Use in memory user database to improve performance.

Use in memory user database to improve performance.

I found pinyin's performance is very low when system IO load is big. So
I let pinyin use im memory user database to improve the performance, and
write the database to the harddisk in 60 seconds or when engine exits.

BUG=none
TEST=manual

[Yusuke Sato, 2010-11-24 07:49:22]

lgtm

http://codereview.appspot.com/3303041/diff/1/src/PYString.h
File src/PYString.h (right):

http://codereview.appspot.com/3303041/diff/1/src/PYString.h#newcode34
src/PYString.h:34: String (const std::string str) : std::string (str) { }
do you mean 'const std::string &str'?

[Peng, 2010-11-24 07:53:20]

http://codereview.appspot.com/3303041/diff/1/src/PYString.h
File src/PYString.h (right):

http://codereview.appspot.com/3303041/diff/1/src/PYString.h#newcode34
src/PYString.h:34: String (const std::string str) : std::string (str) { }
On 2010/11/24 07:49:22, Yusuke Sato wrote:
> do you mean 'const std::string &str'?

Done.