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notification callback handling


Typedefs

typedef enum svn_wc_notify_action_t svn_wc_notify_action_t
 The type of action occurring.

typedef enum svn_wc_notify_state_t svn_wc_notify_state_t
 The type of notification that is occurring.

typedef void(* svn_wc_notify_func_t )(void *baton, const char *path, svn_wc_notify_action_t action, svn_node_kind_t kind, const char *mime_type, svn_wc_notify_state_t content_state, svn_wc_notify_state_t prop_state, svn_revnum_t revision)
 Notify the world that action has happened to path.


Detailed Description

In many cases, the WC library will scan a working copy and make changes. The caller usually wants to know when each of these changes has been made, so that it can display some kind of notification to the user.

These notifications have a standard callback function type, which takes the path of the file that was affected, and a caller- supplied baton.

Note that the callback is a 'void' return -- this is a simple reporting mechanism, rather than an opportunity for the caller to alter the operation of the WC library.

Note also that some of the actions are used across several different Subversion commands. For example, the update actions are also used for checkouts, switches, and merges.


Typedef Documentation

typedef void(* svn_wc_notify_func_t)(void *baton, const char *path, svn_wc_notify_action_t action, svn_node_kind_t kind, const char *mime_type, svn_wc_notify_state_t content_state, svn_wc_notify_state_t prop_state, svn_revnum_t revision)
 

Notify the world that action has happened to path.

path is either absolute or relative to cwd (i.e., not relative to an anchor).

kind, content_state and prop_state are from after action, not before.

If mime_type is non-null, it indicates the mime-type of path. It is always NULL for directories.

revision is SVN_INVALID_REVNUM, except when action is svn_wc_notify_update_completed, in which case revision is the target revision of the update if available, else it is still SVN_INVALID_REVNUM.

Note that if action is svn_wc_notify_update, then path has already been installed, so it is legitimate for an implementation of svn_wc_notify_func_t to examine path in the working copy.

### Design Notes:

The purpose of the kind, mime_type, content_state, and prop_state fields is to provide "for free" information that this function is likely to want, and which it would otherwise be forced to deduce via expensive operations such as reading entries and properties. However, if the caller does not have this information, it will simply pass the corresponding `*_unknown' values, and it is up to the implementation how to handle that (i.e., whether or not to attempt deduction, or just to punt and give a less informative notification).

Recommendation: callers of svn_wc_notify_func_t should avoid invoking it multiple times on the same path within a given operation, and implementations should not bother checking for such duplicate calls. For example, in an update, the caller should not invoke the notify func on receiving a prop change and then again on receiving a text change. Instead, wait until all changes have been received, and then invoke the notify func once (from within an svn_delta_editor_t's close_file(), for example), passing the appropriate content_state and prop_state flags.

Definition at line 448 of file svn_wc.h.


Generated on Wed Oct 13 23:55:36 2004 for Subversion by doxygen 1.3.4