Added column names

c_src/esqlite3_nif.c

@@ -440,7 +440,6 @@ do_get_autocommit(ErlNifEnv *env, esqlite3 *conn)
 }
 */
 
-/*
 static ERL_NIF_TERM
 make_binary(ErlNifEnv *env, const void *bytes, unsigned int size)
 {
@@ -457,7 +456,6 @@ make_binary(ErlNifEnv *env, const void *bytes, unsigned int size)
 
     return term;
 }
-*/
 
 /*
 static ERL_NIF_TERM
@@ -1217,39 +1215,43 @@ esqlite_reset(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 
 /*
  * Get the column names of the prepared statement.
+ */
 static ERL_NIF_TERM
 esqlite_column_names(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[])
 {
-    esqlite3 *conn;
     esqlite3_stmt *stmt;
-    esqlite_command *cmd = NULL;
-    ErlNifPid pid;
 
-    if(argc != 4)
+    if(argc != 1) {
         return enif_make_badarg(env);
-    if(!enif_get_resource(env, argv[0], esqlite3_type, (void **) &conn))
+    }
+
+    if(!enif_get_resource(env, argv[0], esqlite3_stmt_type, (void **) &stmt)) {
         return enif_make_badarg(env);
-    if(!enif_get_resource(env, argv[1], esqlite3_stmt_type, (void **) &stmt))
-        return enif_make_badarg(env);
-    if(!enif_is_ref(env, argv[2]))
-        return make_error_tuple(env, "invalid_ref");
-    if(!enif_get_local_pid(env, argv[3], &pid))
-        return make_error_tuple(env, "invalid_pid");
-    if(!stmt->statement)
-        return make_error_tuple(env, "no_prepared_statement");
+    }
 
-    cmd = command_create();
-    if(!cmd)
-        return make_error_tuple(env, "command_create_failed");
+    if(!stmt->statement) {
+        return enif_raise_exception(env, make_atom(env, "no_prepared_statement"));   
+    }
 
-    cmd->type = cmd_column_names;
-    cmd->ref = enif_make_copy(cmd->env, argv[2]);
-    cmd->pid = pid;
-    cmd->stmt = enif_make_copy(cmd->env, argv[1]);
+    ERL_NIF_TERM column_names = enif_make_list(env, 0);
 
-    return push_command(env, conn, cmd);
+    int size = sqlite3_column_count(stmt->statement);
+    if(size < 0) {
+        return enif_raise_exception(env, make_atom(env, "invalid_column_count"));   
+    }
+
+    for(int i=size; i-- > 0; ) {
+        const char *name = sqlite3_column_name(stmt->statement, i);
+        if(name == NULL) {
+            return enif_raise_exception(env, make_atom(env, "sqlite3_malloc_failure"));   
+        }
+
+        ERL_NIF_TERM ename = make_binary(env, name, strlen(name));
+        column_names = enif_make_list_cell(env, ename, column_names);
+    }
+
+    return column_names;
 }
- */
 
 /*
  * Get the column types of the prepared statement.
@@ -1533,6 +1535,9 @@ static ErlNifFunc nif_funcs[] = {
 
     {"prepare", 2, esqlite_prepare},
 
+    {"column_names", 1, esqlite_column_names},
+    // {"column_types", 1, esqlite_column_types},
+
     {"interrupt", 1, esqlite_interrupt, ERL_NIF_DIRTY_JOB_IO_BOUND}
 
     /*
@@ -1548,8 +1553,6 @@ static ErlNifFunc nif_funcs[] = {
 
     // TODO: {"esqlite_bind", 3, esqlite_bind_named},
     {"bind", 5, esqlite_bind},
-    {"column_names", 4, esqlite_column_names},
-    {"column_types", 4, esqlite_column_types},
 
     {"backup_init", 6, esqlite_backup_init},
     {"backup_step", 5, esqlite_backup_step},

src/esqlite3.erl

@@ -20,7 +20,9 @@
 %% higher-level export
 -export([
     open/1, close/1,
-    prepare/2
+    prepare/2,
+
+    column_names/1
 
 %    set_update_hook/2, set_update_hook/3,
 %    exec/2, exec/3, exec/4,
@@ -33,7 +35,6 @@
 %    bind/2, bind/3,
 %    fetchone/1,
 %    fetchall/1, fetchall/2, fetchall/3,
-%    column_names/1, column_names/2,
 %    column_types/1, column_types/2,
 %    backup_init/4, backup_init/5,
 %    backup_finish/1, backup_finish/2,
@@ -447,15 +448,9 @@ prepare(#esqlite3{db=Connection}, Sql) ->
 %
 %% @doc Return the column names of the prepared statement.
 %%
-%-spec column_names(statement()) -> {atom()}.
-%column_names(Stmt) ->
-%    column_names(Stmt, ?DEFAULT_TIMEOUT).
-
-%-spec column_names(statement(), timeout()) -> {atom()}.
-%column_names(#statement{raw_statement=RawStatement, raw_connection=RawConnection}, Timeout) ->
-%    Ref = make_ref(),
-%    ok = esqlite3_nif:column_names(RawConnection, RawStatement, Ref, self()),
-%    receive_answer(RawConnection, Ref, Timeout).
+-spec column_names(esqlite3_stmt()) -> [binary()].
+column_names(#esqlite3_stmt{stmt=Stmt}) ->
+     esqlite3_nif:column_names(Stmt).
 
 %% @doc Return the column types of the prepared statement.
 %%

src/esqlite3_nif.erl

@@ -24,6 +24,8 @@
     close/1,
     prepare/2,
 
+    column_names/1,
+
     interrupt/1
 %    set_update_hook/4,
 %    exec/4,
@@ -36,7 +38,6 @@
 %    finalize/4,
 %    bind/5,
 
-%    column_names/4,
 %    column_types/4,
 
 %    backup_init/6,
@@ -140,9 +141,9 @@ prepare(_Connection, _Sql) ->
 
 %% @doc Retrieve the column names of the prepared statement
 %%
-%-spec column_names(esqlite3(), esqlite3_stmt(), reference(), pid()) -> ok | {error, _}.
-%column_names(_Db, _Stmt, _Ref, _Dest) ->
-%    erlang:nif_error(nif_library_not_loaded).
+-spec column_names(esqlite3_stmt()) -> list() | {error, _}.
+column_names(_Stmt) ->
+    erlang:nif_error(nif_library_not_loaded).
 
 %% @doc Retrieve the column types of the prepared statement
 %%

test/esqlite_test.erl

@@ -48,6 +48,24 @@ prepare_after_close_test() ->
     ?assertMatch({error, {misuse, _}}, esqlite3:prepare(C, "select 1")),
     ok.
 
+column_names_test() ->
+    {ok, C} = esqlite3:open(":memory:"),
+
+    {ok, Stmt} = esqlite3:prepare(C, "select 1 as one"),
+    ?assertEqual([<<"one">>], esqlite3:column_names(Stmt)),
+
+    {ok, Stmt1} = esqlite3:prepare(C, <<"select 1 as 😀"/utf8>>),
+    ?assertEqual([<<"😀"/utf8>>], esqlite3:column_names(Stmt1)),
+    
+    {ok, Stmt2} = esqlite3:prepare(C, <<"select 1">>),
+    ?assertEqual([<<"1">>], esqlite3:column_names(Stmt2)),
+
+    {ok, Stmt3} = esqlite3:prepare(C, <<"select 1, 2, 3">>),
+    ?assertEqual([<<"1">>, <<"2">>, <<"3">>], esqlite3:column_names(Stmt3)),
+
+    ok.
+
+
 
 %iodata_test() ->
 %    {ok, C} = esqlite3:open(":memory:"),