til_tap: convert taps to intrusive public structs

The previous commit implemented taps in a way requiring
allocations and cleanup.  Let's experiment a bit and just make
them absolutely minimal named typed variable+indirection
bindings.

The helpers are retained, but converted to initializers rather
than new() style constructors.  They provide type-checking of the
variable and indirection pointer, and prevent incorrect TIL_TYPE
values going in til_type_t.type for the supplied bound
elems+ptr.

3 files changed, 75 insertions, 105 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 3b6c0f0..692b56e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,7 @@
 SUBDIRS = libs modules
 
 noinst_LTLIBRARIES = libtil.la
-libtil_la_SOURCES = til_args.c til_args.h til_fb.c til_fb.h til_knobs.h til.c til.h til_module_context.c til_module_context.h til_settings.h til_settings.c til_setup.c til_setup.h til_tap.c til_tap.h til_threads.c til_threads.h til_util.c til_util.h
+libtil_la_SOURCES = til_args.c til_args.h til_fb.c til_fb.h til_knobs.h til.c til.h til_module_context.c til_module_context.h til_settings.h til_settings.c til_setup.c til_setup.h til_tap.h til_threads.c til_threads.h til_util.c til_util.h
 libtil_la_CPPFLAGS = -I@top_srcdir@/src
 libtil_la_LIBADD = modules/blinds/libblinds.la modules/checkers/libcheckers.la modules/compose/libcompose.la modules/drizzle/libdrizzle.la modules/flui2d/libflui2d.la modules/julia/libjulia.la modules/meta2d/libmeta2d.la modules/moire/libmoire.la modules/montage/libmontage.la modules/pixbounce/libpixbounce.la modules/plasma/libplasma.la modules/plato/libplato.la modules/ray/libray.la modules/roto/libroto.la modules/rtv/librtv.la modules/shapes/libshapes.la modules/snow/libsnow.la modules/sparkler/libsparkler.la modules/spiro/libspiro.la modules/stars/libstars.la modules/strobe/libstrobe.la modules/submit/libsubmit.la modules/swab/libswab.la modules/swarm/libswarm.la modules/voronoi/libvoronoi.la libs/grid/libgrid.la libs/puddle/libpuddle.la libs/ray/libray.la libs/sig/libsig.la libs/txt/libtxt.la libs/ascii/libascii.la libs/din/libdin.la
 
diff --git a/src/til_tap.c b/src/til_tap.c
index 44550b6..e69de29 100644
--- a/src/til_tap.c
+++ b/src/til_tap.c
@@ -1,70 +0,0 @@
-#include <assert.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "til_tap.h"
-
-/* A "tap" is a named binding of a local variable+pointer to that variable.
- *
- * It's purpose is to facilitate exposing local variables controlling rendering
- * to potential external influence.
- *
- * While the tap alone does get named, this is mostly for ergonomic reasons since
- * it's convenient and natural to name the tap while specifying its variable and
- * pointer by name as well.  Putting them all in once place.
- *
- * The tap itself is not a registry or otherwise discoverable entity by itself.
- * This is strictly just the local glue, with a name.  Other pieces must tie taps
- * into streams or settings stuff for addressing them by name at a path or other
- * means.
- *
- * Note the intended way for taps to work is that the caller will always access their
- * local variables indirectly via the pointers they provided when creating the taps.
- * There will be a function for managing the tap the caller must call before accessing
- * the variable indirectly as well.  It's that function which will update the indirection
- * pointer to potentially point elsewhere if another tap is driving the variable.
- */
-
-struct til_tap_t {
-	til_tap_type_t	type;
-	void		*ptr;		/* points at the caller-provided tap-managed indirection pointer */
-	size_t		n_elems;	/* when > 1, *ptr is an array of n_elems elements.  Otherwise individual variable. */
-	void		*elems;		/* points at the first element of type type, may or may not be an array of them */
-	char		name[];
-};
-
-
-/* This is the raw tap creator but use the type-checked wrappers in the header and add one if one's missing */
-til_tap_t * til_tap_new(til_tap_type_t type, void *ptr, const char *name, size_t n_elems, void *elems)
-{
-	til_tap_t	*tap;
-
-	assert(name);
-	assert(type < TIL_TAP_TYPE_MAX);
-	assert(ptr);
-	assert(n_elems);
-	assert(elems);
-
-	tap = calloc(1, sizeof(til_tap_t) + strlen(name) + 1);
-	if (!tap)
-		return NULL;
-
-	strcpy(tap->name, name);
-	tap->type = type;
-	tap->ptr = ptr;
-	tap->n_elems = n_elems;
-	tap->elems = elems;
-
-	*((void **)tap->ptr) = elems;
-
-	return tap;
-}
-
-
-til_tap_t * til_tap_free(til_tap_t *tap)
-{
-	free(tap);
-
-	return NULL;
-}
diff --git a/src/til_tap.h b/src/til_tap.h
index b9de6d9..a6384de 100644
--- a/src/til_tap.h
+++ b/src/til_tap.h
@@ -3,6 +3,23 @@
 
 #include <stdint.h>
 
+/* A "tap" is a named binding of a local variable+pointer to that variable.
+ *
+ * Its purpose is to facilitate exposing local variables controlling rendering
+ * to potential external influence.
+ *
+ * The tap itself is not a registry or otherwise discoverable entity by itself.
+ * This is strictly just the local glue, Other pieces must index and tie taps
+ * into streams or settings stuff for addressing them by name at a path or other
+ * means.
+ *
+ * Note the intended way for taps to work is that the caller will always access their
+ * local variables indirectly via the pointers they provided when initializing the taps.
+ * There will be a function for managing the tap the caller must call before accessing
+ * the variable indirectly as well.  It's that function which will update the indirection
+ * pointer to potentially point elsewhere if another tap is driving the variable.
+ */
+
 /* These are all the supported tap types, nothing is set in stone this just
  * seemed like the likely stuff to need.  Feel free to add anything as needed.
  */
@@ -25,10 +42,14 @@ typedef enum til_tap_type_t {
 	TIL_TAP_TYPE_MAX,
 } til_tap_type_t;
 
-typedef struct til_tap_t til_tap_t;
-
-til_tap_t * til_tap_new(til_tap_type_t type, void *ptr, const char *name, size_t n_elems, void *elems);
-til_tap_t * til_tap_free(til_tap_t *tap);
+/* this is deliberately left entirely public so taps can be easily embedded in contexts */
+typedef struct til_tap_t {
+	til_tap_type_t	type;
+	void		*ptr;		/* points at the caller-provided tap-managed indirection pointer */
+	size_t		n_elems;	/* when > 1, *ptr is an array of n_elems elements.  Otherwise individual variable. */
+	void		*elems;		/* points at the first element of type type, may or may not be an array of them */
+	const char	*name;
+} til_tap_t;
 
 /* just some forward declared higher-order vector and matrix types for the wrappers */
 typedef struct v2f_t v2f_t;
@@ -36,82 +57,101 @@ typedef struct v3f_t v3f_t;
 typedef struct v4f_t v4f_t;
 typedef struct m4f_t m4f_t;
 
+/* This is the bare tap initializer but use the type-checked wrappers below and add one if one's missing */
+static inline void til_tap_init(til_tap_t *tap, til_tap_type_t type, void *ptr, size_t n_elems, void *elems, const char *name)
+{
+	assert(tap);
+	assert(type < TIL_TAP_TYPE_MAX);
+	assert(ptr);
+	assert(n_elems);
+	assert(elems);
+	assert(name);
+
+	tap->type = type;
+	tap->ptr = ptr;
+	tap->n_elems = n_elems;
+	tap->elems = elems;
+	tap->name = name;
+
+	*((void **)tap->ptr) = elems;
+}
+
 /* typed wrappers, just supply n_elems=1 for individual variables - note n_elems is just a defensive
  * programming sanity check to catch callers mismatching array sizes
  */
-static inline til_tap_t * til_tap_new_i8(int8_t **ptr, const char *name, size_t n_elems, int8_t *elems)
+static inline void til_tap_init_i8(til_tap_t *tap, int8_t **ptr, size_t n_elems, int8_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_I8, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_I8, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_i16(int16_t **ptr, const char *name, size_t n_elems, int16_t *elems)
+static inline void til_tap_init_i16(til_tap_t *tap, int16_t **ptr, size_t n_elems, int16_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_I16, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_I16, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_i32(int32_t **ptr, const char *name, size_t n_elems, int32_t *elems)
+static inline void til_tap_init_i32(til_tap_t *tap, int32_t **ptr, size_t n_elems, int32_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_I32, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_I32, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_i64(int64_t **ptr, const char *name, size_t n_elems, int64_t *elems)
+static inline void til_tap_init_i64(til_tap_t *tap, int64_t **ptr, size_t n_elems, int64_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_I64, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_I64, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_u8(uint8_t **ptr, const char *name, size_t n_elems, uint8_t *elems)
+static inline void til_tap_init_u8(til_tap_t *tap, uint8_t **ptr, size_t n_elems, uint8_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_U8, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_U8, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_u16(uint16_t **ptr, const char *name, size_t n_elems, uint16_t *elems)
+static inline void til_tap_init_u16(til_tap_t *tap, uint16_t **ptr, size_t n_elems, uint16_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_U16, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_U16, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_u32(uint32_t **ptr, const char *name, size_t n_elems, uint32_t *elems)
+static inline void til_tap_init_u32(til_tap_t *tap, uint32_t **ptr, size_t n_elems, uint32_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_U32, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_U32, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_u64(uint64_t **ptr, const char *name, size_t n_elems, uint64_t *elems)
+static inline void til_tap_init_u64(til_tap_t *tap, uint64_t **ptr, size_t n_elems, uint64_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_U64, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_U64, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_float(float **ptr, const char *name, size_t n_elems, float *elems)
+static inline void til_tap_init_float(til_tap_t *tap, float **ptr, size_t n_elems, float *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_FLOAT, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_FLOAT, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_double(double **ptr, const char *name, size_t n_elems, double *elems)
+static inline void til_tap_init_double(til_tap_t *tap, double **ptr, size_t n_elems, double *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_DOUBLE, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_DOUBLE, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_v2f(v2f_t **ptr, const char *name, size_t n_elems, v2f_t *elems)
+static inline void til_tap_init_v2f(til_tap_t *tap, v2f_t **ptr, size_t n_elems, v2f_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_V2F, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_V2F, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_v3f(v3f_t **ptr, const char *name, size_t n_elems, v3f_t *elems)
+static inline void til_tap_init_v3f(til_tap_t *tap, v3f_t **ptr, size_t n_elems, v3f_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_V3F, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_V3F, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_v4f(v4f_t **ptr, const char *name, size_t n_elems, v4f_t *elems)
+static inline void til_tap_init_v4f(til_tap_t *tap, v4f_t **ptr, size_t n_elems, v4f_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_V4F, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_V4F, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_m4f(m4f_t **ptr, const char *name, size_t n_elems, m4f_t *elems)
+static inline void til_tap_init_m4f(til_tap_t *tap, m4f_t **ptr, size_t n_elems, m4f_t *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_M4F, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_M4F, ptr, n_elems, elems, name);
 }
 
-static inline til_tap_t * til_tap_new_voidp(void **ptr, const char *name, size_t n_elems, void *elems)
+static inline void til_tap_init_voidp(til_tap_t *tap, void **ptr, size_t n_elems, void *elems, const char *name)
 {
-	return til_tap_new(TIL_TAP_TYPE_VOIDP, ptr, name, n_elems, elems);
+	return til_tap_init(tap, TIL_TAP_TYPE_VOIDP, ptr, n_elems, elems, name);
 }
 
 #endif