# Copyright 2020 The Bazel Authors. All rights reserved.
#
# 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
#
#    http://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.

"""Utility functions for C++ rules."""

load(":common/objc/semantics.bzl", "semantics")

CcInfo = _builtins.toplevel.CcInfo
cc_common = _builtins.toplevel.cc_common
cc_internal = _builtins.internal.cc_internal

def _check_src_extension(file, allowed_src_files):
    extension = "." + file.extension
    if _matches_extension(extension, allowed_src_files) or _is_shared_library_extension_valid(file.path):
        return True
    return False

def _check_srcs_extensions(ctx, allowed_src_files, rule_name):
    for src in ctx.attr.srcs:
        if DefaultInfo in src:
            files = src[DefaultInfo].files.to_list()
            if len(files) == 1 and files[0].is_source:
                if not _check_src_extension(files[0], allowed_src_files) and not files[0].is_directory:
                    fail("in srcs attribute of {} rule {}: source file '{}' is misplaced here".format(rule_name, ctx.label, str(src.label)))
            else:
                at_least_one_good = False
                for file in files:
                    if _check_src_extension(file, allowed_src_files) or file.is_directory:
                        at_least_one_good = True
                        break
                if not at_least_one_good:
                    fail("'{}' does not produce any {} srcs files".format(str(src.label), rule_name), attr = "srcs")

def _merge_cc_debug_contexts(compilation_outputs, dep_cc_infos):
    debug_context = cc_common.create_debug_context(compilation_outputs)
    debug_contexts = []
    for dep_cc_info in dep_cc_infos:
        debug_contexts.append(dep_cc_info.debug_context())
    debug_contexts.append(debug_context)

    return cc_common.merge_debug_context(debug_contexts)

def _is_code_coverage_enabled(ctx):
    if ctx.coverage_instrumented():
        return True
    if hasattr(ctx.attr, "deps"):
        for dep in ctx.attr.deps:
            if CcInfo in dep:
                if ctx.coverage_instrumented(dep):
                    return True
    return False

def _get_dynamic_libraries_for_runtime(cc_linking_context, linking_statically):
    libraries = []
    for linker_input in cc_linking_context.linker_inputs.to_list():
        libraries.extend(linker_input.libraries)

    dynamic_libraries_for_runtime = []
    for library in libraries:
        artifact = _get_dynamic_library_for_runtime_or_none(library, linking_statically)
        if artifact != None:
            dynamic_libraries_for_runtime.append(artifact)

    return dynamic_libraries_for_runtime

def _get_dynamic_library_for_runtime_or_none(library, linking_statically):
    if library.dynamic_library == None:
        return None

    if linking_statically and (library.static_library != None or library.pic_static_library != None):
        return None

    return library.dynamic_library

def _find_cpp_toolchain(ctx):
    """
    Finds the c++ toolchain.

    If the c++ toolchain is in use, returns it.  Otherwise, returns a c++
    toolchain derived from legacy toolchain selection.

    Args:
      ctx: The rule context for which to find a toolchain.

    Returns:
      A CcToolchainProvider.
    """

    # Check the incompatible flag for toolchain resolution.
    if hasattr(cc_common, "is_cc_toolchain_resolution_enabled_do_not_use") and cc_common.is_cc_toolchain_resolution_enabled_do_not_use(ctx = ctx):
        if not "@" + semantics.get_repo() + "//tools/cpp:toolchain_type" in ctx.toolchains:
            fail("In order to use find_cpp_toolchain, you must include the '//tools/cpp:toolchain_type' in the toolchains argument to your rule.")
        toolchain_info = ctx.toolchains["@" + semantics.get_repo() + "//tools/cpp:toolchain_type"]
        if hasattr(toolchain_info, "cc_provider_in_toolchain") and hasattr(toolchain_info, "cc"):
            return toolchain_info.cc
        return toolchain_info

    # Otherwise, fall back to the legacy attribute.
    if hasattr(ctx.attr, "_cc_toolchain"):
        return ctx.attr._cc_toolchain[cc_common.CcToolchainInfo]

    # We didn't find anything.
    fail("In order to use find_cpp_toolchain, you must define the '_cc_toolchain' attribute on your rule or aspect.")

def _build_output_groups_for_emitting_compile_providers(
        compilation_outputs,
        compilation_context,
        cpp_configuration,
        cc_toolchain,
        feature_configuration,
        ctx,
        generate_hidden_top_level_group):
    output_groups_builder = {}
    process_hdrs = cpp_configuration.process_headers_in_dependencies()
    use_pic = cc_toolchain.needs_pic_for_dynamic_libraries(feature_configuration = feature_configuration)
    output_groups_builder["temp_files_INTERNAL_"] = compilation_outputs.temps()
    files_to_compile = compilation_outputs.files_to_compile(
        parse_headers = process_hdrs,
        use_pic = use_pic,
    )
    output_groups_builder["compilation_outputs"] = files_to_compile
    output_groups_builder["compilation_prerequisites_INTERNAL_"] = cc_internal.collect_compilation_prerequisites(ctx = ctx, compilation_context = compilation_context)

    if generate_hidden_top_level_group:
        output_groups_builder["_hidden_top_level_INTERNAL_"] = _collect_library_hidden_top_level_artifacts(
            ctx,
            files_to_compile,
        )

    _create_save_feature_state_artifacts(
        output_groups_builder,
        cpp_configuration,
        feature_configuration,
        ctx,
    )

    return output_groups_builder

def _dll_hash_suffix(ctx, feature_configuration):
    return cc_internal.dll_hash_suffix(ctx = ctx, feature_configuration = feature_configuration)

def _gen_empty_def_file(ctx):
    trivial_def_file = ctx.actions.declare_file(ctx.label.name + ".gen.empty.def")
    ctx.actions.write(trivial_def_file, "", False)
    return trivial_def_file

def _get_windows_def_file_for_linking(ctx, custom_def_file, generated_def_file, feature_configuration):
    # 1. If a custom DEF file is specified in win_def_file attribute, use it.
    # 2. If a generated DEF file is available and should be used, use it.
    # 3. Otherwise, we use an empty DEF file to ensure the import library will be generated.
    if custom_def_file != None:
        return custom_def_file
    elif generated_def_file != None and _should_generate_def_file(ctx, feature_configuration) == True:
        return generated_def_file
    else:
        return _gen_empty_def_file(ctx)

def _should_generate_def_file(ctx, feature_configuration):
    windows_export_all_symbols_enabled = cc_common.is_enabled(feature_configuration = feature_configuration, feature_name = "windows_export_all_symbols")
    no_windows_export_all_symbols_enabled = cc_common.is_enabled(feature_configuration = feature_configuration, feature_name = "no_windows_export_all_symbols")
    return windows_export_all_symbols_enabled and (not no_windows_export_all_symbols_enabled) and (ctx.attr.win_def_file == None)

def _generate_def_file(ctx, def_parser, object_files, dll_name):
    def_file = ctx.actions.declare_file(ctx.label.name + ".gen.def")
    args = ctx.actions.args()
    args.add(def_file)
    args.add(dll_name)
    argv = ctx.actions.args()
    argv.use_param_file("@%s", use_always = True)
    argv.set_param_file_format("shell")
    for object_file in object_files:
        argv.add(object_file.path)

    ctx.actions.run(
        mnemonic = "DefParser",
        executable = def_parser,
        arguments = [args, argv],
        inputs = object_files,
        outputs = [def_file],
        use_default_shell_env = True,
    )
    return def_file

CC_SOURCE = [".cc", ".cpp", ".cxx", ".c++", ".C", ".cu", ".cl"]
C_SOURCE = [".c"]
OBJC_SOURCE = [".m"]
OBJCPP_SOURCE = [".mm"]
CLIF_INPUT_PROTO = [".ipb"]
CLIF_OUTPUT_PROTO = [".opb"]
CC_AND_OBJC = []
CC_AND_OBJC.extend(CC_SOURCE)
CC_AND_OBJC.extend(C_SOURCE)
CC_AND_OBJC.extend(OBJC_SOURCE)
CC_AND_OBJC.extend(OBJCPP_SOURCE)
CC_AND_OBJC.extend(CLIF_INPUT_PROTO)
CC_AND_OBJC.extend(CLIF_OUTPUT_PROTO)

CC_HEADER = [".h", ".hh", ".hpp", ".ipp", ".hxx", ".h++", ".inc", ".inl", ".tlh", ".tli", ".H", ".tcc"]
ASSESMBLER_WITH_C_PREPROCESSOR = [".S"]
ASSEMBLER = [".s", ".asm"]
ARCHIVE = [".a", ".lib"]
PIC_ARCHIVE = [".pic.a"]
ALWAYSLINK_LIBRARY = [".lo"]
ALWAYSLINK_PIC_LIBRARY = [".pic.lo"]
SHARED_LIBRARY = [".so", ".dylib", ".dll"]
OBJECT_FILE = [".o", ".obj"]
PIC_OBJECT_FILE = [".pic.o"]

extensions = struct(
    CC_SOURCE = CC_SOURCE,
    C_SOURCE = C_SOURCE,
    CC_HEADER = CC_HEADER,
    ASSESMBLER_WITH_C_PREPROCESSOR = ASSESMBLER_WITH_C_PREPROCESSOR,
    ASSEMBLER = ASSEMBLER,
    ARCHIVE = ARCHIVE,
    PIC_ARCHIVE = PIC_ARCHIVE,
    ALWAYSLINK_LIBRARY = ALWAYSLINK_LIBRARY,
    ALWAYSLINK_PIC_LIBRARY = ALWAYSLINK_PIC_LIBRARY,
    SHARED_LIBRARY = SHARED_LIBRARY,
    OBJECT_FILE = OBJECT_FILE,
    PIC_OBJECT_FILE = PIC_OBJECT_FILE,
    CC_AND_OBJC = CC_AND_OBJC,
)

def _collect_header_tokens(
        ctx,
        cpp_configuration,
        compilation_outputs,
        process_hdrs,
        add_self_tokens):
    header_tokens_transitive = []
    for dep in ctx.attr.deps:
        if "_hidden_header_tokens_INTERNAL_" in dep[OutputGroupInfo]:
            header_tokens_transitive.append(dep[OutputGroupInfo]["_hidden_header_tokens_INTERNAL_"])
        else:
            header_tokens_transitive.append(depset([]))

    header_tokens_direct = []
    if add_self_tokens and process_hdrs:
        header_tokens_direct.extend(compilation_outputs.header_tokens())

    return depset(direct = header_tokens_direct, transitive = header_tokens_transitive)

def _collect_library_hidden_top_level_artifacts(
        ctx,
        files_to_compile):
    artifacts_to_force_builder = [files_to_compile]
    if hasattr(ctx.attr, "deps"):
        for dep in ctx.attr.deps:
            if OutputGroupInfo in dep:
                if "_hidden_top_level_INTERNAL_" in dep[OutputGroupInfo]:
                    artifacts_to_force_builder.append(dep[OutputGroupInfo]["_hidden_top_level_INTERNAL_"])

    return depset(transitive = artifacts_to_force_builder)

def _create_save_feature_state_artifacts(
        output_groups_builder,
        cpp_configuration,
        feature_configuration,
        ctx):
    if cpp_configuration.save_feature_state():
        feature_state_file = ctx.actions.declare_file(ctx.label.name + "_feature_state.txt")

        ctx.actions.write(feature_state_file, str(feature_configuration))
        output_groups_builder["default"] = depset(direct = [feature_state_file])

def _merge_output_groups(output_groups):
    merged_output_groups_builder = {}
    for output_group in output_groups:
        for output_key, output_value in output_group.items():
            depset_list = merged_output_groups_builder.get(output_key, [])
            depset_list.append(output_value)
            merged_output_groups_builder[output_key] = depset_list

    merged_output_group = {}
    for k, v in merged_output_groups_builder.items():
        merged_output_group[k] = depset(transitive = v)

    return merged_output_group

def _rule_error(msg):
    fail(msg)

def _attribute_error(attr_name, msg):
    fail("in attribute '" + attr_name + "': " + msg)

def _get_linking_contexts_from_deps(deps):
    linking_contexts = []
    for dep in deps:
        if CcInfo in dep:
            linking_contexts.append(dep[CcInfo].linking_context)
    return linking_contexts

def _is_test_target(ctx):
    if hasattr(ctx.attr, "testonly"):
        return ctx.attr.testonly

    return False

def _get_compilation_contexts_from_deps(deps):
    compilation_contexts = []
    for dep in deps:
        if CcInfo in dep:
            compilation_contexts.append(dep[CcInfo].compilation_context)
    return compilation_contexts

def _is_compiltion_outputs_empty(compilation_outputs):
    return (len(compilation_outputs.pic_objects) == 0 and
            len(compilation_outputs.objects) == 0)

def _matches_extension(extension, patterns):
    for pattern in patterns:
        if extension.endswith(pattern):
            return True
    return False

def _build_precompiled_files(ctx):
    objects = []
    pic_objects = []
    static_libraries = []
    pic_static_libraries = []
    alwayslink_static_libraries = []
    pic_alwayslink_static_libraries = []
    shared_libraries = []

    for src in ctx.files.srcs:
        short_path = src.short_path

        # For compatibility with existing BUILD files, any ".o" files listed
        # in srcs are assumed to be position-independent code, or
        # at least suitable for inclusion in shared libraries, unless they
        # end with ".nopic.o". (The ".nopic.o" extension is an undocumented
        # feature to give users at least some control over this.) Note that
        # some target platforms do not require shared library code to be PIC.
        if _matches_extension(short_path, OBJECT_FILE):
            objects.append(src)
            if not short_path.endswith(".nopic.o"):
                pic_objects.append(src)

            if _matches_extension(short_path, PIC_OBJECT_FILE):
                pic_objects.append(src)

        elif _matches_extension(short_path, PIC_ARCHIVE):
            pic_static_libraries.append(src)
        elif _matches_extension(short_path, ARCHIVE):
            static_libraries.append(src)
        elif _matches_extension(short_path, ALWAYSLINK_PIC_LIBRARY):
            pic_alwayslink_static_libraries.append(src)
        elif _matches_extension(short_path, ALWAYSLINK_LIBRARY):
            alwayslink_static_libraries.append(src)
        elif _is_shared_library_extension_valid(short_path):
            shared_libraries.append(src)
    return (
        objects,
        pic_objects,
        static_libraries,
        pic_static_libraries,
        alwayslink_static_libraries,
        pic_alwayslink_static_libraries,
        shared_libraries,
    )

def _is_shared_library_extension_valid(shared_library_name):
    if (shared_library_name.endswith(".so") or
        shared_library_name.endswith(".dll") or
        shared_library_name.endswith(".dylib")):
        return True

    # validate agains the regex "^.+\\.((so)|(dylib))(\\.\\d\\w*)+$",
    # must match VERSIONED_SHARED_LIBRARY.
    for ext in (".so.", ".dylib."):
        name, _, version = shared_library_name.rpartition(ext)
        if name and version:
            version_parts = version.split(".")
            for part in version_parts:
                if not part[0].isdigit():
                    return False
                for c in part[1:].elems():
                    if not (c.isalnum() or c == "_"):
                        return False
            return True

    return False

def _get_providers(deps, provider):
    providers = []
    for dep in deps:
        if provider in dep:
            providers.append(dep[provider])
    return providers

def _is_compilation_outputs_empty(compilation_outputs):
    return len(compilation_outputs.pic_objects) == 0 and len(compilation_outputs.objects) == 0

def _get_static_mode_params_for_dynamic_library_libraries(libs):
    linker_inputs = []
    for lib in libs.to_list():
        if lib.pic_static_library:
            linker_inputs.append(lib.pic_static_library)
        elif lib.static_library:
            linker_inputs.append(lib.static_library)
        elif lib.interface_library:
            linker_inputs.append(lib.interface_library)
        else:
            linker_inputs.append(lib.dynamic_library)
    return linker_inputs

def _should_create_per_object_debug_info(feature_configuration, cpp_configuration):
    return cpp_configuration.fission_active_for_current_compilation_mode() and \
           cc_common.is_enabled(
               feature_configuration = feature_configuration,
               feature_name = "per_object_debug_info",
           )

def _libraries_from_linking_context(linking_context):
    libraries = []
    for linker_input in linking_context.linker_inputs.to_list():
        libraries.extend(linker_input.libraries)
    return depset(libraries, order = "topological")

def _additional_inputs_from_linking_context(linking_context):
    inputs = []
    for linker_input in linking_context.linker_inputs.to_list():
        inputs.extend(linker_input.additional_inputs)
    return depset(inputs, order = "topological")

cc_helper = struct(
    merge_cc_debug_contexts = _merge_cc_debug_contexts,
    is_code_coverage_enabled = _is_code_coverage_enabled,
    get_dynamic_libraries_for_runtime = _get_dynamic_libraries_for_runtime,
    get_dynamic_library_for_runtime_or_none = _get_dynamic_library_for_runtime_or_none,
    find_cpp_toolchain = _find_cpp_toolchain,
    build_output_groups_for_emitting_compile_providers = _build_output_groups_for_emitting_compile_providers,
    merge_output_groups = _merge_output_groups,
    rule_error = _rule_error,
    attribute_error = _attribute_error,
    get_linking_contexts_from_deps = _get_linking_contexts_from_deps,
    get_compilation_contexts_from_deps = _get_compilation_contexts_from_deps,
    is_test_target = _is_test_target,
    extensions = extensions,
    build_precompiled_files = _build_precompiled_files,
    is_shared_library_extension_valid = _is_shared_library_extension_valid,
    get_providers = _get_providers,
    is_compilation_outputs_empty = _is_compilation_outputs_empty,
    matches_extension = _matches_extension,
    get_static_mode_params_for_dynamic_library_libraries = _get_static_mode_params_for_dynamic_library_libraries,
    should_create_per_object_debug_info = _should_create_per_object_debug_info,
    check_srcs_extensions = _check_srcs_extensions,
    libraries_from_linking_context = _libraries_from_linking_context,
    additional_inputs_from_linking_context = _additional_inputs_from_linking_context,
    dll_hash_suffix = _dll_hash_suffix,
    get_windows_def_file_for_linking = _get_windows_def_file_for_linking,
    generate_def_file = _generate_def_file,
)