Separates read and write permissions.

1 files changed, 32 insertions, 30 deletions

diff --git a/src/db/logic/db_access.erl b/src/db/logic/db_access.erl
index f7393f0..1591ead 100644
--- a/src/db/logic/db_access.erl
+++ b/src/db/logic/db_access.erl
@@ -10,36 +10,14 @@
 -export
 (
    [
-      read/2,
-      insert/4,
+      read/3,
+      insert/5,
       query/1
    ]
 ).
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--spec get_value (list(shr_db_item:type())) -> ({'ok', any()} | 'not_found').
-get_value ([]) -> not_found;
-get_value ([Regval]) -> {ok, shr_db_item:get_value(Regval)}.
-
--spec read_transaction (atom(), any()) -> ({'ok', any()} | 'not_found').
-read_transaction (DB, ID) ->
-   get_value(mnesia:read(DB, ID)).
-
--spec insert_transaction
-   (
-      atom(),
-      any(),
-      shr_db_user:permission(),
-      any()
-   )
-   -> 'ok'.
-insert_transaction (DB, ID, Perm, Value) ->
-   StoredItem = shr_db_item:new(ID, Perm, Value),
-   % FIXME: handle return value, mnesia:write -> (transaction abort | ok).
-   % FIXME: is this an atomic OP? Is the lock freed afterwards?
-   mnesia:write(DB, StoredItem, sticky_write),
-   ok.
 
 -spec query_transaction (shr_db_query:type()) -> 'ok'.
 query_transaction (Query) ->
@@ -55,15 +33,39 @@ query_transaction (Query) ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
--spec read (atom(), any())
+-spec read
+   (
+      atom(),
+      any(),
+      shr_db_user:user()
+   )
    -> ({'aborted', any()} | {'atomic', ({'ok', any()} | 'not_found')}).
-read (DB, ID) ->
-   mnesia:transaction(fun read_transaction/2, [DB, ID]).
+read (DB, ID, Cred) ->
+   case mnesia:transaction(fun mnesia:read/2, [DB, ID]) of
+      {'atomic', []} -> {'atomic', 'not_found'};
+      {'atomic', [Item]} ->
+         true =
+            shr_db_user:can_access
+            (
+               shr_db_item:get_write_permission(Item),
+               Cred
+            ),
+         {'atomic', {ok, shr_db_item:get_value(Item)}};
+
+      Other -> {'aborted', Other}
+   end.
 
--spec insert (atom(), any(), shr_db_user:permission(), any())
+-spec insert
+   (
+      atom(),
+      any(),
+      shr_db_user:permission(),
+      shr_db_user:permission(),
+      any())
    -> ({'aborted', any()} | {'atomic', 'ok'}).
-insert (DB, ID, Perm, Value) ->
-   mnesia:transaction(fun insert_transaction/4, [DB, ID, Perm, Value]).
+insert (DB, ID, ReadPerm, WritePerm, Value) ->
+   Item = shr_db_item:new(ID, ReadPerm, WritePerm, Value),
+   mnesia:transaction(fun mnesia:write/3, [DB, Item, sticky_write]).
 
 -spec query (shr_db_query:type()) -> ({'aborted', any()} | {'atomic', 'ok'}).
 query (Query) ->