*: add module context machinery

introduces create_context() and destroy_context() methods, and adds a
'void *context' first parameter to the module methods.

If a module doesn't supply create_context() then NULL is simply passed
around as the context, so trivial modules can continue to only implement
render_fragment().

A subsequent commit will update the modules to encapsulate their global
state in module-specific contexts.

1 files changed, 16 insertions, 7 deletions

diff --git a/src/rototiller.c b/src/rototiller.c
index f9cfece..4d84c91 100644
--- a/src/rototiller.c
+++ b/src/rototiller.c
@@ -57,24 +57,24 @@ static void module_select(int *module)
 }
 
 
-static void module_render_page_threaded(rototiller_module_t *module, threads_t *threads, fb_page_t *page)
+static void module_render_page_threaded(rototiller_module_t *module, void *context, threads_t *threads, fb_page_t *page)
 {
 	rototiller_frame_t	frame;
 	unsigned		i;
 
-	module->prepare_frame(threads_num_threads(threads), &page->fragment, &frame);
+	module->prepare_frame(context, threads_num_threads(threads), &page->fragment, &frame);
 
-	threads_frame_submit(threads, &frame, module->render_fragment);
+	threads_frame_submit(threads, &frame, module->render_fragment, context);
 	threads_wait_idle(threads);
 }
 
 
-static void module_render_page(rototiller_module_t *module, threads_t *threads, fb_page_t *page)
+static void module_render_page(rototiller_module_t *module, void *context, threads_t *threads, fb_page_t *page)
 {
 	if (!module->prepare_frame)
-		return module->render_fragment(&page->fragment);
+		return module->render_fragment(context, &page->fragment);
 
-	module_render_page_threaded(module, threads, page);
+	module_render_page_threaded(module, context, threads, page);
 }
 
 
@@ -87,6 +87,7 @@ int main(int argc, const char *argv[])
 	threads_t		*threads;
 	int			module;
 	fb_t			*fb;
+	void			*context = NULL;
 
 	drm_setup(&drm_fd, &drm_crtc_id, &drm_connector_id, &drm_mode);
 	module_select(&module);
@@ -97,6 +98,10 @@ int main(int argc, const char *argv[])
 	pexit_if(!fps_setup(),
 		"unable to setup fps counter");
 
+	exit_if(modules[module]->create_context &&
+		!(context = modules[module]->create_context()),
+		"unable to create module context");
+
 	pexit_if(!(threads = threads_create()),
 		"unable to create threads");
 
@@ -106,11 +111,15 @@ int main(int argc, const char *argv[])
 		fps_print(fb);
 
 		page = fb_page_get(fb);
-		module_render_page(modules[module], threads, page);
+		module_render_page(modules[module], context, threads, page);
 		fb_page_put(fb, page);
 	}
 
 	threads_destroy(threads);
+
+	if (context)
+		modules[module]->destroy_context(context);
+
 	fb_free(fb);
 	close(drm_fd);