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

@@ -455,15 +455,10 @@ typedef twin_time_t (*twin_timeout_proc_t)(twin_time_t now, void *closure);
 
 typedef bool (*twin_work_proc_t)(void *closure);
 
-typedef enum _twin_file_op { TWIN_READ = 1, TWIN_WRITE = 2 } twin_file_op_t;
-
-typedef bool (*twin_file_proc_t)(int file, twin_file_op_t ops, void *closure);
-
 #define twin_time_compare(a, op, b) (((a) - (b)) op 0)
 
 typedef struct _twin_timeout twin_timeout_t;
 typedef struct _twin_work twin_work_t;
-typedef struct _twin_file twin_file_t;
 
 /*
  * Widgets
@@ -619,7 +614,9 @@ 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
@@ -654,17 +651,6 @@ void twin_premultiply_alpha(twin_pixmap_t *px);
 
 void twin_event_enqueue(const twin_event_t *event);
 
-/*
- * file.c
- */
-
-twin_file_t *twin_set_file(twin_file_proc_t file_proc,
-                           int file,
-                           twin_file_op_t ops,
-                           void *closure);
-
-void twin_clear_file(twin_file_t *file);
-
 /*
  * fixed.c
  */

include/twin_private.h

@@ -472,14 +472,6 @@ struct _twin_work {
     void *closure;
 };
 
-struct _twin_file {
-    twin_queue_t queue;
-    int file;
-    twin_file_op_t ops;
-    twin_file_proc_t proc;
-    void *closure;
-};
-
 typedef enum _twin_order {
     TWIN_BEFORE = -1,
     TWIN_AT = 0,
@@ -504,8 +496,6 @@ twin_queue_t *_twin_queue_set_order(twin_queue_t **head);
 
 void _twin_queue_review_order(twin_queue_t *first);
 
-int _twin_run_file(twin_time_t delay);
-
 void _twin_run_timeout(void);
 
 twin_time_t _twin_timeout_delay(void);

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;