better interface (constants for event handler return value, instead of "what does it do again" bool)

This was SVN commit r597.

source/lib/input.cpp

@@ -21,6 +21,8 @@
 #include "precompiled.h"
 
 #include "input.h"
+#include "sdl.h"
+#include "lib.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -28,14 +30,17 @@
 
 #define MAX_HANDLERS 4
 
-static IN_HANDLER handler_stack[MAX_HANDLERS];
+static EventHandler handler_stack[MAX_HANDLERS];
 static int handler_stack_top = 0;
 
 
-int in_add_handler(IN_HANDLER handler)
+int _in_add_handler(EventHandler handler)
 {
 	if(handler_stack_top >= MAX_HANDLERS || !handler)
+	{
+		debug_warn("in_add_handler");
 		return -1;
+	}
 
 	handler_stack[handler_stack_top++] = handler;
 
@@ -44,11 +49,21 @@ int in_add_handler(IN_HANDLER handler)
 
 
 /* send event to each handler (newest first) until one returns true */
-static void dispatch_event(const SDL_Event& event)
+static void dispatch_event(const SDL_Event* event)
 {
 	for(int i = handler_stack_top-1; i >= 0; i--)
-		if(handler_stack[i](event))
+	{
+		int ret = handler_stack[i](event);
+		// .. done, return
+		if(ret == EV_HANDLED)
 			return;
+		// .. next handler
+		else if(ret == EV_PASS)
+			continue;
+		// .. invalid return value
+		else
+			debug_warn("dispatch_event: invalid handler return value");
+	}
 }
 
 
@@ -145,7 +160,7 @@ exit(0x73c07d);
 }
 		next_event_time += time_adjust;			
 
-		dispatch_event(event);	
+		dispatch_event(&event);	
 	}
 
 	/* get new events */
@@ -161,6 +176,6 @@ exit(0x73c07d);
 			if(event.type == SDL_KEYDOWN)
 				in_stop();
 
-		dispatch_event(event);
+		dispatch_event(&event);
 	}
 }

source/lib/input.h

@@ -22,25 +22,34 @@
 #define __INPUT_H__
 
 
-#include "sdl.h"
-#include "types.h"
-
-
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
-extern u32 game_ticks;
+// event handler return value defs (int).
+// don't require an enum type - simplifies user function decl;
+// the dispatcher makes sure each return value is correct.
+enum
+{
+	// pass the event to the next handler in the chain
+	EV_PASS = 4,
 
+	// we've handled it; no other handlers will receive this event.
+	EV_HANDLED = 2
+};
+
+// declare functions to take SDL_Event*; in_add_handler converts to void*
+// (avoids header dependency on SDL)
+typedef int (*EventHandler)(const void* sdl_event);
 
-typedef bool (*IN_HANDLER)(const SDL_Event& event);
 
 /*
  * register an input handler, which will receive all subsequent events first.
  * events are passed to other handlers if handler returns false.
  */
-extern int in_add_handler(IN_HANDLER handler);
+extern int _in_add_handler(EventHandler handler);
+#define in_add_handler(h) _in_add_handler((EventHandler)h)
 
 extern void in_get_events();