rename files, add read support.

src/monic_file_writer.erl → src/monic_file.erl

@@ -12,7 +12,7 @@
 %% License for the specific language governing permissions and limitations under
 %% the License.
 
--module(monic_file_writer).
+-module(monic_file).
 -behavior(gen_server).
 -include("monic.hrl").
 
@@ -27,7 +27,7 @@
 -define(BUFFER_SIZE, 16384).
 
 %% public API
--export([open/1, write/3, close/1]).
+-export([open/1, write/3, read/4, close/1]).
 
 %% gen_server API
 -export([init/1, terminate/2, code_change/3,handle_call/3, handle_cast/2, handle_info/2]).
@@ -40,6 +40,9 @@ open(Path) ->
 write(Pid, Size, Fun) ->
     gen_server:call(Pid, {write, Size, Fun}, infinity).
 
+read(Pid, Key, Cookie, Fun) ->
+    gen_server:call(Pid, {read, Key, Cookie, Fun}, infinity).
+
 close(Pid) ->
     gen_server:call(Pid, close, infinity).
 
@@ -65,6 +68,21 @@ init(Path) ->
             {stop, Else}
     end.
 
+handle_call({read, Key, Cookie, Fun}, _From, #state{tid=Tid, main_fd=Fd}=State) ->
+    case ets:lookup(Tid, Key) of
+        [{Key, Location, Size, _}] ->
+            case monic_utils:pread_header(Fd, Location) of
+                {ok, #header{cookie=Cookie,size=Size}} ->
+                    copy_out(Fd, Fun, Location + ?HEADER_SIZE, Size),
+                    {reply, ok, State};
+                {ok, _} ->
+                    {reply, {error, wrong_cookie}, State};
+                Else ->
+                    {reply, Else, State}
+            end;
+        [] ->
+            {reply, not_found, State}
+    end;
 handle_call({write, Size, Fun}, _From, #state{main_fd=Fd,next_location=NextLocation}=State) ->
     case new_item(Size, Fun, State) of
         {ok, Key, Cookie} ->
@@ -209,6 +227,18 @@ copy_in(Fd, Fun, Location, Remaining, Sha) ->
             Else
     end.
 
+copy_out(_Fd, _Fun, _Location, 0) ->
+    ok;
+copy_out(Fd, Fun, Location, Remaining) ->
+    case file:pread(Fd, Location, min(Remaining, ?BUFFER_SIZE)) of
+        {ok, Bin} ->
+            Size = iolist_size(Bin),
+            Fun({ok, Bin}),
+            copy_out(Fd, Fun, Location + Size, Remaining - Size);
+        Else ->
+            Else
+    end.
+
 cleanup(#state{tid=Tid,index_fd=IndexFd,main_fd=MainFd}=State) ->
     close_int(IndexFd),
     close_int(MainFd),

test/monic_file_writer_test.erl → test/monic_file_test.erl

@@ -12,7 +12,7 @@
 %% License for the specific language governing permissions and limitations under
 %% the License.
 
--module(monic_file_writer_test).
+-module(monic_file_test).
 -include("monic.hrl").
 -include_lib("eunit/include/eunit.hrl").
 
@@ -21,22 +21,26 @@ all_test_() ->
     fun setup/0,
     fun cleanup/1,
     [fun write/1,
+    fun write_read/1,
     fun overflow/1
     ]}.
 
 setup() ->
     file:delete("foo.monic"),
     file:delete("foo.monic.idx"),
-    {ok, Pid} = monic_file_writer:open("foo.monic"),
+    {ok, Pid} = monic_file:open("foo.monic"),
     Pid.
 
 cleanup(Pid) ->
-    monic_file_writer:close(Pid).
+    monic_file:close(Pid).
 
 write(Pid) ->
-    Res = monic_file_writer:write(Pid, 3, fun(_Max) -> {ok, <<"123">>} end),
-    ?_assertMatch({ok, 0, _}, Res).
+    ?_assertMatch({ok, 0, _}, monic_file:write(Pid, 3, fun(_Max) -> {ok, <<"123">>} end)).
+
+write_read(Pid) ->
+    {ok, Key, Cookie} = monic_file:write(Pid, 3, fun(_Max) -> {ok, <<"123">>} end),
+    ?_assertEqual(ok, monic_file:read(Pid, Key, Cookie, fun(_) -> ok end)).
 
 overflow(Pid) ->
-    Res = monic_file_writer:write(Pid, 3, fun(_Max) -> {ok, <<"1234">>} end),
+    Res = monic_file:write(Pid, 3, fun(_Max) -> {ok, <<"1234">>} end),
     ?_assertEqual({error, overflow}, Res).