igor.erl

OTP是开放电信平台的简称

    case sets:is_element(M, Forbid) of
	true ->
	    false;
	false ->
	    not sets:is_element(A, Names)
    end.

%% In this second stage, we resolve any conflicts that may remain
%% because of distinct source modules still containing distinct alias
%% definitions of the same name - in that case we remove *all* of them
%% (mainly for symmetry).

alias_expansions_2(Modules, Table) ->
    %% Get the set of all alias definitions in all modules (collapsing
    %% duplicated but equivalent definitions).
    Aliases = lists:foldl(
		fun (M, A) ->
			ordsets:union(A, M#module.aliases)
		end,
		ordsets:new(), Modules),
    
    %% Get the set of names with multiple (distinct) definitions.
    Names = duplicates([F || {F, _} <- Aliases]),
    
    %% Go through all aliases in all source modules and add necessary
    %% entries to the expansion-table. We expect that there is an entry
    %% in the table here for each module.
    lists:foldl(
      fun (M, T) ->
	      N = M#module.name,
	      lists:foldl(
		fun ({A, F}, T1) ->
			case ordsets:is_element(A, Names) of
			    true ->
				T2 = dict:fetch(N, T1),
				dict:store(N,
					   dict:store(A, F, T2),
					   T1);
			    false ->
				T1
			end
		end,
		T, M#module.aliases)
      end,
      Table, Modules).


%% ---------------------------------------------------------------------
%% Merging the source code.

%% Data structure for code transformation environment.

-record(code, {module,		% = atom()
	       target,		% = atom()
	       sources,		% = ordset(atom())
	       static,		% = ordset(atom())
	       safe,		% = ordset(atom())
	       preserved,	% = bool()
	       no_headers,	% = bool()
	       notes,		% = bool()
	       map,		% = ({atom(), int()}) -> {atom(), int()}
	       renaming,	% = (atom()) -> ({atom(), int()}) ->
				%               {atom(), int()}
	       expand,		% = dict({atom(), int()},
				%      {atom(), {atom(), int()}})
	       redirect		% = dict(atom(), atom())
	      }).

%% `Trees' must be a list of syntax trees of type `form_list'. The
%% result is a pair `{Result, Header}' where `Result' is a `form_list'
%% tree representing the merged code, and if the `preserved' flag is
%% set, `Header' is the list of forms up to and including the first
%% `-module(...)' declaration, but stripped of any `-file(...)'
%% attributes - otherwise `Header' is an empty list.

merge_code(Trees, Modules, Expansions, Renaming, Env, St) ->
    Env1 = #code{target = Env#merge.target,
		 sources = sets:from_list(Env#merge.sources),
		 static = sets:from_list(Env#merge.static),
		 safe = sets:from_list(Env#merge.safe),
		 preserved = Env#merge.preserved,
		 no_headers = Env#merge.no_headers,
		 notes = Env#merge.notes,
		 redirect = Env#merge.redirect,
		 renaming = Renaming},
    Code = order_code(Modules, Trees, Env1),
    {Code1, Header} = case Env1#code.preserved of
			  true ->
			      take_header(Code);
			  false ->
			      {Code, erl_syntax:form_list([])}
		      end,
    {Forms, St1} = merge_code_1(Code1, Expansions, Env1, St),
    Tree = erl_syntax:form_list(Forms),
    {Tree, Header, St1}.

merge_code_1(Code, Expansions, Env, St) ->
      lists:foldr(
	fun ({Module, T}, {Acc, St0}) ->
		M = Module#module.name,
		Expand = case dict:find(M, Expansions) of
			     {ok, Dict} -> Dict;
			     error -> dict:new()
			 end,
		Env1 = Env#code{module = M,
				map = (Env#code.renaming)(M),
				expand = Expand},
		{T1, St1} = transform(T, Env1, St0),
		{[section_header(M, T1, Env1) | Acc], St1}
	end,
	{[], St}, Code).

%% Pair module info and source code, in the order we want, and flatten
%% the form lists. If the name of the target is the same as one of the
%% source modules, and the result should preserve the original module,
%% the code for that module should be first in the output.

order_code(Modules, Trees, Env) ->
    order_code(Modules, Trees, {}, [], Env).

order_code([M | Ms], [T | Ts], First, Rest, Env) ->
    T1 = erl_syntax:flatten_form_list(T),
    case (M#module.name == Env#code.target) and
	Env#code.preserved of
	true ->
	    order_code(Ms, Ts, {M, T1}, Rest, Env);
	false ->
	    order_code(Ms, Ts, First, [{M, T1} | Rest], Env)
    end;
order_code([], [], First, Rest, _Env) ->
    Rest1 = lists:reverse(Rest),
    case First of
	{} ->
	    Rest1;
	M ->
	    [M | Rest1]
    end.

%% Extracting the "original" header (the `-module(...)' declaration is
%% sure to exist).

take_header([{M, T} | Ms]) ->
    Fs = erl_syntax:form_list_elements(T),
    {Header, Fs1} = take_header_1(Fs, []),
    T1 = erl_syntax:form_list(Fs1),
    {[{M, T1} | Ms], Header}.

take_header_1([F | Fs], As) ->
    case erl_syntax_lib:analyze_form(F) of
	{'attribute', {'module', _}} ->
	    {lists:reverse([F | As]), Fs};    % done
	{'attribute', {'file', _}} ->
	    take_header_1(Fs, As);    % discard
	_ ->
	    take_header_1(Fs, [F | As])    % keep
    end.

section_header(Name, Tree, Env) ->
    N = sets:size(Env#code.sources),
    if N > 1, Name /= Env#code.target, Env#code.notes /= no,
       Env#code.no_headers /= true ->
	    Text = io_lib:fwrite("The following code stems "
				 "from module `~w'.", [Name]),
	    Header = comment([?COMMENT_BAR, "",
			      lists:flatten(Text), ""]),
	    erl_syntax:form_list([Header, Tree]);
       true ->
	    Tree
    end.

transform(Tree, Env, St) ->
    case erl_syntax:type(Tree) of
	application ->
	    transform_application(Tree, Env, St);
	attribute ->
	    transform_attribute(Tree, Env, St);
  	function ->
  	    transform_function(Tree, Env, St);
 	implicit_fun ->
 	    transform_implicit_fun(Tree, Env, St);
  	rule ->
  	    transform_rule(Tree, Env, St);
  	record_expr ->
  	    transform_record(Tree, Env, St);
  	record_index_expr ->
  	    transform_record(Tree, Env, St);
  	record_access ->
  	    transform_record(Tree, Env, St);
	_ ->
	    default_transform(Tree, Env, St)
    end.

default_transform(Tree, Env, St) ->
    case erl_syntax:subtrees(Tree) of
	[] ->
	    {Tree, St};
	Gs ->
	    {Gs1, St1} = transform_1(Gs, Env, St),
	    Tree1 = rewrite(Tree, erl_syntax:make_tree(
				    erl_syntax:type(Tree),
				    Gs1)),
	    {Tree1, St1}
    end.

transform_1([G | Gs], Env, St) ->
    {G1, St1} = transform_list(G, Env, St),
    {Gs1, St2} = transform_1(Gs, Env, St1),
    {[G1 | Gs1], St2};
transform_1([], _Env, St) ->
    {[], St}.

transform_list([T | Ts], Env, St) ->
    {T1, St1} = transform(T, Env, St),
    {Ts1, St2} = transform_list(Ts, Env, St1),
    {[T1 | Ts1], St2};
transform_list([], _Env, St) ->
    {[], St}.

%% Renaming function definitions

transform_function(T, Env, St) ->
    {T1, St1} = default_transform(T, Env, St),
    F = erl_syntax_lib:analyze_function(T1),
    {V, Text} = case (Env#code.map)(F) of
		    F ->
			%% Not renamed
			{none, []};
		    {Atom, _Arity} ->
			%% Renamed
			Cs = erl_syntax:function_clauses(T1),
			N = rename_atom(
			      erl_syntax:function_name(T1),
			      Atom),
			T2 = erl_syntax:function(N, Cs),
			{{value, T2}, renaming_note(Atom)}
		end,
    {maybe_modified(V, T1, 2, Text, Env), St1}.

renaming_note(Name) ->
    [lists:flatten(io_lib:fwrite("renamed function to `~w'",
				 [Name]))].

rename_atom(Node, Atom) ->
    rewrite(Node, erl_syntax:atom(Atom)).

%% Renaming Mnemosyne rules (just like function definitions)

transform_rule(T, Env, St) ->
    {T1, St1} = default_transform(T, Env, St),
    F = erl_syntax_lib:analyze_rule(T1),
    {V, Text} = case (Env#code.map)(F) of
		    F ->
			%% Not renamed
			{none, []};
		    {Atom, _Arity} ->
			%% Renamed
			Cs = erl_syntax:rule_clauses(T1),
			N = rename_atom(
			      erl_syntax:rule_name(T1),
			      Atom),
			T2 = rewrite(T1,
				     erl_syntax:rule(N, Cs)),
			{{value, T2}, renaming_note(Atom)}
		end,
    {maybe_modified(V, T1, 2, Text, Env), St1}.

%% Renaming "implicit fun" expressions (done quietly).

transform_implicit_fun(T, Env, St) ->
    {T1, St1} = default_transform(T, Env, St),
    F = erl_syntax_lib:analyze_implicit_fun(T1),
    {V, Text} = case (Env#code.map)(F) of
		    F ->
			%% Not renamed
			{none, []};
		    {Atom, Arity} ->
			%% Renamed
			N = rewrite(
			      erl_syntax:implicit_fun_name(T1),
			      erl_syntax:arity_qualifier(
				erl_syntax:atom(Atom),
				erl_syntax:integer(Arity))),
			T2 = erl_syntax:implicit_fun(N),
			{{value, T2}, ["function was renamed"]}
		end,
    {maybe_modified_quiet(V, T1, 2, Text, Env), St1}.

%% Transforming function applications

transform_application(T, Env, St) ->
    %% We transform the arguments first, so we can concentrate on the
    %% application itself after that point.
    {As, St1} = transform_list(
		  erl_syntax:application_arguments(T),
		  Env, St),
    F = erl_syntax:application_operator(T),

    %% See if the operator is an explicit function name.
    %% (Usually, this will be the case.)
    case catch {ok, erl_syntax_lib:analyze_function_name(F)} of
	{ok, Name} ->
	    transform_application_1(Name, F, As, T, Env, St1);
	syntax_error ->
	    %% Oper is not a function name, but might be any other
	    %% expression - we just visit it and reassemble the
	    %% application.
	    %% We do not handle applications of tuples `{M, F}'.
	    {F1, St2} = transform(F, Env, St1),
	    {rewrite(T, erl_syntax:application(F1, As)), St2};
	{'EXIT', R} ->
	    exit(R);
	R ->
	    throw(R)
    end.

%% At this point we should have an explicit function name, which might
%% or might not be qualified by a module name.

transform_application_1(Name, F, As, T, Env, St) ->
    %% Before doing anything else, we must unfold any uses of aliases
    %% whose definitions have been killed.
    Arity = length(As),
    {Name1, F1} = expand_operator(Name, Arity, F, Env),
    F2 = maybe_modified_quiet(F1, F, 7, ["unfolded alias"], Env),
    {V, St1} = transform_application_2(Name1, Arity, F2, As, Env,
				       St),
    T1 = rewrite(T, erl_syntax:application(F2, As)),
    T3 = case V of
	     none ->
		 T1;
	     {value, {T2, Depth, Message}} ->
		 maybe_modified_quiet({value, T2}, T1, Depth,
				      Message, Env)
	 end,
    {T3, St1}.

%% Here, Name has been expanded if necessary (if so, this is also
%% reflected by F), and As have been transformed. We should return
%% `{none, State}' if no further rewriting is necessary, and otherwise
%% `{{value, {Tree, Depth, Message}}, State}', where `Depth' and
%% `Message' are to be passed to `maybe_modified'.

transform_application_2(Name, Arity, F, As, Env, St)
  when is_atom(Name) ->
    transform_atom_application(Name, Arity, F, As, Env, St);
transform_application_2({M, N}, Arity, F, As, Env, St)
  when is_atom(M), is_atom(N) ->
    transform_qualified_application(M, N, Arity, F, As, Env, St);
transform_application_2(_Name, _Arity, _F, _As, _Env, St) ->
    {none, St}.    % strange name - do nothing.

expand_operator(Name, Arity, _F, Env) when is_atom(Name) ->
    %% An unqualified function name - must be looked up. However, we
    %% must first check that it is not an auto-imported name - these
    %% have precedence over normal imports. We do a sanity check on the
    %% found arity.
    case is_auto_import({Name, Arity}) of
	true ->
	    {Name, none};    % auto-import - never expand.
	false ->
	    case dict:find({Name, Arity}, Env#code.expand) of
		{ok, {M, {N, A}}} when A =:= Arity ->
		    %% Expand to a qualified name.
		    F1 = erl_syntax:module_qualifier(
			   erl_syntax:atom(M),
			   erl_syntax:atom(N)),
		    {{M, N}, {value, F1}};
		error ->
		    %% Not in the table - leave it unchanged
		    {Name, none}
	    end