Add Persistent<T>::Reset which disposes the handle and redirects it to point to another object.

Add Persistent<T>::Reset which disposes the handle and redirects it to point to another object.

BUG=
R=dcarney@chromium.org, svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=14570

[marja, 2013-05-06 14:05:26]

dcarney, ptal

[dcarney, 2013-05-06 14:10:59]

lgtm. adding sven as a reviewer

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc#newco...
test/cctest/test-api.cc:2497: 
can drop the empty lines. v8 people seem not to be big fans of whitespace

[dcarney, 2013-05-06 14:10:59]

lgtm. adding sven as a reviewer

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc#newco...
test/cctest/test-api.cc:2497: 
can drop the empty lines. v8 people seem not to be big fans of whitespace

[marja, 2013-05-06 14:15:20]

dcarney: thanks for review

svenpanne: ptal. If you have a preference on what Reset should be called instead
of Reset, I can change it...

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://codereview.chromium.org/14788013/diff/1/test/cctest/test-api.cc#newco...
test/cctest/test-api.cc:2497: 
On 2013/05/06 14:10:59, dcarney wrote:
> can drop the empty lines. v8 people seem not to be big fans of whitespace

Done.

[Sven Panne, 2013-05-07 09:49:31]

https://codereview.chromium.org/14788013/diff/4001/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/14788013/diff/4001/include/v8.h#newcode5363
include/v8.h:5363: return;
Style nit: Put this on the previous line. Debatable, but usual v8 "style"...

https://codereview.chromium.org/14788013/diff/4001/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://codereview.chromium.org/14788013/diff/4001/test/cctest/test-api.cc#ne...
test/cctest/test-api.cc:2489: THREADED_TEST(ResettingGlobalHandle) {
A test for passing an empty handle to reset is missing. Either add this test or
change the API, ASSERTing that it never happens. Don't know the call sites, so I
can't decide...

[marja, 2013-05-07 11:17:17]

Thanks for having a look!

https://codereview.chromium.org/14788013/diff/4001/include/v8.h
File include/v8.h (right):

https://codereview.chromium.org/14788013/diff/4001/include/v8.h#newcode5363
include/v8.h:5363: return;
On 2013/05/07 09:49:31, Sven Panne wrote:
> Style nit: Put this on the previous line. Debatable, but usual v8 "style"...

I added "this->val_ = NULL" here, so this became a multi-line block :)

https://codereview.chromium.org/14788013/diff/4001/test/cctest/test-api.cc
File test/cctest/test-api.cc (right):

https://codereview.chromium.org/14788013/diff/4001/test/cctest/test-api.cc#ne...
test/cctest/test-api.cc:2489: THREADED_TEST(ResettingGlobalHandle) {
On 2013/05/07 09:49:31, Sven Panne wrote:
> A test for passing an empty handle to reset is missing. Either add this test
or
> change the API, ASSERTing that it never happens. Don't know the call sites, so
I
> can't decide...

Added a test here which says that after resetting to an empty handle, the handle
is empty.

[Sven Panne, 2013-05-07 11:31:57]

lgtm

[dcarney, 2013-05-07 12:37:28]

Committed patchset #3 manually as r14570 (presubmit successful).