Add epoll.[ch]

1 files changed, 192 insertions, 0 deletions

diff --git a/epoll.c b/epoll.c
new file mode 100644
index 0000000..a464cc7
--- /dev/null
+++ b/epoll.c
@@ -0,0 +1,192 @@
+#include "epoll.h"
+#include <sys/poll.h>
+
+typedef struct FdInfo FdInfo;
+
+struct FdInfo
+{
+    /* FIXME: we might want to compress this struct at some point.
+     * Though, if we have 100000 fd's, it's only 1.6 MB, which is
+     * almost nothing for that many clients, Still, cache use
+     * would improve.
+     */
+    gboolean		valid;
+    gboolean		disabled;
+    EPollEventType	mask;
+    gpointer		data;
+};
+
+struct EPoll
+{
+    int		n_fds;
+    gsize	n_fd_infos;
+    FdInfo *	fd_info;
+};
+
+EPoll *
+epoll_new (void)
+{
+    EPoll *epoll = g_new0 (EPoll, 1);
+    
+    epoll->n_fds = 0;
+    epoll->n_fd_infos = 1;
+    epoll->fd_info = g_new0 (FdInfo, 1);
+    
+    return epoll;
+}
+
+void
+epoll_add_fd (EPoll   *epoll,
+	      int      fd,
+	      EPollEventType      mask,
+	      gpointer data)
+{
+    g_return_if_fail (!epoll_has_fd (epoll, fd));
+
+    while (fd >= epoll->n_fd_infos)
+	epoll->n_fd_infos *= 2;
+    
+    epoll->fd_info = g_renew (FdInfo, epoll->fd_info, epoll->n_fd_infos);
+    
+    epoll->n_fds++;
+    
+    epoll->fd_info[fd].valid = TRUE;
+    epoll->fd_info[fd].mask = mask;
+    epoll->fd_info[fd].data = data;
+}
+
+gboolean
+epoll_has_fd (EPoll *epoll,
+	      int fd)
+{
+    g_return_val_if_fail (epoll != NULL, FALSE);
+    
+    return (fd < epoll->n_fd_infos && epoll->fd_info[fd].valid);
+}
+
+gint
+epoll_get_n_fds (EPoll *epoll)
+{
+    return epoll->n_fds;
+}
+
+void
+epoll_remove_fd (EPoll  *epoll,
+		 int     fd)
+{
+    g_return_if_fail (epoll_has_fd (epoll, fd));
+    
+    epoll->fd_info[fd].valid = FALSE;
+}
+
+gpointer
+epoll_get_fd_data (EPoll *epoll,
+		   int    fd)
+{
+    g_return_val_if_fail (epoll != NULL, NULL);
+    g_return_val_if_fail (epoll_has_fd (epoll, fd), NULL);
+
+    return epoll->fd_info[fd].data;
+}
+
+/* epoll_wait() is a one-shot polling mechanism, so this function
+ * must be called to reenable fd's after they have been returned
+ * by epoll_wait().
+ */
+void
+epoll_reenable_fd (EPoll *epoll,
+		   int    fd)
+{
+    g_return_if_fail (epoll_has_fd (epoll, fd));
+    
+    epoll->fd_info[fd].disabled = FALSE;
+}
+
+EPollEvent *
+epoll_wait (EPoll      *epoll,
+	    int	       *n_events,
+	    int         timeout)
+{
+    struct pollfd *fds;
+    int i, j;
+    int n_poll_fds;
+    int n_ready;
+    EPollEvent *events;
+
+    fds = g_new (struct pollfd, epoll->n_fds);
+
+    j = 0;
+    for (i = 0; i < epoll->n_fd_infos; ++i)
+    {
+	if (epoll->fd_info[i].valid		&&
+	    !epoll->fd_info[i].disabled		&&
+	    epoll->fd_info[i].mask != 0)
+	{
+	    fds[j].events = 0;
+    
+	    if (epoll->fd_info[i].mask & EPOLL_READ)
+		fds[j].events |= POLLIN;
+
+	    if (epoll->fd_info[i].mask & EPOLL_WRITE)
+		fds[j].events |= POLLOUT;
+	    
+	    if (epoll->fd_info[i].mask & EPOLL_HANGUP)
+		fds[j].events |= POLLHUP;
+	    
+	    if (epoll->fd_info[i].mask & EPOLL_PRIORITY)
+		fds[j].events |= POLLPRI;
+	    
+	    if (epoll->fd_info[i].mask & EPOLL_ERROR)
+		fds[j].events |= POLLERR;
+	    
+	    fds[j].fd = i;
+
+	    j++;
+	}
+    }
+
+    n_poll_fds = j;
+
+    events = NULL;
+    
+    n_ready = poll (fds, n_poll_fds, timeout);
+
+    if (n_ready)
+    {
+	events = g_new0 (EPollEvent, n_ready);
+
+	j = 0;
+	for (i = 0; i < n_poll_fds; ++i)
+	{
+	    if (fds[i].revents)
+	    {
+		events[j].events = 0;
+		
+		if (fds[i].revents & POLLIN)
+		    events[j].events |= EPOLL_READ;
+		
+		if (fds[i].revents & POLLOUT)
+		    events[j].events |= EPOLL_WRITE;
+		
+		if (fds[i].revents & POLLHUP)
+		    events[j].events |= EPOLL_HANGUP;
+		
+		if (fds[i].revents & POLLERR)
+		    events[j].events |= EPOLL_ERROR;
+		
+		if (fds[i].revents & POLLPRI)
+		    events[j].events |= EPOLL_PRIORITY;
+		
+		events[j].fd = fds[i].fd;
+		epoll->fd_info[fds[i].fd].disabled = TRUE;
+	    }
+	}
+    }
+
+    g_free (fds);
+
+    if (n_events)
+	*n_events = n_ready;
+    
+    return events;
+}