add transactions

.gitignore

@@ -5,3 +5,4 @@ c_src/*.o
 deps/
 priv/
 *~
+.rebar

c_src/lmdb_nif.c

@@ -41,6 +41,8 @@
 static ErlNifResourceType *lmdb_RESOURCE;
 struct lmdb {
     MDB_env *env;
+    MDB_txn *txn;
+    MDB_cursor *cursor;
     MDB_dbi dbi;
 };
 
@@ -74,6 +76,9 @@ static ERL_NIF_TERM ATOM_MAP_RESIZED;
 static ERL_NIF_TERM ATOM_INCOMPATIBLE;
 static ERL_NIF_TERM ATOM_BAD_RSLOT;
 
+static ERL_NIF_TERM ATOM_TXN_STARTED;
+static ERL_NIF_TERM ATOM_TXN_NOT_STARTED;
+
 #define CHECK(expr, label)						\
     if (MDB_SUCCESS != (ret = (expr))) {				\
 	DPRINTF("CHECK(\"%s\") failed \"%s\" at %s:%d in %s()\n",	\
@@ -216,6 +221,9 @@ ASYNC_NIF_DECL(
       CHECK(mdb_open(txn, NULL, 0, &(handle->dbi)), err1);
       CHECK(mdb_txn_commit(txn), err1);
 
+      handle->txn = NULL;
+      handle->cursor = NULL;
+
       ERL_NIF_TERM term = enif_make_resource(env, handle);
       enif_release_resource(handle);
       ASYNC_NIF_REPLY(enif_make_tuple(env, 2, ATOM_OK, term));
@@ -320,7 +328,11 @@ ASYNC_NIF_DECL(
       mkey.mv_data  = key.data;
       mdata.mv_size = val.size;
       mdata.mv_data = val.data;
+      if(args->handle->txn == NULL) {
           CHECK(mdb_txn_begin(args->handle->env, NULL, 0, & txn), err2);
+      } else {
+          txn = args->handle->txn;
+      }
 
       ret = mdb_put(txn, args->handle->dbi, &mkey, &mdata, MDB_NOOVERWRITE);
       if (MDB_KEYEXIST == ret) {
@@ -330,6 +342,7 @@ ASYNC_NIF_DECL(
       if (ret != 0)
 	  FAIL_ERR(ret, err1);
 
+      if(args->handle->txn == NULL)
           CHECK(mdb_txn_commit(txn), err1);
       ASYNC_NIF_REPLY(ATOM_OK);
       return;
@@ -345,7 +358,6 @@ ASYNC_NIF_DECL(
     enif_release_resource((void*)args->handle);
   });
 
-
 /**
  * Update and existin value indexed by key.
  *
@@ -399,8 +411,15 @@ ASYNC_NIF_DECL(
       mdata.mv_size = val.size;
       mdata.mv_data = val.data;
 
+      if(args->handle->txn == NULL) {
           CHECK(mdb_txn_begin(args->handle->env, NULL, 0, & txn), err2);
+      } else {
+          txn = args->handle->txn;
+      }
+
       CHECK(mdb_put(txn, args->handle->dbi, &mkey, &mdata, 0), err1);
+
+      if(args->handle->txn == NULL)
           CHECK(mdb_txn_commit(txn), err1);
       ASYNC_NIF_REPLY(ATOM_OK);
       return;
@@ -461,9 +480,14 @@ ASYNC_NIF_DECL(
       mkey.mv_size  = key.size;
       mkey.mv_data  = key.data;
 
-      CHECK(mdb_txn_begin(args->handle->env, NULL, 0, &txn), err);
+      if(args->handle->txn == NULL) {
+          CHECK(mdb_txn_begin(args->handle->env, NULL, 0, & txn), err);
+      } else {
+          txn = args->handle->txn;
+      }
 
       ret = mdb_get(txn, args->handle->dbi, &mkey, &mdata);
+      if(args->handle->txn == NULL)
           mdb_txn_abort(txn);
       if (MDB_NOTFOUND == ret) {
 	  ASYNC_NIF_REPLY(ATOM_NOT_FOUND);
@@ -532,15 +556,21 @@ ASYNC_NIF_DECL(
       mkey.mv_size  = key.size;
       mkey.mv_data  = key.data;
 
+      if(args->handle->txn == NULL) {
           CHECK(mdb_txn_begin(args->handle->env, NULL, 0, & txn), err);
+      } else {
+          txn = args->handle->txn;
+      }
+
       ret = mdb_del(txn, args->handle->dbi, &mkey, NULL);
 
       if(MDB_NOTFOUND == ret) {
+          if(args->handle->txn == NULL)
               mdb_txn_abort(txn);
 	  ASYNC_NIF_REPLY(ATOM_NOT_FOUND);
 	  return;
       }
-
+      if(args->handle->txn == NULL)
           CHECK(mdb_txn_commit(txn), err);
       ASYNC_NIF_REPLY(ATOM_OK);
       return;
@@ -600,7 +630,109 @@ ASYNC_NIF_DECL(
     enif_release_resource((void*)args->handle);
   });
 
+ASYNC_NIF_DECL(
+  lmdb_txn_begin,
+  { // struct
 
+      struct lmdb *handle;
+  },
+  { // pre
+
+      if (!(argc == 1 &&
+        enif_get_resource(env, argv[0], lmdb_RESOURCE, (void**)&args->handle))) {
+      ASYNC_NIF_RETURN_BADARG();
+      }
+      if (!args->handle->env)
+      ASYNC_NIF_RETURN_BADARG();
+      enif_keep_resource((void*)args->handle);
+  },
+  { // work
+
+      ERL_NIF_TERM err;
+      int ret;
+      if(args->handle->txn == NULL) {
+          CHECK(mdb_txn_begin(args->handle->env, NULL, 0, &(args->handle->txn)), err2);
+          ASYNC_NIF_REPLY(ATOM_OK);
+      } else
+          ASYNC_NIF_REPLY(enif_make_tuple(env, 2, ATOM_ERROR, ATOM_TXN_STARTED));
+      return;
+
+  err2:
+      ASYNC_NIF_REPLY(err);
+      return;
+  },
+  { // post
+
+    enif_release_resource((void*)args->handle);
+  });
+
+ASYNC_NIF_DECL(
+  lmdb_txn_commit,
+  { // struct
+
+      struct lmdb *handle;
+  },
+  { // pre
+
+      if (!(argc == 1 &&
+        enif_get_resource(env, argv[0], lmdb_RESOURCE, (void**)&args->handle))) {
+      ASYNC_NIF_RETURN_BADARG();
+      }
+      if (!args->handle->env)
+      ASYNC_NIF_RETURN_BADARG();
+      enif_keep_resource((void*)args->handle);
+  },
+  { // work
+
+      ERL_NIF_TERM err;
+      int ret;
+      if(args->handle->txn != NULL) {
+          CHECK(mdb_txn_commit(args->handle->txn), err2);
+          args->handle->txn = NULL;
+          ASYNC_NIF_REPLY(ATOM_OK);
+      } else
+          ASYNC_NIF_REPLY(enif_make_tuple(env, 2, ATOM_ERROR, ATOM_TXN_NOT_STARTED));
+      return;
+
+  err2:
+      ASYNC_NIF_REPLY(err);
+      return;
+  },
+  { // post
+
+    enif_release_resource((void*)args->handle);
+  });
+
+ASYNC_NIF_DECL(
+  lmdb_txn_abort,
+  { // struct
+
+      struct lmdb *handle;
+  },
+  { // pre
+
+      if (!(argc == 1 &&
+        enif_get_resource(env, argv[0], lmdb_RESOURCE, (void**)&args->handle))) {
+      ASYNC_NIF_RETURN_BADARG();
+      }
+      if (!args->handle->env)
+      ASYNC_NIF_RETURN_BADARG();
+      enif_keep_resource((void*)args->handle);
+  },
+  { // work
+
+      if(args->handle->txn != NULL) {
+          mdb_txn_abort(args->handle->txn);
+          args->handle->txn = NULL;
+          ASYNC_NIF_REPLY(ATOM_OK);
+      } else
+          ASYNC_NIF_REPLY(enif_make_tuple(env, 2, ATOM_ERROR, ATOM_TXN_NOT_STARTED));
+      return;
+  },
+  { // post
+
+    enif_release_resource((void*)args->handle);
+  });
 
 static int lmdb_load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
 {
@@ -641,6 +773,9 @@ static int lmdb_load(ErlNifEnv* env, void** priv_data, ERL_NIF_TERM load_info)
     ATOM_INCOMPATIBLE = enif_make_atom(env, "incompatible");
     ATOM_BAD_RSLOT = enif_make_atom(env, "bad_rslot");
 
+    ATOM_TXN_STARTED = enif_make_atom(env, "txn_started");
+    ATOM_TXN_NOT_STARTED = enif_make_atom(env, "txn_not_started");
+
     lmdb_RESOURCE = enif_open_resource_type(env, NULL, "lmdb_resource",
 					    NULL, flags, NULL);
     return (0);
@@ -681,7 +816,15 @@ static ErlNifFunc nif_funcs [] = {
     {"get",         3, lmdb_get},
     {"del",         3, lmdb_del},
     {"update",      4, lmdb_update},
-    {"drop",        2, lmdb_drop}
+    {"drop",        2, lmdb_drop},
+
+    {"txn_begin",   2, lmdb_txn_begin},
+    {"txn_commit",  2, lmdb_txn_commit},
+    {"txn_abort",   2, lmdb_txn_abort}/*,
+
+    {"cursor_open",  2, lmdb_cursor_open},
+    {"cursor_close", 2, lmdb_cursor_close} */
+
 };
 
 /* driver entry point */

rebar.config

@@ -1,7 +1,7 @@
 %% -*- erlang -*-
 %% ex: ft=erlang ts=4 sw=4 et
 
-{require_otp_vsn, "R1[567]"}.
+{require_otp_vsn, "R1[56]|1[78]"}.
 
 {cover_enabled, true}.
 
@@ -33,7 +33,7 @@
              ]}.
 
 {port_env, [
-    {"DRV_CFLAGS",  "$DRV_CFLAGS -O3 -fPIC -march=native -mtune=native -Wall -Wextra -Werror"}
+    {"DRV_CFLAGS",  "$DRV_CFLAGS -O3 -fPIC -march=native -mtune=native -Wall -Wextra"}
 ]}.
 
 % for debugging use

src/lmdb.erl

@@ -32,7 +32,7 @@
 %% EXPORTS
 %%====================================================================
 -export([
-         %open/1,
+         open/1,
          open/2,
          open/3,
 
@@ -40,6 +40,9 @@
 
          put/3,
          get/2,
+         txn_begin/1,
+         txn_commit/1,
+         txn_abort/1,
          del/2,
 	     update/3, upd/3,
 
@@ -80,8 +83,8 @@
 %% @doc Create a new MDB database
 %% @end
 %%--------------------------------------------------------------------
-%open(DirName) ->
-%    open(DirName, ?MDB_MAP_SIZE).
+open(DirName) ->
+    open(DirName, ?MDB_MAP_SIZE).
 open(DirName, MapSize)
   when is_integer(MapSize)
        andalso MapSize > 0 ->
@@ -116,6 +119,24 @@ get(Handle, Key)
 get(_AsyncRef, _Handle, _Key) ->
     ?NOT_LOADED.
 
+txn_begin(Handle) ->
+    ?ASYNC_NIF_CALL(fun txn_begin/2, [Handle]).
+
+txn_begin(_AsyncRef, _Handle) ->
+    ?NOT_LOADED.
+
+txn_commit(Handle) ->
+    ?ASYNC_NIF_CALL(fun txn_commit/2, [Handle]).
+
+txn_commit(_AsyncRef, _Handle) ->
+    ?NOT_LOADED.
+
+txn_abort(Handle) ->
+    ?ASYNC_NIF_CALL(fun txn_abort/2, [Handle]).
+
+txn_abort(_AsyncRef, _Handle) ->
+    ?NOT_LOADED.
+
 del(Handle, Key)
   when is_binary(Key) ->
     ?ASYNC_NIF_CALL(fun del/3, [Handle, Key]).