to scoped_ptr, scoped_array....

Redo r113722 - Add Pass(), which implements move semantics, to scoped_ptr, scoped_array....

Add Pass(), which implements move semantics, to scoped_ptr, scoped_array, and scoped_ptr_malloc.

This modification to the scopers implements the "moveable but not copyable" semantics that were introduced in C++11's unique_ptr<>.

With this, is now possible to use scopers as an argument type or a return type.  This signifies, in the type system, transfer of ownership into a function or out of a function respectively.  Calling, or returning such a function MUST use the temporary resultin

This distinction makes it possible to avoid the implicit ownership transfer issues of auto_ptr, but still allow us to have compiler enforced ownership transfer.

Also adds a Passed() helper that allows using a scoper with Bind().

BUG=96118
TEST=new unittests

Original review URL: http://codereview.chromium.org/8774032

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=113922

[awong, 2011-12-10 00:43:18]

Aaron, the fancy C++ trip in scoped_ptr broke the Manifest object in
extension_manifest_unittest.cc.

There's a simple workaround.  Can you take a look at just that file?

[willchan no longer on Chromium, 2011-12-10 00:55:14]

Lgtm

Sent from my iNexus.
On Dec 9, 2011 4:43 PM, <ajwong@chromium.org> wrote:

> Reviewers: Aaron Boodman, willchan,
>
> Message:
> Aaron, the fancy C++ trip in scoped_ptr broke the Manifest object in
> extension_manifest_unittest.**cc.
>
> There's a simple workaround.  Can you take a look at just that file?
>
> Description:
> Redo r113722 - Add Pass(), which implements move semantics, to scoped_ptr,
> scoped_array....
>
> Add Pass(), which implements move semantics, to scoped_ptr, scoped_array,
> and
> scoped_ptr_malloc.
>
> This modification to the scopers implements the "moveable but not copyable"
> semantics that were introduced in C++11's unique_ptr<>.
>
> With this, is now possible to use scopers as an argument type or a return
> type.
> This signifies, in the type system, transfer of ownership into a function
> or out
> of a function respectively.  Calling, or returning such a function MUST
> use the
> temporary resultin
>
> This distinction makes it possible to avoid the implicit ownership transfer
> issues of auto_ptr, but still allow us to have compiler enforced ownership
> transfer.
>
> Also adds a Passed() helper that allows using a scoper with Bind().
>
> BUG=96118
> TEST=new unittests
>
> Original review URL:
http://codereview.chromium.**org/8774032<http://codereview.chromium.org/8774032>
>
>
> Please review this at
http://codereview.chromium.**org/8897005/<http://codereview.chromium.org/8897...
>
> SVN Base:
svn://svn.chromium.org/chrome/**trunk/src<http://svn.chromium.org/chrome/trunk/src>
>
> Affected files:
>  M base/bind_helpers.h
>  M base/bind_internal.h
>  M base/bind_internal.h.pump
>  M base/bind_unittest.cc
>  M base/callback.h
>  M base/callback.h.pump
>  M base/callback_internal.h
>  M base/memory/scoped_ptr.h
>  M base/memory/scoped_ptr_**unittest.cc
>  M chrome/common/extensions/**extension_manifests_unittest.**cc
>
>
>

[Aaron Boodman, 2011-12-10 01:48:44]

LGTM

Can you recommend another way to write extension_manifests_unittest.cc so that
this hack would not be required?

What if we pass a ptr instead of const ref.

[awong, 2011-12-10 01:53:46]

On 2011/12/10 01:48:44, Aaron Boodman wrote:
> LGTM

Thanks!

> Can you recommend another way to write extension_manifests_unittest.cc so that
> this hack would not be required?
> 
> What if we pass a ptr instead of const ref.

There aren't a lot of great solutions if you want to preserve the syntax of
LoadAndExpect(Manifest(x)).  You can't use a ptr or a non-const ref because
neither of those can be used with a temporary.

You could push the overload downwards into  LoadExtension(), LoadAndExpect*()
and then make it LoadAndExpect(x).

That might be the best solution.