rules_foreign_cc/tools/build_defs/cmake.bzl

""" Defines the rule for building external library with CMake
"""

load(
    "//tools/build_defs:framework.bzl",
    "CC_EXTERNAL_RULE_ATTRIBUTES",
    "cc_external_rule_impl",
    "create_attrs",
)
load(
    "//tools/build_defs:detect_root.bzl",
    "detect_root",
)
load(
    "//tools/build_defs:cc_toolchain_util.bzl",
    "get_flags_info",
    "get_tools_info",
    "is_debug_mode",
)
load(":cmake_script.bzl", "create_cmake_script")
load("//tools/build_defs/shell_toolchain/toolchains:access.bzl", "create_context")
load(
    "//tools/build_defs/native_tools:tool_access.bzl",
    "get_cmake_data",
    "get_ninja_data",
    "get_make_data",
)
load("@rules_foreign_cc//tools/build_defs:shell_script_helper.bzl", "os_name")

def _cmake_external(ctx):
    cmake_data = get_cmake_data(ctx)
    make_data = get_make_data(ctx)

    tools_deps = ctx.attr.tools_deps + cmake_data.deps + make_data.deps

    ninja_data = get_ninja_data(ctx)
    make_commands = ctx.attr.make_commands
    if _uses_ninja(ctx.attr.make_commands):
        tools_deps += ninja_data.deps
        make_commands = [command.replace("ninja", ninja_data.path) for command in make_commands]

    attrs = create_attrs(
        ctx.attr,
        configure_name = "CMake",
        create_configure_script = _create_configure_script,
        postfix_script = "##copy_dir_contents_to_dir## $$BUILD_TMPDIR$$/$$INSTALL_PREFIX$$ $$INSTALLDIR$$\n" + ctx.attr.postfix_script,
        tools_deps = tools_deps,
        cmake_path = cmake_data.path,
        ninja_path = ninja_data.path,
        make_path = make_data.path,
        make_commands = make_commands,
    )

    return cc_external_rule_impl(ctx, attrs)

def _uses_ninja(make_commands):
    for command in make_commands:
        (before, separator, after) = command.partition(" ")
        if before == "ninja":
            return True
    return False

def _create_configure_script(configureParameters):
    ctx = configureParameters.ctx
    inputs = configureParameters.inputs

    root = detect_root(ctx.attr.lib_source)
    if len(ctx.attr.working_directory) > 0:
        root = root + "/" + ctx.attr.working_directory

    tools = get_tools_info(ctx)

    # CMake will replace <TARGET> with the actual output file
    flags = get_flags_info(ctx, "<TARGET>")
    no_toolchain_file = ctx.attr.cache_entries.get("CMAKE_TOOLCHAIN_FILE") or not ctx.attr.generate_crosstool_file

    define_install_prefix = "export INSTALL_PREFIX=\"" + _get_install_prefix(ctx) + "\"\n"
    configure_script = create_cmake_script(
        workspace_name = ctx.workspace_name,
        # as default, pass execution OS as target OS
        target_os = os_name(ctx),
        cmake_path = configureParameters.attrs.cmake_path,
        tools = tools,
        flags = flags,
        install_prefix = "$$INSTALL_PREFIX$$",
        root = root,
        no_toolchain_file = no_toolchain_file,
        user_cache = dict(ctx.attr.cache_entries),
        user_env = dict(ctx.attr.env_vars),
        options = ctx.attr.cmake_options,
        include_dirs = inputs.include_dirs,
        is_debug_mode = is_debug_mode(ctx),
    )
    return define_install_prefix + configure_script

def _get_install_prefix(ctx):
    if ctx.attr.install_prefix:
        return ctx.attr.install_prefix
    if ctx.attr.lib_name:
        return ctx.attr.lib_name
    return ctx.attr.name

def _attrs():
    attrs = dict(CC_EXTERNAL_RULE_ATTRIBUTES)
    attrs.update({
        # Relative install prefix to be passed to CMake in -DCMAKE_INSTALL_PREFIX
        "install_prefix": attr.string(mandatory = False),
        # CMake cache entries to initialize (they will be passed with -Dkey=value)
        # Values, defined by the toolchain, will be joined with the values, passed here.
        # (Toolchain values come first)
        "cache_entries": attr.string_dict(mandatory = False, default = {}),
        # CMake environment variable values to join with toolchain-defined.
        # For example, additional CXXFLAGS.
        "env_vars": attr.string_dict(mandatory = False, default = {}),
        # Other CMake options
        "cmake_options": attr.string_list(mandatory = False, default = []),
        # When True, CMake crosstool file will be generated from the toolchain values,
        # provided cache-entries and env_vars (some values will still be passed as -Dkey=value
        # and environment variables).
        # If CMAKE_TOOLCHAIN_FILE cache entry is passed, specified crosstool file will be used
        # When using this option, it makes sense to specify CMAKE_SYSTEM_NAME in the
        # cache_entries - the rule makes only a poor guess about the target system,
        # it is better to specify it manually.
        "generate_crosstool_file": attr.bool(mandatory = False, default = False),
        # Working directory, with the main CMakeLists.txt
        # (otherwise, the top directory of the lib_source label files is used.)
        "working_directory": attr.string(mandatory = False, default = ""),
    })
    return attrs

""" Rule for building external library with CMake.
 Attributes:
   See line comments in _attrs() method.
 Other attributes are documented in framework.bzl:CC_EXTERNAL_RULE_ATTRIBUTES
"""
cmake_external = rule(
    attrs = _attrs(),
    fragments = ["cpp"],
    output_to_genfiles = True,
    implementation = _cmake_external,
    toolchains = [
        "@rules_foreign_cc//tools/build_defs:cmake_toolchain",
        "@rules_foreign_cc//tools/build_defs:ninja_toolchain",
        "@rules_foreign_cc//tools/build_defs:make_toolchain",
        "@rules_foreign_cc//tools/build_defs/shell_toolchain/toolchains:shell_commands",
        "@bazel_tools//tools/cpp:toolchain_type",
    ],
)