Add function to get the last insert rowid (#62)

* Add function to get the last insert rowid

* Update esqlite3.erl

Co-authored-by: Maas-Maarten Zeeman <mmzeeman@xs4all.nl>

c_src/esqlite3_nif.c

@@ -64,6 +64,7 @@ typedef enum {
     cmd_close,
     cmd_stop,
     cmd_insert,
+    cmd_last_insert_rowid,
     cmd_get_autocommit,
 } command_type;
 
@@ -373,6 +374,14 @@ do_insert(ErlNifEnv *env, esqlite_connection *conn, const ERL_NIF_TERM arg)
     return make_ok_tuple(env, last_rowid_term);
 }
 
+static ERL_NIF_TERM
+do_last_insert_rowid(ErlNifEnv *env, esqlite_connection *conn)
+{
+    sqlite3_int64 last_rowid = sqlite3_last_insert_rowid(conn->db);
+    ERL_NIF_TERM last_rowid_term = enif_make_int64(env, last_rowid);
+    return make_ok_tuple(env, last_rowid_term);
+}
+
 /*
  */
 static ERL_NIF_TERM
@@ -731,6 +740,8 @@ evaluate_command(esqlite_command *cmd, esqlite_connection *conn)
 	    return do_close(cmd->env, conn, cmd->arg);
 	case cmd_insert:
 	    return do_insert(cmd->env, conn, cmd->arg);
+    case cmd_last_insert_rowid:
+        return do_last_insert_rowid(cmd->env, conn);
     case cmd_get_autocommit:
         return do_get_autocommit(cmd->env, conn);
     default:
@@ -968,6 +979,34 @@ esqlite_insert(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
     return push_command(env, db, cmd);
 }
 
+static ERL_NIF_TERM
+esqlite_last_insert_rowid(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
+{
+    esqlite_connection *db;
+    esqlite_command *cmd = NULL;
+    ErlNifPid pid;
+
+    if(argc != 3)
+        return enif_make_badarg(env);
+    if(!enif_get_resource(env, argv[0], esqlite_connection_type, (void **) &db))
+        return enif_make_badarg(env);
+    if(!enif_is_ref(env, argv[1]))
+        return make_error_tuple(env, "invalid_ref");
+    if(!enif_get_local_pid(env, argv[2], &pid))
+        return make_error_tuple(env, "invalid_pid");
+
+    cmd = command_create();
+    if(!cmd)
+        return make_error_tuple(env, "command_create_failed");
+
+    /* command */
+    cmd->type = cmd_last_insert_rowid;
+    cmd->ref = enif_make_copy(cmd->env, argv[1]);
+    cmd->pid = pid;
+
+    return push_command(env, db, cmd);
+}
+
 static ERL_NIF_TERM
 esqlite_get_autocommit(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
@@ -1308,6 +1347,7 @@ static ErlNifFunc nif_funcs[] = {
     {"changes", 3, esqlite_changes},
     {"prepare", 4, esqlite_prepare},
     {"insert", 4, esqlite_insert},
+    {"last_insert_rowid", 3, esqlite_last_insert_rowid},
     {"get_autocommit", 3, esqlite_get_autocommit},
     {"multi_step", 5, esqlite_multi_step},
     {"reset", 4, esqlite_reset},

src/esqlite3.erl

@@ -26,6 +26,7 @@
          exec/2, exec/3, exec/4,
          changes/1, changes/2,
          insert/2,
+         last_insert_rowid/1,
          get_autocommit/1,
          get_autocommit/2,
          prepare/2, prepare/3,
@@ -380,6 +381,21 @@ insert(Sql, {connection, _Ref, Connection}, Timeout) ->
     ok = esqlite3_nif:insert(Connection, Ref, self(), Sql),
     receive_answer(Connection, Ref, Timeout).
 
+%% @doc Get the last insert rowid, using the default timeout.
+%%
+-spec last_insert_rowid(connection()) -> {ok, rowid()} | {error, _}.
+last_insert_rowid(Connection) ->
+    last_insert_rowid(Connection, ?DEFAULT_TIMEOUT).
+
+%% @doc Get the last insert rowid.
+%%
+-spec last_insert_rowid(connection(), timeout()) -> {ok, integer()} | {error, _}.
+last_insert_rowid({connection, _Ref, Connection}, Timeout) ->
+    Ref = make_ref(),
+    ok = esqlite3_nif:last_insert_rowid(Connection, Ref, self()),
+    receive_answer(Connection, Ref, Timeout).
+
+%% @doc Get autocommit
 %% @doc Check if the connection is in auto-commit mode.
 %% See: [https://sqlite.org/c3ref/get_autocommit.html] for more details.
 %%

src/esqlite3_nif.erl

@@ -27,6 +27,7 @@
          exec/4,
          changes/3,
          insert/4,
+         last_insert_rowid/3,
          get_autocommit/3,
          prepare/4,
          multi_step/5,
@@ -145,6 +146,12 @@ close(_Db, _Ref, _Dest) ->
 insert(_Db, _Ref, _Dest, _Sql) ->
     erlang:nif_error(nif_library_not_loaded).
 
+%% @doc Get the last insert rowid.
+%%
+%% @spec insert(connection(), Ref::reference(), Dest::pid()) -> {ok, integer()} | {error, message()}
+last_insert_rowid(_Db, _Ref, _Dest) ->
+    erlang:nif_error(nif_library_not_loaded).
+
 %% @doc Get automcommit
 %%
 -spec get_autocommit(esqlite:connection(), reference(), pid()) -> ok | {error, any()}.

test/esqlite_test.erl

@@ -31,6 +31,15 @@ get_autocommit_test() ->
     true = esqlite3:get_autocommit(Db),
     ok.
 
+last_insert_rowid_test() ->
+    {ok, Db} = esqlite3:open(":memory:"),
+    ok = esqlite3:exec("CREATE TABLE test (id INTEGER PRIMARY KEY, val STRING);", Db),
+    ok = esqlite3:exec("INSERT INTO test (val) VALUES ('this is a test');", Db),
+    {ok, 1} = esqlite3:last_insert_rowid(Db),
+    ok = esqlite3:exec("INSERT INTO test (val) VALUES ('this is another test');", Db),
+    {ok, 2} = esqlite3:last_insert_rowid(Db),
+    ok.
+
 update_hook_test() ->
     {ok, Db} = esqlite3:open(":memory:"),
     ok = esqlite3:set_update_hook(self(), Db),