Fix excess memory usage problem in StringInputStream.

Fix excess memory usage problem in StringInputStream.


BUG=dart:555
TEST=

Committed: https://code.google.com/p/dart/source/detail?r=1777

[Bill Hesse, 2011-11-22 18:04:55]

Use a List<int> instead of a StringBuffer to accumulate characters.  Solves the
memory problem completely.  The List<int> even seems to go into old space.

BUG=dart:555

[Søren Gjesse, 2011-11-23 07:37:13]

lgtm

[Mads Ager (google), 2011-11-23 07:41:22]

LGTM

I think this change is fine. For this use a List<int> seems like the right
thing. I do think that the StringBuffer should be able to handle this case
better. As the user of a StringBuffer I would expect it to have better growth
strategies so this code would not be a problem.

[Mads Ager (google), 2011-11-23 07:50:59]

Hmm, looking at the StringBuffer implementation in the VM I don't see why this
would make a huge difference. In the StringBuffer we are using a list of
strings. So, as far as I can tell, the size difference here should be a smallish
constant factor? Instead of storing a smi in the list we store strings. These
strings are allocated outside of the list itself. What is the precise size
reduction here? A factor of 3-5? I think it is fine to put this back, but it
will still be easy to exhaust new space. The VM team is working on a better GC
so this would be promoted to old space and not be an issue.

On 2011/11/23 07:41:22, Mads Ager wrote:
> LGTM
> 
> I think this change is fine. For this use a List<int> seems like the right
> thing. I do think that the StringBuffer should be able to handle this case
> better. As the user of a StringBuffer I would expect it to have better growth
> strategies so this code would not be a problem.