igor.erl

OTP是开放电信平台的简称

    %% the target is the same as one of the source modules). It is
    %% however not "safe" by default. If no modules are explicitly
    %% specified as static, it is assumed that *all* are static.
    Static0 = ordsets:from_list(proplists:append_values(static, Opts)),
    case proplists:is_defined(static, Opts) of
	false ->
	    Static = All;
	true ->
	    Static = ordsets:add_element(Name, Static0)
    end,
    check_module_names(Static, All, "declared 'static'"),
    verbose("static modules: ~p.", [Static], Opts),

    %% If no modules are explicitly specified as "safe", it is assumed
    %% that *all* source modules are "safe" except the target module and
    %% those explicitly specified as "static".
    Safe = case proplists:is_defined(safe, Opts) of
	       false ->
		   ordsets:subtract(Sources,
				    ordsets:add_element(Name, Static0));
	       true ->
		   ordsets:from_list(
		     proplists:append_values(safe, Opts))
	   end,
    check_module_names(Safe, All, "declared 'safe'"),
    verbose("safe modules: ~p.", [Safe], Opts),

    Preserved = (ordsets:is_element(Name, Sources)
		 and ordsets:is_element(Name, Export))
	or proplists:get_bool(no_banner, Opts),
    NoHeaders = proplists:get_bool(no_headers, Opts),
    Notes = proplists:get_value(notes, Opts, always),
    Rs = proplists:append_values(redirect, Opts),
    Redirect = case is_atom_map(Rs) of
		   true ->
		       Ms = ordsets:from_list([M || {M, _} <- Rs]),
		       case ordsets:intersection(Sources, Ms) of
			   [] ->
			       ok;
			   Ms1 ->
			       report_error("cannot redirect calls to "
					    "modules in input set: ~p.",
					    [Ms1]),
			       exit(error)
		       end,
		       dict:from_list(Rs);
		   false ->
		       report_error("bad value for `redirect' option: "
				    "~P.",
				    [Rs, 10]),
		       exit(error)
	       end,
    NoImports = case proplists:get_bool(no_imports, Opts) of
		    true ->
			ordsets:from_list(Sources ++
					  dict:fetch_keys(Redirect));
		    false ->
			ordsets:from_list(dict:fetch_keys(Redirect))
		end,
    Env = #merge{target = Name,
		 sources = Sources,
		 export = Export,
		 safe = Safe,
		 static = Static,
		 preserved = Preserved,
		 no_headers = NoHeaders,
		 notes = Notes,
		 redirect = Redirect,
		 no_imports = NoImports,
		 options = Opts},
    merge_sources_2(Env, Modules, Trees, Opts).

is_atom_map([{A1, A2} | As]) when is_atom(A1), is_atom(A2) ->
    is_atom_map(As);
is_atom_map([]) ->
    true;
is_atom_map(_) ->
    false.

check_module_names(Names, Sources, Txt) ->
    case Names -- Sources of
	[] ->
	    ok;
	Xs ->
	    report_error("unknown modules ~s: ~p.", [Txt, Xs]),
	    exit(error)
    end.

%% This function performs all the stages of the actual merge:

merge_sources_2(Env, Modules, Trees, Opts) ->
    %% Compute the merged name space and the list of renamings.
    {Names, Renaming} = merge_namespaces(Modules, Env),
    
    %% Merge the source module descriptions, computing a structure
    %% describing the resulting module, and a table of aliases which
    %% must be expanded.
    {Module, Expansions} = merge_info(Modules, Names, Renaming,
				      Env),
    
    %% Merge the actual source code, also returning the "original
    %% header" (for the first code section in the output).
    St = #state{export = sets:new()},
    {Tree, Header, St1} = merge_code(Trees, Modules, Expansions,
				     Renaming, Env, St),

    %% Filter out unwanted program forms and add a preamble to the code,
    %% making a complete module.
    Tree1 = erl_syntax:form_list([make_preamble(Module, Header,
						Env, St1),
				  filter_forms(Tree, Env)]),
    
    %% Tidy the final syntax tree (removing unused functions) and return
    %% it together with the list of stub descriptors.
    {tidy(Tree1, Opts), make_stubs(Modules, Renaming, Env)}.

make_preamble(Module, Header, Env, St) ->
    Name = Module#module.name,
    Vars = Module#module.vars,
    Extras = ordsets:from_list(sets:to_list(St#state.export)),
    Exports = make_exports(Module#module.exports, Extras),
    Imports = make_imports(Module#module.aliases),
    Attributes = make_attributes(Module#module.attributes),
    erl_syntax:form_list(module_header(Header, Name, Vars, Env)
			 ++ Exports
			 ++ Imports
			 ++ Attributes).

%% If the target preserves one of the source modules, we do not generate
%% a new header, but use the original.

module_header(Forms, Name, Vars, Env) ->
    case Env#merge.preserved of
	true ->
	    update_header(Forms, Name, Vars);
	false ->
	    [comment([?COMMENT_BAR,
		      "This module was formed by merging "
		      "the following modules:",
		      ""]
		     ++ [lists:flatten(io_lib:fwrite("\t\t`~w'",
						     [M]))
			 || M <- Env#merge.sources]
		     ++ ["",
			 timestamp(),
			 ""]),
	     erl_syntax:attribute(erl_syntax:atom('module'),
				  [erl_syntax:atom(Name)])]
    end.

update_header(Fs, Name, Vars) ->
    [M | Fs1] = lists:reverse(Fs),
    Ps = if Vars == none -> [];
	    true -> [erl_syntax:list([erl_syntax:variable(V)
				      || V <- Vars])]
	 end,
    M1 = rewrite(M, erl_syntax:attribute(erl_syntax:atom('module'),
					 [erl_syntax:atom(Name) | Ps])),
    lists:reverse([M1 | Fs1]).

%% Some functions may have been noted as necessary to export (because of
%% how they are called) even though the user did not specify that the
%% modules in which these functions originated should be part of the
%% interface of the resulting module.

make_exports(Exports, Extras) ->
    case ordsets:subtract(Extras, Exports) of
	[] ->
	    [make_export(Exports)];
	Es ->
	    [make_export(Exports),
	     comment(["** The following exports "
		      "are not official: **"]),
	     make_export(Es)]
    end.

make_export(Names) ->
    Es = [erl_syntax:arity_qualifier(erl_syntax:atom(F),
				     erl_syntax:integer(A))
	  || {F, A} <- Names],
    if Es == [] ->
	    comment(["** Nothing is officially exported "
		    "from this module! **"]);
       true ->
	    erl_syntax:attribute(erl_syntax:atom('export'),
				 [erl_syntax:list(Es)])
    end.

%% Any aliases that cannot be expressed using `import' (i.e. those not
%% on the form `{F, {M, F}}') are ignored.

make_imports(As) ->
    %% First remove any auto-imports and "non-proper" imports from
    %% the list.
    As1 = [A || {F, {_M, F}} = A <- As, not is_auto_import(F)],
    [make_import(M, Fs) || {M, Fs} <- group_imports(As1)].

make_import(Module, Names) ->
    Is = [erl_syntax:arity_qualifier(erl_syntax:atom(F),
				     erl_syntax:integer(A))
	  || {F, A} <- Names],
    erl_syntax:attribute(erl_syntax:atom('import'),
			 [erl_syntax:atom(Module),
			  erl_syntax:list(Is)]).

%% Group aliases by module.

group_imports(Imports) ->
    dict:to_list(
      lists:foldl(
	fun ({F, {M, F}}, D) ->
		case dict:find(M, D) of
		    {ok, V} ->
			V1 = ordsets:add_element(F, V),
			dict:store(M, V1, D);
		    error ->
			dict:store(M, [F], D)
		end
	end,
	dict:new(), Imports)).


%% ---------------------------------------------------------------------
%% Making stub descriptors
%%
%% These are generated for all exported modules that are not the target
%% module.

make_stubs(Modules, Renaming, Env) ->
    make_stubs_1(Modules, Renaming, Env).

make_stubs_1([M | Ms], Renaming, Env) ->
    Name = M#module.name,
    if Name /= Env#merge.target ->
	    case ordsets:is_element(Name, Env#merge.export) of
		true ->
		    [make_stub(M, Renaming(Name), Env)
		     | make_stubs_1(Ms, Renaming, Env)];
		false ->
		    make_stubs_1(Ms, Renaming, Env)
	    end;
       true ->
	    make_stubs_1(Ms, Renaming, Env)
    end;
make_stubs_1([], _, _) ->
    [].

make_stub(M, Map, Env) ->
    Target = Env#merge.target,
    Es = [{F, {Target, Map(F)}} || F <- M#module.exports],
    {M#module.name, Es, M#module.attributes}.


%% ---------------------------------------------------------------------
%% Removing and/or out-commenting program forms. The returned form
%% sequence tree is not necessarily flat.

-record(filter, {records, file_attributes, attributes}).

filter_forms(Tree, Env) ->
    Forms = erl_syntax:form_list_elements(
	      erl_syntax:flatten_form_list(Tree)),
    erl_syntax:form_list(filter_forms_1(Forms, Env)).

filter_forms_1(Forms, Env) ->
    {Fs, _} = filter_forms_2(Forms, Env),
    lists:reverse(Fs).

filter_forms_2(Forms, Env) ->
    FileAttrsOpt = proplists:get_value(file_attributes,
				       Env#merge.options, comment),
    %% Sanity check and translation of option value:
    FileAttrs = case FileAttrsOpt of
		    yes -> keep;
		    no -> delete;
		    comment -> kill;
		    _ ->
			report_error("invalid value for option "
				     "`file_attributes': ~w.",
				     [FileAttrsOpt]),
			exit(error)
		end,
    Attrs = if length(Env#merge.sources) =:= 1 ->
		    delete;    %% keeping the originals looks weird
	       true ->
		    kill
	    end,
    S = #filter{records = sets:new(),
		file_attributes = FileAttrs,
		attributes = Attrs},
    lists:foldl(
      fun (F, {Fs, S0}) ->
	      case filter_form(F, S0) of
		  {keep, S1} ->
		      {[F | Fs], S1};    % keep
		  {kill, S1} ->
		      {[kill_form(F) | Fs], S1};    % kill
		  {delete, S1} ->
		      %% Remove, or kill if it has comments (only
		      %% top-level comments are examined).
		      case erl_syntax:has_comments(F) of
			  false ->
			      {Fs, S1};
			  true ->
			      {[kill_form(F) | Fs], S1}
		      end
	      end
      end,
      {[], S}, Forms).

filter_form(F, S) ->
    case erl_syntax_lib:analyze_form(F) of
	{attribute, {'file', _}} ->
	    {S#filter.file_attributes, S};
	{attribute, {'module', _}} ->
	    {delete, S};
	{attribute, {'export', _}} ->
	    {delete, S};
	{attribute, {'import', _}} ->
	    {delete, S};
	{attribute, {'record', {R, _}}} ->
	    Records = S#filter.records,
	    case sets:is_element(R, Records) of
		true ->
		    {kill, S};    % already defined above
		false ->
		    S1 = S#filter{records =
				  sets:add_element(R, Records)},
		    {keep, S1}
	    end;
	{attribute, preprocessor} ->
	    {keep, S};    %% keep all preprocessor attributes
	{attribute, _} ->
	    {S#filter.attributes, S};    %% handle all other attributes
	{error_marker, _} ->
	    {delete, S};
	{warning_marker, _} ->
	    {delete, S};
	eof_marker ->
	    {delete, S};    % these must be deleted!
	_ ->
	    {keep, S}    % keep all other Erlang forms
    end.

%% This out-comments (kills) a program form. Any top-level pre-comments
%% are moved out, to avoid "nested" comments.

kill_form(F) ->
    F1 = erl_syntax:set_precomments(F, []),
    F2 = erl_syntax_lib:to_comment(F1, ?KILL_PREFIX),
    erl_syntax:set_precomments(F2,
			       erl_syntax:get_precomments(F)).


%% ---------------------------------------------------------------------
%% Merging the name spaces of a set of modules. Returns the final set
%% (see module `sets') of names and a total renaming function (atom())
%% -> ({atom(), integer()}) -> {atom(), integer()}.
%%
%% Names are added in two passes, in order to avoid renaming the
%% interface functions whenever possible: all exported functions are
%% added to the name space before any nonexported are added, and
%% "exported" modules are taken before any other. Thus, the order is:
%%
%%   - exported functions of exported modules
%%   - exported functions of nonexported modules
%%   - internal functions of exported modules
%%   - internal functions of nonexported modules
%%
%% In fact, only the first group is important, but there might be some
%% point in establishing the above order, for better readability of the
%% final code.

merge_namespaces(Modules, Env) ->
    Export = Env#merge.export,