Adding support for not_found on get and txn abort

c_src/bdberl_drv.c

@@ -24,7 +24,7 @@ static void do_async_put(void* arg);
 static void do_async_put_free(void* arg);
 static void do_async_get(void* arg);
 static void do_async_get_free(void* arg);
-static void do_async_commit(void* arg);
+static void do_async_txnop(void* arg);
 
 static int add_dbref(PortData* data, int dbref);
 static int del_dbref(PortData* data, int dbref);
@@ -260,6 +260,7 @@ static int bdberl_drv_control(ErlDrvData handle, unsigned int cmd,
         RETURN_INT(rc, outbuf);
     }
     case CMD_TXN_COMMIT:
+    case CMD_TXN_ABORT:
     {
         // If an async operation is pending, fail
         if (d->async_op != CMD_NONE)
@@ -278,11 +279,11 @@ static int bdberl_drv_control(ErlDrvData handle, unsigned int cmd,
         adata->port = d;
 
         // Update port data to indicate we have an operation in progress
-        d->async_op = CMD_TXN_COMMIT;
+        d->async_op = cmd;
 
-        // Schedule async operation to execute the commit
+        // Schedule async operation to execute the commit/abort
         unsigned int key = (unsigned int)d->port;
-        driver_async(d->port, &key, &do_async_commit, adata, 0);
+        driver_async(d->port, &key, &do_async_txnop, adata, 0);
 
         // Outbuf is <<Rc:32>>
         RETURN_INT(0, outbuf);
@@ -382,8 +383,8 @@ static void bdberl_drv_ready_async(ErlDrvData handle, ErlDrvThreadData thread_da
     }
     case CMD_GET:
     {
-        // Extract return code == if it's zero, send back {ok, Payload} to driver process; otherwise
-        // send a {error, Reason} tuple
+        // Extract return code == if it's zero, send back {ok, Payload} or not_found to driver
+        // process; otherwise send a {error, Reason} tuple
         AsyncData* adata = (AsyncData*)thread_data;
         if (adata->rc == 0)
         {
@@ -392,6 +393,12 @@ static void bdberl_drv_ready_async(ErlDrvData handle, ErlDrvThreadData thread_da
                                           ERL_DRV_TUPLE, 2};
             driver_output_term(d->port, response, sizeof(response) / sizeof(response[0]));
         }
+        else if (adata->rc == DB_NOTFOUND)
+        {
+            printf("not foudn\n");
+            ErlDrvTermData response[] = { ERL_DRV_ATOM, driver_mk_atom("not_found") };
+            driver_output_term(d->port, response, sizeof(response) / sizeof(response[0]));
+        }
         else
         {
             ErlDrvTermData response[] = { ERL_DRV_ATOM, driver_mk_atom("error"),
@@ -639,13 +646,20 @@ static void do_async_get_free(void* arg)
 }
 
 
-static void do_async_commit(void* arg)
+static void do_async_txnop(void* arg)
 {
-    printf("do_async_commit\n");
+    printf("do_async_txnop\n");
 
-    // Execute the actual commit
+    // Execute the actual commit/abort
     AsyncData* adata = (AsyncData*)arg;
-    adata->rc = adata->port->txn->commit(adata->port->txn, 0);
+    if (adata->port->async_op == CMD_TXN_COMMIT)
+    {
+        adata->rc = adata->port->txn->commit(adata->port->txn, 0);
+    }
+    else 
+    {
+        adata->rc = adata->port->txn->abort(adata->port->txn);
+    }
 }
 
 

src/bdberl_port.erl

@@ -9,7 +9,7 @@
 -export([new/0,
          open_database/3,
          close_database/2,
-         txn_begin/1, txn_commit/1,
+         txn_begin/1, txn_commit/1, txn_abort/1,
          put/4,
          get/3]).
 
@@ -37,7 +37,10 @@
 -define(ERROR_NO_TXN,        -29004).           % No transaction open on this port
 
 new() ->
-    ok = erl_ddll:load_driver(code:priv_dir(bdberl), bdberl_drv),
+    case erl_ddll:load_driver(code:priv_dir(bdberl), bdberl_drv) of
+        ok -> ok;
+        {error, permanent} -> ok               % Means that the driver is already active
+    end,
     Port = open_port({spawn, bdberl_drv}, [binary]),
     {ok, Port}.
 
@@ -84,6 +87,18 @@ txn_commit(Port) ->
         ?ERROR_ASYNC_PENDING -> {error, async_pending};
         ?ERROR_NO_TXN -> {error, no_txn}
     end.
+
+txn_abort(Port) ->
+    <<Result:32/native>> = erlang:port_control(Port, ?CMD_TXN_ABORT, <<>>),
+    case Result of
+        ?ERROR_NONE -> 
+            receive
+                ok -> ok;
+                {error, Reason} -> {error, Reason}
+            end;
+        ?ERROR_ASYNC_PENDING -> {error, async_pending};
+        ?ERROR_NO_TXN -> {error, no_txn}
+    end.
             
             
 put(Port, DbRef, Key, Value) ->
@@ -110,6 +125,7 @@ get(Port, DbRef, Key) ->
         ?ERROR_NONE ->
             receive
                 {ok, Bin} -> {ok, binary_to_term(Bin)};
+                not_found -> not_found;
                 {error, Reason} -> {error, Reason}
             end;
         ?ERROR_ASYNC_PENDING -> {error, async_pending};

test/port_SUITE.erl

@@ -10,7 +10,7 @@
 
 all() ->
 %    [test_db].
-    [test_put].
+    [test_put, test_txn].
 
 init_per_testcase(TestCase, Config) ->
     Config.
@@ -52,18 +52,28 @@ test_put(_Config) ->
     {ok, 0} = bdberl_port:open_database(P, "test1", hash),
 
     ok = bdberl_port:txn_begin(P),
-
     ok = bdberl_port:put(P, 0, akey, avalue),
-
     ok = bdberl_port:txn_commit(P),
 
-    ok = bdberl_port:txn_begin(P),
-    
-    {ok, avalue} = bdberl_port:get(P, 0, akey),
-    
+    ok = bdberl_port:txn_begin(P),    
+    {ok, avalue} = bdberl_port:get(P, 0, akey),   
     ok = bdberl_port:txn_commit(P).
 
 
+test_txn(_Config) ->
+    {ok, P} = bdberl_port:new(),
+    {ok, 0} = bdberl_port:open_database(P, "test2", btree),
+    
+    ok = bdberl_port:txn_begin(P),
+    ok = bdberl_port:put(P, 0, akey, avalue),
+    ok = bdberl_port:txn_abort(P),
+
+    ok = bdberl_port:txn_begin(P),
+    not_found = bdberl_port:get(P, 0, akey),
+    ok = bdberl_port:txn_commit(P).
+    
+
+