Added DCHECK() to prevent NULL-pointer dereference

Added DCHECK() to prevent NULL-pointer dereference

CID=103708
BUG=
TEST=
TBR=tommi

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=148476

[Tyler Breisacher (Chromium), 2012-07-25 21:18:15]

https://chromiumcodereview.appspot.com/10834013/diff/1/media/audio/win/wavein...
File media/audio/win/wavein_input_win.cc (right):

https://chromiumcodereview.appspot.com/10834013/diff/1/media/audio/win/wavein...
media/audio/win/wavein_input_win.cc:101: DCHECK(first);
This can only be NULL if num_buffers_ is 0, I think. Let's make sure that it's
impossible for num_buffers_ to be 0 rather than just adding a DCHECK?

[Kyle Horimoto, 2012-07-25 21:56:40]

https://chromiumcodereview.appspot.com/10834013/diff/1/media/audio/win/wavein...
File media/audio/win/wavein_input_win.cc (right):

https://chromiumcodereview.appspot.com/10834013/diff/1/media/audio/win/wavein...
media/audio/win/wavein_input_win.cc:101: DCHECK(first);
On 2012/07/25 21:18:15, Tyler Breisacher wrote:
> This can only be NULL if num_buffers_ is 0, I think. Let's make sure that it's
> impossible for num_buffers_ to be 0 rather than just adding a DCHECK?

num_buffers_ is only assigned to within the constructor. Thus, we can't be sure
what its value is.

[Tyler Breisacher (Chromium), 2012-07-25 22:02:52]

In that case, I would argue that this DCHECK is not the right solution. Maybe we
should do

DCHECK(num_buffers_ > 0)

in the constructor? (Also make num_buffers_ const if it's not already and it
never changes.)

[Kyle Horimoto, 2012-07-25 22:11:47]

On 2012/07/25 22:02:52, Tyler Breisacher wrote:
> In that case, I would argue that this DCHECK is not the right solution. Maybe
we
> should do
> 
> DCHECK(num_buffers_ > 0)
> 
> in the constructor? (Also make num_buffers_ const if it's not already and it
> never changes.)

Done.

[Tyler Breisacher (Chromium), 2012-07-25 22:13:51]

lgtm, hopefully Coverity is smart enough to realize that this fixes the problem.

[commit-bot: I haz the power, 2012-07-25 22:28:21]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/khorimoto@chromium.org/10834013/6001

[commit-bot: I haz the power, 2012-07-25 23:52:47]

Try job failure for 10834013-6001 (retry) on linux_rel for step "browser_tests".
It's a second try, previously, step "browser_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_rel&...

[commit-bot: I haz the power, 2012-07-25 23:55:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/khorimoto@chromium.org/10834013/6001

[commit-bot: I haz the power, 2012-07-26 02:13:57]

Change committed as 148476

[James Hawkins, 2012-07-26 17:20:26]

https://chromiumcodereview.appspot.com/10834013/diff/6001/media/audio/win/wav...
File media/audio/win/wavein_input_win.cc (right):

https://chromiumcodereview.appspot.com/10834013/diff/6001/media/audio/win/wav...
media/audio/win/wavein_input_win.cc:38: DCHECK(num_buffers_ > 0);
DCHECK_LE(0, num_buffers_)