events: Let arbitrary signals to simulate iOS/Android backgrounding events.

This lets you build a custom embedded device that roughly offers the "this
process is going to the background NOW" semantics of SDL on a mobile device.

3 files changed, 92 insertions, 47 deletions

diff --git a/src/events/SDL_events.c b/src/events/SDL_events.c
index 1177d6c41d..74db470bed 100644
--- a/src/events/SDL_events.c
+++ b/src/events/SDL_events.c
@@ -689,7 +689,7 @@ SDL_PumpEvents(void)
     }
 #endif
 
-    SDL_SendPendingQuit();  /* in case we had a signal handler fire, etc. */
+    SDL_SendPendingSignalEvents();  /* in case we had a signal handler fire, etc. */
 }
 
 /* Public functions */
diff --git a/src/events/SDL_events_c.h b/src/events/SDL_events_c.h
index 6d6809633f..d8c92fee70 100644
--- a/src/events/SDL_events_c.h
+++ b/src/events/SDL_events_c.h
@@ -52,7 +52,7 @@ extern int SDL_SendQuit(void);
 extern int SDL_EventsInit(void);
 extern void SDL_EventsQuit(void);
 
-extern void SDL_SendPendingQuit(void);
+extern void SDL_SendPendingSignalEvents(void);
 
 #endif /* SDL_events_c_h_ */
 
diff --git a/src/events/SDL_quit.c b/src/events/SDL_quit.c
index 6daed40414..78864f236f 100644
--- a/src/events/SDL_quit.c
+++ b/src/events/SDL_quit.c
@@ -34,6 +34,14 @@
 static SDL_bool disable_signals = SDL_FALSE;
 static SDL_bool send_quit_pending = SDL_FALSE;
 
+#ifdef SDL_BACKGROUNDING_SIGNAL
+static SDL_bool send_backgrounding_pending = SDL_FALSE;
+#endif
+
+#ifdef SDL_FOREGROUNDING_SIGNAL
+static SDL_bool send_foregrounding_pending = SDL_FALSE;
+#endif
+
 #ifdef HAVE_SIGNAL_H
 static void
 SDL_HandleSIG(int sig)
@@ -43,46 +51,81 @@ SDL_HandleSIG(int sig)
 
     /* Send a quit event next time the event loop pumps. */
     /* We can't send it in signal handler; malloc() might be interrupted! */
-    send_quit_pending = SDL_TRUE;
+    if ((sig == SIGINT) || (sig == SIGTERM)) {
+        send_quit_pending = SDL_TRUE;
+    }
+
+    #ifdef SDL_BACKGROUNDING_SIGNAL
+    else if (sig == SDL_BACKGROUNDING_SIGNAL) {
+        send_backgrounding_pending = SDL_TRUE;
+    }
+    #endif
+
+    #ifdef SDL_FOREGROUNDING_SIGNAL
+    else if (sig == SDL_FOREGROUNDING_SIGNAL) {
+        send_foregrounding_pending = SDL_TRUE;
+    }
+    #endif
 }
 #endif /* HAVE_SIGNAL_H */
 
-/* Public functions */
-static int
-SDL_QuitInit_Internal(void)
+static void
+SDL_EventSignal_Init(const int sig)
 {
 #ifdef HAVE_SIGACTION
     struct sigaction action;
-    sigaction(SIGINT, NULL, &action);
+
+    sigaction(sig, NULL, &action);
 #ifdef HAVE_SA_SIGACTION
     if ( action.sa_handler == SIG_DFL && (void (*)(int))action.sa_sigaction == SIG_DFL ) {
 #else
     if ( action.sa_handler == SIG_DFL ) {
 #endif
         action.sa_handler = SDL_HandleSIG;
-        sigaction(SIGINT, &action, NULL);
+        sigaction(sig, &action, NULL);
+    }
+#elif HAVE_SIGNAL_H
+    void (*ohandler) (int) = signal(sig, SDL_HandleSIG);
+    if (ohandler != SIG_DFL) {
+        signal(sig, ohandler);
     }
-    sigaction(SIGTERM, NULL, &action);
-
-#ifdef HAVE_SA_SIGACTION
-    if ( action.sa_handler == SIG_DFL && (void (*)(int))action.sa_sigaction == SIG_DFL ) {
-#else
-    if ( action.sa_handler == SIG_DFL ) {
 #endif
-        action.sa_handler = SDL_HandleSIG;
-        sigaction(SIGTERM, &action, NULL);
+}
+
+static void
+SDL_EventSignal_Quit(const int sig)
+{
+#ifdef HAVE_SIGACTION
+    struct sigaction action;
+    sigaction(sig, NULL, &action);
+    if ( action.sa_handler == SDL_HandleSIG ) {
+        action.sa_handler = SIG_DFL;
+        sigaction(sig, &action, NULL);
     }
 #elif HAVE_SIGNAL_H
-    void (*ohandler) (int);
+    void (*ohandler) (int) = signal(sig, SIG_DFL);
+    if (ohandler != SDL_HandleSIG) {
+        signal(sig, ohandler);
+    }
+#endif /* HAVE_SIGNAL_H */
+}
 
+/* Public functions */
+static int
+SDL_QuitInit_Internal(void)
+{
     /* Both SIGINT and SIGTERM are translated into quit interrupts */
-    ohandler = signal(SIGINT, SDL_HandleSIG);
-    if (ohandler != SIG_DFL)
-        signal(SIGINT, ohandler);
-    ohandler = signal(SIGTERM, SDL_HandleSIG);
-    if (ohandler != SIG_DFL)
-        signal(SIGTERM, ohandler);
-#endif /* HAVE_SIGNAL_H */
+    /* and SDL can be built to simulate iOS/Android semantics with arbitrary signals. */
+    SDL_EventSignal_Init(SIGINT);
+    SDL_EventSignal_Init(SIGTERM);
+
+    #ifdef SDL_BACKGROUNDING_SIGNAL
+    SDL_EventSignal_Init(SDL_BACKGROUNDING_SIGNAL);
+    #endif
+
+    #ifdef SDL_FOREGROUNDING_SIGNAL
+    SDL_EventSignal_Init(SDL_FOREGROUNDING_SIGNAL);
+    #endif
 
     /* That's it! */
     return 0;
@@ -100,28 +143,16 @@ SDL_QuitInit(void)
 static void
 SDL_QuitQuit_Internal(void)
 {
-#ifdef HAVE_SIGACTION
-    struct sigaction action;
-    sigaction(SIGINT, NULL, &action);
-    if ( action.sa_handler == SDL_HandleSIG ) {
-        action.sa_handler = SIG_DFL;
-        sigaction(SIGINT, &action, NULL);
-    }
-    sigaction(SIGTERM, NULL, &action);
-    if ( action.sa_handler == SDL_HandleSIG ) {
-        action.sa_handler = SIG_DFL;
-        sigaction(SIGTERM, &action, NULL);
-    }
-#elif HAVE_SIGNAL_H
-    void (*ohandler) (int);
-
-    ohandler = signal(SIGINT, SIG_DFL);
-    if (ohandler != SDL_HandleSIG)
-        signal(SIGINT, ohandler);
-    ohandler = signal(SIGTERM, SIG_DFL);
-    if (ohandler != SDL_HandleSIG)
-        signal(SIGTERM, ohandler);
-#endif /* HAVE_SIGNAL_H */
+    SDL_EventSignal_Quit(SIGINT);
+    SDL_EventSignal_Quit(SIGTERM);
+
+    #ifdef SDL_BACKGROUNDING_SIGNAL
+    SDL_EventSignal_Quit(SDL_BACKGROUNDING_SIGNAL);
+    #endif
+
+    #ifdef SDL_FOREGROUNDING_SIGNAL
+    SDL_EventSignal_Quit(SDL_FOREGROUNDING_SIGNAL);
+    #endif
 }
 
 void
@@ -141,12 +172,26 @@ SDL_SendQuit(void)
 }
 
 void
-SDL_SendPendingQuit(void)
+SDL_SendPendingSignalEvents(void)
 {
     if (send_quit_pending) {
         SDL_SendQuit();
         SDL_assert(!send_quit_pending);
     }
+
+    #ifdef SDL_BACKGROUNDING_SIGNAL
+    if (send_backgrounding_pending) {
+        send_backgrounding_pending = SDL_FALSE;
+        SDL_OnApplicationWillResignActive();
+    }
+    #endif
+
+    #ifdef SDL_FOREGROUNDING_SIGNAL
+    if (send_foregrounding_pending) {
+        send_foregrounding_pending = SDL_FALSE;
+        SDL_OnApplicationDidBecomeActive();
+    }
+    #endif
 }
 
 /* vi: set ts=4 sw=4 expandtab: */