Started implementing events.

common/events.c

@@ -0,0 +1,101 @@
+// 15 may 2019
+#include <stdlib.h>
+#include "ui.h"
+#include "uipriv.h"
+
+struct handler {
+	int id;
+	uiHandlerFunc f;
+	void *sender;
+	void *data;
+	bool blocked;
+};
+
+static int handlerCmp(const void *a, const void *b)
+{
+	const struct handler *ha = (const struct handler *) a;
+	const struct handler *hb = (const struct handler *) b;
+
+	// This could be ha->id - hb->id, but let's do it the explicit way to avoid integer overflow/underflow.
+	if (ha->id < hb->id)
+		return -1;
+	if (ha->id > hb->id)
+		return 1;
+	return 0;
+}
+
+static struct handler *handlerFind(struct handler *handlers, size_t len, int id)
+{
+	struct handler key;
+
+	memset(&key, 0, sizeof (struct handler));
+	key.id = id;
+	return (struct handler *) bsearch(&key, handlers, len, sizeof (struct handler), handlerCmp);
+}
+
+static void handlerSort(struct handler *handlers, size_t len)
+{
+	qsort(handlers, len, sizeof (struct handler), handlerCmp);
+}
+
+struct uiEvent {
+	uiEventOptions opts;
+	struct handler *handlers;
+	size_t len;
+	size_t cap;
+	bool firing;
+};
+
+uiEvent *uiNewEvent(uiEventOptions *options)
+{
+}
+
+int uiEventAddHandler(uiEvent *e, uiEventHandler handler, void *sender, void *data)
+{
+}
+
+void uiEventDeleteHandler(uiEvent *e, int id)
+{
+	struct handler *h;
+
+	if (e == NULL)
+		TODO
+	if (e->firing)
+		TODO
+	if (e->len == 0)
+		TODO
+	h = handlerFind(e->handlers, e->len, id);
+	if (h == NULL)
+		TODO
+	e->len--;
+	memmove(h + 1, h, (e->len - (h - e->handlers)) * sizeof (struct handler));
+}
+
+void uiEventFire(uiEvent *e, void *sender, void *args)
+{
+	struct handler *h;
+	size_t i;
+
+	if (e == NULL)
+		TODO
+	if (e->firing)
+		TODO
+	if (e->opts.Global && sender != NULL)
+		TODO
+	e->firing = true;
+	h = e->handlers;
+	for (i = 0; i < e->len; i++) {
+		if (h->sender == sender && !h->blocked)
+			(*(h->f))(sender, args, h->data);
+		h++;
+	}
+	e->firing = false;
+}
+
+bool uiEventHandlerBlocked(const uiEvent *e, int id)
+{
+}
+
+void uiEventSetHandlerBlocked(uiEvent *e, int id, bool blocked)
+{
+}

common/meson.build

@@ -2,5 +2,6 @@
 
 libui_sources += [
 	'common/errors.c',
+	'common/events.c',
 	'common/init.c',
 ]

doc/events.md

@@ -72,6 +72,8 @@ It is a programmer error to specify `NULL` for `e` or `handler`. It is also a pr
 void uiEventDeleteHandler(uiEvent *e, int id);
 ```
 
+`uiEventDeleteHandler()` removes an event handler registration; you specify which handler to unregister by passing in the ID returned from `uiEventAddHandler()`.
+
 It is a programmer error to specify `NULL` for `e` or a currently unregistered value for `id`. It is also a programmer error to call `uiEventDeleteHandler()` on an event while that event is being fired.
 
 ### `uiEventFire()`

ui.h

@@ -43,6 +43,24 @@ uiprivExtern void uiMain(void);
 uiprivExtern void uiQuit(void);
 uiprivExtern void uiQueueMain(void (*f)(void *data), void *data);
 
+typedef struct uiEvent uiEvent;
+typedef struct uiEventOptions uiEventOptions;
+
+typedef void (*uiEventHandler)(void *sender, void *args, void *data);
+
+struct uiEventOptions {
+	size_t Size;
+	bool Global;
+};
+
+uiprivExtern uiEvent *uiNewEvent(uiEventOptions *options);
+// TODO uiFreeEvent()
+uiprivExtern int uiEventAddHandler(uiEvent *e, uiEventHandler handler, void *sender, void *data);
+uiprivExtern void uiEventDeleteHandler(uiEvent *e, int id);
+uiprivExtern void uiEventFire(uiEvent *e, void *sender, void *args);
+uiprivExtern bool uiEventHandlerBlocked(const uiEvent *e, int id);
+uiprivExtern void uiEventSetHandlerBlocked(uiEvent *e, int id, bool blocked);
+
 #ifdef __cplusplus
 }
 #endif