Include RE2 library

third_party/re2/README.chromium

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+Name: re2 - an efficient, principled regular expression library
+Short Name: re2
+URL: http://code.google.com/p/re2/

[Mark Mentovai, 2012/07/19 16:30:06]

Don’t we already have more than one RE library in Chrome? What’s the plan for
this one?

I find it interesting that when I look at this page, the project’s own home
site, the last line of the description is:

“If you absolutely need backreferences and generalized assertions, then RE2 is
not for you, but you might be interested in irregexp, Google Chrome's regular
expression engine.”

[battre, 2012/07/19 16:39:06]

We have already 2 RE libraries (ICU and one in V8). The key difference of this
one is:

- the algorithm is guaranteed to be linear in the input size (not possible to
generate DoS attacks by extension supplied RegEx)
- the engine does not generate byte code (a safety concern that allows us to
execute extension supplied RegEx in the browser process)

I talked to the V8 guys about using the V8 RegEx implementation and it requires
a significant setup (it does not work without a V8 context) and has to run in a
sandboxed process. Both are significant disadvantages four our use case (using
it for extensions; in particular the declarative web request API).

+Version: 83:c79416ca4228
+Date: 2012-06-20
+Revision: 83:c79416ca4228
+License: BSD 3-Clause License
+License File: LICENSE
+Security Critical: yes
+
+Description:
+RE2 is a fast, safe, thread-friendly alternative to backtracking regular
+expression engines like those used in PCRE, Perl, and Python.
+
+Local Modifications (to be applied in this order):
+- Dropped POSIX configuration (remove-posix-option.patch)

[Mark Mentovai, 2012/07/24 14:56:29]

Do you want to put the patches into their own directory for better organization?

[battre, 2012/07/24 16:24:07]

Done.

+- Support for Windows (re2-msvc9-chrome.patch)
+- Remove valgrind specific code that exists in chromium already
+  (remove-valgrind-code.patch)