add functions `system_tmpdir/0,1` and `reset_dir/1`

(in `rebar_file_utils`)

src/rebar_file_utils.erl

@@ -30,7 +30,10 @@
          cp_r/2,
          mv/2,
          delete_each/1,
-         write_file_if_contents_differ/2]).
+         write_file_if_contents_differ/2,
+         system_tmpdir/0,
+         system_tmpdir/1,
+         reset_dir/1]).
 
 -include("rebar.hrl").
 
@@ -123,6 +126,33 @@ write_file_if_contents_differ(Filename, Bytes) ->
             file:write_file(Filename, ToWrite)
     end.
 
+%% returns an os appropriate tmpdir given a path
+-spec system_tmpdir() -> file:filename(). 
+-spec system_tmpdir(PathComponents) -> file:filename() when
+      PathComponents :: [file:name()].
+
+system_tmpdir() -> system_tmpdir([]).
+system_tmpdir(PathComponents) ->
+    Tmp = case erlang:system_info(system_architecture) of
+        "win32" ->
+            "./tmp";
+        _SysArch ->
+            "/tmp"
+    end,
+    filename:join([Tmp|PathComponents]).
+
+%% recursively removes a directory and then recreates the same
+%%  directory but empty
+-spec reset_dir(Path) -> ok | {error, Reason} when
+      Path   :: file:name(),
+      Reason :: file:posix().
+
+reset_dir(Path) ->
+    %% delete the directory if it exists
+    _ = ec_file:remove(Path, [recursive]),
+    %% recreate the directory
+    filelib:ensure_dir(filename:join([Path, "dummy.beam"])).
+
 %% ===================================================================
 %% Internal functions
 %% ===================================================================

test/rebar_file_utils_SUITE.erl

@@ -0,0 +1,86 @@
+-module(rebar_file_utils_SUITE).
+
+-export([all/0,
+         groups/0,
+         init_per_group/2,
+         end_per_group/2,
+         raw_tmpdir/1,
+         empty_tmpdir/1,
+         simple_tmpdir/1,
+         multi_tmpdir/1,
+         reset_nonexistent_dir/1,
+         reset_empty_dir/1,
+         reset_dir/1]).
+
+-include_lib("common_test/include/ct.hrl").
+-include_lib("eunit/include/eunit.hrl").
+-include_lib("kernel/include/file.hrl").
+
+
+all() ->
+    [{group, tmpdir},
+     {group, reset_dir}].
+
+groups() ->
+    [{tmpdir, [], [raw_tmpdir, empty_tmpdir, simple_tmpdir, multi_tmpdir]},
+     {reset_dir, [], [reset_nonexistent_dir, reset_empty_dir, reset_dir]}].
+
+init_per_group(reset_dir, Config) ->
+    TmpDir = rebar_file_utils:system_tmpdir(["rebar_file_utils_SUITE", "resetable"]),
+    [{tmpdir, TmpDir}|Config];
+init_per_group(_, Config) -> Config.
+end_per_group(_, Config) -> Config.
+
+raw_tmpdir(_Config) ->
+    case rebar_file_utils:system_tmpdir() of
+        "/tmp"  -> ok;
+        "./tmp" -> ok
+    end.
+
+empty_tmpdir(_Config) ->
+    case rebar_file_utils:system_tmpdir([]) of
+        "/tmp"  -> ok;
+        "./tmp" -> ok
+    end.
+
+simple_tmpdir(_Config) ->
+    case rebar_file_utils:system_tmpdir(["test"]) of
+        "/tmp/test"  -> ok;
+        "./tmp/test" -> ok
+    end.
+
+multi_tmpdir(_Config) ->
+    case rebar_file_utils:system_tmpdir(["a", "b", "c"]) of
+        "/tmp/a/b/c"  -> ok;
+        "./tmp/a/b/c" -> ok
+    end.
+
+reset_nonexistent_dir(Config) ->
+    TmpDir = ?config(tmpdir, Config),
+    _ = ec_file:remove(TmpDir, [recursive]),
+    ?assertNot(filelib:is_dir(TmpDir)),
+    ok = rebar_file_utils:reset_dir(TmpDir),
+    ?assert(filelib:is_dir(TmpDir)),
+    {ok, []} = file:list_dir_all(TmpDir).
+
+reset_empty_dir(Config) ->
+    TmpDir = ?config(tmpdir, Config),
+    _ = ec_file:remove(TmpDir, [recursive]),
+    _ = filelib:ensure_dir(filename:join([TmpDir, "dummy.beam"])),
+    ?assert(filelib:is_dir(TmpDir)),
+    ok = rebar_file_utils:reset_dir(TmpDir),
+    ?assert(filelib:is_dir(TmpDir)),
+    {ok, []} = file:list_dir_all(TmpDir).
+
+reset_dir(Config) ->
+    TmpDir = ?config(tmpdir, Config),
+    _ = ec_file:remove(TmpDir, [recursive]),
+    _ = filelib:ensure_dir(filename:join([TmpDir, "dummy.beam"])),
+    ?assert(filelib:is_dir(TmpDir)),
+    lists:foreach(fun(Name) -> file:write_file(filename:join([TmpDir, Name]), <<>>) end,
+                  ["a", "b", "c"]),
+    lists:foreach(fun(File) -> ?assert(filelib:is_file(filename:join([TmpDir, File]))) end,
+                  ["a", "b", "c"]),
+    ok = rebar_file_utils:reset_dir(TmpDir),
+    ?assert(filelib:is_dir(TmpDir)),
+    {ok, []} = file:list_dir_all(TmpDir).