Implement hooks for foreign select-using systems (currently not well

tested).

diff --git a/sel.c b/sel.c
index 43f95dc063d688a363ea4b90b6a2af6adea8e61c..de8cdefb2b69bc23f7fd609b10a9bfccb0d1fef2 100644 (file)
--- a/sel.c
+++ b/sel.c
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
 /* -*-c-*-
  *

- * $Id: sel.c,v 1.3 1999/05/21 22:13:59 mdw Exp $
+ * $Id: sel.c,v 1.4 1999/08/19 18:30:26 mdw Exp $

  *
  * I/O multiplexing support
  *
  *
  * I/O multiplexing support
  *


@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: sel.c,v $
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: sel.c,v $

+ * Revision 1.4  1999/08/19 18:30:26  mdw
+ * Implement hooks for foreign select-using systems (currently not well
+ * tested).
+ *

  * Revision 1.3  1999/05/21 22:13:59  mdw
  * Use new `tv' macros.  Fix ordering bug for timeout selectors.
  *
  * Revision 1.3  1999/05/21 22:13:59  mdw
  * Use new `tv' macros.  Fix ordering bug for timeout selectors.
  *


@@ -69,6 +73,7 @@ void sel_init(sel_state *s)
 {
   s->files = 0;
   s->timers = 0;
 {
   s->files = 0;
   s->timers = 0;

+  s->hooks = 0;

   FD_ZERO(&s->fd[SEL_READ]);
   FD_ZERO(&s->fd[SEL_WRITE]);
   FD_ZERO(&s->fd[SEL_EXC]);
   FD_ZERO(&s->fd[SEL_READ]);
   FD_ZERO(&s->fd[SEL_WRITE]);
   FD_ZERO(&s->fd[SEL_EXC]);


@@ -197,6 +202,74 @@ void sel_rmtimer(sel_timer *t)
     t->next->prev = t->prev;
 }
 
     t->next->prev = t->prev;
 }
 

+/* --- @sel_addhook@ --- *
+ *
+ * Arguments:  @sel_state *s@ = pointer to state block
+ *             @sel_hook *h@ = pointer to hook block
+ *             @sel_hookfn before, after@ = hook functions
+ *             @void *p@ = pointer argument to pass to hook functions
+ *
+ * Returns:    ---
+ *
+ * Use:                Registers hook functions to be called on each select call.
+ */
+
+void sel_addhook(sel_state *s, sel_hook *h,
+                sel_hookfn before, sel_hookfn after,
+                void *p)
+{
+  h->before = before;
+  h->after = after;
+  h->p = p;
+  h->next = s->hooks;
+  h->prev = (sel_hook *)&s->hooks;
+  if (s->hooks)
+    s->hooks->prev = h;
+  s->hooks = h;
+}
+
+/* --- @sel_rmhook@ --- *
+ *
+ * Arguments:  @sel_hook *h@ = pointer to hook block
+ *
+ * Returns:    ---
+ *
+ * Use:                Removes hook functions.
+ */
+
+void sel_rmhook(sel_hook *h)
+{
+  if (h->next)
+    h->next->prev = h->prev;
+  h->prev->next = h->next;
+}
+
+/* --- @sel_fdmerge@ --- *
+    *
+ * Arguments:   @fd_set *dest@ = destination FD set
+ *              @fd_set *fd@ = pointer to set to merge
+ *              @int maxfd@ = highest numbered descriptor in @fd@ + 1
+ *
+ * Returns:     Actual highest numbered descriptor.
+ *
+ * Use:         Merges file descriptor sets, and returns an accurate @maxfd@
+ *              value.
+ */
+
+int sel_fdmerge(fd_set *dest, fd_set *fd, int maxfd)
+{
+  int i, m = -1;
+
+  for (i = 0; i < maxfd; i++) {
+    if (FD_ISSET(i, fd)) {
+      FD_SET(i, dest);
+      m = i;
+    }
+  }
+
+  return (m + 1);
+}
+

 /* --- @sel_select@ --- *
  *
  * Arguments:  @sel_state *s@ = pointer to state block
 /* --- @sel_select@ --- *
  *
  * Arguments:  @sel_state *s@ = pointer to state block


@@ -208,44 +281,77 @@ void sel_rmtimer(sel_timer *t)
 
 int sel_select(sel_state *s)
 {
 
 int sel_select(sel_state *s)
 {

-  fd_set fd[SEL_MODES];
-  struct timeval tv;
+  sel_args a;

   int err;
 
   int err;
 

-  memcpy(fd, s->fd, sizeof(s->fd));
-  if (s->timers) {
-    struct timeval now;
-    gettimeofday(&now, 0);
-    TV_SUB(&tv, &s->timers->tv, &now);
-    err = select(s->files ? s->files->fd + 1 : 0,
-                fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
-                &tv);
-    gettimeofday(&tv, 0);
-  } else
-    err = select(s->files ? s->files->fd + 1 : 0,
-                fd + SEL_READ, fd + SEL_WRITE, fd + SEL_EXC,
-                0);
-
-  if (err < 0)
+  /* --- Initialize the argument block --- */
+
+  a.maxfd = s->files ? s->files->fd + 1 : 0;
+  memcpy(a.fd, s->fd, sizeof(a.fd));
+  if (s->timers || s->hooks)
+    gettimeofday(&a.now, 0);
+  if (!s->timers)
+    a.tvp = 0;
+  else {
+    TV_SUB(&a.tv, &s->timers->tv, &a.now);
+    a.tvp = &a.tv;
+  }
+
+  /* --- Grind through the pre hooks --- */
+
+  {
+    sel_hook *h = s->hooks;
+    while (h) {
+      sel_hook *hh = h;
+      h = h->next;
+      if (hh->before)
+       hh->before(s, &a, hh->p);
+    }
+  }
+
+  /* --- Run the @select@ call --- */
+  
+  if ((err = select(a.maxfd,
+                   &a.fd[SEL_READ], &a.fd[SEL_WRITE], &a.fd[SEL_EXC],
+                   a.tvp)) < 0)

     return (err);
 
     return (err);
 

+  if (a.tvp)
+    gettimeofday(&a.now, 0);
+
+  /* --- Run through the hooks again --- */
+
+  {
+    sel_hook *h = s->hooks;
+    while (h) {
+      sel_hook *hh = h;
+      h = h->next;
+      if (hh->after)
+       hh->after(s, &a, hh->p);
+    }
+  }
+
+  /* --- Run through the timers --- */
+

   {
     sel_timer *t, *tt;
   {
     sel_timer *t, *tt;

-    for (t = s->timers; t && TV_CMP(&t->tv, <=, &tv); t = tt) {
+    for (t = s->timers; t && TV_CMP(&t->tv, <=, &a.now); t = tt) {

       tt = t->next;
       t->next = t->prev = t;
       tt = t->next;
       t->next = t->prev = t;

-      t->func(&tv, t->p);
+      t->func(&a.now, t->p);

     }
     s->timers = t;
     if (t)
       t->prev = (sel_timer *)&s->timers;
   }
 
     }
     s->timers = t;
     if (t)
       t->prev = (sel_timer *)&s->timers;
   }
 

+  /* --- And finally run through the files --- */
+

   {
     sel_file *f, *ff;
     for (f = s->files; f; f = ff) {
       ff = f->next;
   {
     sel_file *f, *ff;
     for (f = s->files; f; f = ff) {
       ff = f->next;

-      if (FD_ISSET(f->fd, fd + f->mode))
+      if (FD_ISSET(f->fd, a.fd + f->mode))

        f->func(f->fd, f->mode, f->p);
     }
   }
        f->func(f->fd, f->mode, f->p);
     }
   }

diff --git a/sel.h b/sel.h
index 8d121ef4bbed5b5f8bf134ffaad28e64d49835c0..c2aa57f6f99bb6b384d28c4222bcd15440697f7d 100644 (file)
--- a/sel.h
+++ b/sel.h
@@ -1,6 +1,6 @@
 /* -*-c-*-
  *
 /* -*-c-*-
  *

- * $Id: sel.h,v 1.4 1999/05/22 13:39:15 mdw Exp $
+ * $Id: sel.h,v 1.5 1999/08/19 18:30:26 mdw Exp $

  *
  * I/O multiplexing support
  *
  *
  * I/O multiplexing support
  *


@@ -30,6 +30,10 @@
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: sel.h,v $
 /*----- Revision history --------------------------------------------------* 
  *
  * $Log: sel.h,v $

+ * Revision 1.5  1999/08/19 18:30:26  mdw
+ * Implement hooks for foreign select-using systems (currently not well
+ * tested).
+ *

  * Revision 1.4  1999/05/22 13:39:15  mdw
  * Change spelling of `multiplexor'. ;-)
  *
  * Revision 1.4  1999/05/22 13:39:15  mdw
  * Change spelling of `multiplexor'. ;-)
  *


@@ -95,6 +99,28 @@
 
 /*----- Data structures ---------------------------------------------------*/
 
 
 /*----- Data structures ---------------------------------------------------*/
 

+/* --- A multiplexor --- *
+ *
+ * The files are sorted in reverse order of file descriptor number; the
+ * timers are in normal order of occurrence.  Thus, the interesting one
+ * is always at the front of the list.
+ */
+
+enum {
+  SEL_READ,
+  SEL_WRITE,
+  SEL_EXC,
+  SEL_MODES
+};
+
+typedef struct sel_state {
+  struct sel_file *files;
+  struct sel_timer *timers;
+  struct sel_hook *hooks;
+  fd_set fd[SEL_MODES];
+  struct timeval tv;
+} sel_state;
+

 /* --- Listening for a file --- */
 
 typedef struct sel_file {
 /* --- Listening for a file --- */
 
 typedef struct sel_file {


@@ -107,36 +133,40 @@ typedef struct sel_file {
   void *p;
 } sel_file;
 
   void *p;
 } sel_file;
 

-enum {
-  SEL_READ,
-  SEL_WRITE,
-  SEL_EXC,
-  SEL_MODES
-};
-

 /* --- Waiting for a timeout --- */
 
 typedef struct sel_timer {
   struct sel_timer *next;
   struct sel_timer *prev;
   struct timeval tv;
 /* --- Waiting for a timeout --- */
 
 typedef struct sel_timer {
   struct sel_timer *next;
   struct sel_timer *prev;
   struct timeval tv;

-  void (*func)(struct timeval *tv, void *p);
+  void (*func)(struct timeval */*tv*/, void */*p*/);

   void *p;
 } sel_timer;
 
   void *p;
 } sel_timer;
 

-/* --- A multiplexor --- *
+/* --- A select argument block --- */
+
+typedef struct sel_args {
+  int maxfd;
+  fd_set fd[SEL_MODES];
+  struct timeval tv, *tvp;
+  struct timeval now;
+} sel_args;
+
+/* --- A selector hook --- *

  *
  *

- * The files are sorted in reverse order of file descriptor number; the
- * timers are in normal order of occurrence.  Thus, the interesting one
- * is always at the front of the list.
+ * The hooks are called (in arbitrary order) on each select.

  */
 
  */
 

-typedef struct sel_state {
-  struct sel_file *files;
-  struct sel_timer *timers;
-  fd_set fd[SEL_MODES];
-  struct timeval tv;
-} sel_state;
+typedef void (*sel_hookfn)(sel_state */*s*/,
+                          sel_args */*a*/,
+                          void */*p*/);
+
+typedef struct sel_hook {
+  struct sel_hook *next;
+  struct sel_hook *prev;
+  sel_hookfn before, after;
+  void *p;
+} sel_hook;

 
 /*----- Functions provided ------------------------------------------------*/
 
 
 /*----- Functions provided ------------------------------------------------*/
 


@@ -201,7 +231,6 @@ extern void sel_rmfile(sel_file */*f*/);
  * Arguments:  @sel_state *s@ = pointer to a state block
  *             @sel_timer *t@ = pointer to a timer block
  *             @struct timeval *tv@ = pointer to time to activate
  * Arguments:  @sel_state *s@ = pointer to a state block
  *             @sel_timer *t@ = pointer to a timer block
  *             @struct timeval *tv@ = pointer to time to activate

- *             @void (*func)(struct timeval *tv, void *p)@ = handler

  *             @void *p@ = argument for handler function
  *
  * Returns:    ---
  *             @void *p@ = argument for handler function
  *
  * Returns:    ---


@@ -226,6 +255,47 @@ extern void sel_addtimer(sel_state */*s*/, sel_timer */*t*/,
 
 extern void sel_rmtimer(sel_timer */*t*/);
 
 
 extern void sel_rmtimer(sel_timer */*t*/);
 

+/* --- @sel_addhook@ --- *
+ *
+ * Arguments:  @sel_state *s@ = pointer to state block
+ *             @sel_hook *h@ = pointer to hook block
+ *             @sel_hookfn before, after@ = hook functions
+ *             @void *p@ = pointer argument to pass to hook functions
+ *
+ * Returns:    ---
+ *
+ * Use:                Registers hook functions to be called on each select call.
+ */
+
+extern void sel_addhook(sel_state */*s*/, sel_hook */*h*/,
+                       sel_hookfn /*before*/, sel_hookfn /*after*/,
+                       void */*p*/);
+
+/* --- @sel_rmhook@ --- *
+ *
+ * Arguments:  @sel_hook *h@ = pointer to hook block
+ *
+ * Returns:    ---
+ *
+ * Use:                Removes hook functions.
+ */
+
+extern void sel_rmhook(sel_hook */*h*/);
+
+/* --- @sel_fdmerge@ --- *
+ *
+ * Arguments:  @fd_set *dest@ = destination FD set
+ *             @fd_set *fd@ = pointer to set to merge
+ *             @int maxfd@ = highest numbered descriptor in @fd@ + 1
+ *
+ * Returns:    Actual highest numbered descriptor.
+ *
+ * Use:                Merges file descriptor sets, and returns an accurate @maxfd@
+ *             value.
+ */
+
+extern int sel_fdmerge(fd_set */*dest*/, fd_set */*fd*/, int /*maxfd*/);
+

 /* --- @sel_select@ --- *
  *
  * Arguments:  @sel_state *s@ = pointer to state block
 /* --- @sel_select@ --- *
  *
  * Arguments:  @sel_state *s@ = pointer to state block