device: cache pointer to private-data in NMDevice structure

We often lookup the private data and retrieve it via NM_DEVICE_GET_PRIVATE(),
which in turn calls G_TYPE_INSTANCE_GET_PRIVATE().

Instead cache the pointer to the private data.

There are up- and downsides:

 - requries additional sizeof(gpointer) bytes for each NMDevice.
 + retrieving the private pointer will be slightly faster.
 + easier debugging in gdb as it is currently often a pain to
   retrieve the private data.

But most importantly, the allows to change our common pattern
to first cache the private data in a variable @priv. That is
often cumbersome to write, especially for short functions.
This change gives us a choice to use self->priv directly.

Such a change should not be aimed for every class. Instead it makes
mostly sense for NMDevice, where it pays off better due to the
class' size and ubiquitous use.

https://mail.gnome.org/archives/networkmanager-list/2015-December/msg00017.html

2 files changed, 12 insertions, 3 deletions

diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 1d31224bbc..3d4fb7b041 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -78,7 +78,7 @@ static void nm_device_start_ip_check (NMDevice *self);
 
 G_DEFINE_ABSTRACT_TYPE (NMDevice, nm_device, NM_TYPE_EXPORTED_OBJECT)
 
-#define NM_DEVICE_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NM_TYPE_DEVICE, NMDevicePrivate))
+#define NM_DEVICE_GET_PRIVATE(o) ((o)->priv)
 
 enum {
 	STATE_CHANGED,
@@ -190,7 +190,7 @@ typedef struct {
 	int ifindex;
 } DeleteOnDeactivateData;
 
-typedef struct {
+typedef struct _NMDevicePrivate {
 	gboolean in_state_changed;
 	gboolean initialized;
 	gboolean platform_link_initialized;
@@ -10033,7 +10033,11 @@ _activation_func_to_string (ActivationHandleFunc func)
 static void
 nm_device_init (NMDevice *self)
 {
-	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
+	NMDevicePrivate *priv;
+
+	priv = G_TYPE_INSTANCE_GET_PRIVATE (self, NM_TYPE_DEVICE, NMDevicePrivate);
+
+	self->priv = priv;
 
 	priv->type = NM_DEVICE_TYPE_UNKNOWN;
 	priv->capabilities = NM_DEVICE_CAP_NM_SUPPORTED;
diff --git a/src/devices/nm-device.h b/src/devices/nm-device.h
index 5d8104b428..45c7306459 100644
--- a/src/devices/nm-device.h
+++ b/src/devices/nm-device.h
@@ -110,8 +110,13 @@ typedef enum { /*< skip >*/
 	NM_DEVICE_CHECK_CON_AVAILABLE_ALL                                   = (((__NM_DEVICE_CHECK_CON_AVAILABLE_ALL - 1) << 1) - 1),
 } NMDeviceCheckConAvailableFlags;
 
+struct _NMDevicePrivate;
+
 struct _NMDevice {
 	NMExportedObject parent;
+
+	/* private */
+	struct _NMDevicePrivate *priv;
 };
 
 /* The flags have an relaxing meaning, that means, specifying more flags, can make