349 lines
12 KiB
C
349 lines
12 KiB
C
/* EINA - EFL data type library
|
|
* Copyright (C) 2008 Cedric Bail
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* This library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with this library;
|
|
* if not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifndef EINA_ACCESSOR_H__
|
|
#define EINA_ACCESSOR_H__
|
|
|
|
#include "eina_config.h"
|
|
|
|
#include "eina_types.h"
|
|
#include "eina_magic.h"
|
|
|
|
/**
|
|
* @page eina_accessor_example_01_page Eina_Accessor usage
|
|
* @dontinclude eina_accessor_01.c
|
|
*
|
|
* We start by including necessary headers, declaring variables and
|
|
* initializing eina:
|
|
* @skip #include
|
|
* @until eina_init
|
|
*
|
|
* Next we populate our array and list:
|
|
* @until }
|
|
*
|
|
* Now that we have two containers populated we can actually start the example
|
|
* and create an accessor:
|
|
* @until accessor_new
|
|
*
|
|
* Once having the accessor we can use it to access certain elements in the
|
|
* container:
|
|
* @until }
|
|
* @note Unlike iterators accessors allow us non-linear access, which allows us
|
|
* to print only the odd elements in the container.
|
|
*
|
|
* As with every other resource we allocate we need to free the accessor(and the
|
|
* array):
|
|
* @until array_free
|
|
*
|
|
* Now we create another accessor, this time for the list:
|
|
* @until accessor_new
|
|
*
|
|
* And now the interesting bit, we use the same code we used above to print
|
|
* parts of the array to print parts of the list:
|
|
* @until }
|
|
*
|
|
* And to free the list we use a gimmick, instead of freeing @a list, we ask the
|
|
* accessor for it's container and free that:
|
|
* @until list_free
|
|
*
|
|
* Finally we shut eina down and leave:
|
|
* @until }
|
|
*
|
|
* The full source code can be found on the examples folder
|
|
* on the @ref eina_accessor_01_c "eina_accessor_01.c" file.
|
|
*/
|
|
|
|
/**
|
|
* @page eina_accessor_01_c Eina_Accessor usage example
|
|
*
|
|
* @include eina_accessor_01.c
|
|
* @example eina_accessor_01.c
|
|
*/
|
|
|
|
/**
|
|
* @addtogroup Eina_Accessor_Group Accessor Functions
|
|
*
|
|
* @brief These functions manage accessor on containers.
|
|
*
|
|
* These functions allow to access elements of a container in a
|
|
* generic way, without knowing which container is used (a bit like
|
|
* iterators in the C++ STL). Accessors allows random access (that is, any
|
|
* element in the container). For sequential access, see
|
|
* @ref Eina_Iterator_Group.
|
|
*
|
|
* Getting an accessor to access elements of a given container is done through
|
|
* the functions of that particular container. There is no function to create
|
|
* a generic accessor as accessors absolutely depend on the container. This
|
|
* means you won't find accessor creation function here, those can be found on
|
|
* the documentation of the container type you're using. Though created with
|
|
* container specific functions accessors are always deleted with the same
|
|
* function: eina_accessor_free().
|
|
*
|
|
* To get the data of an element at a given
|
|
* position, use eina_accessor_data_get(). To call a function on
|
|
* chosen elements of a container, use eina_accessor_over().
|
|
*
|
|
* See an example @ref eina_accessor_example_01_page "here".
|
|
*/
|
|
|
|
/**
|
|
* @addtogroup Eina_Content_Access_Group Content Access
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @defgroup Eina_Accessor_Group Accessor Functions
|
|
*
|
|
* @{
|
|
*/
|
|
|
|
/**
|
|
* @typedef Eina_Accessor
|
|
* Abstract type for accessors.
|
|
*/
|
|
typedef struct _Eina_Accessor Eina_Accessor;
|
|
|
|
/**
|
|
* @typedef Eina_Accessor_Get_At_Callback
|
|
* Type for a callback that returns the data of a container as the given index.
|
|
*/
|
|
typedef Eina_Bool (*Eina_Accessor_Get_At_Callback)(Eina_Accessor *it,
|
|
unsigned int idx,
|
|
void **data);
|
|
|
|
/**
|
|
* @typedef Eina_Accessor_Get_Container_Callback
|
|
* Type for a callback that returns the container.
|
|
*/
|
|
typedef void *(*Eina_Accessor_Get_Container_Callback)(Eina_Accessor *it);
|
|
|
|
/**
|
|
* @typedef Eina_Accessor_Free_Callback
|
|
* Type for a callback that frees the container.
|
|
*/
|
|
typedef void (*Eina_Accessor_Free_Callback)(Eina_Accessor *it);
|
|
|
|
/**
|
|
* @typedef Eina_Accessor_Lock_Callback
|
|
* Type for a callback that lock the container.
|
|
*/
|
|
typedef Eina_Bool (*Eina_Accessor_Lock_Callback)(Eina_Accessor *it);
|
|
|
|
/**
|
|
* @struct _Eina_Accessor
|
|
* Type to provide random access to data structures.
|
|
*
|
|
* If creating an accessor remember to set the type using @ref EINA_MAGIC_SET.
|
|
*/
|
|
struct _Eina_Accessor
|
|
{
|
|
#define EINA_ACCESSOR_VERSION 1
|
|
int version; /**< Version of the Accessor API. */
|
|
|
|
Eina_Accessor_Get_At_Callback get_at EINA_ARG_NONNULL(1, 3) EINA_WARN_UNUSED_RESULT; /**< Callback called when a data element is requested. */
|
|
Eina_Accessor_Get_Container_Callback get_container EINA_ARG_NONNULL(1) EINA_WARN_UNUSED_RESULT; /**< Callback called when the container is requested. */
|
|
Eina_Accessor_Free_Callback free EINA_ARG_NONNULL(1); /**< Callback called when the container is freed. */
|
|
|
|
Eina_Accessor_Lock_Callback lock EINA_WARN_UNUSED_RESULT; /**< Callback called when the container is locked. */
|
|
Eina_Accessor_Lock_Callback unlock EINA_WARN_UNUSED_RESULT; /**< Callback called when the container is unlocked. */
|
|
|
|
#define EINA_MAGIC_ACCESSOR 0x98761232
|
|
EINA_MAGIC
|
|
};
|
|
|
|
/**
|
|
* @def FUNC_ACCESSOR_GET_AT(Function)
|
|
* Helper macro to cast @p Function to a Eina_Accessor_Get_At_Callback.
|
|
*/
|
|
#define FUNC_ACCESSOR_GET_AT(Function) ((Eina_Accessor_Get_At_Callback)Function)
|
|
|
|
/**
|
|
* @def FUNC_ACCESSOR_GET_CONTAINER(Function)
|
|
* Helper macro to cast @p Function to a Eina_Accessor_Get_Container_Callback.
|
|
*/
|
|
#define FUNC_ACCESSOR_GET_CONTAINER(Function) ((Eina_Accessor_Get_Container_Callback)Function)
|
|
|
|
/**
|
|
* @def FUNC_ACCESSOR_FREE(Function)
|
|
* Helper macro to cast @p Function to a Eina_Accessor_Free_Callback.
|
|
*/
|
|
#define FUNC_ACCESSOR_FREE(Function) ((Eina_Accessor_Free_Callback)Function)
|
|
|
|
/**
|
|
* @def FUNC_ACCESSOR_LOCK(Function)
|
|
* Helper macro to cast @p Function to a Eina_Iterator_Lock_Callback.
|
|
*/
|
|
#define FUNC_ACCESSOR_LOCK(Function) ((Eina_Accessor_Lock_Callback)Function)
|
|
|
|
|
|
/**
|
|
* @brief Free an accessor.
|
|
*
|
|
* @param accessor The accessor to free.
|
|
*
|
|
* This function frees @p accessor if it is not @c NULL;
|
|
*/
|
|
EAPI void eina_accessor_free(Eina_Accessor *accessor);
|
|
|
|
/**
|
|
* @brief Retrieve the data of an accessor at a given position.
|
|
*
|
|
* @param accessor The accessor.
|
|
* @param position The position of the element.
|
|
* @param data The pointer that stores the data to retrieve.
|
|
* @return #EINA_TRUE on success, #EINA_FALSE otherwise.
|
|
*
|
|
* This function retrieves the data of the element pointed by
|
|
* @p accessor at the porition @p position, and stores it in
|
|
* @p data. If @p accessor is @c NULL or if an error occurred, #EINA_FALSE
|
|
* is returned, otherwise #EINA_TRUE is returned.
|
|
*/
|
|
EAPI Eina_Bool eina_accessor_data_get(Eina_Accessor *accessor,
|
|
unsigned int position,
|
|
void **data) EINA_ARG_NONNULL(1);
|
|
|
|
/**
|
|
* @brief Return the container of an accessor.
|
|
*
|
|
* @param accessor The accessor.
|
|
* @return The container which created the accessor.
|
|
*
|
|
* This function returns the container which created @p accessor. If
|
|
* @p accessor is @c NULL, this function returns @c NULL.
|
|
*/
|
|
EAPI void *eina_accessor_container_get(Eina_Accessor *accessor) EINA_ARG_NONNULL(1) EINA_PURE;
|
|
|
|
/**
|
|
* @brief Iterate over the container and execute a callback on chosen elements.
|
|
*
|
|
* @param accessor The accessor.
|
|
* @param cb The callback called on the chosen elements.
|
|
* @param start The position of the first element.
|
|
* @param end The position of the last element.
|
|
* @param fdata The data passed to the callback.
|
|
*
|
|
* This function iterates over the elements pointed by @p accessor,
|
|
* starting from the element at position @p start and ending to the
|
|
* element at position @p end. For Each element, the callback
|
|
* @p cb is called with the data @p fdata. If @p accessor is @c NULL
|
|
* or if @p start is greter or equal than @p end, the function returns
|
|
* immediately.
|
|
*/
|
|
EAPI void eina_accessor_over(Eina_Accessor *accessor,
|
|
Eina_Each_Cb cb,
|
|
unsigned int start,
|
|
unsigned int end,
|
|
const void *fdata) EINA_ARG_NONNULL(2);
|
|
|
|
/**
|
|
* @brief Lock the container of the accessor.
|
|
*
|
|
* @param accessor The accessor.
|
|
* @return #EINA_TRUE on success, #EINA_FALSE otherwise.
|
|
*
|
|
* If the container of the @p accessor permits it, it will be locked. When a
|
|
* container is locked calling eina_accessor_over() on it will return
|
|
* immediately. If @p accessor is @c NULL or if a problem occurred, #EINA_FALSE
|
|
* is returned, otherwise #EINA_TRUE is returned. If the container isn't
|
|
* lockable, it will return #EINA_TRUE.
|
|
*
|
|
* @warning None of the existing eina data structures are lockable.
|
|
*/
|
|
EAPI Eina_Bool eina_accessor_lock(Eina_Accessor *accessor) EINA_ARG_NONNULL(1);
|
|
|
|
/**
|
|
* @brief Unlock the container of the accessor.
|
|
*
|
|
* @param accessor The accessor.
|
|
* @return #EINA_TRUE on success, #EINA_FALSE otherwise.
|
|
*
|
|
* If the container of the @p accessor permits it and was previously
|
|
* locked, it will be unlocked. If @p accessor is @c NULL or if a
|
|
* problem occurred, #EINA_FALSE is returned, otherwise #EINA_TRUE
|
|
* is returned. If the container is not lockable, it will
|
|
* return #EINA_TRUE.
|
|
*
|
|
* @warning None of the existing eina data structures are lockable.
|
|
*/
|
|
EAPI Eina_Bool eina_accessor_unlock(Eina_Accessor *accessor) EINA_ARG_NONNULL(1);
|
|
|
|
/**
|
|
* @def EINA_ACCESSOR_FOREACH
|
|
* @brief Macro to iterate over all elements easily.
|
|
*
|
|
* @param accessor The accessor to use.
|
|
* @param counter A counter used by eina_accessor_data_get() when
|
|
* iterating over the container.
|
|
* @param data Where to store * data, must be a pointer support getting
|
|
* its address since * eina_accessor_data_get() requires a pointer to
|
|
* pointer!
|
|
*
|
|
* This macro allows a convenient way to loop over all elements in an
|
|
* accessor, very similar to EINA_LIST_FOREACH().
|
|
*
|
|
* This macro can be used for freeing the data of a list, like in the
|
|
* following example. It has the same goal as the one documented in
|
|
* EINA_LIST_FOREACH(), but using accessors:
|
|
*
|
|
* @code
|
|
* Eina_List *list;
|
|
* Eina_Accessor *accessor;
|
|
* unsigned int i;
|
|
* char *data;
|
|
*
|
|
* // list is already filled,
|
|
* // its elements are just duplicated strings
|
|
*
|
|
* accessor = eina_list_accessor_new(list);
|
|
* EINA_ACCESSOR_FOREACH(accessor, i, data)
|
|
* free(data);
|
|
* eina_accessor_free(accessor);
|
|
* eina_list_free(list);
|
|
* @endcode
|
|
*
|
|
* @note if the datatype provides both iterators and accessors prefer
|
|
* to use iterators to iterate over, as they're likely to be more
|
|
* optimized for such task.
|
|
*
|
|
* @note this example is not optimal algorithm to release a list since
|
|
* it will walk the list twice, but it serves as an example. For
|
|
* optimized version use EINA_LIST_FREE()
|
|
*
|
|
* @warning unless explicitly stated in functions returning accessors,
|
|
* do not modify the accessed object while you walk it, in this
|
|
* example using lists, do not remove list nodes or you might
|
|
* crash! This is not a limitation of accessors themselves,
|
|
* rather in the accessors implementations to keep them as simple
|
|
* and fast as possible.
|
|
*/
|
|
#define EINA_ACCESSOR_FOREACH(accessor, counter, data) \
|
|
for ((counter) = 0; \
|
|
eina_accessor_data_get((accessor), (counter), (void **)(void *)&(data)); \
|
|
(counter)++)
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
/**
|
|
* @}
|
|
*/
|
|
|
|
#endif
|