%% -*- erlang-indent-level: 2 -*-
%%
%% 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.

%%%-------------------------------------------------------------------
%%% File    : dialyzer_cplt.erl
%%% Author  : Tobias Lindahl <tobiasl@it.uu.se>
%%% Description : Interface to display information in the persistent
%%%               lookup table files.
%%%               This file handles persistent of "classic" PLT
%%%               files (rather than incremental ones). It intentionally
%%%               duplicates dialyzer_iplt.erl, since they are
%%%               expected to diverge, and for this file to potentially
%%%               be deprecated in favour of the incremental one at
%%%               some point in the future.
%%%
%%% Created : 23 Jul 2004 by Tobias Lindahl <tobiasl@it.uu.se>
%%%-------------------------------------------------------------------
-module(dialyzer_cplt).
-moduledoc false.

-export([check_plt/3,
	 compute_md5_from_files/1,
	 included_files/1,
	 from_file/1,
	 get_default_cplt_filename/0,
         merge_plts_or_report_conflicts/2,
	 plt_and_info_from_file/1,
	 to_file/4,
         is_cplt/1
	]).

%% Debug utilities
-export([pp_non_returning/0, pp_mod/1]).

-export_type([file_md5/0]).

-include_lib("stdlib/include/ms_transform.hrl").

%%----------------------------------------------------------------------

-type deep_string() :: string() | [deep_string()].

%%----------------------------------------------------------------------


-include("dialyzer.hrl").

-type file_md5() :: {file:filename(), binary()}.

-record(file_plt, {version = ""                :: string(),
		   file_md5_list = []          :: [file_md5()],
		   info = dict:new()           :: dict:dict(),
		   contracts = dict:new()      :: dict:dict(),
		   callbacks = dict:new()      :: dict:dict(),
		   types = dict:new()          :: dict:dict(),
                   exported_types = sets:new() :: sets:set(),
		   mod_deps                    :: dialyzer_callgraph:mod_deps(),
		   implementation_md5 = []     :: [file_md5()]}).

%%----------------------------------------------------------------------

-spec get_default_cplt_filename() -> file:filename().

get_default_cplt_filename() ->
  case os:getenv("DIALYZER_PLT") of
    false ->
      CacheDir = filename:basedir(user_cache, "erlang"),
      filename:join(CacheDir, ".dialyzer_plt");
    UserSpecPlt -> UserSpecPlt
  end.

-spec plt_and_info_from_file(file:filename()) -> {dialyzer_plt:plt(), #plt_info{}}.

plt_and_info_from_file(FileName) ->
  from_file(FileName, true).

-spec from_file(file:filename()) -> dialyzer_plt:plt().

from_file(FileName) ->
  from_file(FileName, false).

from_file(FileName, ReturnInfo) ->
  Plt = dialyzer_plt:new(),
  Fun = fun() -> from_file1(Plt, FileName, ReturnInfo) end,
  case subproc(Fun) of
    {ok, Return} ->
      Return;
    {error, Msg} ->
      dialyzer_plt:delete(Plt),
      plt_error(Msg)
  end.

from_file1(Plt, FileName, ReturnInfo) ->
  case get_record_from_file(FileName) of
    {ok, Rec} ->
      case check_version(Rec) of
	error ->
	  Msg = io_lib:format("Old PLT file ~ts\n", [FileName]),
          {error, Msg};
	ok ->
          #file_plt{info = FileInfo,
                    contracts = FileContracts,
                    callbacks = FileCallbacks,
                    types = FileTypes,
                    exported_types = FileExpTypes} = Rec,
          Types = [{Mod, maps:from_list(dict:to_list(Types))} ||
                    {Mod, Types} <- dict:to_list(FileTypes)],
          CallbacksList = dict:to_list(FileCallbacks),
          CallbacksByModule =
            [{M, [Cb || {{M1,_,_},_} = Cb <- CallbacksList, M1 =:= M]} ||
              M <- lists:usort([M || {{M,_,_},_} <- CallbacksList])],
          #plt{info = ETSInfo,
               types = ETSTypes,
               contracts = ETSContracts,
               callbacks = ETSCallbacks,
               exported_types = ETSExpTypes} = Plt,
          [true, true, true] =
            [ets:insert(ETS, Data) ||
              {ETS, Data} <- [{ETSInfo, dict:to_list(FileInfo)},
                              {ETSTypes, Types},
                              {ETSContracts, dict:to_list(FileContracts)}]],
          true = ets:insert(ETSCallbacks, CallbacksByModule),
          true = ets:insert(ETSExpTypes, [{ET} ||
                                           ET <- sets:to_list(FileExpTypes)]),
	  case ReturnInfo of
	    false -> {ok, Plt};
	    true ->
	      PltInfo = #plt_info{files = Rec#file_plt.file_md5_list,
                            mod_deps = Rec#file_plt.mod_deps},
	      {ok, {Plt, PltInfo}}
	  end
      end;
    {error, Reason} ->
      Msg = io_lib:format("Could not read PLT file ~ts: ~p\n",
			  [FileName, Reason]),
      {error, Msg}
  end.

-type err_rsn() :: 'not_valid' | 'no_such_file' | 'read_error'.

-spec included_files(file:filename()) -> {'ok', [file:filename()]}
				      |  {'error', err_rsn()}.

included_files(FileName) ->
  Fun = fun() -> included_files1(FileName) end,
  subproc(Fun).

included_files1(FileName) ->
  case get_record_from_file(FileName) of
    {ok, #file_plt{file_md5_list = Md5}} ->
      {ok, [File || {File, _} <- Md5]};
    {error, _What} = Error ->
      Error
  end.

check_version(#file_plt{version = ?VSN, implementation_md5 = ImplMd5}) ->
  case compute_new_md5(ImplMd5, [], []) of
    ok -> ok;
    {differ, _, _} -> error;
    {error, _} -> error
  end;
check_version(#file_plt{}) -> error.

get_record_from_file(FileName) ->
  case file:read_file(FileName) of
    {ok, Bin} ->
      try binary_to_term(Bin) of
	  #file_plt{} = FilePLT -> {ok, FilePLT};
	  _ -> {error, not_valid}
      catch
	_:_ -> {error, not_valid}
      end;
    {error, enoent} ->
      {error, no_such_file};
    {error, _} ->
      {error, read_error}
  end.

-spec is_cplt(file:filename()) -> boolean().
is_cplt(FileName) ->
  case get_record_from_file(FileName) of
    {ok, _} -> true;
    {error, _} -> false
  end.

-spec merge_disj_plts([#plt{}]) -> #plt{}.

%% One of the PLTs of the list is augmented with the contents of the
%% other PLTs, and returned. The other PLTs are deleted.
%%
%% The keys are compared when checking for disjointness. Sometimes the
%% key is a module(), sometimes an mfa(). It boils down to checking if
%% any module occurs more than once.
merge_disj_plts(List) ->
  {InfoList, TypesList, ExpTypesList, ContractsList, CallbacksList} =
    group_fields(List),
  #plt{info = table_disj_merge(InfoList),
       types = table_disj_merge(TypesList),
       exported_types = sets_disj_merge(ExpTypesList),
       contracts = table_disj_merge(ContractsList),
       callbacks = table_disj_merge(CallbacksList)
      }.

group_fields(List) ->
  InfoList = [Info || #plt{info = Info} <- List],
  TypesList = [Types || #plt{types = Types} <- List],
  ExpTypesList = [ExpTypes || #plt{exported_types = ExpTypes} <- List],
  ContractsList = [Contracts || #plt{contracts = Contracts} <- List],
  CallbacksList = [Callbacks || #plt{callbacks = Callbacks} <- List],
  {InfoList, TypesList, ExpTypesList, ContractsList, CallbacksList}.

-spec merge_plts_or_report_conflicts([file:filename()], [#plt{}]) -> #plt{}.

merge_plts_or_report_conflicts(PltFiles, Plts) ->
  try
    merge_disj_plts(Plts)
  catch throw:{dialyzer_error, not_disjoint_plts} ->
      IncFiles = lists:append([begin {ok, Fs} = included_files(F), Fs end
                               || F <- PltFiles]),
      ConfFiles = find_duplicates(IncFiles),
      Msg = io_lib:format("Could not merge PLTs since they are not disjoint\n"
                          "The following files are included in more than one "
                          "PLTs:\n~tp\n", [ConfFiles]),
      plt_error(Msg)
  end.

find_duplicates(List) ->
  ModList = [filename:basename(E) || E <- List],
  SortedList = lists:usort(ModList),
  lists:usort(ModList -- SortedList).

-spec to_file(file:filename(), #plt{}, dialyzer_callgraph:mod_deps(), #plt_info{}) -> 'ok'.

%% Write the PLT to file, and delete the PLT.
to_file(FileName, Plt, ModDeps, MD5_OldModDeps) ->
  Fun = fun() -> to_file1(FileName, Plt, ModDeps, MD5_OldModDeps) end,
  Return = subproc(Fun),
  dialyzer_plt:delete(Plt),
  case Return of
    ok -> ok;
    {error, Msg} -> plt_error(Msg)
  end.

to_file1(FileName,
	#plt{info = ETSInfo, types = ETSTypes, contracts = ETSContracts,
	     callbacks = ETSCallbacks, exported_types = ETSExpTypes},
	ModDeps, #plt_info{files = MD5, mod_deps = OldModDeps}) ->
  NewModDeps = dict:merge(fun(_Key, OldVal, NewVal) ->
			      ordsets:union(OldVal, NewVal)
			  end,
			  OldModDeps, ModDeps),
  ImplMd5 = compute_implementation_md5(),
  CallbacksList =
      [Cb ||
        {_M, Cbs} <- dialyzer_utils:ets_tab2list(ETSCallbacks),
        Cb <- Cbs],
  Callbacks = dict:from_list(CallbacksList),
  Info = dict:from_list(dialyzer_utils:ets_tab2list(ETSInfo)),
  Types = dialyzer_utils:ets_tab2list(ETSTypes),
  Contracts = dict:from_list(dialyzer_utils:ets_tab2list(ETSContracts)),
  ExpTypes = sets:from_list([E || {E} <- dialyzer_utils:ets_tab2list(ETSExpTypes)]),
  FileTypes = dict:from_list([{Mod, dict:from_list(maps:to_list(MTypes))} ||
                               {Mod, MTypes} <- Types]),
  Record = #file_plt{version = ?VSN,
		     file_md5_list = MD5,
		     info = Info,
		     contracts = Contracts,
		     callbacks = Callbacks,
		     types = FileTypes,
                     exported_types = ExpTypes,
		     mod_deps = NewModDeps,
		     implementation_md5 = ImplMd5},
  Bin = term_to_binary(Record, [compressed]),
  case file:write_file(FileName, Bin) of
    ok -> ok;
    {error, Reason} ->
      Msg = io_lib:format("Could not write PLT file ~ts: ~w\n",
			  [FileName, Reason]),
      {error, Msg}
  end.

-type md5_diff()    :: [{'differ', atom()} | {'removed', atom()}].
-type check_error() :: err_rsn() | {'no_file_to_remove', file:filename()}.

-spec check_plt(file:filename(), [file:filename()], [file:filename()]) ->
	 'ok'
       | {'error', check_error()}
       | {'differ', [file_md5()], md5_diff(), dialyzer_callgraph:mod_deps()}
       | {'old_version', [file_md5()]}.

check_plt(FileName, RemoveFiles, AddFiles) ->
  Fun = fun() -> check_plt1(FileName, RemoveFiles, AddFiles) end,
  subproc(Fun).

check_plt1(FileName, RemoveFiles, AddFiles) ->
  case get_record_from_file(FileName) of
    {ok, #file_plt{file_md5_list = Md5, mod_deps = ModDeps} = Rec} ->
      case check_version(Rec) of
	ok ->
	  case compute_new_md5(Md5, RemoveFiles, AddFiles) of
	    ok -> ok;
	    {differ, NewMd5, DiffMd5} -> {differ, NewMd5, DiffMd5, ModDeps};
	    {error, _What} = Err -> Err
	  end;
	error ->
	  case compute_new_md5(Md5, RemoveFiles, AddFiles) of
	    ok -> {old_version, Md5};
	    {differ, NewMd5, _DiffMd5} -> {old_version, NewMd5};
	    {error, _What} = Err -> Err
	  end
      end;
    Error -> Error
  end.

compute_new_md5(Md5, [], []) ->
  compute_new_md5_1(Md5, [], []);
compute_new_md5(Md5, RemoveFiles0, AddFiles0) ->
  %% Assume that files are first removed and then added. Files that
  %% are both removed and added will be checked for consistency in the
  %% normal way. If they have moved, we assume that they differ.
  RemoveFiles = RemoveFiles0 -- AddFiles0,
  AddFiles = AddFiles0 -- RemoveFiles0,
  InitDiffList = init_diff_list(RemoveFiles, AddFiles),
  case init_md5_list(Md5, RemoveFiles, AddFiles) of
    {ok, NewMd5} -> compute_new_md5_1(NewMd5, [], InitDiffList);
    {error, _What} = Error -> Error
  end.

compute_new_md5_1([{File, Md5} = Entry|Entries], NewList, Diff) ->
  case compute_md5_from_file(File) of
    Md5 -> compute_new_md5_1(Entries, [Entry|NewList], Diff);
    NewMd5 ->
      ModName = beam_file_to_module(File),
      compute_new_md5_1(Entries, [{File, NewMd5}|NewList], [{differ, ModName}|Diff])
  end;
compute_new_md5_1([], _NewList, []) ->
  ok;
compute_new_md5_1([], NewList, Diff) ->
  {differ, lists:keysort(1, NewList), Diff}.

-spec compute_implementation_md5() -> [file_md5()].

compute_implementation_md5() ->
  Dir = code:lib_dir(dialyzer),
  Files1 = ["erl_bif_types.beam", "erl_types.beam"],
  Files2 = [filename:join([Dir, "ebin", F]) || F <- Files1],
  compute_md5_from_files(Files2).

-spec compute_md5_from_files([file:filename()]) -> [file_md5()].

compute_md5_from_files(Files) ->
  lists:keysort(1, [{F, compute_md5_from_file(F)} || F <- Files]).

compute_md5_from_file(File) ->
  case beam_lib:all_chunks(File) of
    {ok, _, Chunks} ->
      %% We cannot use beam_lib:md5 because it does not consider
      %% the debug_info chunk, where typespecs are likely stored.
      %% So we consider almost all chunks except the useless ones.
      Filtered = [[ID, Chunk] || {ID, Chunk} <- Chunks, ID =/= "CInf", ID =/= "Docs"],
      erlang:md5(lists:sort(Filtered));
    {error, beam_lib, {file_error, _, enoent}} ->
      Msg = io_lib:format("File not found: ~ts\n", [File]),
      plt_error(Msg);
    {error, beam_lib, _} ->
      Msg = io_lib:format("Could not compute MD5 for .beam: ~ts\n", [File]),
      plt_error(Msg)
  end.

init_diff_list(RemoveFiles, AddFiles) ->
  RemoveSet0 = sets:from_list([beam_file_to_module(F) || F <- RemoveFiles]),
  AddSet0 = sets:from_list([beam_file_to_module(F) || F <- AddFiles]),
  DiffSet = sets:intersection(AddSet0, RemoveSet0),
  RemoveSet = sets:subtract(RemoveSet0, DiffSet),
  %% Added files and diff files will appear as diff files from the md5 check.
  [{removed, F} || F <- sets:to_list(RemoveSet)].

init_md5_list(Md5, RemoveFiles, AddFiles) ->
  Files = [{remove, F} || F <- RemoveFiles] ++ [{add, F} || F <- AddFiles],
  DiffFiles = lists:keysort(2, Files),
  Md5Sorted = lists:keysort(1, Md5),
  init_md5_list_1(Md5Sorted, DiffFiles, []).

init_md5_list_1([{File, _Md5}|Md5Left], [{remove, File}|DiffLeft], Acc) ->
  init_md5_list_1(Md5Left, DiffLeft, Acc);
init_md5_list_1([{File, _Md5} = Entry|Md5Left], [{add, File}|DiffLeft], Acc) ->
  init_md5_list_1(Md5Left, DiffLeft, [Entry|Acc]);
init_md5_list_1([{File1, _Md5} = Entry|Md5Left] = Md5List,
		[{Tag, File2}|DiffLeft] = DiffList, Acc) ->
  case File1 < File2 of
    true -> init_md5_list_1(Md5Left, DiffList, [Entry|Acc]);
    false ->
      %% Just an assert.
      true = File1 > File2,
      case Tag of
	add -> init_md5_list_1(Md5List, DiffLeft, [{File2, <<>>}|Acc]);
	remove -> {error, {no_file_to_remove, File2}}
      end
  end;
init_md5_list_1([], DiffList, Acc) ->
  AddFiles = [{F, <<>>} || {add, F} <- DiffList],
  {ok, lists:reverse(Acc, AddFiles)};
init_md5_list_1(Md5List, [], Acc) ->
  {ok, lists:reverse(Acc, Md5List)}.


subproc(Fun) ->
  F = fun() ->
          exit(try Fun()
               catch throw:T ->
                   {thrown, T}
               end)
      end,
  {Pid, Ref} = erlang:spawn_monitor(F),
  receive {'DOWN', Ref, process, Pid, Return} ->
    case Return of
      {thrown, T} -> throw(T);
      _ -> Return
    end
  end.


beam_file_to_module(Filename) ->
  list_to_atom(filename:basename(Filename, ".beam")).


-spec plt_error(deep_string()) -> no_return().

plt_error(Msg) ->
  throw({dialyzer_error, lists:flatten(Msg)}).

table_disj_merge([H|T]) ->
  table_disj_merge(T, H).

table_disj_merge([], Acc) ->
  Acc;
table_disj_merge([Plt|Plts], Acc) ->
  case table_is_disjoint(Plt, Acc) of
    true ->
      NewAcc = merge_tables(Plt, Acc),
      table_disj_merge(Plts, NewAcc);
    false -> throw({dialyzer_error, not_disjoint_plts})
  end.

sets_disj_merge([H|T]) ->
  sets_disj_merge(T, H).

sets_disj_merge([], Acc) ->
  Acc;
sets_disj_merge([Plt|Plts], Acc) ->
  case table_is_disjoint(Plt, Acc) of
    true ->
      NewAcc = merge_tables(Plt, Acc),
      sets_disj_merge(Plts, NewAcc);
    false -> throw({dialyzer_error, not_disjoint_plts})
  end.

table_is_disjoint(T1, T2) ->
  tab_is_disj(ets:first(T1), T1, T2).

tab_is_disj('$end_of_table', _T1, _T2) ->
  true;
tab_is_disj(K1, T1, T2) ->
  case ets:member(T2, K1) of
    false ->
      tab_is_disj(ets:next(T1, K1), T1, T2);
    true ->
      false
  end.

merge_tables(T1, T2) ->
  tab_merge(ets:first(T1), T1, T2).

tab_merge('$end_of_table', T1, T2) ->
  case ets:first(T1) of % no safe_fixtable()...
    '$end_of_table' ->
      true = ets:delete(T1),
      T2;
    Key ->
      tab_merge(Key, T1, T2)
  end;
tab_merge(K1, T1, T2) ->
  NextK1 = ets:next(T1, K1),
  Vs = ets:take(T1, K1),
  true = ets:insert(T2, Vs),
  tab_merge(NextK1, T1, T2).


%%---------------------------------------------------------------------------
%% Debug utilities.

-spec pp_non_returning() -> 'ok'.

pp_non_returning() ->
  PltFile = get_default_cplt_filename(),
  Plt = from_file(PltFile),
  List = ets:tab2list(Plt#plt.info),
  Unit = [{MFA, erl_types:t_fun(Args, Ret)} || {MFA, {Ret, Args}} <- List,
						erl_types:t_is_unit(Ret)],
  None = [{MFA, erl_types:t_fun(Args, Ret)} || {MFA, {Ret, Args}} <- List,
						erl_types:t_is_none(Ret)],
  io:format("=========================================\n"),
  io:format("=                Loops                  =\n"),
  io:format("=========================================\n\n"),
  lists:foreach(fun({{M, F, _}, Type}) ->
		    io:format("~w:~tw~ts.\n",
			      [M, F, dialyzer_utils:format_sig(Type)])
		end, lists:sort(Unit)),
  io:format("\n"),
  io:format("=========================================\n"),
  io:format("=                Errors                 =\n"),
  io:format("=========================================\n\n"),
  lists:foreach(fun({{M, F, _}, Type}) ->
		    io:format("~w:~w~s.\n",
			      [M, F, dialyzer_utils:format_sig(Type)])
		end, lists:sort(None)),
  dialyzer_plt:delete(Plt).

-spec pp_mod(atom()) -> 'ok'.

pp_mod(Mod) when is_atom(Mod) ->
  PltFile = get_default_cplt_filename(),
  Plt = from_file(PltFile),
  case dialyzer_plt:lookup_module(Plt, Mod) of
    {value, List} ->
      lists:foreach(fun({{_, F, _}, Ret, Args}) ->
			T = erl_types:t_fun(Args, Ret),
			S = dialyzer_utils:format_sig(T),
			io:format("-spec ~tw~ts.\n", [F, S])
		    end, lists:sort(List));
    none ->
      io:format("dialyzer: Found no module named '~s' in the PLT\n", [Mod])
  end,
  dialyzer_plt:delete(Plt).
