3 files changed, 77 insertions, 1 deletions
diff --git a/src/Makefile.am b/src/Makefile.am
index 0313a1a..1641711 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_settings.h til_settings.c til_setup.c til_setup.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_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/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/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_module_context.c b/src/til_module_context.c
new file mode 100644
index 0000000..a029f37
--- /dev/null
+++ b/src/til_module_context.c
@@ -0,0 +1,60 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+
+#include "til.h"
+#include "til_module_context.h"
+
+
+/* Allocate and initialize a new til_module_context_t of size bytes.
+ * It'd be nice to assign module_context->module here as well, but since this gets called
+ * almost exclusively as a helper from within modules' create_context(), it'd make the
+ * frequently-written module code more annoying and verbose to do so, since their til_module_t is
+ * preferably at EOF.  So in the interests of preserving that clean/ergonomic layout for modules,
+ * assignment of the .module memeber occurs in the public til_module_create_context(), which seems
+ * like an OK compromise.
+ *
+ * If the assigned module's til_module_t->destroy_context is NULL, libc's free() will be used to
+ * free the context.  This should be fine as long as statically allocated contexts never become a
+ * thing, which seems unlikely.  Doing it this way permits modules to omit their destroy_context()
+ * altogether if it would simply free(context).
+ *
+ * Note this returns void * despite creating a til_module_context_t, this is for convenience
+ * as the callers are generally using it in place of calloc(), and assign it to a
+ * container struct of some other type but having an embedded til_module_context_t.
+ */
+void * til_module_context_new(size_t size, unsigned seed, unsigned n_cpus)
+{
+	til_module_context_t	*module_context;
+
+	assert(size >= sizeof(til_module_context_t));
+	assert(n_cpus > 0);
+
+	module_context = calloc(1, size);
+	if (!module_context)
+		return NULL;
+
+	module_context->seed = seed;
+	module_context->n_cpus = n_cpus;
+
+	return module_context;
+}
+
+
+/* Free the module_context when non-NULL, using module_context->module->destroy_context if non-NULL.
+ * Always returns NULL for uses like foo = til_module_context_free(foo);
+ *
+ * Note this replaces til_module_destroy_context(), which has been removed.
+ */
+void * til_module_context_free(til_module_context_t *module_context)
+{
+	if (!module_context)
+		return NULL;
+
+	if (module_context->module->destroy_context)
+		module_context->module->destroy_context(module_context);
+	else
+		free(module_context);
+
+	return NULL;
+}
diff --git a/src/til_module_context.h b/src/til_module_context.h
new file mode 100644
index 0000000..3751b84
--- /dev/null
+++ b/src/til_module_context.h
@@ -0,0 +1,16 @@
+#ifndef _TIL_MODULE_CONTEXT_H
+#define _TIL_MODULE_CONTEXT_H
+
+typedef struct til_module_context_t til_module_context_t;
+typedef struct til_module_t til_module_t;
+
+struct til_module_context_t {
+	const til_module_t	*module;
+	unsigned		seed;
+	unsigned		n_cpus;
+};
+
+void * til_module_context_new(size_t size, unsigned seed, unsigned n_cpus);
+void * til_module_context_free(til_module_context_t *module_context);
+
+#endif