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Diffstat (limited to 'src/rebar_paths.erl')
| -rw-r--r-- | src/rebar_paths.erl | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/rebar_paths.erl b/src/rebar_paths.erl new file mode 100644 index 0000000..82c0218 --- /dev/null +++ b/src/rebar_paths.erl @@ -0,0 +1,208 @@ +-module(rebar_paths). +-include("rebar.hrl"). + +-type target() :: deps | plugins. +-type targets() :: [target(), ...]. +-export_type([target/0, targets/0]). +-export([set_paths/2, unset_paths/2]). +-export([clashing_apps/2]). + +-ifdef(TEST). +-export([misloaded_modules/2]). +-endif. + +-spec set_paths(targets(), rebar_state:t()) -> ok. +set_paths(UserTargets, State) -> + Targets = normalize_targets(UserTargets), + GroupPaths = path_groups(Targets, State), + Paths = lists:append(lists:reverse([P || {_, P} <- GroupPaths])), + code:add_pathsa(Paths), + AppGroups = app_groups(Targets, State), + purge_and_load(AppGroups, sets:new()), + ok. + +-spec unset_paths(targets(), rebar_state:t()) -> ok. +unset_paths(UserTargets, State) -> + Targets = normalize_targets(UserTargets), + GroupPaths = path_groups(Targets, State), + Paths = lists:append([P || {_, P} <- GroupPaths]), + [code:del_path(P) || P <- Paths], + purge(Paths, code:all_loaded()), + ok. + +-spec clashing_apps(targets(), rebar_state:t()) -> [{target(), [binary()]}]. +clashing_apps(Targets, State) -> + AppGroups = app_groups(Targets, State), + AppNames = [{G, sets:from_list( + [rebar_app_info:name(App) || App <- Apps] + )} || {G, Apps} <- AppGroups], + clashing_app_names(sets:new(), AppNames, []). + +%%%%%%%%%%%%%%% +%%% PRIVATE %%% +%%%%%%%%%%%%%%% + +%% The paths are to be set in the reverse order; i.e. the default +%% path is always last when possible (minimize cases where a build +%% tool version clashes with an app's), and put the highest priorities +%% first. +-spec normalize_targets(targets()) -> targets(). +normalize_targets(List) -> + %% Plan for the eventuality of getting values piped in + %% from future versions of rebar3, possibly from plugins and so on, + %% which means we'd risk failing kind of violently. We only support + %% deps and plugins + TmpList = lists:foldl( + fun(deps, [deps | _] = Acc) -> Acc; + (plugins, [plugins | _] = Acc) -> Acc; + (deps, Acc) -> [deps | Acc -- [deps]]; + (plugins, Acc) -> [plugins | Acc -- [plugins]]; + (_, Acc) -> Acc + end, + [], + List + ), + lists:reverse(TmpList). + +purge_and_load([], _) -> + ok; +purge_and_load([{_Group, Apps}|Rest], Seen) -> + %% We have: a list of all applications in the current priority group, + %% a list of all loaded modules with their active path, and a list of + %% seen applications. + %% + %% We do the following: + %% 1. identify the apps that have not been solved yet + %% 2. find the paths for all apps in the current group + %% 3. unload and reload apps that may have changed paths in order + %% to get updated module lists and specs + %% (we ignore started apps and apps that have not run for this) + %% This part turns out to be the bottleneck of this module, so + %% to speed it up, using clash detection proves useful: + %% only reload apps that clashed since others are unlikely to + %% conflict in significant ways + %% 4. create a list of modules to check from that app list—only loaded + %% modules make sense to check. + %% 5. check the modules to match their currently loaded paths with + %% the path set from the apps in the current group; modules + %% that differ must be purged; others can stay + + %% 1) + AppNames = [AppName || App <- Apps, + AppName <- [rebar_app_info:name(App)], + not sets:is_element(AppName, Seen)], + GoodApps = [App || AppName <- AppNames, + App <- Apps, + rebar_app_info:name(App) =:= AppName], + %% 2) + %% (no need for extra_src_dirs since those get put into ebin; + %% also no need for OTP libs; we want to allow overtaking them) + GoodAppPaths = [rebar_app_info:ebin_dir(App) || App <- GoodApps], + %% 3) + [begin + AtomApp = binary_to_atom(AppName, utf8), + %% blind load/unload won't interrupt an already-running app, + %% preventing odd errors, maybe! + case application:unload(AtomApp) of + ok -> application:load(AtomApp); + _ -> ok + end + end || AppName <- AppNames, + %% Shouldn't unload ourselves; rebar runs without ever + %% being started and unloading breaks logging! + AppName =/= <<"rebar">>], + + %% 4) + CandidateMods = lists:append( + %% Start by asking the currently loaded app (if loaded) + %% since it would be the primary source of conflicting modules + [case application:get_key(AppName, modules) of + {ok, Mods} -> + Mods; + undefined -> + %% if not found, parse the app file on disk, in case + %% the app's modules are used without it being loaded + case rebar_app_info:app_details(App) of + [] -> []; + Details -> proplists:get_value(modules, Details, []) + end + end || App <- GoodApps, + AppName <- [binary_to_atom(rebar_app_info:name(App), utf8)]] + ), + ModPaths = [{Mod,Path} || Mod <- CandidateMods, + erlang:function_exported(Mod, module_info, 0), + {file, Path} <- [code:is_loaded(Mod)]], + + %% 5) + Mods = misloaded_modules(GoodAppPaths, ModPaths), + [purge_mod(Mod) || Mod <- Mods], + + purge_and_load(Rest, sets:union(Seen, sets:from_list(AppNames))). + +purge(Paths, ModPaths) -> + SortedPaths = lists:sort(Paths), + lists:map(fun purge_mod/1, + [Mod || {Mod, Path} <- ModPaths, + is_list(Path), % not 'preloaded' or mocked + any_prefix(Path, SortedPaths)] + ). + +misloaded_modules(GoodAppPaths, ModPaths) -> + %% Identify paths that are invalid; i.e. app paths that cover an + %% app in the desired group, but are not in the desired group. + lists:usort( + [Mod || {Mod, Path} <- ModPaths, + is_list(Path), % not 'preloaded' or mocked + not any_prefix(Path, GoodAppPaths)] + ). + +any_prefix(Path, Paths) -> + lists:any(fun(P) -> lists:prefix(P, Path) end, Paths). + +%% assume paths currently set are good; only unload a module so next call +%% uses the correctly set paths +purge_mod(Mod) -> + code:soft_purge(Mod) andalso code:delete(Mod). + + +%% This is a tricky O(n²) check since we want to +%% know whether an app clashes with any of the top priority groups. +%% +%% For example, let's say we have `[deps, plugins]', then we want +%% to find the plugins that clash with deps: +%% +%% `[{deps, [ClashingPlugins]}, {plugins, []}]' +%% +%% In case we'd ever have alternative or additional types, we can +%% find all clashes from other 'groups'. +clashing_app_names(_, [], Acc) -> + lists:reverse(Acc); +clashing_app_names(PrevNames, [{G,AppNames} | Rest], Acc) -> + CurrentNames = sets:subtract(AppNames, PrevNames), + NextNames = sets:subtract(sets:union([A || {_, A} <- Rest]), PrevNames), + Clashes = sets:intersection(CurrentNames, NextNames), + NewAcc = [{G, sets:to_list(Clashes)} | Acc], + clashing_app_names(sets:union(PrevNames, CurrentNames), Rest, NewAcc). + +path_groups(Targets, State) -> + [{Target, get_paths(Target, State)} || Target <- Targets]. + +app_groups(Targets, State) -> + [{Target, get_apps(Target, State)} || Target <- Targets]. + +get_paths(deps, State) -> + rebar_state:code_paths(State, all_deps); +get_paths(plugins, State) -> + rebar_state:code_paths(State, all_plugin_deps). + +get_apps(deps, State) -> + %% The code paths for deps also include the top level apps + %% and the extras, which we don't have here; we have to + %% add the apps by hand + case rebar_state:project_apps(State) of + undefined -> []; + List -> List + end ++ + rebar_state:all_deps(State); +get_apps(plugins, State) -> + rebar_state:all_plugin_deps(State). |