options: support parsing values into substructs

Add an alternate mode for option parser objects (struct m_config)
which is not inherently tied to any particular instance of an option
value struct. Instead, this type or parsers can be used to initialize
defaults in or parse values into a struct given as a parameter. They
do not have the save slot functionality used for main player
configuration. The new functionality will be used to replace the
separate subopt_helper.c parsing code that is currently used to parse
per-object suboptions in VOs etc.

Previously, option default values were handled by initializing them in
external code before creating a parser. This initialization was done
with constants even for dynamically-allocated types like strings.
Because trying to free a pointer to a constant would cause a crash
when trying to replace the default with another value, parser
initialization code then replaced all the original defaults with
dynamically-allocated copies. This replace-with-copy behavior is no
longer supported for new-style options; instead the option definition
itself may contain a default value (new OPTDEF macros), and the new
function m_config_initialize() is used to set all options to their
default values. Convert the existing initialized dynamically allocated
options in main config (the string options --dumpfile, --term-osd-esc,
--input=conf) to use this. Other non-dynamic ones could be later
converted to use this style of initialization too.

There's currently no public call to free all dynamically allocated
options in a given option struct because I intend to use talloc
functionality for that (make them children of the struct and free with
it).

1 files changed, 8 insertions, 0 deletions

diff --git a/m_config.h b/m_config.h
index ff54aae8b2..24e80eb538 100644
--- a/m_config.h
+++ b/m_config.h
@@ -96,6 +96,7 @@ typedef struct m_config {
 
     void *optstruct; // struct mpopts or other
     int (*includefunc)(struct m_config *conf, char *filename);
+    bool full;  // main config with save slot handling etc
 } m_config_t;
 
 
@@ -110,6 +111,10 @@ struct m_config *
 m_config_new(void *optstruct,
              int includefunc(struct m_config *conf, char *filename));
 
+struct m_config *m_config_simple(const struct m_option *options);
+
+void m_config_initialize(struct m_config *conf, void *optstruct);
+
 // Free a config object.
 void m_config_free(struct m_config *config);
 
@@ -162,6 +167,9 @@ static inline int m_config_check_option0(struct m_config *config,
     return m_config_check_option(config, bstr(name), bstr(param), ambiguous);
 }
 
+int m_config_parse_suboptions(struct m_config *config, void *optstruct,
+                              char *name, char *subopts);
+
 
 /*  Get the option matching the given name.
  *  \param config The config object.