igor.erl

OTP是开放电信平台的简称

    Split = fun (M) ->
		    ordsets:is_element(M#module.name, Export)
	    end,
    {M1, M2} = split_list(Split, Modules),
    R = dict:new(),
    Acc = {sets:new(), R},
    {M3, Acc1} = merge_namespaces_1(M1, Acc),

    %% Detect and warn about renamed interface functions
    {_, Maps0} = Acc1,
    case [{M, dict:to_list(Map)}
	  || {M, Map} <- dict:to_list(Maps0), dict:size(Map) /= 0] of
	[] ->
	    ok;
	Fs ->
	    report_warning("interface functions renamed:\n\t~p.",
			   [Fs])
    end,
    {M4, Acc2} = merge_namespaces_1(M2, Acc1),
    Ms = M3 ++ M4,
    Acc3 = merge_namespaces_2(Ms, Acc2),
    {{Names, Maps}, _} = merge_namespaces_3(Ms, Acc3),
    {Names, make_renaming_function(Maps)}.

%% Adding exported names. (Note that the list gets a new temporary
%% format also containing the exports.) This first step initialises the
%% Maps "dict-of-dicts" structure.

merge_namespaces_1(Modules, Acc) ->
    lists:mapfoldl(
      fun (Module, {Names, Maps}) ->
	      Exports = sets:from_list(Module#module.exports),
	      M = Module#module.name,
	      {Names1, Map} = add_function_renamings(M, Exports, Names,
						     dict:new()),
	      Maps1 = dict:store(M, Map, Maps),
	      {{Module, Exports}, {Names1, Maps1}}
      end,
      Acc, Modules).

%% Adding nonexported names.

merge_namespaces_2(Modules, Acc) ->
    lists:foldl(
      fun ({Module, Exports}, {Names, Maps}) ->
	      Other = sets:subtract(
			sets:from_list(Module#module.functions),
			Exports),
	      M = Module#module.name,
	      Map = dict:fetch(M, Maps),
	      {Names1, Map1} = add_function_renamings(M, Other, Names,
						      Map),
	      Maps1 = dict:store(M, Map1, Maps),
	      {Names1, Maps1}
      end,
      Acc, Modules).

%% Adding record names. We need to keep a global
%% "record-definition-to-new-record-name" mapping RMap while doing this.

merge_namespaces_3(Modules, Acc) ->
    lists:foldl(
      fun ({Module, _Exports}, {{Names, Maps}, RMap}) ->
	      Records = Module#module.records,
	      M = Module#module.name,
	      Map = dict:fetch(M, Maps),
	      {Names1, Map1, RMap1} = add_record_renamings(M, Records,
							   Names, Map,
							   RMap),
	      Maps1 = dict:store(M, Map1, Maps),
	      {{Names1, Maps1}, RMap1}
      end,
      {Acc, dict:new()}, Modules).

%% This takes the set of added function names together with the existing
%% name set, creates new function names where necessary, and returns the
%% final name set together with the list of renamings.

add_function_renamings(Module, New, Names, Map) ->
    Clashes = sets:to_list(sets:intersection(New, Names)),
    lists:foldl(
      fun (F = {_, A}, {Names, Map}) when is_integer(A) ->
	      F1 = new_function_name(Module, F, Names),
	      {sets:add_element(F1, Names), dict:store(F, F1, Map)}
      end,
      {sets:union(New, Names), Map}, Clashes).

%% This is similar to the above, but for record names. Note that we add
%% both the record name and the whole definition to the namespace.

add_record_renamings(Module, Records, Names, Map, RMap) ->
    lists:foldl(
      fun (N = {R, Fs}, {Names, Map, RMap}) ->
	      case sets:is_element(?record_name(R), Names) of
		  true ->
		      %% The name is already in use.
		      case sets:is_element(?record_name(N), Names) of
			  true ->
			      %% We have seen this definition before;
			      %% make sure we use the same name.
			      {R1, _} = remap_record_name(N, RMap),
			      Map1 = dict:store(?record_name(R),
						?record_name(R1), Map),
			      {Names, Map1, RMap};
			  false ->
			      %% Redefinition of existing name. Create
			      %% new name and set up renamings.
			      N1 = {R1, _} = new_record_name(Module, R,
							     Fs, Names),
			      Map1 = dict:store(?record_name(R),
						?record_name(R1), Map),
			      RMap1 = dict:store(N, N1, RMap),
			      Names1 = sets:add_element(?record_name(N1),
							Names),
			      {Names1, Map1, RMap1}
		      end;
		  false ->
		      %% A previously unused record name.
		      Names1 = sets:add_element(?record_name(R), Names),
		      Names2 = sets:add_element(?record_name(N), Names1),
		      {Names2, Map, RMap}
	      end
      end,
      {Names, Map, RMap}, Records).

remap_record_name(N, Map) ->
    case dict:find(N, Map) of
	{ok, N1} -> N1;
	error -> N
    end.

%% This hides the implementation of the record namespace. Since Map
%% yields identity for non-remapped names, the remapped names must be
%% stored in wrapped form.

map_record_name(R, Map) ->
    ?record_name(R1) = Map(?record_name(R)),
    R1.

%% When we rename a function, we want the new name to be as close as
%% possible to the old, and as informative as possible. Therefore, we
%% first prefix it with the name of the originating module, followed by
%% two underscore characters, and then if there still is a name clash,
%% we suffix the name by "_N", where N is the smallest possible positive
%% integer that does not cause a clash.

new_function_name(M, {F, A}, Names) ->
    Base = atom_to_list(M) ++ "__" ++ atom_to_list(F),
    Name = {list_to_atom(Base), A},
    case sets:is_element(Name, Names) of
	false ->
	    Name;
	true ->
	    new_function_name(1, A, Base, Names)
    end.

new_function_name(N, Arity, Base, Names) ->
    Name = {list_to_atom(Base ++ "_" ++ integer_to_list(N)),
	    Arity},
    case sets:is_element(Name, Names) of
	false ->
	    Name;
	true ->
	    %% Increment counter and try again.
	    new_function_name(N + 1, Arity, Base, Names)
    end.

%% This is pretty much the same as new_function_name, for now.

new_record_name(M, R, Fs, Names) ->
    Base = atom_to_list(M) ++ "__" ++ atom_to_list(R),
    Name = {list_to_atom(Base), Fs},
    case sets:is_element(?record_name(Name), Names) of
	false ->
	    Name;
	true ->
	    new_record_name_1(1, Base, Fs, Names)
    end.

new_record_name_1(N, Base, Fs, Names) ->
    Name = {list_to_atom(Base ++ "_" ++ integer_to_list(N)), Fs},
    case sets:is_element(?record_name(Name), Names) of
	false ->
	    Name;
	true ->
	    %% Increment counter and try again.
	    new_record_name_1(N + 1, Base, Fs, Names)
    end.

%% This returns a *total* function from the set of module names to the
%% set of *total* operators on function names, yielding identity for all
%% function names that are not specified in the given partial map
%% (ModuleName -> (Name -> Name)).

make_renaming_function(Maps) ->
    fun (Module) ->
	    case dict:find(Module, Maps) of
		{ok, Map} ->
		    fun (Name) ->
			    case dict:find(Name, Map) of
				{ok, Name1} ->
				    Name1;    % renamed
				error ->
				    Name    % identity
			    end
		    end;
		error ->
		    %% Other module - yield identity map.
		    fun (Name) -> Name end
	    end
    end.


%% ---------------------------------------------------------------------
%% Merging module info records into a target module record, and finding
%% necessary alias expansions. Returns `{Module, Expansions}' where
%% `Expansions' has type `dict(ModuleName, dict(Alias, FullName))'

merge_info(Modules, Names, Renaming, Env) ->
    Forbid = sets:from_list(Env#merge.no_imports),
    Expansions = alias_expansions(Modules, Names, Forbid),
    Module = merge_info_1(Modules, Renaming, Expansions, Env),
    {Module, Expansions}.

merge_info_1(Modules, Renaming, Expansions, Env) ->
    lists:foldl(
      fun (M, A) ->
	      Name = M#module.name,
	      Map = Renaming(Name),
	      Functions = join_functions(Map,
					 M#module.functions,
					 A#module.functions),
	      Exports = join_exports(Env, Name, Map,
				     M#module.exports,
				     A#module.exports),
	      Aliases = join_aliases(Name, Expansions,
				     M#module.aliases,
				     A#module.aliases),
	      Attributes = join_attributes(Env, Name,
					   M#module.attributes,
					   A#module.attributes),
	      Records = join_records(Map,
				     M#module.records,
				     A#module.records),
	      A#module{functions = Functions,
		       exports = Exports,
		       aliases = Aliases,
		       attributes = Attributes,
		       records = Records}
      end,
      #module{name = Env#merge.target,
	      functions = ordsets:new(),
	      exports = ordsets:new(),
	      aliases = ordsets:new(),
	      attributes = ordsets:new(),
	      records = ordsets:new()},
      Modules).

%% Functions must be renamed before including.

join_functions(Map, Source, Target) ->
    ordsets:union(ordsets:from_list([Map(A) || A <- Source]),
		  Target).

%% Exports also need renaming, and are kept only if their originating
%% modules are exported.

join_exports(Env, Name, Map, Source, Target) ->
    case ordsets:is_element(Name, Env#merge.export) of
	true ->
	    ordsets:union(ordsets:from_list([Map(F)
					     || F <- Source]),
			  Target);
	false ->
	    Target
    end.

%% Aliases never need renaming; instead we always expand uses which
%% could cause name clashes. We must then remove the expanded names from
%% the imports of the target.

join_aliases(Name, Expansions, Source, Target) ->
    As = case dict:find(Name, Expansions) of
	     {ok, As1} ->
		 ordsets:from_list(dict:to_list(As1));
	     error ->
		 []
	 end,
    ordsets:union(ordsets:subtract(Source, As), Target).

%% We only propagate attributes if the number of source modules is 1 or
%% the source module has the same name as the resulting module.

join_attributes(Env, Name, Source, Target) ->
    if Env#merge.target == Name ->
	    ordsets:union(Source, Target);
       true ->
	    if length(Env#merge.sources) =:= 1 ->
		    ordsets:union(Source, Target);
	       true ->
		    Target
	    end
    end.

%% The final record info in itself is not used at present, but we
%% compute the join anyway. We apply renaming to records much like we do
%% to functions, but records have a separate namespace.

join_records(Map, Source, Target) ->
    Renamed = [{map_record_name(R, Map), Fs} || {R, Fs} <- Source],
    ordsets:union(ordsets:from_list(Renamed), Target).

%% This finds aliases that are in conflict or are for other reasons
%% necessary to expand while transforming the code later. It is assumed
%% that each module is in itself correct, and thus does not contain
%% conflicting definitions of the same alias.
%%
%% We could of course simply say that *all* aliases, without exception,
%% should be expanded, but such a big change in the style of the code
%% should not be done unless the user explicitly specifies it.
%%
%% The returned `Expansions' is a dictionary (module `dict') mapping
%% each module name in `Modules' to a dictionary which maps those
%% aliases to be expanded for that module to their corresponding full
%% names.
%%
%% Aliases are filtered according to the following rules:
%%
%%	1. If a name is defined (in some source module) as an alias of a
%%	name `M:...', where `M' is any of the source modules(*), then
%%	the definition of that alias should be removed, and all its uses
%%	(in the same module as the definition) be expanded.
%%
%%	2. Then, if a name is defined (in some source module) as an
%%	alias, but the name occurs in the name space of the resulting
%%	module, then the definition should be removed and all uses (in
%%	the same module) expanded.
%%
%%	3. Finally, if a name has two or more distinct alias definitions
%%	in the source modules, then all definitions of that alias should
%%	be removed and all uses (in all modules) expanded. (We remove
%%	all definitions mainly for symmetry.)
%%
%%	(*) It is actually possible for an alias to refer to the module
%%	in which it is itself defined. However, since we also in this
%%	case want to expand all uses, we don't have to do any extra work
%%	to handle it.

%% The filtering is done in two stages.

alias_expansions(Modules, Names, Forbid) ->
    Table = alias_expansions_1(Modules, Forbid, Names),
    alias_expansions_2(Modules, Table).

%% First consider each alias in isolation.

alias_expansions_1(Modules, Forbid, Names) ->
    lists:foldl(
      fun (M, T) ->
	      Map = lists:foldl(
		      fun ({A, F}, T1) ->
			      case keep_alias(A, F, Forbid, Names)
				  of
				  true ->
				      T1;
				  false ->
				      dict:store(A, F, T1)
			      end
		      end,
		      dict:new(), M#module.aliases),
	      dict:store(M#module.name, Map, T)
      end,
      dict:new(), Modules).

keep_alias(A, {M, _}, Forbid, Names) ->