Add xcb event loop using glib's mainloop

3 files changed, 123 insertions, 16 deletions

diff --git a/Makefile b/Makefile
index 0494403..2e62337 100644
--- a/Makefile
+++ b/Makefile
@@ -3,12 +3,14 @@ OBJ = $(SRC:.c=.o)
 BIN = comet.bin
 
 DEPS = cairo \
-	   xcb \
-	   xcb-icccm \
-	   xcb-xrm \
-	   xcb-randr \
-	   glib-2.0
-CFLAGS  := $(shell pkg-config --cflags $(DEPS))
+       xcb \
+       xcb-icccm \
+       xcb-xrm \
+       "xcb-randr >= 1.5" \
+       "glib-2.0 >= 2.44" \
+       gio-2.0
+
+CFLAGS  := $(shell pkg-config --cflags $(DEPS)) -ggdb
 LDFLAGS := $(shell pkg-config --libs $(DEPS)) -lm
 
 all: $(BIN)
diff --git a/comet.c b/comet.c
index b125d78..40a302d 100644
--- a/comet.c
+++ b/comet.c
@@ -5,14 +5,41 @@
 #include "log.h"
 #include "draw.h"
 
+    GMainLoop *mainloop = NULL;
+
+static gboolean mainloop_quit(gpointer data)
+{
+        g_main_loop_quit(mainloop);
+        return G_SOURCE_CONTINUE;
+}
+
+static gboolean mainloop_do(gpointer data)
+{
+        draw(data);
+        return G_SOURCE_REMOVE;
+}
+
 int main(int argc, char **argv)
 {
     log_init(G_LOG_LEVEL_DEBUG);
 
+    mainloop = g_main_loop_new(g_main_context_default(), FALSE);
+
     Window *win = window_create();
 
-    draw(win);
-    sleep(10);
+    guint source_term = g_unix_signal_add(SIGTERM, mainloop_quit, mainloop);
+    guint source_int  = g_unix_signal_add(SIGINT,  mainloop_quit, mainloop);
+
+    guint id = g_timeout_add(100, mainloop_do, win);
+
+    log_debug("Starting main loop");
+    g_main_loop_run(mainloop);
+
+    log_debug("Cleaning main loop");
+    g_clear_pointer(&mainloop, g_main_loop_unref);
+
+    g_source_remove(source_term);
+    g_source_remove(source_int);
 
     window_destroy(win);
     return 0;
diff --git a/x11.c b/x11.c
index 92e8680..7d59038 100644
--- a/x11.c
+++ b/x11.c
@@ -1,5 +1,3 @@
-#include <stdbool.h>
-#include <assert.h>
 #include <glib.h>
 #include <math.h>
 #include <cairo.h>
@@ -28,8 +26,15 @@ struct Window {
     uint16_t screen_height;
     int x, y;
     int width, height;
+    GSource *source;
 };
 
+typedef struct {
+    GSource source;
+    Window *win;
+    xcb_generic_event_t *event;
+} XcbSource;
+
 static xcb_atom_t intern_atom(Window *win, const char *atom)
 {
     // TODO: Error handling
@@ -37,13 +42,80 @@ static xcb_atom_t intern_atom(Window *win, const char *atom)
     return xcb_intern_atom_reply(win->connection, cookie, NULL)->atom;
 }
 
+static gboolean xcb_source_prepare(GSource *source, gint *timeout)
+{
+    // Always ready to poll
+    if (timeout) *timeout = -1;
+    return G_SOURCE_REMOVE;
+}
+
+static gboolean xcb_source_check(GSource *source)
+{
+    XcbSource *xsource = (XcbSource *)source;
+    g_assert_null(xsource->event);
+    xsource->event = xcb_poll_for_event(xsource->win->connection);
+    return xsource->event != NULL;
+}
+
+static gboolean xcb_source_dispatch(GSource *source, GSourceFunc callback, gpointer data)
+{
+    XcbSource *xsource = (XcbSource *)source;
+    g_assert_nonnull(xsource->event);
+
+    do {
+        switch (xsource->event->response_type & ~0x80) {
+            case 0:
+                log_debug("Error in Xcb event loop");
+                break;
+
+            case XCB_BUTTON_PRESS: {
+                log_debug("Keypress event");
+                break;
+            }
+
+            default: {
+                log_debug("Ignoring event '%d'", xsource->event->response_type);
+            }
+        }
+    } while ((xsource->event = xcb_poll_for_event(xsource->win->connection)) != NULL);
+
+    return G_SOURCE_CONTINUE;
+}
+
+static void xcb_source_finalize(GSource *source)
+{
+    log_debug("Xcb event loop finalized");
+}
+
+static GSourceFuncs source_fns = {
+    xcb_source_prepare,
+    xcb_source_check,
+    xcb_source_dispatch,
+    xcb_source_finalize,
+    NULL,
+    NULL,
+};
+
+static void attach_source(Window *win)
+{
+    XcbSource *source = (XcbSource *)g_source_new(&source_fns, sizeof(XcbSource));
+    source->win = win;
+    source->event = NULL;
+
+    win->source = (GSource *)source;
+    g_source_set_name(win->source, "XcbSource");
+
+    g_source_add_unix_fd(win->source, xcb_get_file_descriptor(win->connection), G_IO_IN | G_IO_HUP | G_IO_ERR);
+    g_source_attach(win->source, g_main_context_default());
+}
+
 Window *window_create(void)
 {
     Window *win = g_malloc0(sizeof(Window));
 
     int preferred_screen = 0;
     win->connection = xcb_connect(NULL, &preferred_screen);
-    assert(win->connection != NULL && !xcb_connection_has_error(win->connection));
+    g_assert_true(win->connection != NULL && !xcb_connection_has_error(win->connection));
     log_debug("Xcb established connection");
 
     xcb_screen_iterator_t iter = xcb_setup_roots_iterator(xcb_get_setup(win->connection));
@@ -66,11 +138,11 @@ Window *window_create(void)
                                                                                    &error);
 
     log_debug("RandR version %d.%d", randr_version->major_version, randr_version->minor_version);
-    assert(error == NULL || randr_version->major_version < 1);
+    g_assert_true(error == NULL || randr_version->major_version < 1);
 
     xcb_randr_get_screen_info_cookie_t cookie = xcb_randr_get_screen_info(win->connection, win->screen->root);
     xcb_randr_get_screen_info_reply_t *info_reply = xcb_randr_get_screen_info_reply(win->connection, cookie, &error);
-    assert(error == NULL);
+    g_assert_null(error);
 
     xcb_randr_screen_size_t *screen_size = xcb_randr_get_screen_info_sizes(info_reply);
     log_debug("Screen size [width=%d, height=%d]", screen_size->width, screen_size->height);
@@ -88,7 +160,7 @@ Window *window_create(void)
                            XCB_RANDR_NOTIFY_MASK_OUTPUT_PROPERTY);
 
     win->database = xcb_xrm_database_from_default(win->connection);
-    assert(win->database != NULL);
+    g_assert_nonnull(win->database);
 
     char *dpi_value;
     if (xcb_xrm_resource_get_string(win->database, "Xft.dpi", "Xft.dpi", &dpi_value) >= 0) {
@@ -193,13 +265,16 @@ found_visual:
                                             screen_size->width,
                                             screen_size->height);
 
-    assert(cairo_surface_status(win->surface) == CAIRO_STATUS_SUCCESS);
+    g_assert_cmpint(cairo_surface_status(win->surface), ==, CAIRO_STATUS_SUCCESS);
 
     win->cr = cairo_create(win->surface);
-    assert(cairo_status(win->cr) == CAIRO_STATUS_SUCCESS);
+    g_assert_cmpint(cairo_status(win->cr), ==, CAIRO_STATUS_SUCCESS);
 
     log_debug("Cairo initialized");
 
+    attach_source(win);
+    log_debug("Xcb event loop attached");
+
     return win;
 }
 
@@ -265,6 +340,9 @@ void window_paint_surface(Window *win, cairo_surface_t *surface, int width, int
 
 void window_destroy(Window *win)
 {
+    g_source_destroy(win->source);
+    g_source_unref(win->source);
+
     cairo_destroy(win->cr);
     cairo_surface_destroy(win->surface);