Refine event handling

This commit adds a member function for event handling to the backend
interface, replacing the previous file-based system that relies on
poll(2). The new design addresses issues created by backends like SDL,
which do not expose underlying file descriptors. Integrating the fbdev
backend into the updated interface remains to be completed.

Close #4

Author: alanjian85

Makefile

@@ -23,7 +23,6 @@ libtwin.a_cflags-y :=
 
 libtwin.a_files-y = \
 	src/box.c \
-	src/file.c \
 	src/poly.c \
 	src/toplevel.c \
 	src/button.c \

apps/main.c

@@ -128,7 +128,7 @@ int main(void)
                          20);
 #endif
 
-    twin_dispatch();
+    twin_dispatch(tx);
 
     return 0;
 }

backend/linux_input.c

@@ -144,11 +144,6 @@ static void *twin_linux_evdev_thread(void *arg)
     return NULL;
 }
 
-static bool dummy(int file, twin_file_op_t ops, void *closure)
-{
-    return true;
-}
-
 void *twin_linux_input_create(twin_screen_t *screen)
 {
     /* Create object for handling Linux input system */
@@ -162,14 +157,6 @@ void *twin_linux_input_create(twin_screen_t *screen)
     tm->x = screen->width / 2;
     tm->y = screen->height / 2;
 
-#if 1
-    /* FIXME: Need to fix the unexpected termination of the program.
-     * Hooking a dummy function here is only a hack*/
-
-    /* Set file handler for reading input device file */
-    twin_set_file(dummy, tm->fd, TWIN_READ, tm);
-#endif
-
     /* Start event handling thread */
     if (pthread_create(&tm->evdev_thread, NULL, twin_linux_evdev_thread, tm)) {
         log_error("Failed to create evdev thread");

backend/sdl.c

@@ -72,55 +72,6 @@ static void twin_sdl_damage(twin_screen_t *screen, twin_sdl_t *tx)
     twin_screen_damage(screen, 0, 0, width, height);
 }
 
-static bool twin_sdl_read_events(int file maybe_unused,
-                                 twin_file_op_t ops maybe_unused,
-                                 void *closure)
-{
-    twin_screen_t *screen = SCREEN(closure);
-    twin_sdl_t *tx = PRIV(closure);
-
-    SDL_Event ev;
-    while (SDL_PollEvent(&ev)) {
-        twin_event_t tev;
-        switch (ev.type) {
-        case SDL_WINDOWEVENT:
-            if (ev.window.event == SDL_WINDOWEVENT_EXPOSED ||
-                ev.window.event == SDL_WINDOWEVENT_SHOWN) {
-                twin_sdl_damage(screen, tx);
-            }
-            break;
-        case SDL_QUIT:
-            _twin_sdl_destroy(screen, tx);
-            return false;
-        case SDL_MOUSEBUTTONDOWN:
-        case SDL_MOUSEBUTTONUP:
-            tev.u.pointer.screen_x = ev.button.x;
-            tev.u.pointer.screen_y = ev.button.y;
-            tev.u.pointer.button =
-                ((ev.button.state >> 8) | (1 << (ev.button.button - 1)));
-            tev.kind = ((ev.type == SDL_MOUSEBUTTONDOWN) ? TwinEventButtonDown
-                                                         : TwinEventButtonUp);
-            twin_screen_dispatch(screen, &tev);
-            break;
-        case SDL_KEYDOWN:
-        case SDL_KEYUP:
-            tev.u.key.key = ev.key.keysym.sym;
-            tev.kind = ((ev.key.type == SDL_KEYDOWN) ? TwinEventKeyDown
-                                                     : TwinEventKeyUp);
-            twin_screen_dispatch(screen, &tev);
-            break;
-        case SDL_MOUSEMOTION:
-            tev.u.pointer.screen_x = ev.motion.x;
-            tev.u.pointer.screen_y = ev.motion.y;
-            tev.kind = TwinEventMotion;
-            tev.u.pointer.button = ev.motion.state;
-            twin_screen_dispatch(screen, &tev);
-            break;
-        }
-    }
-    return true;
-}
-
 static bool twin_sdl_work(void *closure)
 {
     twin_screen_t *screen = SCREEN(closure);
@@ -174,8 +125,6 @@ twin_context_t *twin_sdl_init(int width, int height)
     ctx->screen = twin_screen_create(width, height, _twin_sdl_put_begin,
                                      _twin_sdl_put_span, ctx);
 
-    twin_set_file(twin_sdl_read_events, 0, TWIN_READ, ctx);
-
     twin_set_work(twin_sdl_work, TWIN_WORK_REDISPLAY, ctx);
 
     return ctx;
@@ -195,6 +144,53 @@ static void twin_sdl_configure(twin_context_t *ctx)
     twin_screen_resize(ctx->screen, width, height);
 }
 
+static bool twin_sdl_poll(twin_context_t *ctx)
+{
+    twin_screen_t *screen = SCREEN(ctx);
+    twin_sdl_t *tx = PRIV(ctx);
+
+    SDL_Event ev;
+    while (SDL_PollEvent(&ev)) {
+        twin_event_t tev;
+        switch (ev.type) {
+        case SDL_WINDOWEVENT:
+            if (ev.window.event == SDL_WINDOWEVENT_EXPOSED ||
+                ev.window.event == SDL_WINDOWEVENT_SHOWN) {
+                twin_sdl_damage(screen, tx);
+            }
+            break;
+        case SDL_QUIT:
+            _twin_sdl_destroy(screen, tx);
+            return false;
+        case SDL_MOUSEBUTTONDOWN:
+        case SDL_MOUSEBUTTONUP:
+            tev.u.pointer.screen_x = ev.button.x;
+            tev.u.pointer.screen_y = ev.button.y;
+            tev.u.pointer.button =
+                ((ev.button.state >> 8) | (1 << (ev.button.button - 1)));
+            tev.kind = ((ev.type == SDL_MOUSEBUTTONDOWN) ? TwinEventButtonDown
+                                                         : TwinEventButtonUp);
+            twin_screen_dispatch(screen, &tev);
+            break;
+        case SDL_KEYDOWN:
+        case SDL_KEYUP:
+            tev.u.key.key = ev.key.keysym.sym;
+            tev.kind = ((ev.key.type == SDL_KEYDOWN) ? TwinEventKeyDown
+                                                     : TwinEventKeyUp);
+            twin_screen_dispatch(screen, &tev);
+            break;
+        case SDL_MOUSEMOTION:
+            tev.u.pointer.screen_x = ev.motion.x;
+            tev.u.pointer.screen_y = ev.motion.y;
+            tev.kind = TwinEventMotion;
+            tev.u.pointer.button = ev.motion.state;
+            twin_screen_dispatch(screen, &tev);
+            break;
+        }
+    }
+    return true;
+}
+
 static void twin_sdl_exit(twin_context_t *ctx)
 {
     if (!ctx)
@@ -209,5 +205,6 @@ static void twin_sdl_exit(twin_context_t *ctx)
 const twin_backend_t g_twin_backend = {
     .init = twin_sdl_init,
     .configure = twin_sdl_configure,
+    .poll = twin_sdl_poll,
     .exit = twin_sdl_exit,
 };

include/twin.h

@@ -619,7 +619,9 @@ twin_pixmap_t *twin_make_cursor(int *hx, int *hy);
  * dispatch.c
  */
 
-void twin_dispatch(void);
+struct _twin_context;
+
+void twin_dispatch(struct _twin_context *ctx);
 
 /*
  * draw.c

src/dispatch.c

@@ -4,14 +4,21 @@
  * All rights reserved.
  */
 
+#include <unistd.h>
+
+#include "twin_backend.h"
 #include "twin_private.h"
 
-void twin_dispatch(void)
+extern twin_backend_t g_twin_backend;
+
+void twin_dispatch(twin_context_t *ctx)
 {
     for (;;) {
         _twin_run_timeout();
         _twin_run_work();
-        if (!_twin_run_file(_twin_timeout_delay()))
+        if (!g_twin_backend.poll(ctx)) {
+            usleep(_twin_timeout_delay() * 1000);
             break;
+        }
     }
 }

src/file.c

@@ -19,6 +19,8 @@ typedef struct twin_backend {
     /* FIXME: Refine the parameter list */
     void (*configure)(twin_context_t *ctx);
 
+    bool (*poll)(twin_context_t *ctx);
+
     /* Device cleanup when drawing is done */
     void (*exit)(twin_context_t *ctx);
 } twin_backend_t;