Eo: Add reference functions for objects data

We want to introduce a new mechanism concerning the data of the Eo
objects.
The goal is to improve the memory management by defragmenting the memory
banks used by the Eo objects. The first phase has been done by raster
and consists in allocating the objects into a separate memory region
that the one used by malloc. So now, we know where our objects are
located.
Now, moving objects means moving data of objects. The issue we have here
is that a lot of data pointers are stored into data of other objects,
e.g Evas Object data into lists for rendering...
We need a way to reference the data and eo_data_get doesn't provide us
that. So we need to improve the API for data extraction by requesting
from the developer if the data will be stored or not. Five functions are
supplied:
- eo_data_scope_get: no referencing, the data pointer is no more used after
exiting the function.
- eo_data_ref: reference the data of the object. It means that while the
data is referenced, the object cannot be moved.
- eo_data_xref: reference the data of the object but for debug purpose,
we associate the objects that references. Same behavior as eo_data_ref
for non-debug.
- eo_data_unref: unreference the data of an object.
- eo_data_xunref: unreference the data of an object previously
referenced by another object.

I deprecated the eo_data_get function. Most of the time,
eo_data_scope_get needs to be used.

In the next patches, I changed the eo_data_get to the corresponding
functions, according to the usage of the data pointer.

The next step is to find all the places in the code where the data is
stored but not yet referenced. This will be done by:
- requesting from every object to unreference all data to other objects.
- moving all the objects from one region to another
- requesting from every object to rerefenrence the data.
- debugging by hunting the segmentation faults and other weird
creatures.

1 files changed, 17 insertions, 6 deletions

diff --git a/doc/eo_tutorial.dox b/doc/eo_tutorial.dox
index 364ff5415..333bdee90 100644
--- a/doc/eo_tutorial.dox
+++ b/doc/eo_tutorial.dox
@@ -55,10 +55,19 @@
  * @endcode
  * 
  *   - Eo way:
+ *     Two functions can be used to extract object data. The use depends if you want to store the data or not. If you just need to access data in the function (most of the time), just use eo_data_scope_get. If you need to store the data (for example in a list of objects data), you have to use eo_data_ref. This function references the data. If you don't need the referenced data anymore, call eo_data_unref.
+ *     This reference mechanism will be used in the future to detect bad usage of objects, defragment the memory space used by the objects...
  * @code
- *    Evas_Object_Line *o = eo_data_get(obj, EVAS_OBJ_LINE_CLASS);
+ *    Evas_Object_Line *o = eo_data_scope_get(obj, EVAS_OBJ_LINE_CLASS);
  *    if (!o) return;
  * @endcode
+ *    or
+ * @code
+ *    Evas_Object_Line *o = eo_data_ref(obj, EVAS_OBJ_LINE_CLASS);
+ *    if (!o) return;
+ *    ...
+ *    eo_data_unref(obj, o);
+ * @endcode
  * 
  * - Call function of parent
  *   - Old way:
@@ -74,10 +83,12 @@
  * @section Important to know
  * - eo_do() is the function used to invoke functions of a specific class on an object.
  * 
- * - eo_data_get() receives an object and a class and returns the data of the given class for the object. The class must belong to the object class hierarchy.
- * 
+ * - eo_data_scope_get() and eo_data_ref() receives an object and a class and returns the data of the given class for the object. The class must belong to the object class hierarchy.
+ *
+ * - eo_data_unref() receives an object and the data to unreference. The data MUST belong to this object.
+ *
  * - eo_isa() indicates if a given object is of a given type.
- * 
+ *
  * - eo_do_super() is in charge to invoke a function in the next parents that implement it. It is recommended to use eo_do_super() only from a function with the same op id.\n
  * In addition, there is no way to jump over classes who implement the function. If A inherits from B, B from C and A, B and C implement a virtual function defined in C, the function calls order will be A, then B and finally C. It is impossible to pass over B.
  * 
@@ -242,7 +253,7 @@
  *    Evas_Coord *x2 = va_arg(*list, Evas_Coord *);
  *    Evas_Coord *y2 = va_arg(*list, Evas_Coord *);
  * 
- *    Evas_Object_Protected_Data *obj = eo_data_get(eo_obj, EVAS_OBJ_CLASS);
+ *    Evas_Object_Protected_Data *obj = eo_data_scope_get(eo_obj, EVAS_OBJ_CLASS);
  *    if (x1) *x1 = obj->cur.geometry.x + o->cur.x1;
  *    if (y1) *y1 = obj->cur.geometry.y + o->cur.y1;
  *    if (x2) *x2 = obj->cur.geometry.x + o->cur.x2;
@@ -254,7 +265,7 @@
  * {
  *    eo_do_super(eo_obj, eo_constructor());
  * 
- *    Evas_Object_Protected_Data *obj = eo_data_get(eo_obj, EVAS_OBJ_CLASS);
+ *    Evas_Object_Protected_Data *obj = eo_data_scope_get(eo_obj, EVAS_OBJ_CLASS);
  *    evas_object_line_init(eo_obj);
  * }
  *