From 0bcccf6577555ed605e12a02ee09ffa8595b8a51 Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Fri, 22 Jan 2010 14:20:31 +0000
Subject: [PATCH] finishing nc implementation

---
 src/util/server_nc.c | 137 +++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 132 insertions(+), 5 deletions(-)

diff --git a/src/util/server_nc.c b/src/util/server_nc.c
index 89e59b799..e9c2f5a38 100644
--- a/src/util/server_nc.c
+++ b/src/util/server_nc.c
@@ -50,11 +50,15 @@ struct ClientList
 
   struct ClientList *next;
 
+  struct GNUNET_SERVER_NotificationContext *nc;
+
   struct GNUNET_SERVER_Client *client;
 
   struct GNUNET_CONNECTION_TransmitHandle *th;
 
-  struct PendingMessageList *pending;
+  struct PendingMessageList *pending_head;
+
+  struct PendingMessageList *pending_tail;
 
   unsigned int num_pending;
 
@@ -105,9 +109,9 @@ handle_client_disconnect (void *cls,
     nc->clients = pos->next;
   else
     prev->next = pos->next;
-  while (NULL != (pml = pos->pending))
+  while (NULL != (pml = pos->pending_head))
     {
-      pos->pending = pml->next;
+      pos->pending_head = pml->next;
       GNUNET_free (pml);
     }
   GNUNET_free (pos);
@@ -155,9 +159,9 @@ GNUNET_SERVER_notification_context_destroy (struct GNUNET_SERVER_NotificationCon
       nc->clients = pos->next;
       GNUNET_SERVER_receive_done (pos->client, GNUNET_NO);
       GNUNET_SERVER_client_drop (pos->client); 
-      while (NULL != (pml = pos->pending))
+      while (NULL != (pml = pos->pending_head))
 	{
-	  pos->pending = pml->next;
+	  pos->pending_head = pml->next;
 	  GNUNET_free (pml);
 	}
       GNUNET_free (pos);
@@ -179,9 +183,113 @@ void
 GNUNET_SERVER_notification_context_add (struct GNUNET_SERVER_NotificationContext *nc,
 					struct GNUNET_SERVER_Client *client)
 {
+  struct ClientList *cl;
+
+  cl = GNUNET_malloc (sizeof (struct ClientList));
+  cl->next = nc->clients;
+  cl->nc = nc;
+  cl->client = client;
+  nc->clients = cl;
 }
 
 
+/**
+ * Function called to notify a client about the socket begin ready to
+ * queue more data.  "buf" will be NULL and "size" zero if the socket
+ * was closed for writing in the meantime.
+ *
+ * @param cls the 'struct ClientList *'
+ * @param size number of bytes available in buf
+ * @param buf where the callee should write the message
+ * @return number of bytes written to buf
+ */
+static size_t
+transmit_message (void *cls,
+		  size_t size,
+		  void *buf)
+{
+  struct ClientList *cl = cls;
+  char *cbuf = buf;
+  struct PendingMessageList *pml;
+  uint16_t msize;
+  size_t ret;
+
+  cl->th = NULL;
+  if (buf == NULL)
+    {
+      /* 'cl' should be freed via disconnect notification shortly */
+      return 0;
+    }
+  ret = 0;
+  while (cl->pending_head != NULL)
+    {
+      pml = cl->pending_head;
+      cl->pending_head = pml->next;
+      if (pml->next == NULL)
+	cl->pending_tail = NULL;
+      msize = ntohs (pml->msg->size);
+      if (size < msize)
+	break;
+      memcpy (&cbuf[ret], pml->msg, msize);
+      ret += msize;
+      size -= msize;
+      GNUNET_free (pml);
+    }
+  if (cl->pending_head != NULL)    
+    cl->th = GNUNET_SERVER_notify_transmit_ready (cl->client,
+						  ntohs (cl->pending_head->msg->size),
+						  GNUNET_TIME_UNIT_FOREVER_REL,
+						  &transmit_message,
+						  cl);
+  return ret;
+}
+
+
+/**
+ * Send a message to a particular client.
+ *
+ * @param nc context to modify
+ * @param client client to transmit to
+ * @param msg message to send
+ * @param can_drop can this message be dropped due to queue length limitations
+ */
+static void
+do_unicast (struct GNUNET_SERVER_NotificationContext *nc,
+	    struct ClientList *client,
+	    const struct GNUNET_MessageHeader *msg,
+	    int can_drop)
+{
+  struct PendingMessageList *pml;
+  uint16_t size;
+
+  if ( (client->num_pending > nc->queue_length) &&
+       (GNUNET_YES == can_drop) )
+    return; /* drop! */
+  if (client->num_pending > nc->queue_length)
+    {
+      /* FIXME: consider checking for other messages in the
+	 queue that are 'droppable' */
+    }
+  size = ntohs (msg->size);
+  pml = GNUNET_malloc (sizeof (struct PendingMessageList) + size);
+  pml->msg = (const struct GNUNET_MessageHeader*) &pml[1];
+  pml->can_drop = can_drop;
+  memcpy (&pml[1], msg, size);
+  /* append */
+  if (client->pending_tail != NULL)
+    client->pending_tail->next = pml;
+  else
+    client->pending_head = pml;
+  client->pending_tail = pml;
+  if (client->th == NULL)
+    client->th = GNUNET_SERVER_notify_transmit_ready (client->client,
+						      ntohs (client->pending_head->msg->size),
+						      GNUNET_TIME_UNIT_FOREVER_REL,
+						      &transmit_message,
+						      client);
+} 
+
+
 /**
  * Send a message to a particular client; must have
  * already been added to the notification context.
@@ -197,6 +305,17 @@ GNUNET_SERVER_notification_context_unicast (struct GNUNET_SERVER_NotificationCon
 					    const struct GNUNET_MessageHeader *msg,
 					    int can_drop)
 {
+  struct ClientList *pos;
+  
+  pos = nc->clients;
+  while (NULL != pos)
+    {
+      if (pos->client == client)
+	break;
+      pos = pos->next;
+    }
+  GNUNET_assert (pos != NULL);
+  do_unicast (nc, pos, msg, can_drop); 
 }
 
 
@@ -212,6 +331,14 @@ GNUNET_SERVER_notification_context_broadcast (struct GNUNET_SERVER_NotificationC
 					      const struct GNUNET_MessageHeader *msg,
 					      int can_drop)
 {
+  struct ClientList *pos;
+  
+  pos = nc->clients;
+  while (NULL != pos)
+    {
+      do_unicast (nc, pos, msg, can_drop);
+      pos = pos->next;
+    }
 }
 
 
-- 
2.25.1