Adds toolchain for freebsd. (#794)

* Adds toolchain for freebsd.

* Address buildifier lint warnings.

* Use /usr/bin/env bash

* Leave the Linux-specific shebang alone.

* Adds note about Bazel CI issue requesting for FreeBSD support and experimental status.

* Fix typo.

* Clean up trailing whitespace.

* Updates bazel-skylib version for tests to pass on FreeBSD.

* Update foreign_cc/repositories.bzl

Co-authored-by: UebelAndre <github@uebelandre.com>

.github/docs-0.1.0.patch

@@ -4,7 +4,7 @@ index a5a37ac..e381ce8 100644
 +++ b/docs/BUILD.bazel
 @@ -35,7 +35,7 @@ genrule(
      cmd = """cat << EOF > $@
- #!/bin/bash
+ #!/usr/bin/env bash
  set -e
 -cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/README.md
 +cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/src/index.md

.github/docs-0.2.0.patch

@@ -4,7 +4,7 @@ index a5a37ac..091e679 100644
 +++ b/docs/BUILD.bazel
 @@ -35,7 +35,7 @@ genrule(
      cmd = """cat << EOF > $@
- #!/bin/bash
+ #!/usr/bin/env bash
  set -e
 -cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/README.md
 +cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/src/index.md

.github/docs-0.3.0.patch

@@ -10,7 +10,7 @@ index 461df15..efa4c26 100644
 +    srcs = DOCS_TARGETS + ["index.md"],
      outs = ["generate_docs.sh"],
      cmd = """cat << EOF > $@
- #!/bin/bash
+ #!/usr/bin/env bash
  set -euo pipefail
 -cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:flatten_docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/flatten.md
 -cat \\$${BUILD_WORKSPACE_DIRECTORY}/$(location //:cmake_docs) > \\$${BUILD_WORKSPACE_DIRECTORY}/cmake.md

README.md

@@ -30,3 +30,10 @@ For more generalized updates, please see [NEWS.md](./NEWS.md) or checkout the
 [ccb]: https://docs.bazel.build/versions/master/be/c-cpp.html#cc_binary
 [ccl]: https://docs.bazel.build/versions/master/be/c-cpp.html#cc_library
 [cct]: https://docs.bazel.build/versions/master/be/c-cpp.html#cc_toolchain
+
+## Caveats
+
+* FreeBSD support is currently experimental and on a best-effort basis.
+  Google currently doesn't have a CI test environment for FreeBSD,
+  but please make your voice heard by upvoting this
+  [issue](https://github.com/bazelbuild/continuous-integration/issues/258).

docs/BUILD.bazel

@@ -92,7 +92,7 @@ export COMMIT="$$(cat bazel-out/stable-status.txt | grep STABLE_SCM_VERSION | cu
 export SHORT_COMMIT="$$(cat bazel-out/stable-status.txt | grep STABLE_SCM_SHORT_VERSION | cut -d' ' -f2)"
 export RELEASE="$$(cat bazel-out/stable-status.txt | grep STABLE_RELEASE | cut -d' ' -f2)"
 cat << EOF > $@
-#!/bin/bash
+#!/usr/bin/env bash
 set -euo pipefail
 
 short_commit="$${SHORT_COMMIT}"

docs/gen_header.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 

docs/tools/workspace_status.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -euo pipefail
 

examples/configure_with_bazel_transitive/simple_lib/configure

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 echo "# simple" > Makefile
 
 echo "CC = ${CC}" > Makefile

examples/make_simple/code/cxx_wrapper.sh

@@ -1,4 +1,7 @@
-#!/bin/bash -eu
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
 
 if [[ $(uname) == *"NT"* ]]; then
  # If Windows

examples/ninja_simple/code/clang_wrapper.sh

@@ -1,4 +1,7 @@
-#!/bin/bash -eu
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
 
 if [[ $(uname) == *"NT"* ]]; then
  # If Windows

examples/third_party/gn/gn_test.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 if [[ ! -e "$GN" ]]; then
     echo "gn does not exist"

examples/third_party/gn/patch.gen_ninja.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 if [[ "$OSTYPE" == "win32" ]]; then
     python.exe build/gen.py --no-last-commit-position

foreign_cc/private/framework/toolchains/freebsd_commands.bzl

@@ -0,0 +1,263 @@
+"""Define default foreign_cc framework commands.
+
+FreeBSD doesn't use bash by default but users can install it
+using:
+
+    $ sudo pkg install bash
+
+Also, Bash is one of the prerequisites for Bazel:
+https://docs.bazel.build/versions/main/install-compile-source.html#bootstrap-unix-prereq
+"""
+
+load(":commands.bzl", "FunctionAndCallInfo")
+
+def shebang():
+    return "#!/usr/bin/env bash"
+
+def script_extension():
+    return ".sh"
+
+def pwd():
+    return "$(pwd)"
+
+def echo(text):
+    return "echo \"{text}\"".format(text = text)
+
+def export_var(name, value):
+    return "export {name}={value}".format(name = name, value = value)
+
+def local_var(name, value):
+    return "local {name}={value}".format(name = name, value = value)
+
+def use_var(name):
+    return "$" + name
+
+def env():
+    return "env"
+
+def path(expression):
+    return "export PATH=\"{expression}:$PATH\"".format(expression = expression)
+
+def touch(path):
+    return "touch " + path
+
+def enable_tracing():
+    return "set -x"
+
+def disable_tracing():
+    return "set +x"
+
+def mkdirs(path):
+    return "mkdir -p " + path
+
+def rm_rf(path):
+    return "rm -rf " + path
+
+def if_else(condition, if_text, else_text):
+    return """\
+if [ {condition} ]; then
+  {if_text}
+else
+  {else_text}
+fi
+""".format(condition = condition, if_text = if_text, else_text = else_text)
+
+# buildifier: disable=function-docstring
+def define_function(name, text):
+    lines = []
+    lines.append("function " + name + "() {")
+    for line_ in text.splitlines():
+        lines.append("  " + line_)
+    lines.append("}")
+    return "\n".join(lines)
+
+def replace_in_files(dir, from_, to_):
+    return FunctionAndCallInfo(
+        text = """\
+if [ -d "$1" ]; then
+  SAVEIFS=$IFS
+  IFS=$'\n'
+  # Find all real files. Symlinks are assumed to be relative to something within the directory we're seaching and thus ignored
+  local files=$(find -P -f $1 \\( -type f -and \\( -name "*.pc" -or -name "*.la" -or -name "*-config" -or -name "*.mk" -or -name "*.cmake" \\) \\))
+  IFS=$SAVEIFS
+  for file in ${files[@]}; do
+    local backup=$(mktemp)
+    touch -r "${file}" "${backup}"
+    sed -i '' -e 's@'"$2"'@'"$3"'@g' "${file}"
+    if [[ "$?" -ne "0" ]]; then
+      exit 1
+    fi
+    touch -r "${backup}" "${file}"
+    rm "${backup}"
+  done
+fi
+""",
+    )
+
+def copy_dir_contents_to_dir(source, target):
+    # Beause FreeBSD `cp` doesn't have `--no-copy-directory`, we have to
+    # do something more complex for this environment.
+    return """\
+if [[ -d "{source}" ]]; then
+  cp -L -R "{source}"/* "{target}"
+else
+  cp -L -R "{source}" "{target}"
+fi
+find {target} -type f -exec touch -r "{source}" "{{}}" \\;
+""".format(
+        source = source,
+        target = target,
+    )
+
+def symlink_contents_to_dir(source, target):
+    text = """\
+if [[ -z "$1" ]]; then
+  echo "arg 1 to symlink_contents_to_dir is unexpectedly empty"
+  exit 1
+fi
+if [[ -z "$2" ]]; then
+  echo "arg 2 to symlink_contents_to_dir is unexpectedly empty"
+  exit 1
+fi
+local target="$2"
+mkdir -p "$target"
+if [[ -f "$1" ]]; then
+  ##symlink_to_dir## "$1" "$target"
+elif [[ -L "$1" && ! -d "$1" ]]; then
+  local actual=$(readlink "$1")
+  ##symlink_contents_to_dir## "$actual" "$target"
+elif [[ -d "$1" ]]; then
+  SAVEIFS=$IFS
+  IFS=$'\n'
+  local children=($(find "$1/" -maxdepth 1 -mindepth 1))
+  IFS=$SAVEIFS
+  for child in "${children[@]:-}"; do
+    ##symlink_to_dir## "$child" "$target"
+  done
+fi
+"""
+    return FunctionAndCallInfo(text = text)
+
+def symlink_to_dir(source, target):
+    text = """\
+if [[ -z "$1" ]]; then
+  echo "arg 1 to symlink_to_dir is unexpectedly empty"
+  exit 1
+fi
+if [[ -z "$2" ]]; then
+  echo "arg 2 to symlink_to_dir is unexpectedly empty"
+  exit 1
+fi
+local target="$2"
+mkdir -p "$target"
+if [[ -f "$1" ]]; then
+  # In order to be able to use `replace_in_files`, we ensure that we create copies of specfieid
+  # files so updating them is possible.
+  if [[ "$1" == *.pc || "$1" == *.la || "$1" == *-config || "$1" == *.mk || "$1" == *.cmake ]]; then
+    dest="$target/$(basename $1)"
+    cp "$1" "$dest" && chmod +w "$dest" && touch -r "$1" "$dest"
+  else
+    ln -s -f "$1" "$target"
+  fi
+elif [[ -L "$1" && ! -d "$1" ]]; then
+  cp -pR "$1" "$2"
+elif [[ -d "$1" ]]; then
+  SAVEIFS=$IFS
+  IFS=$'\n'
+  local children=($(find "$1/" -maxdepth 1 -mindepth 1))
+  IFS=$SAVEIFS
+  local dirname=$(basename "$1")
+  mkdir -p "$target/$dirname"
+  for child in "${children[@]:-}"; do
+    if [[ -n "$child" && "$dirname" != *.ext_build_deps ]]; then
+      ##symlink_to_dir## "$child" "$target/$dirname"
+    fi
+  done
+else
+  echo "Can not copy $1"
+fi
+"""
+    return FunctionAndCallInfo(text = text)
+
+def script_prelude():
+    return "set -euo pipefail"
+
+def increment_pkg_config_path(source):
+    text = """\
+local children=$(find "$1/" -mindepth 1 -name '*.pc')
+# assume there is only one directory with pkg config
+for child in $children; do
+  export PKG_CONFIG_PATH="$${PKG_CONFIG_PATH:-}$$:$(dirname $child)"
+  return
+done
+"""
+    return FunctionAndCallInfo(text = text)
+
+def cat(filepath):
+    return "cat \"{}\"".format(filepath)
+
+def redirect_out_err(from_process, to_file):
+    return from_process + " &> " + to_file
+
+def assert_script_errors():
+    return "set -e"
+
+def cleanup_function(on_success, on_failure):
+    text = "\n".join([
+        "local ecode=$?",
+        "if [ $ecode -eq 0 ]; then",
+        on_success,
+        "else",
+        on_failure,
+        "fi",
+    ])
+    return FunctionAndCallInfo(text = text, call = "trap \"cleanup_function\" EXIT")
+
+def children_to_path(dir_):
+    text = """\
+if [ -d {dir_} ]; then
+  local tools=$(find $EXT_BUILD_DEPS/bin/ -maxdepth 1 -mindepth 1)
+  for tool in $tools;
+  do
+    if  [[ -d \"$tool\" ]] || [[ -L \"$tool\" ]]; then
+      export PATH=$PATH:$tool
+    fi
+  done
+fi""".format(dir_ = dir_)
+    return FunctionAndCallInfo(text = text)
+
+def define_absolute_paths(dir_, abs_path):
+    return "##replace_in_files## {dir_} {REPLACE_VALUE} {abs_path}".format(
+        dir_ = dir_,
+        REPLACE_VALUE = "\\${EXT_BUILD_DEPS}",
+        abs_path = abs_path,
+    )
+
+def replace_absolute_paths(dir_, abs_path):
+    return "##replace_in_files## {dir_} {abs_path} {REPLACE_VALUE}".format(
+        dir_ = dir_,
+        REPLACE_VALUE = "\\${EXT_BUILD_DEPS}",
+        abs_path = abs_path,
+    )
+
+def define_sandbox_paths(dir_, abs_path):
+    return "##replace_in_files## {dir_} {REPLACE_VALUE} {abs_path}".format(
+        dir_ = dir_,
+        REPLACE_VALUE = "\\${EXT_BUILD_ROOT}",
+        abs_path = abs_path,
+    )
+
+def replace_sandbox_paths(dir_, abs_path):
+    return "##replace_in_files## {dir_} {abs_path} {REPLACE_VALUE}".format(
+        dir_ = dir_,
+        REPLACE_VALUE = "\\${EXT_BUILD_ROOT}",
+        abs_path = abs_path,
+    )
+
+def replace_symlink(file):
+    return """\
+if [[ -L "{file}" ]]; then
+  target="$(readlink -f "{file}")"
+  rm "{file}" && cp -a "${{target}}" "{file}"
+fi
+""".format(file = file)

foreign_cc/private/framework/toolchains/mappings.bzl

@@ -25,6 +25,12 @@ TOOLCHAIN_MAPPINGS = [
         ],
         file = Label("@rules_foreign_cc//foreign_cc/private/framework/toolchains:linux_commands.bzl"),
     ),
+    _toolchain_mapping(
+        exec_compatible_with = [
+            "@platforms//os:freebsd",
+        ],
+        file = Label("@rules_foreign_cc//foreign_cc/private/framework/toolchains:freebsd_commands.bzl"),
+    ),
     _toolchain_mapping(
         exec_compatible_with = [
             "@platforms//os:windows",

foreign_cc/repositories.bzl

@@ -63,9 +63,11 @@ def rules_foreign_cc_dependencies(
     maybe(
         http_archive,
         name = "bazel_skylib",
+        # `main` as of 2021-10-27
+        # Release request: https://github.com/bazelbuild/bazel-skylib/issues/336
         urls = [
-            "https://github.com/bazelbuild/bazel-skylib/releases/download/1.1.1/bazel-skylib-1.1.1.tar.gz",
-            "https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.1.1/bazel-skylib-1.1.1.tar.gz",
+            "https://github.com/bazelbuild/bazel-skylib/archive/6e30a77347071ab22ce346b6d20cf8912919f644.zip",
         ],
-        sha256 = "c6966ec828da198c5d9adbaa94c05e3a1c7f21bd012a0b29ba8ddbccb2c93b0d",
+        strip_prefix = "bazel-skylib-6e30a77347071ab22ce346b6d20cf8912919f644",
+        sha256 = "247361e64b2a85b40cb45b9c071e42433467c6c87546270cbe2672eb9f317b5a",
     )

test/BUILD.bazel

@@ -29,10 +29,17 @@ config_setting(
     visibility = ["//visibility:private"],
 )
 
+config_setting(
+    name = "freebsd",
+    constraint_values = ["@platforms//os:freebsd"],
+    visibility = ["//visibility:private"],
+)
+
 diff_test(
     name = "shell_script_inner_fun_test",
     file1 = ":shell_script_inner_fun",
     file2 = select({
+        ":freebsd": "expected/inner_fun_text_freebsd.txt",
         ":macos": "expected/inner_fun_text_macos.txt",
         "//conditions:default": "expected/inner_fun_text.txt",
     }),
@@ -58,6 +65,7 @@ symlink_contents_to_dir_test_rule(
 diff_test(
     name = "shell_method_symlink_contents_to_dir_test",
     file1 = select({
+        ":freebsd": "expected/out_symlinked_dirs_freebsd.txt",
         ":macos": "expected/out_symlinked_dirs_macos.txt",
         "//conditions:default": "expected/out_symlinked_dirs.txt",
     }),

test/expected/inner_fun_text_freebsd.txt

@@ -0,0 +1,67 @@
+function symlink_contents_to_dir() {
+if [[ -z "$1" ]]; then
+echo "arg 1 to symlink_contents_to_dir is unexpectedly empty"
+exit 1
+fi
+if [[ -z "$2" ]]; then
+echo "arg 2 to symlink_contents_to_dir is unexpectedly empty"
+exit 1
+fi
+local target="$2"
+mkdir -p "$target"
+if [[ -f "$1" ]]; then
+symlink_to_dir "$1" "$target"
+elif [[ -L "$1" && ! -d "$1" ]]; then
+local actual=$(readlink "$1")
+symlink_contents_to_dir "$actual" "$target"
+elif [[ -d "$1" ]]; then
+SAVEIFS=$IFS
+IFS=$'
+'
+local children=($(find "$1/" -maxdepth 1 -mindepth 1))
+IFS=$SAVEIFS
+for child in "${children[@]:-}"; do
+symlink_to_dir "$child" "$target"
+done
+fi
+}
+function symlink_to_dir() {
+if [[ -z "$1" ]]; then
+echo "arg 1 to symlink_to_dir is unexpectedly empty"
+exit 1
+fi
+if [[ -z "$2" ]]; then
+echo "arg 2 to symlink_to_dir is unexpectedly empty"
+exit 1
+fi
+local target="$2"
+mkdir -p "$target"
+if [[ -f "$1" ]]; then
+# In order to be able to use `replace_in_files`, we ensure that we create copies of specfieid
+# files so updating them is possible.
+if [[ "$1" == *.pc || "$1" == *.la || "$1" == *-config || "$1" == *.mk || "$1" == *.cmake ]]; then
+dest="$target/$(basename $1)"
+cp "$1" "$dest" && chmod +w "$dest" && touch -r "$1" "$dest"
+else
+ln -s -f "$1" "$target"
+fi
+elif [[ -L "$1" && ! -d "$1" ]]; then
+cp -pR "$1" "$2"
+elif [[ -d "$1" ]]; then
+SAVEIFS=$IFS
+IFS=$'
+'
+local children=($(find "$1/" -maxdepth 1 -mindepth 1))
+IFS=$SAVEIFS
+local dirname=$(basename "$1")
+mkdir -p "$target/$dirname"
+for child in "${children[@]:-}"; do
+if [[ -n "$child" && "$dirname" != *.ext_build_deps ]]; then
+symlink_to_dir "$child" "$target/$dirname"
+fi
+done
+else
+echo "Can not copy $1"
+fi
+}
+symlink_contents_to_dir $SOURCE_DIR $TARGET_DIR

test/expected/out_symlinked_dirs_freebsd.txt

@@ -0,0 +1,2 @@
+header1.h
+header2.h