setup: constify settings passed to setup_func

setup_func isn't formally defined for libtil, but
setup_interactively() defacto establishes it and
til_module_t.setup() reflects the same signature and calling
convention except with til_settings_t constified.

This change makes them all consistent in this regard, but there
should probably be a formal typedef added for the function.

The reason for constifying this is I don't want setup functions
directly manipulating the settings instance.  In the case of
rototiller::setup_interactively() we ensure the stdio-based
interactive setup is always the side doing the manipulation of
the settings.  For a libtil-user like glimmer, it's slightly
different beast with GTK+ in the loop, but by preventing the
setup_funcs from messing directly with the settings (instead
having to describe what they want done iteratively), the
front-end always gets its opportunity to maintain its state while
doing the described things.

Of course, this is mostly a lie, and within libtil the constified
til_settings_t gets cast away to modify it in places.  But
keeping that limited to within libtil is tolerable IMO.  We just
don't want to see such casts in module code.

5 files changed, 5 insertions, 5 deletions

diff --git a/src/main.c b/src/main.c
index 2d28700..efc9d12 100644
--- a/src/main.c
+++ b/src/main.c
@@ -78,7 +78,7 @@ typedef struct setup_t {
  */
 
 /* select video backend if not yet selected, then setup the selected backend. */
-static int setup_video(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
+static int setup_video(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
 {
 	til_setting_t	*setting;
 	const char	*video;
diff --git a/src/setup.c b/src/setup.c
index 7d413f9..f85ac10 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -23,7 +23,7 @@ static int add_value(til_settings_t *settings, const char *key, const char *valu
 
 
 /* returns negative on error, otherwise number of additions made to settings */
-int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup), int defaults, til_setup_t **res_setup, const til_setting_desc_t **res_failed_desc)
+int setup_interactively(til_settings_t *settings, int (*setup_func)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup), int defaults, til_setup_t **res_setup, const til_setting_desc_t **res_failed_desc)
 {
 	unsigned			additions = 0;
 	char				buf[256] = "\n";
diff --git a/src/setup.h b/src/setup.h
index 948b820..0862e45 100644
--- a/src/setup.h
+++ b/src/setup.h
@@ -4,6 +4,6 @@
 #include "til_settings.h"
 #include "til_setup.h"
 
-int setup_interactively(til_settings_t *settings, int (*setup_func)(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup), int defaults, til_setup_t **res_setup, const til_setting_desc_t **res_failed_desc);
+int setup_interactively(til_settings_t *settings, int (*setup_func)(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup), int defaults, til_setup_t **res_setup, const til_setting_desc_t **res_failed_desc);
 
 #endif
diff --git a/src/til.c b/src/til.c
index 58e52bb..9053c2d 100644
--- a/src/til.c
+++ b/src/til.c
@@ -264,7 +264,7 @@ int til_module_create_context(const til_module_t *module, til_stream_t *stream,
 
 
 /* select module if not yet selected, then setup the module. */
-int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
+int til_module_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup)
 {
 	til_setting_t		*setting;
 	const til_module_t	*module;
diff --git a/src/til.h b/src/til.h
index 49823ba..fabee0a 100644
--- a/src/til.h
+++ b/src/til.h
@@ -45,7 +45,7 @@ void til_get_modules(const til_module_t ***res_modules, size_t *res_n_modules);
 void til_module_render(til_module_context_t *context, til_stream_t *stream, unsigned ticks, til_fb_fragment_t **fragment_ptr);
 int til_module_create_context(const til_module_t *module, til_stream_t *stream, unsigned seed, unsigned ticks, unsigned n_cpus, const char *parent_path, til_setup_t *setup, til_module_context_t **res_context);
 til_module_context_t * til_module_destroy_context(til_module_context_t *context, til_stream_t *stream);
-int til_module_setup(til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
+int til_module_setup(const til_settings_t *settings, til_setting_t **res_setting, const til_setting_desc_t **res_desc, til_setup_t **res_setup);
 int til_module_randomize_setup(const til_module_t *module, unsigned seed, til_setup_t **res_setup, char **res_arg);
 int til_fragmenter_slice_per_cpu(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment);
 int til_fragmenter_tile64(til_module_context_t *context, const til_fb_fragment_t *fragment, unsigned number, til_fb_fragment_t *res_fragment);