adding notification API to peerinfo

1 files changed, 243 insertions, 0 deletions

diff --git a/src/peerinfo/peerinfo_api.c b/src/peerinfo/peerinfo_api.c
index b5c6c99d7..906c01d77 100644
--- a/src/peerinfo/peerinfo_api.c
+++ b/src/peerinfo/peerinfo_api.c
@@ -298,4 +298,247 @@ GNUNET_PEERINFO_for_all (const struct GNUNET_CONFIGURATION_Handle *cfg,
     }
 }
 
+
+
+/**
+ * Context for the info handler.
+ */
+struct GNUNET_PEERINFO_NotifyContext
+{
+
+  /**
+   * Our connection to the PEERINFO service.
+   */
+  struct GNUNET_CLIENT_Connection *client;
+
+  /**
+   * Function to call with information.
+   */
+  GNUNET_PEERINFO_Processor callback;
+
+  /**
+   * Closure for callback.
+   */
+  void *callback_cls;
+
+  /**
+   * Handle to our initial request for message transmission to
+   * the peerinfo service.
+   */
+  struct GNUNET_CLIENT_TransmitHandle *init;
+
+  /**
+   * Configuration.
+   */
+  const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+  /**
+   * Scheduler.
+   */
+  struct GNUNET_SCHEDULER_Handle *sched;
+};
+
+
+/**
+ * Send a request to the peerinfo service to start being
+ * notified about all changes to peer information.
+ *
+ * @param nc our context
+ */
+static void
+request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);
+
+
+/**
+ * Read notifications from the client handle and pass them
+ * to the callback.
+ *
+ * @param nc our context
+ */
+static void
+receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc);
+
+
+/**
+ * Receive a peerinfo information message, process it and
+ * go for more.
+ *
+ * @param cls closure
+ * @param msg message received, NULL on timeout or fatal error
+ */
+static void
+process_notification (void *cls,
+                      const struct
+                      GNUNET_MessageHeader * msg)
+{
+  struct GNUNET_PEERINFO_NotifyContext *nc = cls;
+  const struct InfoMessage *im;
+  const struct GNUNET_HELLO_Message *hello;
+  uint16_t ms;
+
+  if (msg == NULL)
+    {
+      GNUNET_CLIENT_disconnect (nc->client);
+      nc->client = GNUNET_CLIENT_connect (nc->sched, "peerinfo", nc->cfg);
+      request_notifications (nc);
+      return;
+    }
+  ms = ntohs (msg->size);
+  if ((ms < sizeof (struct InfoMessage)) ||
+      (ntohs (msg->type) != GNUNET_MESSAGE_TYPE_PEERINFO_INFO))
+    {
+      GNUNET_break (0);
+      GNUNET_CLIENT_disconnect (nc->client);
+      nc->client = GNUNET_CLIENT_connect (nc->sched, "peerinfo", nc->cfg);
+      request_notifications (nc);
+      return;
+    }
+  im = (const struct InfoMessage *) msg;
+  hello = NULL;
+  if (ms > sizeof (struct InfoMessage) + sizeof (struct GNUNET_MessageHeader))
+    {
+      hello = (const struct GNUNET_HELLO_Message *) &im[1];
+      if (ms != sizeof (struct InfoMessage) + GNUNET_HELLO_size (hello))
+        {
+          GNUNET_break (0);
+          GNUNET_CLIENT_disconnect (nc->client);
+          nc->client = GNUNET_CLIENT_connect (nc->sched, "peerinfo", nc->cfg);
+          request_notifications (nc);
+          return;
+        }
+    }
+#if DEBUG_PEERINFO
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received information about peer `%s' from peerinfo database\n",
+              GNUNET_i2s (&im->peer));
+#endif
+  nc->callback (nc->callback_cls, &im->peer, hello, ntohl (im->trust));
+  receive_notifications (nc);
+}
+
+
+/**
+ * Read notifications from the client handle and pass them
+ * to the callback.
+ *
+ * @param nc our context
+ */
+static void
+receive_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
+{
+  GNUNET_CLIENT_receive (nc->client,
+                         &process_notification,
+                         nc,
+                         GNUNET_TIME_UNIT_FOREVER_REL);
+}
+
+
+/**
+ * Transmit our init-notify request, start receiving.
+ *
+ * @param cls closure (our 'struct GNUNET_PEERINFO_NotifyContext')
+ * @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_notify_request (void *cls,
+                         size_t size, 
+                         void *buf)
+{
+  struct GNUNET_PEERINFO_NotifyContext *nc = cls;
+  struct GNUNET_MessageHeader hdr;
+
+  nc->init = NULL;
+  if (buf == NULL)
+    {
+      GNUNET_CLIENT_disconnect (nc->client);
+      nc->client = GNUNET_CLIENT_connect (nc->sched, "peerinfo", nc->cfg);
+      request_notifications (nc);
+      return 0;
+    }
+  GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader));
+  hdr.size = htons (sizeof (struct GNUNET_MessageHeader));
+  hdr.type = htons (GNUNET_MESSAGE_TYPE_PEERINFO_NOTIFY);
+  memcpy (buf, &hdr, sizeof (struct GNUNET_MessageHeader));
+  receive_notifications (nc);
+  return sizeof (struct GNUNET_MessageHeader);
+}
+
+
+/**
+ * Send a request to the peerinfo service to start being
+ * notified about all changes to peer information.
+ *
+ * @param nc our context
+ */
+static void
+request_notifications (struct GNUNET_PEERINFO_NotifyContext *nc)
+{
+  GNUNET_assert (NULL == nc->init);
+  nc->init =GNUNET_CLIENT_notify_transmit_ready (nc->client,
+                                                 sizeof (struct GNUNET_MessageHeader),
+                                                 GNUNET_TIME_UNIT_FOREVER_REL,
+                                                 GNUNET_YES,
+                                                 &transmit_notify_request,
+                                                 nc);
+}
+
+
+/**
+ * Call a method whenever our known information about peers
+ * changes.  Initially calls the given function for all known
+ * peers and then only signals changes.
+ *
+ * @param cfg configuration to use
+ * @param sched scheduler to use
+ * @param callback the method to call for each peer
+ * @param callback_cls closure for callback
+ * @return NULL on error
+ */
+struct GNUNET_PEERINFO_NotifyContext *
+GNUNET_PEERINFO_notify (const struct GNUNET_CONFIGURATION_Handle *cfg,
+                        struct GNUNET_SCHEDULER_Handle *sched,
+                        GNUNET_PEERINFO_Processor callback,
+                        void *callback_cls)
+{
+  struct GNUNET_PEERINFO_NotifyContext *nc;
+  struct GNUNET_CLIENT_Connection *client;
+
+  client = GNUNET_CLIENT_connect (sched, "peerinfo", cfg);
+  if (client == NULL)
+    {      
+      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                  _("Could not connect to `%s' service.\n"), "peerinfo");
+      return NULL;
+    }
+  nc = GNUNET_malloc (sizeof (struct GNUNET_PEERINFO_NotifyContext));
+  nc->sched = sched;
+  nc->cfg = cfg;
+  nc->client = client;
+  nc->callback = callback;
+  nc->callback_cls = callback_cls; 
+  request_notifications (nc);
+  return nc;
+}
+
+
+/**
+ * Stop notifying about changes.
+ *
+ * @param nc context to stop notifying
+ */
+void
+GNUNET_PEERINFO_notify_cancel (struct GNUNET_PEERINFO_NotifyContext *nc)
+{
+  if (NULL != nc->init)
+    {
+      GNUNET_CLIENT_notify_transmit_ready_cancel (nc->init);
+      nc->init = NULL;
+    }
+  GNUNET_CLIENT_disconnect (nc->client);
+  GNUNET_free (nc);
+}
+
+
 /* end of peerinfo_api.c */