skia2/include/utils
Kevin Lubick 1f8c31b101 [infra] Add initial Bazel rules and files
These rules can be used to build our GMs on WASM+WebGL and
libskia.a with just the CPU backend (and most other features
turned off).

This can be done with the following commands:
  - bazel build //modules/canvaskit:gm-bindings-wasm --gpu_backend=gl_backend --with_gl_standard=webgl_standard
  - bazel build :skia-core --config clang

This pivots slightly from http://review.skia.org/463517
by using config_settings [1] instead of platforms for
the optional features that we control. This pivot was
suggested in [2]

We have BUILD.bazel files in many of the subdirectories
that specify filegroups for the appropriate files. In
an effort to make //BUILD.bazel more readable, it is
the responsibility of these subfolders to deal with
conditionally including certain .h or .cpp files.
This is done using select statements and config_settings
or platform constraints as necessary.

For example, src/gpu/BUILD.bazel will different private
filegroups for each of the supported gpu backends [3]
and a more-visible filegroup called "srcs" that has
the right selection of the private files to be used
for compilation.

An effort has been made to avoid using glob() in our
BUILD.bazel files. These file lists were made by using
`ls -1` and some regex to add in quotes. We might want
to make a helper script to assist with that, if necessary.

To specify which options we have, the settings in
//bazel/common_config_settings/BUILD.bazel have been
redesigned. They make use of a macro `string_flag_with_values`
that removes the boilerplate. Patchset 36 shows what the
file looks like w/o the macro.

The top level BUILD.bazel file will still need to use
some logic to handle defines, because local_defines is
a list of strings, not a list of labels [4].

Suggested Review Order:
  - WORKSPACE.bazel to see the new dependencies on the
    emsdk toolchain and bazel_skylib
  - bazel/common_config_settings/* to see the few settings
    defined (we have more to define, see BUILD.gn and
    //gn/skia.gni for ideas)
  - BUILD.bazel to see the "skia-core" cc_library rule.
    See also "gms" and "tests"
  - modules/canvaskit/BUILD.bazel to see the use of
    the emscripten "wasm_cc_binary" rule, which depends
    on the "skia-core", "gms", and "tests" rule. Note that
    it only builds some of the gms as a proof of concept.
  - The other BUILD.bazel files. Some of these are not
    platform or feature dependent (e.g. pathops). Others
    are (e.g. gpu).
  - All other files.

[1] https://docs.bazel.build/versions/4.2.1/skylark/config.html#user-defined-build-settings
[2] https://github.com/emscripten-core/emsdk/pull/920
[3] In this CL, that's just the webgl one.
[4] https://docs.bazel.build/versions/main/be/c-cpp.html#cc_library.local_defines

Change-Id: Ieecf9c106d5e3a6ae97d13d66be06b4b3c207089
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/458637
Reviewed-by: Ben Wagner <bungeman@google.com>
Reviewed-by: Leandro Lovisolo <lovisolo@google.com>
Owners-Override: Kevin Lubick <kjlubick@google.com>
2021-11-09 12:32:25 +00:00
..
mac Enable ClangTidy check modernize-use-nullptr. 2020-08-14 16:14:30 +00:00
BUILD.bazel [infra] Add initial Bazel rules and files 2021-11-09 12:32:25 +00:00
SkAnimCodecPlayer.h Handle EXIF orientation in SkAnimCodecPlayer 2020-11-12 14:43:47 +00:00
SkBase64.h Remove deprecated SkBase64 interface. 2021-01-20 17:47:16 +00:00
SkCamera.h remove legacy utils for camera3d 2020-05-18 02:05:28 +00:00
SkCanvasStateUtils.h rewrite includes to not need so much -Ifoo 2019-04-24 16:27:11 +00:00
SkCustomTypeface.h SkCustomTypefaceBuilder to set SkFontStyle 2020-08-19 00:09:55 +00:00
SkEventTracer.h Reenable Wdeprecated-copy-dtor 2021-02-16 17:53:28 +00:00
SkNoDrawCanvas.h remove dead code from old drawimage virtuals 2021-01-21 01:26:15 +00:00
SkNullCanvas.h rewrite includes to not need so much -Ifoo 2019-04-24 16:27:11 +00:00
SkNWayCanvas.h Rename/simplify SkCanvas::resetClip() and make recordable 2021-07-23 19:05:42 +00:00
SkOrderedFontMgr.h Purge 2020 picture versions 2021-07-19 19:35:49 +00:00
SkPaintFilterCanvas.h Feed all top-level GPU accessors through skgpu::BaseDevice (take 2) 2021-07-26 14:56:37 +00:00
SkParse.h rewrite includes to not need so much -Ifoo 2019-04-24 16:27:11 +00:00
SkParsePath.h [svgcanvas] Add support for relative path encoding 2021-05-11 17:44:59 +00:00
SkRandom.h Wsign-conversion for public headers 2020-06-02 12:34:54 +00:00
SkShadowUtils.h Add SkShadowUtils::GetLocalBounds. 2021-01-11 17:53:47 +00:00
SkTextUtils.h Use SkTextEncoding enum instead of macros. 2019-05-07 20:54:16 +00:00
SkTraceEventPhase.h make includes available for flutter 2018-06-21 18:12:47 +00:00