options: simplify somewhat by introducing a union for option values

The m_option_value union is supposed to contain a field for each
possible option type (as long as it actually stores data). This helps
avoiding silly temporary memory alocations. Using a pointer to an union
and to a field of the union interchangeably should be allowed by
standard C.

1 files changed, 6 insertions, 14 deletions

diff --git a/m_property.c b/m_property.c
index e75cbe43ac..ac68d86163 100644
--- a/m_property.c
+++ b/m_property.c
@@ -69,7 +69,7 @@ int m_property_do(const m_option_t *prop_list, const char *name,
                   int action, void *arg, void *ctx)
 {
     const m_option_t *opt;
-    void *val;
+    union m_option_value val = {0};
     int r;
 
     switch (action) {
@@ -85,15 +85,11 @@ int m_property_do(const m_option_t *prop_list, const char *name,
         if ((r =
              do_action(prop_list, name, M_PROPERTY_GET_TYPE, &opt, ctx)) <= 0)
             return r;
-        val = calloc(1, opt->type->size);
-        if ((r = do_action(prop_list, name, M_PROPERTY_GET, val, ctx)) <= 0) {
-            free(val);
+        if ((r = do_action(prop_list, name, M_PROPERTY_GET, &val, ctx)) <= 0)
             return r;
-        }
         if (!arg)
             return M_PROPERTY_ERROR;
-        char *str = m_option_print(opt, val);
-        free(val);
+        char *str = m_option_print(opt, &val);
         *(char **)arg = str;
         return str != NULL;
     case M_PROPERTY_PARSE:
@@ -107,14 +103,10 @@ int m_property_do(const m_option_t *prop_list, const char *name,
             return r;
         if (!arg)
             return M_PROPERTY_ERROR;
-        val = calloc(1, opt->type->size);
-        if ((r = m_option_parse(opt, bstr0(opt->name), bstr0(arg), val)) <= 0) {
-            free(val);
+        if ((r = m_option_parse(opt, bstr0(opt->name), bstr0(arg), &val)) <= 0)
             return r;
-        }
-        r = do_action(prop_list, name, M_PROPERTY_SET, val, ctx);
-        m_option_free(opt, val);
-        free(val);
+        r = do_action(prop_list, name, M_PROPERTY_SET, &val, ctx);
+        m_option_free(opt, &val);
         return r;
     }
     return do_action(prop_list, name, action, arg, ctx);