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-rw-r--r--src/rebar.app.src1
-rw-r--r--src/rebar_prv_xref.erl296
2 files changed, 297 insertions, 0 deletions
diff --git a/src/rebar.app.src b/src/rebar.app.src
index 73c1eff..1230436 100644
--- a/src/rebar.app.src
+++ b/src/rebar.app.src
@@ -43,6 +43,7 @@
rebar_prv_release,
rebar_prv_version,
rebar_prv_common_test,
+ rebar_prv_xref,
rebar_prv_help]}
]}
]}.
diff --git a/src/rebar_prv_xref.erl b/src/rebar_prv_xref.erl
new file mode 100644
index 0000000..32ebf46
--- /dev/null
+++ b/src/rebar_prv_xref.erl
@@ -0,0 +1,296 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+
+-module(rebar_prv_xref).
+
+-behaviour(provider).
+
+-export([init/1,
+ do/1,
+ format_error/1]).
+
+-include("rebar.hrl").
+
+-define(PROVIDER, xref).
+-define(DEPS, [compile]).
+-define(SUPPORTED_XREFS, [undefined_function_calls, undefined_functions,
+ locals_not_used, exports_not_used,
+ deprecated_function_calls, deprecated_functions]).
+
+%% ===================================================================
+%% Public API
+%% ===================================================================
+
+-spec init(rebar_state:t()) -> {ok, rebar_state:t()}.
+init(State) ->
+ Provider = providers:create([{name, ?PROVIDER},
+ {module, ?MODULE},
+ {deps, ?DEPS},
+ {bare, false},
+ {example, "rebar3 xref"},
+ {short_desc, short_desc()},
+ {desc, desc()}]),
+ State1 = rebar_state:add_provider(State, Provider),
+ {ok, State1}.
+
+-spec do(rebar_state:t()) -> {ok, rebar_state:t()} | {error, string()}.
+do(State) ->
+ {OriginalPath, XrefChecks} = prepare(State),
+
+ %% Run xref checks
+ ?INFO("Running cross reference analysis...", []),
+ XrefResults = xref_checks(XrefChecks),
+
+ %% Run custom queries
+ QueryChecks = rebar_state:get(State, xref_queries, []),
+ QueryResults = lists:foldl(fun check_query/2, [], QueryChecks),
+
+ ok = cleanup(OriginalPath),
+
+ case XrefResults =:= [] andalso QueryResults =:= [] of
+ true ->
+ {ok, State};
+ false ->
+ {error, {?MODULE, {xref_issues, XrefResults, QueryResults}}}
+ end.
+
+-spec format_error(any()) -> iolist().
+format_error({xref_issues, XrefResults, QueryResults}) ->
+ lists:flatten(display_results(XrefResults, QueryResults));
+format_error(Reason) ->
+ io_lib:format("~p", [Reason]).
+
+%% ===================================================================
+%% Internal functions
+%% ===================================================================
+
+short_desc() ->
+ "Run cross reference analysis".
+
+desc() ->
+ io_lib:format(
+ "~s~n"
+ "~n"
+ "Valid rebar.config options:~n"
+ " ~p~n"
+ " ~p~n"
+ " ~p~n"
+ " ~p~n",
+ [short_desc(),
+ {xref_warnings, false},
+ {xref_extra_paths,[]},
+ {xref_checks, [undefined_function_calls, undefined_functions,
+ locals_not_used, exports_not_used,
+ deprecated_function_calls, deprecated_functions]},
+ {xref_queries,
+ [{"(xc - uc) || (xu - x - b"
+ " - (\"mod\":\".*foo\"/\"4\"))",[]}]}
+ ]).
+
+-spec prepare(rebar_state:t()) -> list(atom()).
+prepare(State) ->
+ {ok, _} = xref:start(xref),
+ ok = xref:set_library_path(xref, code_path(State)),
+
+ xref:set_default(xref, [{warnings,
+ rebar_state:get(State, xref_warnings, false)},
+ {verbose, rebar_log:is_verbose(State)}]),
+
+ {ok, _} = xref:add_directory(xref, "ebin"),
+
+ %% Save the code path prior to doing any further code path
+ %% manipulation
+ OriginalPath = code:get_path(),
+ true = code:add_path(rebar_dir:ebin_dir()),
+
+ %% Get list of xref checks we want to run
+ ConfXrefChecks = rebar_state:get(State, xref_checks,
+ [exports_not_used,
+ undefined_function_calls]),
+
+ XrefChecks = sets:to_list(sets:intersection(
+ sets:from_list(?SUPPORTED_XREFS),
+ sets:from_list(ConfXrefChecks))),
+ {OriginalPath, XrefChecks}.
+
+cleanup(Path) ->
+ %% Restore the code path using the provided path
+ true = rebar_utils:cleanup_code_path(Path),
+
+ %% Stop xref
+ stopped = xref:stop(xref),
+ ok.
+
+xref_checks(XrefChecks) ->
+ lists:foldl(fun run_xref_check/2, [], XrefChecks).
+
+run_xref_check(XrefCheck, Acc) ->
+ {ok, Results} = xref:analyze(xref, XrefCheck),
+ case filter_xref_results(XrefCheck, Results) of
+ [] ->
+ Acc;
+ FilterResult ->
+ [{XrefCheck, FilterResult} | Acc]
+ end.
+
+check_query({Query, Value}, Acc) ->
+ {ok, Answer} = xref:q(xref, Query),
+ case Answer =:= Value of
+ false ->
+ [{Query, Value, Answer} | Acc];
+ _ ->
+ Acc
+ end.
+
+code_path(State) ->
+ [P || P <- code:get_path() ++
+ rebar_state:get(State, xref_extra_paths, []),
+ filelib:is_dir(P)].
+
+%% Ignore behaviour functions, and explicitly marked functions
+%%
+%% Functions can be ignored by using
+%% -ignore_xref([{F, A}, {M, F, A}...]).
+get_xref_ignorelist(Mod, XrefCheck) ->
+ %% Get ignore_xref attribute and combine them in one list
+ Attributes =
+ try
+ Mod:module_info(attributes)
+ catch
+ _Class:_Error -> []
+ end,
+
+ IgnoreXref = keyall(ignore_xref, Attributes),
+
+ BehaviourCallbacks = get_behaviour_callbacks(XrefCheck, Attributes),
+
+ %% And create a flat {M,F,A} list
+ lists:foldl(
+ fun({F, A}, Acc) -> [{Mod,F,A} | Acc];
+ ({M, F, A}, Acc) -> [{M,F,A} | Acc]
+ end, [], lists:flatten([IgnoreXref, BehaviourCallbacks])).
+
+keyall(Key, List) ->
+ lists:flatmap(fun({K, L}) when Key =:= K -> L; (_) -> [] end, List).
+
+get_behaviour_callbacks(exports_not_used, Attributes) ->
+ [B:behaviour_info(callbacks) || B <- keyall(behaviour, Attributes)];
+get_behaviour_callbacks(_XrefCheck, _Attributes) ->
+ [].
+
+parse_xref_result({_, MFAt}) -> MFAt;
+parse_xref_result(MFAt) -> MFAt.
+
+filter_xref_results(XrefCheck, XrefResults) ->
+ SearchModules = lists:usort(
+ lists:map(
+ fun({Mt,_Ft,_At}) -> Mt;
+ ({{Ms,_Fs,_As},{_Mt,_Ft,_At}}) -> Ms;
+ (_) -> undefined
+ end, XrefResults)),
+
+ Ignores = lists:flatmap(fun(Module) ->
+ get_xref_ignorelist(Module, XrefCheck)
+ end, SearchModules),
+
+ [Result || Result <- XrefResults,
+ not lists:member(parse_xref_result(Result), Ignores)].
+
+display_results(XrefResults, QueryResults) ->
+ [lists:map(fun display_xref_results_for_type/1, XrefResults),
+ lists:map(fun display_query_result/1, QueryResults)].
+
+display_query_result({Query, Answer, Value}) ->
+ io_lib:format("Query ~s~n answer ~p~n did not match ~p~n",
+ [Query, Answer, Value]).
+
+display_xref_results_for_type({Type, XrefResults}) ->
+ lists:map(display_xref_result_fun(Type), XrefResults).
+
+display_xref_result_fun(Type) ->
+ fun(XrefResult) ->
+ {Source, SMFA, TMFA} =
+ case XrefResult of
+ {MFASource, MFATarget} ->
+ {format_mfa_source(MFASource),
+ format_mfa(MFASource),
+ format_mfa(MFATarget)};
+ MFATarget ->
+ {format_mfa_source(MFATarget),
+ format_mfa(MFATarget),
+ undefined}
+ end,
+ case Type of
+ undefined_function_calls ->
+ io_lib:format("~sWarning: ~s calls undefined function ~s (Xref)\n",
+ [Source, SMFA, TMFA]);
+ undefined_functions ->
+ io_lib:format("~sWarning: ~s is undefined function (Xref)\n",
+ [Source, SMFA]);
+ locals_not_used ->
+ io_lib:format("~sWarning: ~s is unused local function (Xref)\n",
+ [Source, SMFA]);
+ exports_not_used ->
+ io_lib:format("~sWarning: ~s is unused export (Xref)\n",
+ [Source, SMFA]);
+ deprecated_function_calls ->
+ io_lib:format("~sWarning: ~s calls deprecated function ~s (Xref)\n",
+ [Source, SMFA, TMFA]);
+ deprecated_functions ->
+ io_lib:format("~sWarning: ~s is deprecated function (Xref)\n",
+ [Source, SMFA]);
+ Other ->
+ io_lib:format("~sWarning: ~s - ~s xref check: ~s (Xref)\n",
+ [Source, SMFA, TMFA, Other])
+ end
+ end.
+
+format_mfa({M, F, A}) ->
+ ?FMT("~s:~s/~w", [M, F, A]).
+
+format_mfa_source(MFA) ->
+ case find_mfa_source(MFA) of
+ {module_not_found, function_not_found} -> "";
+ {Source, function_not_found} -> ?FMT("~s: ", [Source]);
+ {Source, Line} -> ?FMT("~s:~w: ", [Source, Line])
+ end.
+
+%%
+%% Extract an element from a tuple, or undefined if N > tuple size
+%%
+safe_element(N, Tuple) ->
+ case catch(element(N, Tuple)) of
+ {'EXIT', {badarg, _}} ->
+ undefined;
+ Value ->
+ Value
+ end.
+
+%%
+%% Given a MFA, find the file and LOC where it's defined. Note that
+%% xref doesn't work if there is no abstract_code, so we can avoid
+%% being too paranoid here.
+%%
+find_mfa_source({M, F, A}) ->
+ case code:get_object_code(M) of
+ error -> {module_not_found, function_not_found};
+ {M, Bin, _} -> find_function_source(M,F,A,Bin)
+ end.
+
+find_function_source(M, F, A, Bin) ->
+ AbstractCode = beam_lib:chunks(Bin, [abstract_code]),
+ {ok, {M, [{abstract_code, {raw_abstract_v1, Code}}]}} = AbstractCode,
+ %% Extract the original source filename from the abstract code
+ [{attribute, 1, file, {Source, _}} | _] = Code,
+ %% Extract the line number for a given function def
+ Fn = [E || E <- Code,
+ safe_element(1, E) == function,
+ safe_element(3, E) == F,
+ safe_element(4, E) == A],
+ case Fn of
+ [{function, Line, F, _, _}] -> {Source, Line};
+ %% do not crash if functions are exported, even though they
+ %% are not in the source.
+ %% parameterized modules add new/1 and instance/1 for example.
+ [] -> {Source, function_not_found}
+ end.