[Spice-devel] [PATCH 02/16] Replace RedCharDevice::on_free_self_token with a signal

[Jonathon Jongsma]

From: Christophe Fergeau <cfergeau at redhat.com>

It's more natural to do things this way with glib, and this allows to
remove some coupling between Reds and RedCharDeviceVDIPort. Before this
commit, the RedCharDeviceVDIPort has to provide a on_free_self_token()
because Reds needs to know about it. With a signal, RedCharDeviceVDIPort
does not have to do anything special, and Reds can just connect to the
signal it's interested in.
---
Frediano didn't like the signal approach. I think it's OK. Still needs resolution.

 server/char-device.c | 47 ++++++++++++++++++++++++++++++++++++-----------
 server/char-device.h |  4 ----
 server/reds.c        |  7 +++++--
 3 files changed, 41 insertions(+), 17 deletions(-)

diff --git a/server/char-device.c b/server/char-device.c
index ebe7633..f3e16da 100644
--- a/server/char-device.c
+++ b/server/char-device.c
@@ -94,6 +94,14 @@ enum {
     PROP_OPAQUE
 };
 
+enum {
+   RED_CHAR_DEVICE_SELF_TOKEN_CONSUMED,
+   RED_CHAR_DEVICE_SELF_TOKEN_RELEASED,
+   RED_CHAR_DEVICE_LAST_SIGNAL
+};
+
+static guint signals[RED_CHAR_DEVICE_LAST_SIGNAL];
+
 static void red_char_device_write_buffer_unref(RedCharDeviceWriteBuffer *write_buf);
 static void red_char_device_write_retry(void *opaque);
 
@@ -131,16 +139,6 @@ red_char_device_send_tokens_to_client(RedCharDevice *dev,
 }
 
 static void
-red_char_device_on_free_self_token(RedCharDevice *dev)
-{
-   RedCharDeviceClass *klass = RED_CHAR_DEVICE_GET_CLASS(dev);
-
-   if (klass->on_free_self_token != NULL) {
-       klass->on_free_self_token(dev->priv->opaque);
-   }
-}
-
-static void
 red_char_device_remove_client(RedCharDevice *dev, RedClient *client)
 {
    RedCharDeviceClass *klass = RED_CHAR_DEVICE_GET_CLASS(dev);
@@ -624,6 +622,9 @@ static RedCharDeviceWriteBuffer *__red_char_device_write_buffer_get(
         }
     } else if (origin == WRITE_BUFFER_ORIGIN_SERVER) {
         dev->priv->num_self_tokens--;
+        g_signal_emit(G_OBJECT(dev),
+                      signals[RED_CHAR_DEVICE_SELF_TOKEN_CONSUMED],
+                      0);
     }
 
     ret->token_price = migrated_data_tokens ? migrated_data_tokens : 1;
@@ -711,7 +712,9 @@ void red_char_device_write_buffer_release(RedCharDevice *dev,
         red_char_device_client_tokens_add(dev, dev_client, buf_token_price);
     } else if (buf_origin == WRITE_BUFFER_ORIGIN_SERVER) {
         dev->priv->num_self_tokens++;
-        red_char_device_on_free_self_token(dev);
+        g_signal_emit(G_OBJECT(dev),
+                      signals[RED_CHAR_DEVICE_SELF_TOKEN_RELEASED],
+                      0);
     }
 }
 
@@ -1215,6 +1218,28 @@ red_char_device_class_init(RedCharDeviceClass *klass)
                                                          "User data to pass to callbacks",
                                                       G_PARAM_STATIC_STRINGS |
                                                       G_PARAM_READWRITE));
+    signals[RED_CHAR_DEVICE_SELF_TOKEN_CONSUMED] =
+       g_signal_new("self-token-consumed",
+                    G_OBJECT_CLASS_TYPE(object_class),
+                    G_SIGNAL_RUN_FIRST,
+                    0, NULL, NULL,
+                    g_cclosure_marshal_VOID__VOID,
+                    G_TYPE_NONE,
+                    0);
+
+    /* FIXME: find a better name for the signal? It replaces a
+     * on_free_self_token vfunc whose description was:
+     * « The cb is called when a server (self) message that was addressed to the device,
+     *   has been completely written to it »
+     */
+    signals[RED_CHAR_DEVICE_SELF_TOKEN_RELEASED] =
+       g_signal_new("self-token-released",
+                    G_OBJECT_CLASS_TYPE(object_class),
+                    G_SIGNAL_RUN_FIRST,
+                    0, NULL, NULL,
+                    g_cclosure_marshal_VOID__VOID,
+                    G_TYPE_NONE,
+                    0);
 
 }
 
diff --git a/server/char-device.h b/server/char-device.h
index f793c54..c18ce66 100644
--- a/server/char-device.h
+++ b/server/char-device.h
@@ -67,10 +67,6 @@ struct RedCharDeviceClass
      * device */
     void (*send_tokens_to_client)(RedClient *client, uint32_t tokens, void *opaque);
 
-    /* The cb is called when a server (self) message that was addressed to the device,
-     * has been completely written to it */
-    void (*on_free_self_token)(void *opaque);
-
     /* This cb is called if it is recommanded that a client will be removed
      * due to slow flow or due to some other error.
      * The called instance should disconnect the client, or at least the corresponding channel */
diff --git a/server/reds.c b/server/reds.c
index 6e4fee4..7e5626a 100644
--- a/server/reds.c
+++ b/server/reds.c
@@ -876,7 +876,7 @@ static void vdi_port_send_tokens_to_client(RedClient *client, uint32_t tokens, v
                                           tokens);
 }
 
-static void vdi_port_on_free_self_token(void *opaque)
+static void vdi_port_on_free_self_token(RedCharDevice *device, gpointer opaque)
 {
     RedsState *reds = opaque;
 
@@ -3377,6 +3377,10 @@ static int do_spice_init(RedsState *reds, SpiceCoreInterface *core_interface)
     reds->listen_socket = -1;
     reds->secure_listen_socket = -1;
     reds->agent_dev = red_char_device_vdi_port_new(reds);
+    g_signal_connect(G_OBJECT(reds->agent_dev),
+                     "self-token-released",
+                     (GCallback)vdi_port_on_free_self_token,
+                     reds);
     ring_init(&reds->clients);
     reds->num_clients = 0;
     reds->main_dispatcher = main_dispatcher_new(reds, reds->core);
@@ -4322,7 +4326,6 @@ red_char_device_vdi_port_class_init(RedCharDeviceVDIPortClass *klass)
     char_dev_class->send_msg_to_client = vdi_port_send_msg_to_client;
     char_dev_class->send_tokens_to_client = vdi_port_send_tokens_to_client;
     char_dev_class->remove_client = vdi_port_remove_client;
-    char_dev_class->on_free_self_token = vdi_port_on_free_self_token;
 }
 
 static RedCharDeviceVDIPort *red_char_device_vdi_port_new(RedsState *reds)
-- 
2.4.11