## MateConfChangeSet

MateConfChangeSet — a set of configuration changes to be made.

## Synopsis

                        MateConfChangeSet;
    void                (*MateConfChangeSetForeachFunc)        (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value,
                                                             gpointer user_data);
    gboolean            mateconf_engine_commit_change_set      (MateConfEngine *conf,
                                                             MateConfChangeSet *cs,
                                                             gboolean remove_committed,
                                                             GError **err);
    MateConfChangeSet *    mateconf_engine_reverse_change_set     (MateConfEngine *conf,
                                                             MateConfChangeSet *cs,
                                                             GError **err);
    MateConfChangeSet *    mateconf_engine_change_set_from_currentv
                                                            (MateConfEngine *conf,
                                                             const gchar **keys,
                                                             GError **err);
    MateConfChangeSet *    mateconf_engine_change_set_from_current
                                                            (MateConfEngine *conf,
                                                             GError **err,
                                                             const gchar *first_key,
                                                             ...);
    MateConfChangeSet *    mateconf_change_set_new                (void);
    MateConfChangeSet *    mateconf_change_set_ref                (MateConfChangeSet *cs);
    void                mateconf_change_set_unref              (MateConfChangeSet *cs);
    void                mateconf_change_set_clear              (MateConfChangeSet *cs);
    guint               mateconf_change_set_size               (MateConfChangeSet *cs);
    void                mateconf_change_set_remove             (MateConfChangeSet *cs,
                                                             const gchar *key);
    void                mateconf_change_set_foreach            (MateConfChangeSet *cs,
                                                             MateConfChangeSetForeachFunc func,
                                                             gpointer user_data);
    gboolean            mateconf_change_set_check_value        (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue **value_retloc);
    void                mateconf_change_set_set                (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value);
    void                mateconf_change_set_set_nocopy         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value);
    void                mateconf_change_set_unset              (MateConfChangeSet *cs,
                                                             const gchar *key);
    void                mateconf_change_set_set_float          (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gdouble val);
    void                mateconf_change_set_set_int            (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gint val);
    void                mateconf_change_set_set_string         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             const gchar *val);
    void                mateconf_change_set_set_bool           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gboolean val);
    void                mateconf_change_set_set_schema         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfSchema *val);
    void                mateconf_change_set_set_list           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValueType list_type,
                                                             GSList *list);
    void                mateconf_change_set_set_pair           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValueType car_type,
                                                             MateConfValueType cdr_type,
                                                             gconstpointer address_of_car,
                                                             gconstpointer address_of_cdr);
    void                mateconf_change_set_set_user_data      (MateConfChangeSet *cs,
                                                             gpointer data,
                                                             GDestroyNotify dnotify);
    gpointer            mateconf_change_set_get_user_data      (MateConfChangeSet *cs);

## Description

a MateConfChangeSet allows you to collect a set of changes to configuration keys (set/unset operations). You can then commit all the changes at once. This is convenient for something like a preferences dialog; you can collect all the pending changes in a MateConfChangeSet, then when the user clicks "apply" send them all to the configuration database. The MateConfChangeSet allows you to avoid sending every preferences setting when "apply" is clicked; you only have to send the settings the user changed.

In the future, MateConf may also have optimizations so that changing a group of values with MateConfChangeSet is faster than calling `mateconf_engine_set()` for each value. In the future, MateConfChangeSet may also represent an atomic transaction, where all or none of the values are set; however, for now the operation is not atomic.

## Details

### MateConfChangeSet

    typedef struct _MateConfChangeSet MateConfChangeSet;

An opaque data type representing a set of changes to be made. A change set can contain "set" and "unset" operations.

### MateConfChangeSetForeachFunc ()

    void                (*MateConfChangeSetForeachFunc)        (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value,
                                                             gpointer user_data);

The type of a function passed to `mateconf_change_set_foreach()`. The `cs` argument is the MateConfChangeSet you're iterating over. `key` is a key in the change set. `value` is the value the key will be set to, or NULL if the key will be unset. `user_data` is the user data passed to `mateconf_change_set_foreach()`.

`cs` : | the MateConfChangeSet being iterated over.
`key` : | the current key.
`value` : | the current value, or NULL.
`user_data` : | user data passed to `mateconf_change_set_foreach()`.

### mateconf_engine_commit_change_set ()

    gboolean            mateconf_engine_commit_change_set      (MateConfEngine *conf,
                                                             MateConfChangeSet *cs,
                                                             gboolean remove_committed,
                                                             GError **err);

Applies the changes in the change set to the MateConfEngine passed as the first argument. If `remove_committed` is TRUE, then any successfully-committed changes are removed from the change set. If `remove_committed` is FALSE, the MateConfChangeSet is left unmodified.

If any set or unset operation results in an error, then processing terminates and the error is returned in `err` (unless `err` was NULL). If `remove_committed` was TRUE, then all the changes committed before the error occurred will have been removed from the set. If any error occurs, FALSE is returned.

`conf` : | a MateConfEngine.
`cs` : | a MateConfChangeSet.
`remove_committed` : | whether to remove successfully-committed changes from the set
`err` : | the return location for an allocated GError, or NULL to ignore errors.
Returns : | TRUE on success, FALSE if an error occurs.

### mateconf_engine_reverse_change_set ()

    MateConfChangeSet *    mateconf_engine_reverse_change_set     (MateConfEngine *conf,
                                                             MateConfChangeSet *cs,
                                                             GError **err);

Creates a change set that would reverse `cs`. That is, for each change in `cs`, save the current state of that key in the returned change set.

`conf` : | a MateConfEngine.
`cs` : | the MateConfChangeSet to be reverted.
`err` : | the return location for an allocated GError, or NULL to ignore errors.
Returns : | the modified MateConfChangeSet.

### mateconf_engine_change_set_from_currentv ()

    MateConfChangeSet *    mateconf_engine_change_set_from_currentv
                                                            (MateConfEngine *conf,
                                                             const gchar **keys,
                                                             GError **err);

Creates a change set that will change the keys in NULLterminated array `keys` to their current state.

`conf` : | a MateConfEngine.
`keys` : | NULLterminated array of key names.
`err` : | the return location for an allocated GError, or NULL to ignore errors.
Returns : | the newly allocated MateConfChangeSet.

### mateconf_engine_change_set_from_current ()

    MateConfChangeSet *    mateconf_engine_change_set_from_current
                                                            (MateConfEngine *conf,
                                                             GError **err,
                                                             const gchar *first_key,
                                                             ...);

Convenient Varags version of `mateconf_engine_change_set_from_current()`.

`conf` : | a MateConfEngine.
`err` : | the return location for an allocated GError, or NULL to ignore errors.
`first_key` : | the first key, a char* value.
`...` : | the keys to be set.
Returns : | the newly allocated MateConfChangeSet.

### mateconf_change_set_new ()

    MateConfChangeSet *    mateconf_change_set_new                (void);

Creates a new, empty MateConfChangeSet. The caller assumes one reference count, and must call `mateconf_change_set_unref()` eventually.

Returns : | a new MateConfChangeSet.

### mateconf_change_set_ref ()

    MateConfChangeSet *    mateconf_change_set_ref                (MateConfChangeSet *cs);

Increases the reference count of a MateConfChangeSet by one.

`cs` : | a MateConfChangeSet.
Returns : | the referenced MateConfChangeSet.

### mateconf_change_set_unref ()

    void                mateconf_change_set_unref              (MateConfChangeSet *cs);

Decreases the reference count of a MateConfChangeSet by one. If the reference count reaches 0, destroys the MateConfChangeSet.

`cs` : | a MateConfChangeSet.

### mateconf_change_set_clear ()

    void                mateconf_change_set_clear              (MateConfChangeSet *cs);

Clears all changes from a MateConfChangeSet, so that committing the change set would have no effect.

`cs` : | a MateConfChangeSet.

### mateconf_change_set_size ()

    guint               mateconf_change_set_size               (MateConfChangeSet *cs);

Returns the size of the changeset, a guint value.

`cs` : | a MateConfChangeSet.
Returns : | the size, a guint value.

### mateconf_change_set_remove ()

    void                mateconf_change_set_remove             (MateConfChangeSet *cs,
                                                             const gchar *key);

Removes a change from a MateConfChangeSet. The key given as the `key` argument will not be modified if this change set is committed. If `key` is not in the change set, this function has no effect.

`cs` : | a MateConfChangeSet.
`key` : | key to remove from the change set.

### mateconf_change_set_foreach ()

    void                mateconf_change_set_foreach            (MateConfChangeSet *cs,
                                                             MateConfChangeSetForeachFunc func,
                                                             gpointer user_data);

Iterates over a MateConfChangeSet by calling a MateConfChangeSetForeachFunc for each change in the set. See the description of MateConfChangeSetForeachFunc for details. You may not call `mateconf_change_set_remove()` during the iteration, because you'll confuse the internal data structures and cause memory corruption.

`cs` : | a MateConfChangeSet.
`func` : | function to call for each change in the change set. [scope call]
`user_data` : | user data to pass to the MateConfChangeSetForeachFunc.

### mateconf_change_set_check_value ()

    gboolean            mateconf_change_set_check_value        (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue **value_retloc);

Looks up the hash table associated with the MateConfChangeSet for the key `key`. If the key is found , the value is set in value_retloc.

`cs` : | a MateConfChangeSet.
`key` : | the key to be searched in the changeset.
`value_retloc` : | a MateConfValue ** to hold the key, if found.
Returns : | TRUE on finding the key, FALSE if key is not found.

### mateconf_change_set_set ()

    void                mateconf_change_set_set                (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value);

Adds a "set" operation to a change set. This function is similar to `mateconf_engine_set()`, except that no errors can occur (errors occur later, when you try to commit the change set).

`cs` : | a MateConfChangeSet.
`key` : | the key to change.
`value` : | the value to change the key to.

### mateconf_change_set_set_nocopy ()

    void                mateconf_change_set_set_nocopy         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValue *value);

Like `mateconf_change_set_set()`, except that the MateConfChangeSet takes ownership of the MateConfValue. You should not use the value again. It will be destroyed when the change is removed from the MateConfChangeSet, the change is modified, or the MateConfChangeSet is destroyed.

`cs` : | a MateConfChangeSet.
`key` : | the key to change.
`value` : | the new value of `key`.

### mateconf_change_set_unset ()

    void                mateconf_change_set_unset              (MateConfChangeSet *cs,
                                                             const gchar *key);

Adds an "unset" operation to a MateConfChangeSet. This function schedules a `mateconf_engine_unset()`.

`cs` : | a MateConfChangeSet.
`key` : | the key to unset.

### mateconf_change_set_set_float ()

    void                mateconf_change_set_set_float          (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gdouble val);

Adds a "set" operation; takes a gdouble argument, so you can avoid creating a MateConfValue.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`val` : | the new value of `key`.

### mateconf_change_set_set_int ()

    void                mateconf_change_set_set_int            (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gint val);

Adds a "set" operation; takes a gint argument, so you can avoid creating a MateConfValue.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`val` : | the new value of `key`.

### mateconf_change_set_set_string ()

    void                mateconf_change_set_set_string         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             const gchar *val);

Adds a "set" operation; takes a gchar* argument, so you can avoid creating a MateConfValue.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`val` : | the new value of `key`.

### mateconf_change_set_set_bool ()

    void                mateconf_change_set_set_bool           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             gboolean val);

Adds a "set" operation; takes a gboolean argument, so you can avoid creating a MateConfValue.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`val` : | the new value of `key`.

### mateconf_change_set_set_schema ()

    void                mateconf_change_set_set_schema         (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfSchema *val);

Adds a "set" operation; takes a MateConfSchema argument, so you can avoid creating a MateConfValue. The schema is copied, `val` is left unmodified.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`val` : | the new value of `key`.

### mateconf_change_set_set_list ()

    void                mateconf_change_set_set_list           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValueType list_type,
                                                             GSList *list);

Adds a "set" operation; takes a GList argument and the type of the list, so you can avoid creating a MateConfValue. This results in the list of values being set for the key.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`list_type` : | the type of the list.
`list` : | a GList containing the values to be set.

### mateconf_change_set_set_pair ()

    void                mateconf_change_set_set_pair           (MateConfChangeSet *cs,
                                                             const gchar *key,
                                                             MateConfValueType car_type,
                                                             MateConfValueType cdr_type,
                                                             gconstpointer address_of_car,
                                                             gconstpointer address_of_cdr);

Adds a "set" operation; takes a pointer to the addresses of the pair of values, so you can avoid creating a MateConfValue. This results in the pair of values being set for the key.

`cs` : | a MateConfChangeSet.
`key` : | the key to set.
`car_type` : | the type of the pair's first field. (car)
`cdr_type` : | the type of the pair's second field. (cdr)
`address_of_car` : | address of the car.
`address_of_cdr` : | address of the cdr.

### mateconf_change_set_set_user_data ()

    void                mateconf_change_set_set_user_data      (MateConfChangeSet *cs,
                                                             gpointer data,
                                                             GDestroyNotify dnotify);

Sets the user_data and the destroy notification function fields of the MateConfChangeSet.

`cs` : | a MateConfChangeSet.
`data` : | a gpointer.
`dnotify` : | a pointer to the function to be called during destroy.

### mateconf_change_set_get_user_data ()

    gpointer            mateconf_change_set_get_user_data      (MateConfChangeSet *cs);

Returns the user_data field of the MateConfChangeSet.

`cs` : | a MateConfChangeSet.
Returns : | a pointer to the user_data.