[evolution-data-server/openismus-work-3-8: 62/118] EBookBackendSqliteDB: Changed cursor move_by() API

[Tristan Van Berkom <tvb src gnome org>]

commit b6e51ca93c0a81d4d043d7d9cf12582a089293d8
Author: Tristan Van Berkom <tristanvb openismus com>
Date:   Mon Jun 17 15:40:28 2013 +0900

    EBookBackendSqliteDB: Changed cursor move_by() API
    
    e_book_backend_sqlitedb_cursor_move_by() now takes a 'GSList **results'
    argument to report results and returns a boolean success status.
    
    This allows one to pass NULL for the results and ignore the results.

 .../libedata-book/e-book-backend-sqlitedb.c        |   53 ++++++++++++++-----
 .../libedata-book/e-book-backend-sqlitedb.h        |    3 +-
 2 files changed, 41 insertions(+), 15 deletions(-)
---
diff --git a/addressbook/libedata-book/e-book-backend-sqlitedb.c 
b/addressbook/libedata-book/e-book-backend-sqlitedb.c
index 9bdaf6b..edb9ed8 100644
--- a/addressbook/libedata-book/e-book-backend-sqlitedb.c
+++ b/addressbook/libedata-book/e-book-backend-sqlitedb.c
@@ -5735,6 +5735,8 @@ e_book_backend_sqlitedb_cursor_free (EBookBackendSqliteDB *ebsdb,
  * @cursor: The #EbSdbCursor to use
  * @origin: The #EbSdbCurorOrigin for this move
  * @count: A positive or negative amount of contacts to try and fetch
+ * @results: (out) (allow-none) (element-type EbSdbSearchData) (transfer full):
+ *   A return location to store the results, or %NULL to move the cursor without retrieving any results.
  * @error: A return location to story any error that might be reported.
  *
  * Moves @cursor through the @ebsdb by @count and fetch a maximum of @count contacts.
@@ -5747,28 +5749,34 @@ e_book_backend_sqlitedb_cursor_free (EBookBackendSqliteDB *ebsdb,
  *
  * If @cursor reaches the beginning or end of the query results, then the
  * returned list might not contain the amount of desired contacts, or might
- * return no results. This is not considered an error condition.
+ * return no results if the cursor currently points to the last contact.
+ * This is not considered an error condition.
  *
- * Returns: (element-type EbSdbSearchData) (transfer full):
- *   A list of #EbSdbSearchData, the list should be freed with g_slist_free()
- *   and all elements freed with e_book_backend_sqlitedb_search_data_free().
+ * If @results is specified, it should be a pointer to a %NULL #GSList,
+ * the result list will be stored to @results and should be freed with g_slist_free()
+ * and all elements freed with e_book_backend_sqlitedb_search_data_free().
+ *
+ * Returns: %TRUE on Success, otherwise %FALSE is returned if any error occurred
+ * and @error is set to reflect the error which occurred.
  *
  * Since: 3.10
  */
-GSList *
+gboolean
 e_book_backend_sqlitedb_cursor_move_by (EBookBackendSqliteDB *ebsdb,
                                        EbSdbCursor          *cursor,
                                        EbSdbCurorOrigin      origin,
                                        gint                  count,
+                                       GSList              **results,
                                        GError              **error)
 {
-       GSList *results = NULL;
+       GSList *local_results = NULL;
        GString *query;
        gboolean success;
 
-       g_return_val_if_fail (E_IS_BOOK_BACKEND_SQLITEDB (ebsdb), NULL);
-       g_return_val_if_fail (cursor != NULL, NULL);
-       g_return_val_if_fail (count != 0, NULL);
+       g_return_val_if_fail (E_IS_BOOK_BACKEND_SQLITEDB (ebsdb), FALSE);
+       g_return_val_if_fail (cursor != NULL, FALSE);
+       g_return_val_if_fail (count != 0 || origin == EBSDB_CURSOR_ORIGIN_RESET, FALSE);
+       g_return_val_if_fail (results == NULL || *results == NULL, FALSE);
 
        /* Every query starts with the STATE_CURRENT position, first
         * fix up the cursor state according to 'origin'
@@ -5787,6 +5795,12 @@ e_book_backend_sqlitedb_cursor_move_by (EBookBackendSqliteDB *ebsdb,
                break;
        }
 
+       /* Count can be 0 only for the sake of resetting the current
+        * cursor state without fetching any results
+        */
+       if (count == 0)
+               return TRUE;
+
        query = g_string_new (cursor->select_vcards);
 
        /* Add the filter constraints (if any) */
@@ -5829,7 +5843,7 @@ e_book_backend_sqlitedb_cursor_move_by (EBookBackendSqliteDB *ebsdb,
        /* Execute the query */
        LOCK_MUTEX (&ebsdb->priv->lock);
        success = book_backend_sql_exec (ebsdb->priv->db, query->str,
-                                        addto_vcard_list_cb , &results,
+                                        addto_vcard_list_cb , &local_results,
                                         error);
        UNLOCK_MUTEX (&ebsdb->priv->lock);
 
@@ -5838,26 +5852,37 @@ e_book_backend_sqlitedb_cursor_move_by (EBookBackendSqliteDB *ebsdb,
        /* Correct the order of results, since
         * addto_vcard_list_cb() prepends them (as it should)
         */
-       results = g_slist_reverse (results);
+       local_results = g_slist_reverse (local_results);
 
        /* If there was no error, update the internal cursor state */
        if (success) {
 
-               if (g_slist_length (results) < ABS (count)) {
+               if (g_slist_length (local_results) < ABS (count)) {
                        /* We've reached the end, clear the current state, allow
                         * a repeat query from the previously recorded position */
                        ebsdb_cursor_swap_state (cursor);
                        ebsdb_cursor_clear_state (cursor, STATE_CURRENT);
                } else {
                        /* Set the cursor state to the last result */
-                       GSList *last = g_slist_last (results);
+                       GSList *last = g_slist_last (local_results);
                        EbSdbSearchData *data = last->data;
 
                        ebsdb_cursor_set_state (ebsdb, cursor, data->vcard);
                }
        }
 
-       return results;
+       if (results) {
+               *results = local_results;
+       } else {
+               /* Even if we are not returning the results, we have to fetch them
+                * so that we can store the state of the last returned result as the
+                * new cursor state.
+                */
+               g_slist_free_full (local_results,
+                                  (GDestroyNotify)e_book_backend_sqlitedb_search_data_free);
+       }
+
+       return success;
 }
 
 /**
diff --git a/addressbook/libedata-book/e-book-backend-sqlitedb.h 
b/addressbook/libedata-book/e-book-backend-sqlitedb.h
index 3f8d4ec..d723a4e 100644
--- a/addressbook/libedata-book/e-book-backend-sqlitedb.h
+++ b/addressbook/libedata-book/e-book-backend-sqlitedb.h
@@ -329,11 +329,12 @@ EbSdbCursor    *e_book_backend_sqlitedb_cursor_new
 void            e_book_backend_sqlitedb_cursor_free
                                                 (EBookBackendSqliteDB *ebsdb,
                                                 EbSdbCursor          *cursor);
-GSList         *e_book_backend_sqlitedb_cursor_move_by
+gboolean        e_book_backend_sqlitedb_cursor_move_by
                                                 (EBookBackendSqliteDB *ebsdb,
                                                 EbSdbCursor          *cursor,
                                                 EbSdbCurorOrigin      origin,
                                                 gint                  count,
+                                                GSList              **results,
                                                 GError              **error);
 void            e_book_backend_sqlitedb_cursor_set_target_alphabetic_index
                                                 (EBookBackendSqliteDB *ebsdb,