Add code:module_status/1 and modified_modules/0

These functions use the MD5 beam/native checksum to determine whether the
code for a module has changed on disk and is a candidate for loading.

1 files changed, 180 insertions, 0 deletions

diff --git a/lib/kernel/test/code_SUITE.erl b/lib/kernel/test/code_SUITE.erl
index 29b3f7caaf..4914ce9e4c 100644
--- a/lib/kernel/test/code_SUITE.erl
+++ b/lib/kernel/test/code_SUITE.erl
@@ -38,6 +38,7 @@
 	 on_load_purge/1, on_load_self_call/1, on_load_pending/1,
 	 on_load_deleted/1,
 	 big_boot_embedded/1,
+         module_status/1,
 	 native_early_modules/1, get_mode/1,
 	 normalized_paths/1]).
 
@@ -68,6 +69,7 @@ all() ->
      on_load_binary, on_load_embedded, on_load_errors, on_load_update,
      on_load_purge, on_load_self_call, on_load_pending,
      on_load_deleted,
+     module_status,
      big_boot_embedded, native_early_modules, get_mode, normalized_paths].
 
 groups() ->
@@ -93,6 +95,11 @@ init_per_suite(Config) ->
 end_per_suite(Config) ->
     Config.
 
+-define(TESTMOD, test_dummy).
+-define(TESTMODSTR, "test_dummy").
+-define(TESTMODSRC, ?TESTMODSTR ".erl").
+-define(TESTMODOBJ, ?TESTMODSTR ".beam").
+
 init_per_testcase(big_boot_embedded, Config) ->
     case catch crypto:start() of
 	ok ->
@@ -104,6 +111,13 @@ init_per_testcase(_Func, Config) ->
     P = code:get_path(),
     [{code_path, P}|Config].
 
+end_per_testcase(module_status, Config) ->
+    code:purge(?TESTMOD),
+    code:delete(?TESTMOD),
+    code:purge(?TESTMOD),
+    file:delete(?TESTMODOBJ),
+    file:delete(?TESTMODSRC),
+    end_per_testcase(Config);
 end_per_testcase(TC, Config) when TC == mult_lib_roots;
 				  TC == big_boot_embedded ->
     {ok, HostName} = inet:gethostname(),
@@ -1757,6 +1771,172 @@ do_normalized_paths([M|Ms]) ->
 do_normalized_paths([]) ->
     ok.
 
+%% Test that module_status/1 behaves as expected
+module_status(_Config) ->
+    %% basics
+    not_loaded = code:module_status(fubar),     % nonexisting
+    {file, preloaded} = code:is_loaded(erlang),
+    loaded = code:module_status(erlang),        % preloaded
+    loaded = code:module_status(?MODULE),       % normal known loaded
+
+    non_existing = code:which(?TESTMOD), % verify dummy name not in path
+    code:purge(?TESTMOD), % ensure no previous version in memory
+    code:delete(?TESTMOD),
+    code:purge(?TESTMOD),
+
+    %% generated code is detected as such
+    {ok,?TESTMOD,Bin} = compile:forms(dummy_ast(), []),
+    {module,?TESTMOD} = code:load_binary(?TESTMOD,"",Bin),  % no source file
+    ok = ?TESTMOD:f(),
+    "" = code:which(?TESTMOD), % verify empty string for source file
+    loaded = code:module_status(?TESTMOD),
+
+    %% deleting generated code
+    true = code:delete(?TESTMOD),
+    non_existing = code:which(?TESTMOD), % verify still not in path
+    not_loaded = code:module_status(?TESTMOD),
+
+    %% beam file exists but not loaded
+    make_source_file(<<"0">>),
+    compile_beam(0),
+    true = (non_existing =/= code:which(?TESTMOD)), % verify in path
+    not_loaded = code:module_status(?TESTMOD),
+
+    %% loading code from disk makes it loaded
+    load_code(),
+    loaded = code:module_status(?TESTMOD), % loaded
+
+    %% cover compiling a module
+    {ok,?TESTMOD} = cover:compile(?TESTMOD),
+    {file, cover_compiled} = code:is_loaded(?TESTMOD), % verify cover compiled
+    modified = code:module_status(?TESTMOD), % loaded cover code but file exists
+    remove_code(),
+    removed = code:module_status(?TESTMOD), % removed
+    compile_beam(0),
+    modified = code:module_status(?TESTMOD), % recreated
+    load_code(),
+    loaded = code:module_status(?TESTMOD), % loading removes cover status
+    code:purge(?TESTMOD),
+    true = code:delete(?TESTMOD),
+    not_loaded = code:module_status(?TESTMOD), % deleted
+
+    %% recompilation ignores timestamps, only md5 matters
+    load_code(),
+    compile_beam(1100),
+    loaded = code:module_status(?TESTMOD),
+
+    %% modifying module detects different md5
+    make_source_file(<<"1">>),
+    compile_beam(0),
+    modified = code:module_status(?TESTMOD),
+
+    %% loading the modified code from disk makes it loaded
+    load_code(),
+    loaded = code:module_status(?TESTMOD),
+
+    %% removing and recreating a module with same md5
+    remove_code(),
+    removed = code:module_status(?TESTMOD),
+    compile_beam(0),
+    loaded = code:module_status(?TESTMOD),
+
+    case erlang:system_info(hipe_architecture) of
+	undefined ->
+	    %% no native support
+	    ok;
+	_ ->
+	    %% native chunk is ignored if beam code is already loaded
+	    load_code(),
+	    loaded = code:module_status(?TESTMOD),
+	    false = has_native(?TESTMOD),
+	    compile_native(0),
+	    BeamMD5 = erlang:get_module_info(?TESTMOD, md5),
+	    {ok,{?TESTMOD,BeamMD5}} = beam_lib:md5(?TESTMODOBJ), % beam md5 unchanged
+	    loaded = code:module_status(?TESTMOD),
+
+	    %% native code reported as loaded, though different md5 from beam
+	    load_code(),
+	    true = has_native(?TESTMOD),
+	    NativeMD5 = erlang:get_module_info(?TESTMOD, md5),
+	    true = (BeamMD5 =/= NativeMD5),
+	    loaded = code:module_status(?TESTMOD),
+
+	    %% recompilation ignores timestamps, only md5 matters
+	    compile_native(1100), % later timestamp
+	    loaded = code:module_status(?TESTMOD),
+
+	    %% modifying native module detects different md5
+	    make_source_file(<<"2">>),
+	    compile_native(0),
+	    modified = code:module_status(?TESTMOD),
+
+	    %% loading the modified native code from disk makes it loaded
+	    load_code(),
+	    true = has_native(?TESTMOD),
+	    NativeMD5_2 = erlang:get_module_info(?TESTMOD, md5),
+	    true = (NativeMD5 =/= NativeMD5_2), % verify native md5 changed
+	    {ok,{?TESTMOD,BeamMD5_2}} = beam_lib:md5(?TESTMODOBJ),
+	    true = (BeamMD5_2 =/= NativeMD5_2), % verify md5 differs from beam
+	    loaded = code:module_status(?TESTMOD),
+
+	    %% removing and recreating a native module with same md5
+	    remove_code(),
+	    removed = code:module_status(?TESTMOD),
+	    compile_native(0),
+	    loaded = code:module_status(?TESTMOD),
+
+	    %% purging/deleting native module
+	    code:purge(?TESTMOD),
+	    true = code:delete(?TESTMOD),
+	    not_loaded = code:module_status(?TESTMOD)
+    end,
+    ok.
+
+compile_beam(Sleep) ->
+    compile(Sleep, []).
+
+compile_native(Sleep) ->
+    compile(Sleep, [native]).
+
+compile(Sleep, Opts) ->
+    timer:sleep(Sleep),  % increment compilation timestamp
+    {ok,?TESTMOD} = compile:file(?TESTMODSRC, Opts).
+
+load_code() ->
+    code:purge(?TESTMOD),
+    {module,?TESTMOD} = code:load_file(?TESTMOD).
+
+remove_code() ->
+    ok = file:delete(?TESTMODOBJ).
+
+has_native(Module) ->
+    case erlang:get_module_info(Module, native_addresses) of
+	[] -> false;
+	[_|_] -> true
+    end.
+
+make_source_file(Body) ->
+    ok = file:write_file(?TESTMODSRC, dummy_source(Body)).
+
+dummy_source(Body) ->
+    [<<"-module(" ?TESTMODSTR ").\n"
+       "-export([f/0]).\n"
+       "f() -> ">>, Body, <<".\n">>].
+
+dummy_ast() ->
+    dummy_ast(?TESTMODSTR).
+
+dummy_ast(Mod) when is_atom(Mod) ->
+    dummy_ast(atom_to_list(Mod));
+dummy_ast(ModStr) ->
+    [scan_form("-module(" ++ ModStr ++ ")."),
+     scan_form("-export([f/0])."),
+     scan_form("f() -> ok.")].
+
+scan_form(String) ->
+    {ok,Ts,_} = erl_scan:string(String),
+    {ok,F} = erl_parse:parse_form(Ts),
+    F.
 
 %%-----------------------------------------------------------------
 %% error_logger handler.