[sysprof] perf: ping the sysprofd service before we consider it up

[Christian Hergert <chergert src gnome org>]

commit afadd90834e488423261e5df3ab7703e22ffd32a
Author: Christian Hergert <christian hergert me>
Date:   Sun Apr 24 17:49:03 2016 -0700

    perf: ping the sysprofd service before we consider it up
    
    This should help catch failures where the peer is not yet up and might
    fail to start, before we actually block on communicating with it.

 lib/sp-perf-counter.c |   43 ++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 42 insertions(+), 1 deletions(-)
---
diff --git a/lib/sp-perf-counter.c b/lib/sp-perf-counter.c
index f08039d..f2cdc59 100644
--- a/lib/sp-perf-counter.c
+++ b/lib/sp-perf-counter.c
@@ -503,6 +503,27 @@ get_authorized_proxy (void)
   return NULL;
 }
 
+static void
+sp_perf_counter_ping_cb (GObject      *object,
+                         GAsyncResult *result,
+                         gpointer      user_data)
+{
+  GDBusProxy *proxy = (GDBusProxy *)object;
+  g_autoptr(GTask) task = user_data;
+  g_autoptr(GVariant) ret = NULL;
+  GError *error = NULL;
+
+  g_assert (G_IS_DBUS_PROXY (proxy));
+  g_assert (G_IS_TASK (task));
+  g_assert (G_IS_ASYNC_RESULT (result));
+
+  ret = g_dbus_proxy_call_finish (proxy, result, &error);
+
+  if (error != NULL)
+    g_task_return_error (task, error);
+  else
+    g_task_return_boolean (task, TRUE);
+}
 
 static void
 sp_perf_counter_acquire_cb (GObject      *object,
@@ -511,6 +532,7 @@ sp_perf_counter_acquire_cb (GObject      *object,
 {
   g_autoptr(GTask) task = user_data;
   GPermission *permission = (GPermission *)object;
+  g_autoptr(GDBusProxy) proxy = NULL;
   GError *error = NULL;
 
   g_assert (G_IS_PERMISSION (permission));
@@ -523,7 +545,26 @@ sp_perf_counter_acquire_cb (GObject      *object,
       return;
     }
 
-  g_task_return_boolean (task, TRUE);
+  proxy = get_proxy ();
+
+  if (proxy == NULL)
+    {
+      /* We don't connect at startup, shouldn't happen */
+      g_task_return_new_error (task,
+                               G_IO_ERROR,
+                               G_IO_ERROR_FAILED,
+                               "Failed to create proxy");
+      return;
+    }
+
+  g_dbus_proxy_call (proxy,
+                     "org.freedesktop.DBus.Peer.Ping",
+                     NULL,
+                     G_DBUS_CALL_FLAGS_NONE,
+                     5000,
+                     g_task_get_cancellable (task),
+                     sp_perf_counter_ping_cb,
+                     g_object_ref (task));
 }
 
 static void