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%% Copyright (c) Meta Platforms, Inc. and affiliates. %% %% This source code is licensed under both the MIT license found in the %% LICENSE-MIT file in the root directory of this source tree and the Apache %% License, Version 2.0 found in the LICENSE-APACHE file in the root directory %% of this source tree. %% @format -module(transform_project_root). -eqwalizer(ignore). -export([parse_transform/2]). -type mapping() :: #{file:filename_all() => {true | false, file:filename_all()}}. -spec parse_transform(Forms, Options) -> Forms when Forms :: [erl_parse:abstract_form() | erl_parse:form_info()], Options :: [compile:option()]. parse_transform(Forms, Options) -> Mapping = get_mapping(Options), rewrite_file_attributes(Forms, Mapping). -spec rewrite_file_attributes([erl_parse:abstract_form() | erl_parse:form_info()], mapping()) -> [erl_parse:abstract_form() | erl_parse:form_info()]. rewrite_file_attributes(Forms, Mapping) -> OTPRoot = code:root_dir(), [ case Form of {attribute, Anno, file, {File, Line}} -> {attribute, Anno, file, {path_relativize(File, OTPRoot, Mapping), Line}}; _ -> Form end || Form <- Forms ]. -spec path_relativize(file:filename(), file:filename(), mapping()) -> file:filename(). path_relativize( File, OTPRoot, Mapping ) -> case Mapping of #{File := {true, RelativePath}} -> RelativePath; #{File := {false, MaybeOTPPath}} -> case find_in_otp(MaybeOTPPath, OTPRoot) of {true, FoundPath} -> FoundPath; false -> %% We failed to find the file in OTP, at this point the build should %% have already failed and we let the compiler report the error. MaybeOTPPath end; _ -> %% We don't know where the file comes from, and fall back to the information %% in the beam, this happens usually with transitve header includes from OTP. File end. -spec find_in_otp(file:filename_all(), file:filename_all()) -> {true, file:filename_all()} | false. find_in_otp(Path, OTPRoot) -> [App, "include", Header] = filename:split(Path), Pattern = filename:join(["lib", [App, "-*"], "include", Header]), case filelib:wildcard(Pattern, OTPRoot) of [FoundPath] -> {true, filename:join("/otp", FoundPath)}; _ -> false end. -spec get_source([compile:option()]) -> file:filename_all(). get_source(Options) -> case proplists:get_value(compile_info, Options) of undefined -> error(missing_compile_info); CompileInfo -> case proplists:get_value(source, CompileInfo) of undefined -> error(corrupt_compile_info); Source -> Source end end. -spec get_mapping([compile:option()]) -> mapping(). get_mapping(Options) -> Source = get_source(Options), BaseMapping = #{filename:basename(Source) => {true, Source}}, case os:getenv("BUCK2_FILE_MAPPING") of false -> BaseMapping; MappingFile -> {ok, Contents} = file:read_file(MappingFile, [raw]), {Mapping, ok, <<>>} = json:decode(Contents, ok, #{object_push => fun json_mapping_push/3}), maps:merge(BaseMapping, Mapping) end. json_mapping_push(Key, [Bool, Path], Acc) when is_binary(Key), is_boolean(Bool), is_binary(Path) -> [{binary_to_list(Key), {Bool, binary_to_list(Path)}} | Acc]; json_mapping_push(Key, Value, Acc) -> [{Key, Value} | Acc].