From 088dbd956fceb16c2f185694e42e5b7041acb2f6 Mon Sep 17 00:00:00 2001
From: Rui Guo <firemeteor.guo@gmail.com>
Date: Fri, 5 Jun 2009 01:33:36 +0800
Subject: [PATCH] Event dispatching (Binding independing part)

Finished binding independing part of event dispatching framework.
Register interface provided for script to setup handler for event
notification. trigger interface provided for screen to notify scripts.

TODO: unregister interface.
---
 src/script.c | 82 +++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 src/script.h | 33 ++++++++++++++++++------
 2 files changed, 99 insertions(+), 16 deletions(-)

diff --git a/src/script.c b/src/script.c
index 156ca31..36b9d3a 100644
--- a/src/script.c
+++ b/src/script.c
@@ -118,24 +118,39 @@ ScriptCmd(int argc, const char **argv)
 
 struct gevents {
     struct script_event cmdexecuted;
+    struct script_event detached;
 } globalevents;
 
-/* To add new event, introduce a filed for that event to the object in
- * question, don't forget to put a name, offset pair here.  NOTE: keep the
+/* To add a new event, introduce a field for that event to the object in
+ * question, and don't forget to put an descriptor here.  NOTE: keep the
  * name field sorted in alphabet order, the searching relies on it.
+ *
+ * the params string specifies the expected parameters. The length of the
+ * string equals to the number of parameters. Each char specifies the type of
+ * the parameter, with its meaning similar to those in printf().
+ *
+ * s: string (char *)
+ * S: string array (char **)
+ * i: signed int
+ * 
  */
 
 struct {
     char *name;
+    char *params;
     int offset;
 } event_table[] = {
-      {"global_cmdexecuted", offsetof(struct gevents, cmdexecuted)},
-      {"window_resize", offsetof(struct win, resize)},
-      {"window_can_resize", offsetof(struct win, canresize)}
+      {"global_cmdexecuted", "sSi", offsetof(struct gevents, cmdexecuted)},
+      {"global_detached", "", offsetof(struct gevents, detached)},
+      {"window_resize", "", offsetof(struct win, w_sev.resize)},
+      {"window_can_resize", "", offsetof(struct win, w_sev.canresize)}
 };
 
+/* Get the event queue with the given name in the obj.  If the obj is NULL,
+ * global events are searched.  If no event is found, a NULL is returned.
+ */
 struct script_event *
-get_object_event_queue(char *name, char *obj) {
+object_get_event(char *obj, char *name) {
     int lo, hi, n, cmp;
     if (!obj)
       obj = (char *)&globalevents;
@@ -154,13 +169,62 @@ get_object_event_queue(char *name, char *obj) {
 
     if (lo >= n || strcmp(name, event_table[lo].name))
       return 0;
-    else 
-      return (struct event *)(obj + event_table[lo].offset);
+    else {
+        //found an entry.
+        struct script_event *res;
+        res = (struct script_event *) (obj + event_table[lo].offset);
+        //Setup the parameter record.
+        res->params = event_table[lo].params;
+        return res;
+    }
 }
 
+/* Put a listener in a proper position in the chain 
+ * according to the privlege.*/
+#define PRIV_MIN  -31
 void
-register_listener(struct script_event * event, struct listener *listener)
+register_listener(struct script_event *ev, struct listener *l)
+{
+  int priv;
+  struct listener head, *p;
+  head.chain = ev->listeners;
+  p = &head;
+
+  if (l->priv < PRIV_MIN)
+    l->priv = PRIV_MIN;
+  priv = l->priv;
+
+  while (p->chain && priv >= p->chain->priv)
+    p = p->chain;
+
+  l->chain = p->chain;
+  p->chain = l;
+  ev->listeners = head.chain;
+}
+
+/* Trigger event with given parameters.*/
+int
+trigger_sevent(struct script_event *ev, VA_DOTS)
 {
+  int res = 0;
+  struct listener *chain;
+  char *params;
+  VA_LIST(va);
+  /*invalid or un-registered event structure*/
+  if (!ev || !ev->params)
+    return 0;
+
+  //process the chain in order, stop if any of the handler returns true.
+  chain = ev->listeners;
+  params = ev->params;
+  while (chain)
+    {
+      res = chain->dispatcher(chain->handler, params, va);
+      if (res)
+        break;
+    }
+
+  return res;
 }
 
 #define ALL_SCRIPTS(fn, params, stop) do { \
diff --git a/src/script.h b/src/script.h
index 832838d..00e09f8 100644
--- a/src/script.h
+++ b/src/script.h
@@ -22,16 +22,15 @@
 #define SCRIPT_H
 struct win;
 
+//Obsolete
 struct ScriptFuncs
 {
-  int (*sf_Init) __P((void));
-  int (*sf_Finit) __P((void));
   int (*sf_ForeWindowChanged) __P((void));
-  int (*sf_Source) __P((const char *, int));
   int (*sf_ProcessCaption) __P((const char *, struct win *, int len));
   int (*sf_CommandExecuted) __P((const char *, const char **, int));
 };
 
+/***Language binding***/
 struct binding
 {
   char * name;
@@ -49,13 +48,33 @@ void LoadBindings(void);
 void FinializeBindings(void);
 void ScriptCmd __P((int argc, const char **argv));
 
-struct listener {
+/***Script events***/
 
+// Script event listener
+struct listener 
+{
+  /*Binding dependent event handler data*/
+  void *handler; 
+
+  /* dispatcher provided by the binding.
+   * The return value is significant: 
+   * a non-zero value will stop further
+   * notification to the rest of the chain.*/
+  int (*dispatcher) __P((void *handler, char *params, VA_DOTS)); 
+  
+  /* smaller means higher privilege.*/
+  int priv;
+  struct listener *chain;
 };
 
-struct script_event {
-    int blockable;
-    struct listener *listeners;
+/* the script_event structure needs to be zeroed before using.
+ * embeding this structure directly into screen objects will do the job, as
+ * long as the objects are created from calloc() call.*/
+struct script_event
+{
+  /* expected parameter description of this event. */
+  char *params;
+  struct listener *listeners;
 };
 
 #endif
-- 
2.11.4.GIT