Adding column names functionality

c_src/esqlite3_nif.c

@@ -388,8 +388,25 @@ do_step(ErlNifEnv *env, sqlite3_stmt *stmt)
 static ERL_NIF_TERM
 do_column_names(ErlNifEnv *env, sqlite3_stmt *stmt)
 {
-     fprintf(stderr, "Called column names\n");
-     return _atom_ok;
+     int i, size;
+     const char *name;
+     ERL_NIF_TERM *array;
+     ERL_NIF_TERM column_names;
+     
+     size = sqlite3_column_count(stmt);
+     array = (ERL_NIF_TERM *) malloc(sizeof(ERL_NIF_TERM) * size);
+     
+     if(!array)
+	  return make_error_tuple(env, "no_memory");
+
+     for(i = 0; i < size; i++) {
+	  name = sqlite3_column_name(stmt, i);
+	  array[i] = make_atom(env, name);
+     }
+
+     column_names = enif_make_tuple_from_array(env, array, size);
+     free(array);
+     return column_names;
 }
 
 static ERL_NIF_TERM

src/esqlite3.erl

@@ -26,6 +26,7 @@
 	 prepare/2, prepare/3, 
 	 step/1, step/2, 
 	 bind/2, bind/3, 
+	 column_names/1, column_names/2,
 	 close/1, close/2]).
 
 -export([q/2, map/3, foreach/3]).
@@ -164,6 +165,16 @@ bind(Stmt, Args, Timeout) ->
     ok = esqlite3_nif:bind(Stmt, Ref, self(), Args),
     receive_answer(Ref, Timeout).
 
+%% @doc Return the column names of the prepared statement.
+%%
+column_names(Stmt) ->
+    column_names(Stmt, ?DEFAULT_TIMEOUT).
+
+column_names(Stmt, Timeout) ->
+    Ref = make_ref(),
+    ok = esqlite3_nif:column_names(Stmt, Ref, self()),
+    receive_answer(Ref, Timeout).
+
 %% @doc Close the database
 %%
 %% @spec close(connection()) -> ok | {error, error_message()}

test/esqlite_test.erl

@@ -83,7 +83,7 @@ column_names_test() ->
 
     {ok, Stmt} = esqlite3:prepare("select * from test_table", Db),
     
-    test = esqlite3:column_names(Stmt),
+    {one, two} = esqlite3:column_names(Stmt),
     
     ok.