From 62e2a6e4849d342f90a3860554bf44df4e563d3b Mon Sep 17 00:00:00 2001
From: Magnus Ahltorp <map@kth.se>
Date: Thu, 25 Sep 2014 15:18:39 +0200
Subject: Added atomic module

---
 src/perm.erl | 73 +++++++++++++-----------------------------------------------
 1 file changed, 15 insertions(+), 58 deletions(-)

(limited to 'src/perm.erl')

diff --git a/src/perm.erl b/src/perm.erl
index 5cd2889..ccb23bc 100644
--- a/src/perm.erl
+++ b/src/perm.erl
@@ -6,16 +6,7 @@
 -module(perm).
 -export([ensurefile/3, readfile/2]).
 
-fsync([]) ->
-    ok;
-fsync([Name | Rest]) ->
-    case fsyncport:fsync(Name) of
-	ok ->
-	    fsync(Rest);
-	{error, Error} ->
-	    {error, Error}
-    end.
-
+-spec readfile_and_verify(string(), binary()) -> ok | differ | {error, atom()}.
 readfile_and_verify(Name, Content) ->
     case file:read_file(Name) of
         {ok, ContentsRead} when Content == ContentsRead ->
@@ -26,21 +17,7 @@ readfile_and_verify(Name, Content) ->
             {error, Error}
     end.
 
-writefile(Name, NurseryName, Content) ->
-    case file:open(NurseryName, [write, exclusive]) of
-        {ok, File} ->
-            %io:format("Write file: ~p~n", [Name]),
-            ok = file:write(File, Content),
-            file:close(File),
-	    Result = file:rename(NurseryName, Name),
-	    Result;
-        {error, eexist} ->
-	    %% Should not happen, file name should be unique
-            {error, eexist};
-        {error, Error} ->
-            {error, Error}
-    end.
-
+-spec make_dir(string()) -> ok | {error, atom()}.
 make_dir(Name) ->
     case file:make_dir(Name) of
 	ok ->
@@ -51,6 +28,7 @@ make_dir(Name) ->
 	    {error, Error}
     end.
 
+-spec make_dirs([string()]) -> ok | {error, atom()}.
 make_dirs([]) ->
     ok;
 make_dirs([Name | Rest]) ->
@@ -61,6 +39,7 @@ make_dirs([Name | Rest]) ->
 	    {error, Error}
     end.
 
+-spec path_for_key(string(), binary()) -> {[string()], string()}.
 path_for_key(Rootdir, Key) ->
     Name = hex:bin_to_hexstr(Key),
     [C1, C2, C3, C4, C5, C6 | _] = Name,
@@ -70,49 +49,27 @@ path_for_key(Rootdir, Key) ->
     Fullpath = Thirdlevel ++ "/" ++ Name,
     {[Firstlevel, Secondlevel, Thirdlevel], Fullpath}.
 
-tempfilename(Base) ->
-    {MegaSecs, Secs, MicroSecs} = now(),
-    Filename = io_lib:format("~s-~s-~p.~p", [Base, os:getpid(),
-			     MegaSecs * 1000000 + Secs, MicroSecs]),
-    Filename.
-
-exit_with_error(Error, Message) ->
-    io:format("~s: ~w~n", [Message, Error]),
-    exit({perm, fileerror, Message, Error}).
-
-check_error(ReturnValue, ErrorMessage) ->
-    case ReturnValue of
-        ok ->
-            ok;
-        {error, Error} ->
-            exit_with_error(Error, ErrorMessage)
-    end.
-
+-spec ensurefile(string(), binary(), binary()) -> ok | differ.
 ensurefile(Rootdir, Key, Content) ->
     {Dirs, Path} = path_for_key(Rootdir, Key),
     case readfile_and_verify(Path, Content) of
 	ok ->
-	    check_error(fsync([Path, Rootdir | Dirs]), "Error in fsync");
+	    util:fsync([Path, Rootdir | Dirs]);
         differ ->
             differ;
 	{error, enoent} ->
-            check_error(make_dirs([Rootdir, Rootdir ++ "nursery/"] ++ Dirs),
-                        "Error creating directory"),
+            util:check_error(make_dirs([Rootdir, Rootdir ++ "nursery/"]
+                                       ++ Dirs),
+                             makedir, "Error creating directory"),
             NurseryName = Rootdir ++ "nursery/" ++
-                tempfilename(hex:bin_to_hexstr(Key)),
-            _Result = writefile(Path, NurseryName, Content),
-            check_error(fsync([Path, Rootdir | Dirs]), "Error in fsync");
+                util:tempfilename(hex:bin_to_hexstr(Key)),
+            util:write_tempfile_and_rename(Path, NurseryName, Content),
+            util:fsync([Path, Rootdir | Dirs]);
 	{error, Error} ->
-            exit_with_error(Error, "Error reading file")
+            util:exit_with_error(Error, readfile, "Error reading file")
     end.
 
+-spec readfile(string(), binary()) -> binary().
 readfile(Rootdir, Key) ->
     {_Dirs, Path} = path_for_key(Rootdir, Key),
-    case file:read_file(Path) of
-        {ok, Contents} ->
-            Contents;
-	{error, enoent} ->
-            noentry;
-        {error, Error} ->
-            exit_with_error(Error, "Error reading file")
-    end.
+    atomic:readfile(Path).
-- 
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