1 files changed, 46 insertions, 28 deletions

diff --git a/core/m_config.c b/core/m_config.c
index 2d994bb802..6ecfa13a39 100644
--- a/core/m_config.c
+++ b/core/m_config.c
@@ -257,6 +257,43 @@ void m_config_leave_file_local(struct m_config *config)
     }
 }
 
+// Given an option --opt, add --no-opt (if applicable).
+static void add_negation_option(struct m_config *config,
+                                struct m_config_option *parent,
+                                const struct m_option *opt)
+{
+    int value;
+    if (opt->type == CONF_TYPE_FLAG) {
+        value = opt->min;
+    } else if (opt->type == CONF_TYPE_CHOICE) {
+        // Find out whether there's a "no" choice.
+        // m_option_parse() should be used for this, but it prints
+        // unsilenceable error messages.
+        struct m_opt_choice_alternatives *alt = opt->priv;
+        for ( ; alt->name; alt++) {
+            if (strcmp(alt->name, "no") == 0)
+                break;
+        }
+        if (!alt->name)
+            return;
+        value = alt->value;
+    } else {
+        return;
+    }
+    struct m_option *no_opt = talloc_ptrtype(config, no_opt);
+    *no_opt = (struct m_option) {
+        .name = talloc_asprintf(no_opt, "no-%s", opt->name),
+        .type = CONF_TYPE_STORE,
+        .flags = opt->flags & (M_OPT_NOCFG | M_OPT_GLOBAL | M_OPT_LOCAL |
+                               M_OPT_PRE_PARSE | M_OPT_PREFIXED | M_OPT_MERGE),
+        .new = opt->new,
+        .p = opt->p,
+        .offset = opt->offset,
+        .max = value,
+    };
+    m_config_add_option(config, parent, no_opt);
+}
+
 static void add_options(struct m_config *config,
                         struct m_config_option *parent,
                         const struct m_option *defs)
@@ -352,6 +389,8 @@ static void m_config_add_option(struct m_config *config,
         co->next = config->opts;
         config->opts = co;
     }
+
+    add_negation_option(config, parent, arg);
 }
 
 int m_config_register_options(struct m_config *config,
@@ -393,10 +432,6 @@ static int m_config_parse_option(struct m_config *config, void *optstruct,
     assert(name.len != 0);
     bool set = !(flags & M_SETOPT_CHECK_ONLY);
 
-    int r = m_config_map_option(config, &name, &param, false);
-    if (r < 0)
-        return r;
-
     struct m_config_option *co = m_config_get_co(config, name);
     if (!co)
         return M_OPT_UNKNOWN;
@@ -516,35 +551,18 @@ const struct m_option *m_config_get_option(const struct m_config *config,
         return NULL;
 }
 
-int m_config_map_option(struct m_config *config, bstr *name, bstr *param,
-                        bool ambiguous)
+int m_config_option_requires_param(struct m_config *config, bstr name)
 {
-    bstr s = *name;
-    const struct m_option *opt = m_config_get_option(config, s);
+    const struct m_option *opt = m_config_get_option(config, name);
     if (opt) {
-        if (bstr_endswith0(s, "-clr"))
-            return (ambiguous || !param->len) ? 0 : M_OPT_DISALLOW_PARAM;
-        if (ambiguous && ((opt->flags & M_OPT_OPTIONAL_PARAM) ||
-                          (opt->type->flags & M_OPT_TYPE_OPTIONAL_PARAM)))
+        if (bstr_endswith0(name, "-clr"))
+            return 0;
+        if (((opt->flags & M_OPT_OPTIONAL_PARAM) ||
+             (opt->type->flags & M_OPT_TYPE_OPTIONAL_PARAM)))
             return 0;
         return 1;
     }
-
-    if (!bstr_eatstart0(&s, "no-"))
-        return M_OPT_UNKNOWN;
-
-    opt = m_config_get_option(config, s);
-    if (!opt || (opt->type != &m_option_type_flag
-                 && opt->type != &m_option_type_choice))
-        return M_OPT_UNKNOWN;
-    // Avoid allowing "--no-no-opt".
-    if (bstr_startswith(bstr0(opt->name), bstr0("no-")))
-        return M_OPT_UNKNOWN;
-    if (param->len)
-        return M_OPT_DISALLOW_PARAM;
-    *name = s;
-    *param = bstr0("no");
-    return 0;
+    return M_OPT_UNKNOWN;
 }
 
 void m_config_print_option_list(const struct m_config *config)