commands: add generic option -> property wrapper

Add mp_property_generic_option(), a property function that can be used
for generic option-based properties that do not require any action
beyond manipulating the value of the option variable. Currently it
directly implements GET and SET, plus STEP_UP for "choice" options
only. Use it to add a property for -pts-association-mode (not
particularly useful in normal use, but serves as a test).

DOCS/tech/slave.txt

@@ -513,6 +513,7 @@ name               type      min     max     get set step comment
 osdlevel           int       0       3       X   X   X    as -osdlevel
 speed              float     0.01    100     X   X   X    as -speed
 loop               int       -1              X   X   X    as -loop
+pts_association_mode string                  X   X   X    as -pts-association-mode
 pause              flag      0       1       X            1 if paused, use with pausing_keep_force
 filename           string                    X            file playing wo path
 path               string                    X            file playing

command.c

@@ -34,6 +34,7 @@
 #include "libvo/sub.h"
 #include "m_option.h"
 #include "m_property.h"
+#include "m_config.h"
 #include "metadata.h"
 #include "libmpcodecs/vf.h"
 #include "libmpcodecs/vd.h"
@@ -226,6 +227,39 @@ static void log_sub(struct MPContext *mpctx)
 /// \ingroup Properties
 ///@{
 
+static int mp_property_generic_option(struct m_option *prop, int action,
+                                      void *arg, MPContext *mpctx)
+{
+    char *optname = prop->priv;
+    const struct m_option *opt = m_config_get_option(mpctx->mconfig, optname);
+    void *valptr = m_option_get_ptr(opt, &mpctx->opts);
+
+    switch (action) {
+    case M_PROPERTY_GET_TYPE:
+        *(const struct m_option **)arg = opt;
+        return M_PROPERTY_OK;
+    case M_PROPERTY_GET:
+        m_option_copy(opt, arg, valptr);
+        return M_PROPERTY_OK;
+    case M_PROPERTY_SET:
+        m_option_copy(opt, valptr, arg);
+        return M_PROPERTY_OK;
+    case M_PROPERTY_STEP_UP:
+        if (opt->type == &m_option_type_choice) {
+            int v = *(int *) valptr;
+            int best = v;
+            struct m_opt_choice_alternatives *alt;
+            for (alt = opt->priv; alt->name; alt++)
+                if ((unsigned) alt->value - v - 1 < (unsigned) best - v - 1)
+                    best = alt->value;
+            *(int *) valptr = best;
+            return M_PROPERTY_OK;
+        }
+        break;
+    }
+    return M_PROPERTY_NOT_IMPLEMENTED;
+}
+
 /// OSD level (RW)
 static int mp_property_osdlevel(m_option_t *prop, int action, void *arg,
                                 MPContext *mpctx)
@@ -2189,6 +2223,8 @@ static const m_option_t mp_properties[] = {
      M_OPT_RANGE, 0, 1, NULL },
     { "capturing", mp_property_capture, CONF_TYPE_FLAG,
      M_OPT_RANGE, 0, 1, NULL },
+    { "pts_association_mode", mp_property_generic_option, &m_option_type_choice,
+     0, 0, 0, "pts-association-mode" },
 
     // Audio
     { "volume", mp_property_volume, CONF_TYPE_FLOAT,
@@ -2362,6 +2398,7 @@ static struct property_osd_display {
     { "loop", 0, -1, _("Loop: %s") },
     { "chapter", -1, -1, NULL },
     { "capturing", 0, -1, _("Capturing: %s") },
+    { "pts_association_mode", 0, -1, "PTS association mode: %s" },
     // audio
     { "volume", OSD_VOLUME, -1, _("Volume") },
     { "mute", 0, -1, _("Mute: %s") },

m_config.c

@@ -150,7 +150,7 @@ static void m_option_save(const m_config_t *config, const m_option_t *opt,
                           void *dst)
 {
     if (opt->type->save) {
-        const void *src = opt->new ? (char*)config->optstruct + opt->offset : opt->p;
+        const void *src = m_option_get_ptr(opt, config->optstruct);
         opt->type->save(opt, dst, src);
     }
 }
@@ -159,7 +159,7 @@ static void m_option_set(const m_config_t *config, const m_option_t *opt,
 			 const void *src)
 {
     if (opt->type->set) {
-        void *dst = opt->new ? (char*)config->optstruct + opt->offset : opt->p;
+        void *dst = m_option_get_ptr(opt, config->optstruct);
         opt->type->set(opt, dst, src);
     }
 }

m_option.h

@@ -493,6 +493,12 @@ struct m_option {
  */
 const m_option_t* m_option_list_find(const m_option_t* list,const char* name);
 
+static inline void *m_option_get_ptr(const struct m_option *opt,
+                                     void *optstruct)
+{
+    return opt->new ? (char *) optstruct + opt->offset : opt->p;
+}
+
 /// Helper to parse options, see \ref m_option_type::parse.
 inline static int
 m_option_parse(const m_option_t* opt,const char *name, const char *param, void* dst, int src) {