third_party: Copybara script for importing fit::function from Fuchsia

pw::Function's implementation will be replaced with fit::function from Fuchsia. fit::function is more advanced than pw::Function and supports features like dynamic allocation and sharing callables between multiple fit::function instances. This copy.bara.sky script will be used to import the fit::function sources and transform them as needed. Change-Id: Iab420eb4c9fca13278f4a0cd19d88c17eea4456b Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/103548 Pigweed-Auto-Submit: Wyatt Hepler <[email protected]> Commit-Queue: Auto-Submit <[email protected]> Reviewed-by: Vadim Spivak <[email protected]> Reviewed-by: Ted Pudlik <[email protected]>
google · Jul 29, 2022 · 1d411dc · 1d411dc
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commit 1d411dc
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diff --git a/docs/BUILD.gn b/docs/BUILD.gn
@@ -78,6 +78,7 @@ group("third_party_docs") {
   deps = [
     "$dir_pigweed/third_party/boringssl:docs",
     "$dir_pigweed/third_party/freertos:docs",
+    "$dir_pigweed/third_party/fuchsia:docs",
     "$dir_pigweed/third_party/googletest:docs",
     "$dir_pigweed/third_party/nanopb:docs",
     "$dir_pigweed/third_party/tinyusb:docs",

diff --git a/pw_presubmit/py/pw_presubmit/format_code.py b/pw_presubmit/py/pw_presubmit/format_code.py
@@ -320,11 +320,15 @@ def extensions(self):
 GN_FORMAT: CodeFormat = CodeFormat('GN', FileFilter(endswith=('.gn', '.gni')),
                                    check_gn_format, fix_gn_format)
 
-# TODO(pwbug/191): Add real code formatting support for Bazel and CMake
 BAZEL_FORMAT: CodeFormat = CodeFormat(
     'Bazel', FileFilter(endswith=('BUILD', '.bazel', '.bzl')),
     check_bazel_format, fix_bazel_format)
 
+COPYBARA_FORMAT: CodeFormat = CodeFormat('Copybara',
+                                         FileFilter(endswith=('.bara.sky', )),
+                                         check_bazel_format, fix_bazel_format)
+
+# TODO(b/234881054): Add real code formatting support for CMake
 CMAKE_FORMAT: CodeFormat = CodeFormat(
     'CMake', FileFilter(endswith=('CMakeLists.txt', '.cmake')),
     check_trailing_space, fix_trailing_space)
@@ -347,6 +351,7 @@ def extensions(self):
     PYTHON_FORMAT,
     GN_FORMAT,
     BAZEL_FORMAT,
+    COPYBARA_FORMAT,
     CMAKE_FORMAT,
     RST_FORMAT,
     MARKDOWN_FORMAT,
@@ -407,7 +412,12 @@ def __init__(self,
         for path in self.paths:
             for code_format in code_formats:
                 if code_format.filter.matches(path):
+                    _LOG.debug('Formatting %s as %s', path,
+                               code_format.language)
                     self._formats[code_format].append(path)
+                    break
+            else:
+                _LOG.debug('No formatter found for %s', path)
 
     def check(self) -> Dict[Path, str]:
         """Returns {path: diff} for files with incorrect formatting."""

diff --git a/third_party/fuchsia/BUILD.gn b/third_party/fuchsia/BUILD.gn
@@ -0,0 +1,21 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+import("//build_overrides/pigweed.gni")
+
+import("$dir_pw_docgen/docs.gni")
+
+pw_doc_group("docs") {
+  sources = [ "docs.rst" ]
+}
diff --git a/third_party/fuchsia/copy.bara.sky b/third_party/fuchsia/copy.bara.sky
@@ -0,0 +1,72 @@
+# Copyright 2022 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+
+fuchsia_repo_files = [
+    ".clang-format",
+    # fit
+    "sdk/lib/fit/include/lib/fit/function.h",
+    "sdk/lib/fit/include/lib/fit/function_internal.h",
+    "sdk/lib/fit/include/lib/fit/nullable.h",
+    "sdk/lib/fit/include/lib/fit/traits.h",
+    "sdk/lib/fit/include/lib/fit/utility_internal.h",
+    # stdcompat
+    "sdk/lib/stdcompat/include/lib/stdcompat/optional.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/type_traits.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/utility.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/version.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/internal/constructors.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/internal/exception.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/internal/storage.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/internal/type_traits.h",
+    "sdk/lib/stdcompat/include/lib/stdcompat/internal/utility.h",
+]
+
+# Replace __builtin_abort with PW_ASSERT.
+replace_builtin_abort_paths = glob([
+    "sdk/lib/fit/include/lib/fit/function_internal.h",
+])
+
+replace_builtin_abort = [
+    core.replace(
+        paths = replace_builtin_abort_paths,
+        before = "namespace fit {",
+        after = "#include \"pw_assert/assert.h\"\n\nnamespace fit {",
+    ),
+    core.replace(
+        paths = replace_builtin_abort_paths,
+        before = "__builtin_abort()",
+        after = "PW_ASSERT(false)",
+    ),
+]
+
+core.workflow(
+    name = "default",
+    description = "Imports files from Fuchsia's fit library",
+    origin = git.origin(
+        url = "https://fuchsia.googlesource.com/fuchsia",
+        ref = "main",
+    ),
+    destination = git.gerrit_destination(
+        url = "https://pigweed.googlesource.com/pigweed/pigweed",
+        fetch = "main",
+        checker = leakr.disable_check("Syncing between OSS projects"),
+    ),
+    origin_files = glob(fuchsia_repo_files),
+    destination_files = glob(["third_party/fuchsia/repo/**"]),
+    authoring = authoring.pass_thru("Fuchsia Authors <[email protected]>"),
+    transformations = replace_builtin_abort + [
+        core.move("", "third_party/fuchsia/repo"),
+        metadata.replace_message("third_party/fuchsia: Copybara import of fit library"),
+    ],
+)
diff --git a/third_party/fuchsia/docs.rst b/third_party/fuchsia/docs.rst
@@ -0,0 +1,55 @@
+.. _module-pw_third_party_fuchsia:
+
+=================
+Fuchsia libraries
+=================
+`Fuchsia <https://fuchsia.dev/>`_ is a modern open source operating system
+developed by Google.
+
+Pigweed does not use the Fuchsia operating system itself, but uses some
+low-level libraries developed for it.
+
+--------
+Features
+--------
+Parts of two Fuchsia libraries are used in Pigweed:
+
+- `FIT <https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/lib/fit/>`_ --
+  Portable library of low-level C++ features.
+- `stdcompat <https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/lib/stdcompat/>`_ --
+  Implements newer C++ features for older standards.
+
+--------------------
+Code synchronization
+--------------------
+Unlike other third party libraries used by Pigweed, some Fuchsia source code is
+included in tree. A few factors drove this decision:
+
+- Core Pigweed features like :cpp:type:`pw::Function` depend on these Fuchsia
+  libraries. Including the source in-tree avoids having Pigweed require an
+  an external repository.
+- The Fuchsia repository is too large to require downstream projects to clone.
+
+If Fuchsia moves ``stdcompat`` and ``fit`` to separate repositories, the
+decision to include Fuchsia code in tree may be reconsidered.
+
+Process
+=======
+Code is synchronized between the `Fuchsia repository
+<https://fuchsia.googlesource.com/fuchsia>`_ and the `Pigweed repository
+<https://pigweed.googlesource.com/pigweed/pigweed>`_ using the
+`third_party/fuchsia/copy.bara.sky
+<https://cs.opensource.google/pigweed/pigweed/+/main:third_party/fuchsia/copy.bara.sky>`_)
+`Copybara <https://github.com/google/copybara>`_ script.
+
+To synchronize with the Fuchsia repository, run the ``copybara`` tool with the
+script:
+
+.. code-block:: bash
+
+   copybara third_party/fuchsia/copy.bara.sky
+
+That creates a Gerrit change with updates from the Fuchsia repo, if any.
+
+Files are synced from Fuchsia repository to their original paths under the
+``third_party/fuchsia/repo`` directory in Pigweed.