Add initial prototype for the GN meta-buildsystem.

Add initial prototype for the GN meta-buildsystem.

This is currently not hooked into the build. To build, add a reference to the
gn.gyp file to build/all.gyp

R=darin@chromium.org, scottmg@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=214254

[brettw, 2013-07-29 18:00:23]

darin, please review toplevel .gn file addition.

scottmg: please review the 12,952 lines of C++ code.

[scottmg, 2013-07-29 18:13:39]

On 2013/07/29 18:00:23, brettw wrote:
> darin, please review toplevel .gn file addition.
> 
> scottmg: please review the 12,952 lines of C++ code.

i don't love the toplevel .gn addition :)

i'll, uh, get back to you on the c++. (i can't believe reitveld didn't barf.)

[scottmg, 2013-07-29 19:14:49]

On 2013/07/29 18:13:39, scottmg wrote:
> On 2013/07/29 18:00:23, brettw wrote:
> > darin, please review toplevel .gn file addition.
> > 
> > scottmg: please review the 12,952 lines of C++ code.

rubberstamp lgtm if you feel you need that :) i'll try and go through the code
to get a handle on it sometime this week.

(should it be named "tools/experimental/gn" or something, or do we not care?)

[darin (slow to review), 2013-07-29 21:39:49]

rubber stamp LGTM

[tfarina, 2013-07-29 21:45:06]

Can you add a README with a simple overview of what GN is? It seems this has
been developed/used internally.

[tfarina, 2013-07-29 21:51:23]

Looks like we will transition from gyp to .gn? Is there a bug that you could
link this to?

https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn
File tools/gn/BUILD.gn (right):

https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn#newcode1
tools/gn/BUILD.gn:1: static_library("gn_lib") {
this looks very similar to the BUILD file shown in
http://google-engtools.blogspot.com.br/2011/08/build-in-cloud-how-build-syste...

[darin (slow to review), 2013-07-29 21:55:34]

On 2013/07/29 21:51:23, tfarina wrote:
> Looks like we will transition from gyp to .gn? Is there a bug that you could
> link this to?
> 
> https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn
> File tools/gn/BUILD.gn (right):
> 
> https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn#newcode1
> tools/gn/BUILD.gn:1: static_library("gn_lib") {
> this looks very similar to the BUILD file shown in
>
http://google-engtools.blogspot.com.br/2011/08/build-in-cloud-how-build-syste...

Hi Thiago,

I agree that a README file is warranted.  Thanks for flagging that.
Note: This is just an experimental tool that Brett is developing.
He wanted to publish it here so that others could join him in
working on it further.  It is not clear yet what a transition to
this tool from GYP might look like.  We are far from that point.
I think there's just a lot of interest in improving upon GYP, and
this is a potential direction.

-Darin

[tfarina, 2013-07-29 22:33:48]

On 2013/07/29 21:55:34, darin wrote:
> On 2013/07/29 21:51:23, tfarina wrote:
> > Looks like we will transition from gyp to .gn? Is there a bug that you could
> > link this to?
> > 
> > https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn
> > File tools/gn/BUILD.gn (right):
> > 
> > https://codereview.chromium.org/21114002/diff/1/tools/gn/BUILD.gn#newcode1
> > tools/gn/BUILD.gn:1: static_library("gn_lib") {
> > this looks very similar to the BUILD file shown in
> >
>
http://google-engtools.blogspot.com.br/2011/08/build-in-cloud-how-build-syste...
> 
> Hi Thiago,
> 
> I agree that a README file is warranted.  Thanks for flagging that.
> Note: This is just an experimental tool that Brett is developing.
> He wanted to publish it here so that others could join him in
> working on it further.  It is not clear yet what a transition to
> this tool from GYP might look like.  We are far from that point.
> I think there's just a lot of interest in improving upon GYP, and
> this is a potential direction.
> 
This is an exciting tool! From what I can see (I just looked briefly over some
files) it seems to resemble cmake? Well, I'm excited to see this code landing on
Chromium (a C++ tool to generate ninja files based on BUILD files, that should
be way faster that the current gyp alternative). Besides README, could you also
add an OWNERS file? Also, sorry for disturbing this review. :(

[brettw, 2013-07-29 23:30:35]

Committed patchset #2 manually as r214254 (presubmit successful).