Moved state to a structure and shifted how it's handled around

1 files changed, 87 insertions, 70 deletions

diff --git a/text.c b/text.c
index 9daedc0..8ad0d75 100644
--- a/text.c
+++ b/text.c
@@ -32,21 +32,27 @@ union Command
 	} span;
 };
 
-int init_x(void);
-void draw_body(cairo_t *);
+struct State
+{
+	int width;
+	int height;
+	xcb_connection_t * c;
+	xcb_screen_t * s;
+	xcb_visualtype_t * v;
+	xcb_window_t w;
+	cairo_t * ctx;
+	cairo_surface_t * surface;
+};
+
+int setup(struct State *);
+void finalize(struct State *);
+int handle(struct State *, xcb_generic_event_t *);
+void draw_body(struct State *, union Command *);
 xcb_visualtype_t * find_visual(xcb_screen_t *);
 
 static const int MARGIN = 20;
 static const char * const FONT = "Serif 16";
 
-static int width = 800;
-static int height = 600;
-
-static xcb_connection_t * c;
-static xcb_screen_t * s;
-static xcb_visualtype_t * v;
-static xcb_window_t w;
-
 #define _BLOCK(_txt) {.block = {.type = COMMAND_BLOCK, .length = sizeof(_txt) - 1, .data = _txt}}
 union Command body[] = {
 	{.span = {.type = COMMAND_SPAN, .position = 28, .length = 11}},
@@ -64,73 +70,84 @@ int main(int argc, const char ** argv)
 {
 	(void) argc;
 	(void) argv;
-	const int res = init_x();
-	if (-1 == res)
+	struct State state;
+	if (-1 == setup(&state))
+	{
+		dprintf(2, "Could not connect to X server\n");  // TODO: Helpful (specific) errors.
 		return 1;
-	cairo_surface_t * surface = cairo_xcb_surface_create(c, w, v, width, height);
-	cairo_t * ctx = cairo_create(surface);
-	xcb_map_window(c, w);
-	xcb_flush(c);
-	int done = 0;
-	xcb_generic_event_t * e;
-	while (!done)
+	}
+	for (;;)
 	{
-		e = xcb_wait_for_event(c);
-		if (NULL == e)
+		xcb_generic_event_t * e = xcb_wait_for_event(state.c);  // TODO: Change it to poll-like behaviour.
+		if (handle(&state, e))
 			break;
-		switch (XCB_EVENT_RESPONSE_TYPE(e))
-		{
-		default:
-			break;
-		case XCB_KEY_PRESS:
-			done = 1;
-			break;
-		case XCB_EXPOSE:
-			cairo_set_source_rgb(ctx, 1., 1., 1.);
-			cairo_paint(ctx);
-			draw_body(ctx);
-			cairo_surface_flush(surface);
-			xcb_flush(c);
-			break;
-		case XCB_CONFIGURE_NOTIFY:
-			;
-			xcb_configure_notify_event_t * conf = (xcb_configure_notify_event_t *) e;
-			if (width != conf->width || height != conf->height)
-			{
-				cairo_xcb_surface_set_size(surface, conf->width, conf->height);
-				width = conf->width;
-				height = conf->height;
-			}
-			break;
-		}
-		free(e);
 	}
-	cairo_destroy(ctx);
-	cairo_surface_destroy(surface);
-	xcb_disconnect(c);
+	finalize(&state);
 }
 
 
-int init_x(void)
+int setup(struct State * state)
 {
-	c = xcb_connect(NULL, NULL);
-	if (xcb_connection_has_error(c))
-	{
-		dprintf(2, "Could not connect to X11 server");
+	static const int initial_width = 800;
+	static const int initial_height = 600;
+	state->c = xcb_connect(NULL, NULL);
+	if (xcb_connection_has_error(state->c))
 		return -1;
-	}
-	s = xcb_setup_roots_iterator(xcb_get_setup(c)).data;
-	w = xcb_generate_id(c);
-	v = find_visual(s);
+	state->s = xcb_setup_roots_iterator(xcb_get_setup(state->c)).data;
+	state->w = xcb_generate_id(state->c);
+	state->v = find_visual(state->s);
 	const uint32_t mask = XCB_CW_BACK_PIXEL | XCB_CW_EVENT_MASK;
 	const uint32_t values[] = {
-		s->white_pixel,
+		state->s->white_pixel,
 		XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_KEY_PRESS | XCB_EVENT_MASK_STRUCTURE_NOTIFY,
 	};
 	xcb_create_window(
-		c, XCB_COPY_FROM_PARENT, w, s->root, 0, 0, width, height, 0, XCB_WINDOW_CLASS_INPUT_OUTPUT,
-		s->root_visual, mask, values);
-	xcb_flush(c);
+		state->c, XCB_COPY_FROM_PARENT, state->w, state->s->root, 0, 0, initial_width, initial_height, 0,
+		XCB_WINDOW_CLASS_INPUT_OUTPUT, state->s->root_visual, mask, values);
+	state->surface = cairo_xcb_surface_create(state->c, state->w, state->v, initial_width, initial_height);
+	state->ctx = cairo_create(state->surface);
+	xcb_map_window(state->c, state->w);
+	xcb_flush(state->c);
+	return 0;
+}
+
+
+void finalize(struct State * state)
+{
+	cairo_destroy(state->ctx);
+	cairo_surface_destroy(state->surface);
+	xcb_disconnect(state->c);
+}
+
+
+int handle(struct State * state, xcb_generic_event_t * e)
+{
+	switch (XCB_EVENT_RESPONSE_TYPE(e))
+	{
+	case XCB_KEY_PRESS:
+		free(e);
+		return 1;
+	case XCB_EXPOSE:
+		cairo_set_source_rgb(state->ctx, 1., 1., 1.);
+		cairo_paint(state->ctx);
+		draw_body(state, body);  // TODO: Redraw outside of handler and don't use global body.
+		cairo_surface_flush(state->surface);
+		xcb_flush(state->c);
+		break;
+	case XCB_CONFIGURE_NOTIFY:
+		;
+		xcb_configure_notify_event_t * conf = (xcb_configure_notify_event_t *) e;
+		if (state->width != conf->width || state->height != conf->height)
+		{
+			cairo_xcb_surface_set_size(state->surface, conf->width, conf->height);
+			state->width = conf->width;
+			state->height = conf->height;
+		}
+		break;
+	default:
+		break;
+	}
+	free(e);
 	return 0;
 }
 
@@ -149,10 +166,10 @@ xcb_visualtype_t * find_visual(xcb_screen_t * screen)
 }
 
 
-void draw_body(cairo_t * ctx)
+void draw_body(struct State * state, union Command * body)
 {
 	PangoFontDescription * desc = pango_font_description_from_string(FONT);
-	cairo_set_source_rgb(ctx, 0., 0., 0.);
+	cairo_set_source_rgb(state->ctx, 0., 0., 0.);
 	int y = MARGIN;
 	PangoAttrList * attrs = pango_attr_list_new();  // TODO-maybe: Don't recreate attributes lists each redraw?
 	for (union Command * command = body; COMMAND_DONE != command->type; ++command)
@@ -167,17 +184,17 @@ void draw_body(cairo_t * ctx)
 			pango_attr_list_change(attrs, attr);
 			break;
 		case COMMAND_BLOCK:
-			cairo_move_to(ctx, MARGIN, y);
-			PangoLayout * layout = pango_cairo_create_layout(ctx);
+			cairo_move_to(state->ctx, MARGIN, y);
+			PangoLayout * layout = pango_cairo_create_layout(state->ctx);
 			pango_layout_set_attributes(layout, attrs);
 			pango_attr_list_unref(attrs);
 			attrs = pango_attr_list_new();
 			pango_layout_set_font_description(layout, desc);
 			pango_layout_set_wrap(layout, PANGO_WRAP_WORD);
-			pango_layout_set_width(layout, (width - 2 * MARGIN) * PANGO_SCALE);
+			pango_layout_set_width(layout, (state->width - 2 * MARGIN) * PANGO_SCALE);
 			pango_layout_set_text(layout, command->block.data, command->block.length);
-			pango_cairo_update_layout(ctx, layout);
-			pango_cairo_show_layout(ctx, layout);
+			pango_cairo_update_layout(state->ctx, layout);
+			pango_cairo_show_layout(state->ctx, layout);
 			int height;
 			pango_layout_get_pixel_size(layout, NULL, &height);
 			y += height + MARGIN;