tree 286821de395ff8a9e2a520c887be2909ea38fb8a
parent 2dd9331a704147be787823a169de51df8d3526bb
author Dirk Pranke <dpranke@google.com> 1738014654 -0800
committer GN LUCI <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1738019400 -0800

Revert "Speed-up GN with custom OutputStream interface."

This reverts commit 2dd9331a704147be787823a169de51df8d3526bb.

Reason for revert: Breaks chromium build.

Original change's description:
> Speed-up GN with custom OutputStream interface.
>
> For legacy reasons, std::ostream is a very inefficient
> interface for appending text to an output stream, something
> that GN does a lot.
>
> This CL speeds GN by:
>
> - Introducing a new OutputStream abstract class to replace
>   std::ostream entirely. It provides the same API subset needed
>   by the rest of the code to minimize changes.
>   See gn/output_stream.h.
>
> - Adding StringOutputStream, a concrete OutputStream to store
>   the result into an std::stream. This replaces
>   std::ostringstream. See gn/output_stream.h.
>
> - Adding FileOutputStream, a concrete OutputStream to store
>   the result into a file. This replaces std::ofstream.
>   See gn/output_stream.h.
>
> - Making StringOutputBuffer an OutputStream derived class
>   as well, simplify its use as an output destination
>   for many calls.
>
> - Adjusting all call sites appropriately.
>
> - Replace `out << std::endl` statements with
>   `out << "\n"` as the type of `std::endl` is unspecified
>   by the standard and hard to guess at compile time for
>   implementing an OutputStream::operator<< overload.
>
> - Remove obsolete `#include <sstream>` statements
>   from the sources. Same for `<fstream>`.
>
> Benchmarking shows that on Linux, this saves about 6% of
> `gn gen` time for a small Fuchsia build graph
> (6.27s -> 5.90s), and that the stripped LTO-optimized
> executable, is reduced by about 50 kiB.
>
> Change-Id: I00c7e1db67c59ab57c64756382683159df0662a6
> Reviewed-on: https://gn-review.googlesource.com/c/gn/+/18140
> Reviewed-by: Dirk Pranke <dpranke@google.com>
> Commit-Queue: David Turner <digit@google.com>

TBR=dpranke@google.com,tikuta@google.com,digit@google.com,gn-scoped@luci-project-accounts.iam.gserviceaccount.com

Change-Id: I8c451f9b698f0e0fbcea843a903c5e6148e8df18
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/18160
Commit-Queue: Dirk Pranke <dpranke@google.com>
Reviewed-by: Dirk Pranke <dpranke@google.com>
Reviewed-by: Takuto Ikuta <tikuta@google.com>