看看GtkWindow如何被生出来的（gtk_window_new()的内部机制）

来源：互联网发布：大数据服务器搭建编辑：程序博客网时间：2024/04/29 18:36

http://blog.csdn.net/cuijpus/article/details/4245828

看看GtkWindow如何被生出来的.

用Glib/GObject/Gtk也有很长时间了，没有时间往下刨根，现在刨一刨。

1 定义GtkWindow

2 展开它：

在gtype.h中定义如下宏：

把定义的宏展开：

再把GtkBin的定义展开：

再展开GtkContainer的定义：//不用展开，直接定义的

GtkWidget的get_type()也是直接定义的

GtkObject的get_type()也是直接定义的：

看看GObject的定义：gtk_init()后，这个对象是已经建立了

3 在用的时候，是直接调用一个宏：

下面我们来跟着一下其流程：（步步跟踪其父类，如果父类还没有创建，则先创建父类）

Step 1: 程序会调用这个接口：

Step 2: 接着会调用 (层层上访)

Step 3:所要先看GtkObject的创立过程：

GtkObject对象存在了，那就看它的子类吧：GtkWidget

接着往下搞：GtkWidget对象也有了，在往下看子类：GtkContainer

Go on: GtkBin

GtkBin创建后，GtkWindow对象也就创建了；

这样一系列的对象存在如下：

上面仅仅是一些对象，那这些对象携带的回调函数都是从哪里调用的呢？

关键之处是g_object_new()里面调用的函数

重点看看g_object_newv：

g_type_class_ref这个就是核心：递归调用

上面的递归调用会调用函数type_class_init_Wm()完成对某个类的初始化，即，分配内存同时调用class_init()

Base_class_init()调用的顺序：

1. g_object_base_class_init

2 gtk_object_base_class_init

3 gtk_widget_base_class_init 是NULL所以不调用

4 gtk_container_base_class_init

5 gtk_bin, gtk_windonw的base_class_init()都是NULL

下面开始class_init:

class_init() 之前有个递归过程（图示）

下面用运行代码来检查实际的过程：

条件：

结果：

1 定义GtkWindow

G_DEFINE_TYPE_WITH_CODE (GtkWindow, gtk_window, GTK_TYPE_BIN,

G_IMPLEMENT_INTERFACE (GTK_TYPE_BUILDABLE,

gtk_window_buildable_interface_init))

2 展开它：

在gtype.h中定义如下宏：

#define G_DEFINE_TYPE_WITH_CODE(TN, t_n, T_P, _C_) _G_DEFINE_TYPE_EXTENDED_BEGIN (TN, t_n, T_P, 0) {_C_;} _G_DEFINE_TYPE_EXTENDED_END()

#define _G_DEFINE_TYPE_EXTENDED_BEGIN(TypeName, type_name, TYPE_PARENT, flags) /

static void type_name##_init (TypeName *self); /

static void type_name##_class_init (TypeName##Class *klass); /

static gpointer type_name##_parent_class = NULL; /

static void type_name##_class_intern_init (gpointer klass) /

{ /

type_name##_parent_class = g_type_class_peek_parent (klass); /

type_name##_class_init ((TypeName##Class*) klass); /

} /

GType /

type_name##_get_type (void) /

{ /

static volatile gsize g_define_type_id__volatile = 0; /

if (g_once_init_enter (&g_define_type_id__volatile)) /

{ /

GType g_define_type_id = /

g_type_register_static_simple (TYPE_PARENT, /

g_intern_static_string (#TypeName), /

sizeof (TypeName##Class), /

(GClassInitFunc) type_name##_class_intern_init, /

sizeof (TypeName), /

(GInstanceInitFunc) type_name##_init, /

(GTypeFlags) flags); /

{ /* custom code follows */

#define _G_DEFINE_TYPE_EXTENDED_END() /

/* following custom code */ /

} /

g_once_init_leave (&g_define_type_id__volatile, g_define_type_id); /

} /

return g_define_type_id__volatile; /

} /* closes type_name##_get_type() */

把定义的宏展开：

static void gtk_window_init (GtkWindow *self);

static void gtk_window_class_init (GtkWindowClass * klass);

static void gtk_window_parent_class = NULL;

static void gtk_window_class_intern_init (gpointer klass)

{

gtk_window_parent_class = g_type_class_peek_parent (klass);

gtk_window_class_init ((GtkWindowClass*) klass);

}

GType

gtk_window_get_type (void)

{

static volatile gsize g_define_type_id__volatile = 0;

if (g_once_init_enter (&g_define_type_id__volatile))

{

GType g_define_type_id =

g_type_register_static_simple (GTK_TYPE_BIN, //父亲

g_intern_static_string ("GtkWindow"),

sizeof (GtkWindowClass),

(GClassInitFunc) gtk_window_class_intern_init,

sizeof (GtkWindow),

(GInstanceInitFunc) gtk_window_init,

0);

{

const GInterfaceInfo g_implement_interface = {

(GInterfaceInitFunc) gtk_window_buildable_interface_init, NULL, NULL };

g_type_add_interface_static (g_define_type_id, GTK_TYPE_BUILDABLE, &g_implement_interface);

}

g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);

}

return g_define_type_id__volatile;

}

再把GtkBin的定义展开：

G_DEFINE_ABSTRACT_TYPE (GtkBin, gtk_bin, GTK_TYPE_CONTAINER)

static void gtk_bin_init (GtkBin *self);

static void gtk_bin_class_init (GtkBinClass * klass);

static void gtk_bin_parent_class = NULL;

static void gtk_bin_class_intern_init (gpointer klass)

{

gtk_bin_parent_class = g_type_class_peek_parent (klass);

gtk_bin_class_init ((GtkBinClass*) klass);

}

GType

gtk_bin_get_type(void)

{

static volatile gsize g_define_type_id__volatile = 0;

if (g_once_init_enter (&g_define_type_id__volatile))

{

GType g_define_type_id =

g_type_register_static_simple (GTK_TYPE_CONTAINER, //GtkBin的父亲

g_intern_static_string ("GtkBin"),

sizeof (GtkBinClass),

(GClassInitFunc) gtk_bin_class_intern_init,

sizeof (GtkBin),

(GInstanceInitFunc) gtk_bin_init,

G_TYPE_FLAG_ABSTRACT);

{

}

g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);

}

return g_define_type_id__volatile;

}

再展开GtkContainer的定义：//不用展开，直接定义的

#define GTK_TYPE_CONTAINER (gtk_container_get_type ())

/* --- functions --- */

GType

gtk_container_get_type (void)

{

static GType container_type = 0;

if (!container_type)

{

const GTypeInfo container_info =

{

sizeof (GtkContainerClass),

(GBaseInitFunc) gtk_container_base_class_init,

(GBaseFinalizeFunc) gtk_container_base_class_finalize,

(GClassInitFunc) gtk_container_class_init,

NULL /* class_finalize */,

NULL /* class_data */,

sizeof (GtkContainer),

0 /* n_preallocs */,

(GInstanceInitFunc) gtk_container_init,

NULL, /* value_table */

};

static const GInterfaceInfo buildable_info =

{

(GInterfaceInitFunc) gtk_container_buildable_init,

NULL,

NULL

};

container_type =

g_type_register_static (GTK_TYPE_WIDGET, //GtkContainer的父亲

I_("GtkContainer"),

&container_info, G_TYPE_FLAG_ABSTRACT);

g_type_add_interface_static (container_type,

GTK_TYPE_BUILDABLE,

&buildable_info);

}

return container_type;

}

GtkWidget的get_type()也是直接定义的

/* --- functions --- */

GType

gtk_widget_get_type (void)

{

static GType widget_type = 0;

if (G_UNLIKELY (widget_type == 0))

{

const GTypeInfo widget_info =

{

sizeof (GtkWidgetClass),

NULL, /* base_init */

(GBaseFinalizeFunc) gtk_widget_base_class_finalize,

(GClassInitFunc) gtk_widget_class_init,

NULL, /* class_finalize */

NULL, /* class_init */

sizeof (GtkWidget),

0, /* n_preallocs */

(GInstanceInitFunc) gtk_widget_init,

NULL, /* value_table */

};

const GInterfaceInfo accessibility_info =

{

(GInterfaceInitFunc) gtk_widget_accessible_interface_init,

(GInterfaceFinalizeFunc) NULL,

NULL /* interface data */

};

const GInterfaceInfo buildable_info =

{

(GInterfaceInitFunc) gtk_widget_buildable_interface_init,

(GInterfaceFinalizeFunc) NULL,

NULL /* interface data */

};

widget_type = g_type_register_static (GTK_TYPE_OBJECT, //GtkWidget的父亲

"GtkWidget",

&widget_info, G_TYPE_FLAG_ABSTRACT);

g_type_add_interface_static (widget_type, ATK_TYPE_IMPLEMENTOR,

&accessibility_info) ;

g_type_add_interface_static (widget_type, GTK_TYPE_BUILDABLE,

&buildable_info) ;

}

return widget_type;

}

GtkObject的get_type()也是直接定义的：

#define GTK_TYPE_OBJECT (gtk_object_get_type ())

GType

gtk_object_get_type (void)

{

static GType object_type = 0;

if (!object_type)

{

const GTypeInfo object_info =

{

sizeof (GtkObjectClass),

(GBaseInitFunc) gtk_object_base_class_init,

(GBaseFinalizeFunc) gtk_object_base_class_finalize,

(GClassInitFunc) gtk_object_class_init,

NULL, /* class_finalize */

NULL, /* class_data */

sizeof (GtkObject),

16, /* n_preallocs */

(GInstanceInitFunc) gtk_object_init,

NULL, /* value_table */

};

object_type = g_type_register_static

(G_TYPE_INITIALLY_UNOWNED, //GtkObject的父亲，就是GObject

I_("GtkObject"),

&object_info, G_TYPE_FLAG_ABSTRACT);

}

return object_type;

}

看看GObject的定义：gtk_init()后，这个对象是已经建立了

GType

g_object_get_type (void)

{

return G_TYPE_OBJECT;

}

//GObject的回调函数什么时候被调用的?

3 在用的时候，是直接调用一个宏：

#define GTK_TYPE_WINDOW (gtk_window_get_type ())

下面我们来跟着一下其流程：（步步跟踪其父类，如果父类还没有创建，则先创建父类）

Step 1: 程序会调用这个接口：

GtkWidget* gtk_window_new (GtkWindowType type);

这个函数内部会调用

window = g_object_new (GTK_TYPE_WINDOW, NULL);

Step 2: 接着会调用 (层层上访)

GType

gtk_window_get_type (void)

//这个函数内部又会找GtkWindows的父类：GtkBin

GtkBin又找其父类GtkContainer,

GtkContainer又找其父类GtkWidget

GtkWidget又找其父类GtkObject

GtkObject又找其父类Gobject，这个类在gtk_init()后，就已经存在了；

所以在反过来进行

Step 3:所要先看GtkObject的创立过程：

GType

gtk_object_get_type (void)

{

static GType object_type = 0;

if (!object_type)

{

const GTypeInfo object_info =

{

sizeof (GtkObjectClass),

(GBaseInitFunc) gtk_object_base_class_init,

(GBaseFinalizeFunc) gtk_object_base_class_finalize,

(GClassInitFunc) gtk_object_class_init,

NULL, /* class_finalize */

NULL, /* class_data */

sizeof (GtkObject),

16, /* n_preallocs */

(GInstanceInitFunc) gtk_object_init,

NULL, /* value_table */

};

//g_type_register_static就从GObject派生出来一个类GtkObject，并填充好以后，放到全局的数组中，以及Hash Table中，具体如下：

//这个函数首先干的事情：检查名字是否合法以及在当前的Hash Table中是不是已经有了？然后再检查和指定的父类之间是否真的具有继承关系

//如果可以注册，

//如果父类不存在，直接放到全局数组中，则先在static_fundamental_type_nodes[]数组中找个位置，来存放这个类型节点指针

//如果父类存在，则从父类拷贝一份内存出来，作为子类，主要在type_node_any_new_W（）中完成，并且把这个新的子类放到父类的一个子类数组中

// 然后把新类放到Hash Table中，这样方便查询

// 然后给类型数据填充一些字段，主要是注册一些回调函数，由type_data_make_W（）来完成

//同时把ref_count置为1，表明这个对象活了！

object_type = g_type_register_static (G_TYPE_INITIALLY_UNOWNED, I_("GtkObject"),

&object_info, G_TYPE_FLAG_ABSTRACT);

}

return object_type;

}

//还有问题没有搞明白，注册的系列回调，何时调用的？

GtkObject对象存在了，那就看它的子类吧：GtkWidget

/* --- functions --- */

GType

gtk_widget_get_type (void)

{

static GType widget_type = 0;

if (G_UNLIKELY (widget_type == 0))

{

const GTypeInfo widget_info =

{

sizeof (GtkWidgetClass),

NULL, /* base_init */

(GBaseFinalizeFunc) gtk_widget_base_class_finalize,

(GClassInitFunc) gtk_widget_class_init,

NULL, /* class_finalize */

NULL, /* class_init */

sizeof (GtkWidget),

0, /* n_preallocs */

(GInstanceInitFunc) gtk_widget_init,

NULL, /* value_table */

};

const GInterfaceInfo accessibility_info =

{

(GInterfaceInitFunc) gtk_widget_accessible_interface_init,

(GInterfaceFinalizeFunc) NULL,

NULL /* interface data */

};

const GInterfaceInfo buildable_info =

{

(GInterfaceInitFunc) gtk_widget_buildable_interface_init,

(GInterfaceFinalizeFunc) NULL,

NULL /* interface data */

};

//也是从GtkObject对象做一个内存拷贝，然后填充数据（注册回调），新创建的对象GtkWidget地址存放于GtkObject维护的一个子类列表里面；当然了，在Hash Table里面也是有的；

widget_type = g_type_register_static (GTK_TYPE_OBJECT, "GtkWidget",

&widget_info, G_TYPE_FLAG_ABSTRACT);

g_type_add_interface_static (widget_type, ATK_TYPE_IMPLEMENTOR,

&accessibility_info) ;

g_type_add_interface_static (widget_type, GTK_TYPE_BUILDABLE,

&buildable_info) ;

}

return widget_type;

}

接着往下搞：GtkWidget对象也有了，在往下看子类：GtkContainer

/* --- functions --- */

GType

gtk_container_get_type (void)

{

static GType container_type = 0;

if (!container_type)

{

const GTypeInfo container_info =

{

sizeof (GtkContainerClass),

(GBaseInitFunc) gtk_container_base_class_init,

(GBaseFinalizeFunc) gtk_container_base_class_finalize,

(GClassInitFunc) gtk_container_class_init,

NULL /* class_finalize */,

NULL /* class_data */,

sizeof (GtkContainer),

0 /* n_preallocs */,

(GInstanceInitFunc) gtk_container_init,

NULL, /* value_table */

};

static const GInterfaceInfo buildable_info =

{

(GInterfaceInitFunc) gtk_container_buildable_init,

NULL,

NULL

};

//也是从GtkWidget对象做一个内存拷贝，然后填充数据（注册回调），新创建的对象GtkContainer地址存放于GtkWidget维护的一个子类列表里面；当然了，在Hash Table里面也是有的；

container_type =

g_type_register_static (GTK_TYPE_WIDGET, I_("GtkContainer"),

&container_info, G_TYPE_FLAG_ABSTRACT);

g_type_add_interface_static (container_type,

GTK_TYPE_BUILDABLE,

&buildable_info);

}

return container_type;

}

Go on: GtkBin

static void gtk_bin_init (GtkBin *self);

static void gtk_bin_class_init (GtkBinClass * klass);

static void gtk_bin_parent_class = NULL;

static void gtk_bin_class_intern_init (gpointer klass)

{

gtk_bin_parent_class = g_type_class_peek_parent (klass);

gtk_bin_class_init ((GtkBinClass*) klass);

}

GType

gtk_bin_get_type(void)

{

static volatile gsize g_define_type_id__volatile = 0;

if (g_once_init_enter (&g_define_type_id__volatile))

{

GType g_define_type_id =

g_type_register_static_simple (GTK_TYPE_CONTAINER,

g_intern_static_string ("GtkBin"),

sizeof (GtkBinClass),

(GClassInitFunc) gtk_bin_class_intern_init,

sizeof (GtkBin),

(GInstanceInitFunc) gtk_bin_init,

G_TYPE_FLAG_ABSTRACT);

{

}

g_once_init_leave (&g_define_type_id__volatile, g_define_type_id);

}

return g_define_type_id__volatile;

}

GtkBin创建后，GtkWindow对象也就创建了；

这样一系列的对象存在如下：

| `GtkObject

| |

| `GtkWidget

| |

| `GtkContainer

| |

| +GtkBin

| | |

| | +GtkWindow

对象的出生过程：老子先出生，然后是儿子，然后是孙子…; 自然界的规律

不过这里是先提出要孙子，谁提呢？如来佛吧！

然后如来就查查这个人的父亲是谁？已经出生了吗？没有再往上找；…

这些对象都有些本领(回调函数)，一般情况下，也是先把老子的钱榨干，然后用儿子的，然后用…

上面仅仅是一些对象，那这些对象携带的回调函数都是从哪里调用的呢？

关键之处是g_object_new()里面调用的函数

要仔细的分析！

window = g_object_new (GTK_TYPE_WINDOW, NULL);

重点看看g_object_newv：

gpointer

g_object_newv (GType object_type,

guint n_parameters,

GParameter *parameters)

{

GObjectConstructParam *cparams, *oparams;

GObjectNotifyQueue *nqueue = NULL; /* shouldn't be initialized, just to silence compiler */

GObject *object;

GObjectClass *class, *unref_class = NULL;

GSList *slist;

guint n_total_cparams = 0, n_cparams = 0, n_oparams = 0, n_cvalues;

GValue *cvalues;

GList *clist = NULL;

gboolean newly_constructed;

guint i;

g_return_val_if_fail (G_TYPE_IS_OBJECT (object_type), NULL);

class = g_type_class_peek_static (object_type);

if (!class)

class = unref_class = g_type_class_ref (object_type);

for (slist = class->construct_properties; slist; slist = slist->next)

{

clist = g_list_prepend (clist, slist->data);

n_total_cparams += 1;

}

/* collect parameters, sort into construction and normal ones */

oparams = g_new (GObjectConstructParam, n_parameters);

cparams = g_new (GObjectConstructParam, n_total_cparams);

for (i = 0; i < n_parameters; i++)

{

GValue *value = &parameters[i].value;

GParamSpec *pspec = g_param_spec_pool_lookup (pspec_pool,

parameters[i].name,

object_type,

TRUE);

if (!pspec)

{

g_warning ("%s: object class `%s' has no property named `%s'",

G_STRFUNC,

g_type_name (object_type),

parameters[i].name);

continue;

}

if (!(pspec->flags & G_PARAM_WRITABLE))

{

g_warning ("%s: property `%s' of object class `%s' is not writable",

G_STRFUNC,

pspec->name,

g_type_name (object_type));

continue;

}

if (pspec->flags & (G_PARAM_CONSTRUCT | G_PARAM_CONSTRUCT_ONLY))

{

GList *list = g_list_find (clist, pspec);

if (!list)

{

g_warning ("%s: construct property /"%s/" for object `%s' can't be set twice",

G_STRFUNC, pspec->name, g_type_name (object_type));

continue;

}

cparams[n_cparams].pspec = pspec;

cparams[n_cparams].value = value;

n_cparams++;

if (!list->prev)

clist = list->next;

else

list->prev->next = list->next;

if (list->next)

list->next->prev = list->prev;

g_list_free_1 (list);

}

else

{

oparams[n_oparams].pspec = pspec;

oparams[n_oparams].value = value;

n_oparams++;

}

/* set remaining construction properties to default values */

n_cvalues = n_total_cparams - n_cparams;

cvalues = g_new (GValue, n_cvalues);

while (clist)

{

GList *tmp = clist->next;

GParamSpec *pspec = clist->data;

GValue *value = cvalues + n_total_cparams - n_cparams - 1;

value->g_type = 0;

g_value_init (value, G_PARAM_SPEC_VALUE_TYPE (pspec));

g_param_value_set_default (pspec, value);

cparams[n_cparams].pspec = pspec;

cparams[n_cparams].value = value;

n_cparams++;

g_list_free_1 (clist);

clist = tmp;

}

/* construct object from construction parameters */

object = class->constructor (object_type, n_total_cparams, cparams);

/* free construction values */

g_free (cparams);

while (n_cvalues--)

g_value_unset (cvalues + n_cvalues);

g_free (cvalues);

/* adjust freeze_count according to g_object_init() and remaining properties */

G_LOCK (construction_mutex);

newly_constructed = slist_maybe_remove (&construction_objects, object);

G_UNLOCK (construction_mutex);

if (newly_constructed || n_oparams)

nqueue = g_object_notify_queue_freeze (object, &property_notify_context);

if (newly_constructed)

g_object_notify_queue_thaw (object, nqueue);

/* run 'constructed' handler if there is one */

if (newly_constructed && class->constructed)

class->constructed (object);

/* set remaining properties */

for (i = 0; i < n_oparams; i++)

object_set_property (object, oparams[i].pspec, oparams[i].value, nqueue);

g_free (oparams);

/* release our own freeze count and handle notifications */

if (newly_constructed || n_oparams)

g_object_notify_queue_thaw (object, nqueue);

if (unref_class)

g_type_class_unref (unref_class);

return object;

}

g_type_class_ref这个就是核心：递归调用

gpointer

g_type_class_ref (GType type)

{

TypeNode *node;

GType ptype;

/* optimize for common code path */

G_WRITE_LOCK (&type_rw_lock);

//如果当前类型对应的节点数据已经存在了，并且也别初始化过，则紧紧增加一个ref_count，然后返回。

node = lookup_type_node_I (type);

if (node && node->is_classed && node->data &&

node->data->class.class &&

node->data->class.init_state == INITIALIZED)

{

type_data_ref_Wm (node);

G_WRITE_UNLOCK (&type_rw_lock);

return node->data->class.class;

}

if (!node || !node->is_classed ||

(node->data && node->data->common.ref_count < 1))

{

G_WRITE_UNLOCK (&type_rw_lock);

g_warning ("cannot retrieve class for invalid (unclassed) type `%s'",

type_descriptive_name_I (type));

return NULL;

}

//给当前节点分配内存等

type_data_ref_Wm (node);

//找到其父节点

ptype = NODE_PARENT_TYPE (node);

G_WRITE_UNLOCK (&type_rw_lock);

g_static_rec_mutex_lock (&class_init_rec_mutex); /* required locking order: 1) class_init_rec_mutex, 2) type_rw_lock */

/* here, we either have node->data->class.class == NULL, or a recursive

* call to g_type_class_ref() with a partly initialized class, or

* node->data->class.init_state == INITIALIZED, because any

* concurrently running initialization was guarded by class_init_rec_mutex.

if (!node->data->class.class) /* class uninitialized */

{

/* acquire reference on parent class */

//这个地方是最重要的，会一直找到最上面的基类

GtkWindow-> GtkBin -> GtkContainer ->GtkWidget->GtkObject

GTypeClass *pclass = ptype ? g_type_class_ref (ptype) : NULL;

G_WRITE_LOCK (&type_rw_lock);

if (node->data->class.class) /* class was initialized during parent class initialization? */

INVALID_RECURSION ("g_type_plugin_*", node->plugin, NODE_NAME (node));

//当上面的递归调用入口的边界条件(ptype == NULL, 即发现GObject没有父类后，就会，就不会再次调用g_type_class_ref了，这时候函数调用堆栈就会返回就从最后一个g_type_class_ref开始往下执行了，此时是GObject, 所以会从类的顶层开始调用其Class_init(); 这样就实现了从父类，到子类，再到孙子类的class_init()的过程。比较巧妙。

type_class_init_Wm (node, pclass);

G_WRITE_UNLOCK (&type_rw_lock);

}

g_static_rec_mutex_unlock (&class_init_rec_mutex);

return node->data->class.class;

}

上面的递归调用会调用函数type_class_init_Wm()完成对某个类的初始化，即，分配内存同时调用class_init()

static void

type_class_init_Wm (TypeNode *node,

GTypeClass *pclass)

{

GSList *slist, *init_slist = NULL;

GTypeClass *class;

IFaceEntry *entry;

TypeNode *bnode, *pnode;

guint i;

g_assert (node->is_classed && node->data &&

node->data->class.class_size &&

!node->data->class.class &&

node->data->class.init_state == UNINITIALIZED);

class = g_malloc0 (node->data->class.class_size);

node->data->class.class = class;

node->data->class.init_state = BASE_CLASS_INIT;

if (pclass)

{

//找到GObjectClass对应的节点

TypeNode *pnode = lookup_type_node_I (pclass->g_type);

//拷贝给子类GtkWidgetClass, 这就是继承？

memcpy (class, pclass, pnode->data->class.class_size);

if (node->is_instantiatable)

{

/* We need to initialize the private_size here rather than in

* type_data_make_W() since the class init for the parent

* class may have changed pnode->data->instance.private_size.

node->data->instance.private_size = pnode->data->instance.private_size;

}

class->g_type = NODE_TYPE (node);

G_WRITE_UNLOCK (&type_rw_lock);

/* stack all base class initialization functions, so we

* call them in ascending order.

//这个遍历是从GtkWindow-> GtkBin -> GtkContainer ->GtkWidget->GtkObject->GObject ，即从子到父亲的顺序;

//而列举出的base_class_init()函数的列表正好是反的：

GObject::class_init_base() à GtkObject::class_init_base()à GtkWidget::class_init_base()àGtkContainer::class_init_base()à GtkBin::class_init_base()à GtkWidow::class_init_base()

//所以首先会调用基类的base_class_init()函数，然后依次进行下去

for (bnode = node; bnode; bnode = lookup_type_node_I (NODE_PARENT_TYPE (bnode)))

if (bnode->data->class.class_init_base)

init_slist = g_slist_prepend (init_slist, (gpointer) bnode->data->class.class_init_base);

for (slist = init_slist; slist; slist = slist->next)

{

GBaseInitFunc class_init_base = (GBaseInitFunc) slist->data;

class_init_base (class);

}

g_slist_free (init_slist);

G_WRITE_LOCK (&type_rw_lock);

node->data->class.init_state = BASE_IFACE_INIT;

/* Before we initialize the class, base initialize all interfaces, either

* from parent, or through our holder info

pnode = lookup_type_node_I (NODE_PARENT_TYPE (node));

i = 0;

while (i < CLASSED_NODE_N_IFACES (node))

{

entry = &CLASSED_NODE_IFACES_ENTRIES (node)[i];

while (i < CLASSED_NODE_N_IFACES (node) &&

entry->init_state == IFACE_INIT)

{

entry++;

i++;

}

if (i == CLASSED_NODE_N_IFACES (node))

break;

if (!type_iface_vtable_base_init_Wm (lookup_type_node_I (entry->iface_type), node))

{

guint j;

/* need to get this interface from parent, type_iface_vtable_base_init_Wm()

* doesn't modify write lock upon FALSE, so entry is still valid;

g_assert (pnode != NULL);

for (j = 0; j < CLASSED_NODE_N_IFACES (pnode); j++)

{

IFaceEntry *pentry = CLASSED_NODE_IFACES_ENTRIES (pnode) + j;

if (pentry->iface_type == entry->iface_type)

{

entry->vtable = pentry->vtable;

entry->init_state = INITIALIZED;

break;

}

g_assert (entry->vtable != NULL);

}

/* If the write lock was released, additional interface entries might

* have been inserted into CLASSED_NODE_IFACES_ENTRIES (node); they'll

* be base-initialized when inserted, so we don't have to worry that

* we might miss them. Uninitialized entries can only be moved higher

* when new ones are inserted.

i++;

}

node->data->class.init_state = CLASS_INIT;

G_WRITE_UNLOCK (&type_rw_lock);

//这句话非常重要，开始class_init的过程了！！！

//从gtk_window_class_init()开始？

if (node->data->class.class_init)

node->data->class.class_init (class, (gpointer) node->data->class.class_data);

G_WRITE_LOCK (&type_rw_lock);

node->data->class.init_state = IFACE_INIT;

/* finish initializing the interfaces through our holder info.

* inherited interfaces are already init_state == INITIALIZED, because

* they either got setup in the above base_init loop, or during

* class_init from within type_add_interface_Wm() for this or

* an anchestor type.

i = 0;

while (TRUE)

{

entry = &CLASSED_NODE_IFACES_ENTRIES (node)[i];

while (i < CLASSED_NODE_N_IFACES (node) &&

entry->init_state == INITIALIZED)

{

entry++;

i++;

}

if (i == CLASSED_NODE_N_IFACES (node))

break;

type_iface_vtable_iface_init_Wm (lookup_type_node_I (entry->iface_type), node);

/* As in the loop above, additional initialized entries might be inserted

* if the write lock is released, but that's harmless because the entries

* we need to initialize only move higher in the list.

i++;

}

node->data->class.init_state = INITIALIZED;

}

Base_class_init()调用的顺序：

1. g_object_base_class_init

static void

g_object_base_class_init (GObjectClass *class)

{

GObjectClass *pclass = g_type_class_peek_parent (class);

/* reset instance specific fields and methods that don't get inherited */

class->construct_properties = pclass ? g_slist_copy (pclass->construct_properties) : NULL;

class->get_property = NULL;

class->set_property = NULL;

}

2 gtk_object_base_class_init

static void

gtk_object_base_class_init (GtkObjectClass *class)

{

/* reset instance specifc methods that don't get inherited */

class->get_arg = NULL;

class->set_arg = NULL;

}

3 gtk_widget_base_class_init 是NULL所以不调用

4 gtk_container_base_class_init

static void

gtk_container_base_class_init (GtkContainerClass *class)

{

/* reset instance specifc class fields that don't get inherited */

class->set_child_property = NULL;

class->get_child_property = NULL;

}

5 gtk_bin, gtk_windonw的base_class_init()都是NULL

下面开始class_init:

class_init() 之前有个递归过程（图示）

GtkWindow

g_type_class_ref

GtkBin

g_type_class_ref

GtkContainer

g_type_class_ref

GtkWidget

g_type_class_ref

GtkObject

g_type_class_ref

GObject

g_type_class_ref

class_init

注意：如果某个类在递归过程中检查是已经被初始化过的类，则跳过其class_init()函数。

下面用运行代码来检查实际的过程：

条件：

g_type_init();

GtkWidget *window =gtk_window_new(GTK_WINDOW_TOPLEVEL);

结果：

GObject: g_type_name (object_type) : GtkWindow

GObject: class == NULL.

GType: enter g_type_class_ref() times = 1.

GType: current type: GtkWindow

GType: type_data_ref_Wm(GtkWindow).

GType: find current type's GtkWindow parent: GtkBin.

GType: enter g_type_class_ref() times = 2.

GType: current type: GtkBin

GType: type_data_ref_Wm(GtkBin).

GType: find current type's GtkBin parent: GtkContainer.

GType: enter g_type_class_ref() times = 3.

GType: current type: GtkContainer

GType: type_data_ref_Wm(GtkContainer).

GType: find current type's GtkContainer parent: GtkWidget.

GType: enter g_type_class_ref() times = 4.

GType: current type: GtkWidget

GType: type_data_ref_Wm(GtkWidget).

GType: find current type's GtkWidget parent: GtkObject.

GType: enter g_type_class_ref() times = 5.

GType: current type: GtkObject

GType: type_data_ref_Wm(GtkObject).

GType: find current type's GtkObject parent: GInitiallyUnowned.

GType: enter g_type_class_ref() times = 6.

GType: current type: GInitiallyUnowned

GType: type_data_ref_Wm(GInitiallyUnowned).

GType: find current type's GInitiallyUnowned parent: GObject.

GType: enter g_type_class_ref() times = 7.

GType: current type: GObject

GType: type_data_ref_Wm(GObject).

GType: find current type's GObject parent: (null).

GType: Node name: GObject.

GType: Node name: GInitiallyUnowned.

GType: Node name: GtkObject.

GType: enter g_type_class_ref() times = 8.

GType: current type: GObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 9.

GType: current type: GParamPointer

GType: type_data_ref_Wm(GParamPointer).

GType: find current type's GParamPointer parent: GParam.

GType: enter g_type_class_ref() times = 10.

GType: current type: GParam

GType: type_data_ref_Wm(GParam).

GType: find current type's GParam parent: (null).

GType: Node name: GParam.

GType: Node name: GParamPointer.

GType: Node name: GtkWidget.

GType: enter g_type_class_ref() times = 11.

GType: current type: GParamString

GType: type_data_ref_Wm(GParamString).

GType: find current type's GParamString parent: GParam.

GType: enter g_type_class_ref() times = 12.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamString.

GType: enter g_type_class_ref() times = 13.

GType: current type: GParamObject

GType: type_data_ref_Wm(GParamObject).

GType: find current type's GParamObject parent: GParam.

GType: enter g_type_class_ref() times = 14.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamObject.

GType: enter g_type_class_ref() times = 15.

GType: current type: GParamInt

GType: type_data_ref_Wm(GParamInt).

GType: find current type's GParamInt parent: GParam.

GType: enter g_type_class_ref() times = 16.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamInt.

GType: enter g_type_class_ref() times = 17.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 18.

GType: current type: GParamBoolean

GType: type_data_ref_Wm(GParamBoolean).

GType: find current type's GParamBoolean parent: GParam.

GType: enter g_type_class_ref() times = 19.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamBoolean.

GType: enter g_type_class_ref() times = 20.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 21.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 22.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 23.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 24.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 25.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 26.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 27.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 28.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 29.

GType: current type: GParamObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 30.

GType: current type: GdkEventMask

GType: type_data_ref_Wm(GdkEventMask).

GType: find current type's GdkEventMask parent: GFlags.

GType: enter g_type_class_ref() times = 31.

GType: current type: GFlags

GType: type_data_ref_Wm(GFlags).

GType: find current type's GFlags parent: (null).

GType: Node name: GFlags.

GType: Node name: GdkEventMask.

GType: enter g_type_class_ref() times = 32.

GType: current type: GParamFlags

GType: type_data_ref_Wm(GParamFlags).

GType: find current type's GParamFlags parent: GParam.

GType: enter g_type_class_ref() times = 33.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamFlags.

GType: enter g_type_class_ref() times = 34.

GType: current type: GdkExtensionMode

GType: type_data_ref_Wm(GdkExtensionMode).

GType: find current type's GdkExtensionMode parent: GEnum.

GType: enter g_type_class_ref() times = 35.

GType: current type: GEnum

GType: type_data_ref_Wm(GEnum).

GType: find current type's GEnum parent: (null).

GType: Node name: GEnum.

GType: Node name: GdkExtensionMode.

GType: enter g_type_class_ref() times = 36.

GType: current type: GParamEnum

GType: type_data_ref_Wm(GParamEnum).

GType: find current type's GParamEnum parent: GParam.

GType: enter g_type_class_ref() times = 37.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamEnum.

GType: enter g_type_class_ref() times = 38.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 39.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 40.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 41.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 42.

GType: current type: GParamObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 43.

GType: current type: GtkTouchSoundType

GType: type_data_ref_Wm(GtkTouchSoundType).

GType: find current type's GtkTouchSoundType parent: GEnum.

GType: enter g_type_class_ref() times = 44.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GtkTouchSoundType.

GType: enter g_type_class_ref() times = 45.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 46.

GType: current type: GtkSvibeEffectType

GType: type_data_ref_Wm(GtkSvibeEffectType).

GType: find current type's GtkSvibeEffectType parent: GEnum.

GType: enter g_type_class_ref() times = 47.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GtkSvibeEffectType.

GType: enter g_type_class_ref() times = 48.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 49.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 50.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 51.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 52.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 53.

GType: current type: GParamBoxed

GType: type_data_ref_Wm(GParamBoxed).

GType: find current type's GParamBoxed parent: GParam.

GType: enter g_type_class_ref() times = 54.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamBoxed.

GType: enter g_type_class_ref() times = 55.

GType: current type: GParamBoxed

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 56.

GType: current type: GParamFloat

GType: type_data_ref_Wm(GParamFloat).

GType: find current type's GParamFloat parent: GParam.

GType: enter g_type_class_ref() times = 57.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamFloat.

GType: enter g_type_class_ref() times = 58.

GType: current type: GParamBoxed

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 59.

GType: current type: GParamBoxed

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 60.

GType: current type: GParamBoxed

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 61.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 62.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 63.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 64.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 65.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 66.

GType: current type: GParamString

GType: current type already exist. return.

GType: Node name: GtkContainer.

GType: enter g_type_class_ref() times = 67.

GType: current type: GtkResizeMode

GType: type_data_ref_Wm(GtkResizeMode).

GType: find current type's GtkResizeMode parent: GEnum.

GType: enter g_type_class_ref() times = 68.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GtkResizeMode.

GType: enter g_type_class_ref() times = 69.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 70.

GType: current type: GParamUInt

GType: type_data_ref_Wm(GParamUInt).

GType: find current type's GParamUInt parent: GParam.

GType: enter g_type_class_ref() times = 71.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamUInt.

GType: enter g_type_class_ref() times = 72.

GType: current type: GParamObject

GType: current type already exist. return.

GType: Node name: GtkBin.

GType: Node name: GtkWindow.

GType: enter g_type_class_ref() times = 73.

GType: current type: GtkWindowType

GType: type_data_ref_Wm(GtkWindowType).

GType: find current type's GtkWindowType parent: GEnum.

GType: enter g_type_class_ref() times = 74.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GtkWindowType.

GType: enter g_type_class_ref() times = 75.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 76.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 77.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 78.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 79.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 80.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 81.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 82.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 83.

GType: current type: GtkWindowPosition

GType: type_data_ref_Wm(GtkWindowPosition).

GType: find current type's GtkWindowPosition parent: GEnum.

GType: enter g_type_class_ref() times = 84.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GtkWindowPosition.

GType: enter g_type_class_ref() times = 85.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 86.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 87.

GType: current type: GParamInt

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 88.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 89.

GType: current type: GParamObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 90.

GType: current type: GParamString

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 91.

GType: current type: GParamObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 92.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 93.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 94.

GType: current type: GdkWindowTypeHint

GType: type_data_ref_Wm(GdkWindowTypeHint).

GType: find current type's GdkWindowTypeHint parent: GEnum.

GType: enter g_type_class_ref() times = 95.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GdkWindowTypeHint.

GType: enter g_type_class_ref() times = 96.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 97.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 98.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 99.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 100.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 101.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 102.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 103.

GType: current type: GParamBoolean

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 104.

GType: current type: GdkGravity

GType: type_data_ref_Wm(GdkGravity).

GType: find current type's GdkGravity parent: GEnum.

GType: enter g_type_class_ref() times = 105.

GType: current type: GEnum

GType: current type already exist. return.

GType: Node name: GdkGravity.

GType: enter g_type_class_ref() times = 106.

GType: current type: GParamEnum

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 107.

GType: current type: GParamObject

GType: current type already exist. return.

GType: enter g_type_class_ref() times = 108.

GType: current type: GParamDouble

GType: type_data_ref_Wm(GParamDouble).

GType: find current type's GParamDouble parent: GParam.

GType: enter g_type_class_ref() times = 109.

GType: current type: GParam

GType: current type already exist. return.

GType: Node name: GParamDouble.

GType: enter g_type_class_ref() times = 110.

GType: current type: GtkWindow

GType: current type already exist. return.

GObject: g_type_name (object_type) : GtkStyle

GObject: class == NULL.

GType: enter g_type_class_ref() times = 111.

GType: current type: GtkStyle

GType: type_data_ref_Wm(GtkStyle).

GType: find current type's GtkStyle parent: GObject.

GType: enter g_type_class_ref() times = 112.

GType: current type: GObject

GType: current type already exist. return.

GType: Node name: GtkStyle.

GType: enter g_type_class_ref() times = 113.

GType: current type: GtkStyle

GType: current type already exist. return.

(process:802): GLib-GObject-WARNING **: invalid (NULL) pointer instance

(process:802): GLib-GObject-CRITICAL **: g_signal_connect_data: assertion `G_TYPE_CHECK_INSTANCE (instance)' failed

`void

`GInterface

+GTypePlugin

+AtkImplementorIface

`GtkBuildable

`gchar

`guchar

`gboolean

`gint

`guint

`glong

`gulong

`gint64

`guint64

`GEnum

+GdkExtensionMode

+GtkTouchSoundType

+GtkSvibeEffectType

+GtkStateType

+GtkTextDirection

+GtkDirectionType

+GtkDragResult

+GtkWidgetHelpType

+GtkResizeMode

+GtkWindowType

+GtkWindowPosition

+GdkWindowTypeHint

`GdkGravity

`GFlags

`GdkEventMask

`gfloat

`gdouble

`gchararray

`gpointer

`GType

`GBoxed

+GValueArray

+GtkRequisition

+GdkRectangle

+GdkEvent

+GtkSelectionData

+GdkColor

`GtkBorder

`GParam

+GParamChar

+GParamUChar

+GParamBoolean

+GParamInt

+GParamUInt

+GParamLong

+GParamULong

+GParamInt64

+GParamUInt64

+GParamUnichar

+GParamEnum

+GParamFlags

+GParamFloat

+GParamDouble

+GParamString

+GParamParam

+GParamBoxed

+GParamPointer

+GParamValueArray

+GParamObject

+GParamOverride

`GParamGType

`GObject

+GInitiallyUnowned

| |

| `GtkObject

| |

| `GtkWidget

| |

| `GtkContainer

| |

| `GtkBin

| |

| `GtkWindow

+GtkStyle

+GdkDrawable

| |

| `GdkWindow

+GdkDragContext

+GtkTooltip

+GdkScreen

+GtkDeviceGroup

`GdkPixbuf