[evolution-data-server/openismus-work-3-8: 70/116] EBookBackendSqliteDB: Added e_book_backend_sqlitedb_cursor_compare()

[Tristan Van Berkom <tvb src gnome org>]

commit c87700ca3cbb090c7f209f19b09614a8a4bf9877
Author: Tristan Van Berkom <tristanvb openismus com>
Date:   Tue Jul 2 17:17:15 2013 +0900

    EBookBackendSqliteDB: Added e_book_backend_sqlitedb_cursor_compare()
    
    Added an api to compare the cursor with an EContact, this allows
    EDataBookCursor to track total / position when the addressbook is
    modified without constantly recalculating it with SQLite queries.

 .../libedata-book/e-book-backend-sqlitedb.c        |   97 +++++++++++++++++++-
 .../libedata-book/e-book-backend-sqlitedb.h        |    5 +
 2 files changed, 101 insertions(+), 1 deletions(-)
---
diff --git a/addressbook/libedata-book/e-book-backend-sqlitedb.c 
b/addressbook/libedata-book/e-book-backend-sqlitedb.c
index 8b84be7..5ecfdc6 100644
--- a/addressbook/libedata-book/e-book-backend-sqlitedb.c
+++ b/addressbook/libedata-book/e-book-backend-sqlitedb.c
@@ -5211,6 +5211,7 @@ typedef enum {
 struct _EbSdbCursor {
        gchar         *folderid;      /* The folderid for this cursor */
 
+       EBookBackendSExp *sexp;       /* An EBookBackendSExp based on the query, used by 
e_book_backend_sqlitedb_cursor_compare() */
        gchar         *select_vcards; /* The first fragment when querying results */
        gchar         *select_count;  /* The first fragment when querying contact counts */
        gchar         *query;         /* The SQL query expression derived from the passed search expression */
@@ -5236,6 +5237,7 @@ ebsdb_cursor_setup_query (EBookBackendSqliteDB *ebsdb,
        g_free (cursor->select_vcards);
        g_free (cursor->select_count);
        g_free (cursor->query);
+       g_clear_object (&(cursor->sexp));
 
        if (query_with_list_attrs) {
                gchar *list_table = g_strconcat (cursor->folderid, "_lists", NULL);
@@ -5258,7 +5260,13 @@ ebsdb_cursor_setup_query (EBookBackendSqliteDB *ebsdb,
        sqlite3_free (stmt);
        sqlite3_free (count_stmt);
 
-       cursor->query = sexp ? sexp_to_sql_query (ebsdb, cursor->folderid, sexp) : NULL;
+       if (sexp) {
+               cursor->query = sexp_to_sql_query (ebsdb, cursor->folderid, sexp);
+               cursor->sexp  = e_book_backend_sexp_new (sexp);
+       } else {
+               cursor->query = NULL;
+               cursor->sexp  = NULL;
+       }
 }
 
 static gchar *
@@ -5377,6 +5385,7 @@ ebsdb_cursor_free (EbSdbCursor *cursor)
                        g_free (cursor->state[i].values);
                }
 
+               g_clear_object (&(cursor->sexp));
                g_free (cursor->folderid);
                g_free (cursor->select_vcards);
                g_free (cursor->select_count);
@@ -5679,6 +5688,10 @@ e_book_backend_sqlitedb_cursor_new (EBookBackendSqliteDB *ebsdb,
        g_return_val_if_fail (E_IS_BOOK_BACKEND_SQLITEDB (ebsdb), NULL);
        g_return_val_if_fail (folderid && folderid[0], NULL);
 
+       /* We don't like '\0' sexps, prefer NULL */
+       if (sexp && !sexp[0])
+               sexp = NULL;
+
        /* We only support cursors for summary fields in the query */
        if (sexp && !e_book_backend_sqlitedb_check_summary_query (ebsdb, sexp, &query_with_list_attrs)) {
                g_set_error (error, E_BOOK_SDB_ERROR, E_BOOK_SDB_ERROR_INVALID_QUERY,
@@ -5960,6 +5973,10 @@ e_book_backend_sqlitedb_cursor_set_sexp (EBookBackendSqliteDB *ebsdb,
        g_return_val_if_fail (E_IS_BOOK_BACKEND_SQLITEDB (ebsdb), FALSE);
        g_return_val_if_fail (cursor != NULL, FALSE);
 
+       /* We don't like '\0' sexps, prefer NULL */
+       if (sexp && !sexp[0])
+               sexp = NULL;
+
        /* We only support cursors for summary fields in the query */
        if (sexp && !e_book_backend_sqlitedb_check_summary_query (ebsdb, sexp, &query_with_list_attrs)) {
                g_set_error (error, E_BOOK_SDB_ERROR, E_BOOK_SDB_ERROR_INVALID_QUERY,
@@ -6037,3 +6054,81 @@ e_book_backend_sqlitedb_cursor_calculate (EBookBackendSqliteDB *ebsdb,
 
        return success;
 }
+
+/**
+ * e_book_backend_sqlitedb_cursor_compare:
+ * @ebsdb: An #EBookBackendSqliteDB
+ * @cursor: The #EbSdbCursor
+ * @contact: The #EContact to compare
+ * @matches_sexp: (out) (allow-none): Whether the contact matches the cursor's search expression
+ *
+ * Compares @contact with @cursor and returns whether @contact is less than, equal to, or greater
+ * than @cursor.
+ *
+ * Returns: A value that is less than, equal to, or greater than zero if @contact is found,
+ * respectively, to be less than, to match, or be greater than the current value of @cursor.
+ */
+gint
+e_book_backend_sqlitedb_cursor_compare (EBookBackendSqliteDB *ebsdb,
+                                       EbSdbCursor          *cursor,
+                                       EContact             *contact,
+                                       gboolean             *matches_sexp)
+{
+       EBookBackendSqliteDBPrivate *priv;
+       gint i;
+       gint comparison = 0;
+
+       g_return_val_if_fail (E_IS_BOOK_BACKEND_SQLITEDB (ebsdb), FALSE);
+       g_return_val_if_fail (cursor != NULL, FALSE);
+
+       priv = ebsdb->priv;
+
+       if (matches_sexp) {
+               if (cursor->sexp == NULL)
+                       *matches_sexp = TRUE;
+               else
+                       *matches_sexp =
+                               e_book_backend_sexp_match_contact (cursor->sexp, contact);
+       }
+
+       for (i = 0; i < cursor->n_sort_fields && comparison == 0; i++) {
+
+               /* Empty state sorts below any contact value, which means the contact sorts above cursor */
+               if (cursor->state[STATE_CURRENT].values[i] == NULL) {
+                       comparison = 1;
+               } else {
+                       const gchar *field_value;
+
+                       field_value = (const gchar *)
+                               e_contact_get_const (contact, cursor->sort_fields[i]);
+
+                       /* Empty contact state sorts below any cursor value */
+                       if (field_value == NULL)
+                               comparison = -1;
+                       else {
+                               gchar *collation_key;
+
+                               /* Check of contact sorts below, equal to, or above the cursor */
+                               collation_key = e_collator_generate_key (priv->collator, field_value, NULL);
+                               comparison = strcmp (collation_key, cursor->state[STATE_CURRENT].values[i]);
+                               g_free (collation_key);
+                       }
+               }
+       }
+
+       /* UID tie-breaker */
+       if (comparison == 0) {
+               const gchar *uid;
+
+               uid = (const gchar *)e_contact_get_const (contact, E_CONTACT_UID);
+
+               if (cursor->state[STATE_CURRENT].last_uid == NULL)
+                       comparison = 1;
+               else if (uid == NULL)
+                       comparison = -1;
+               else
+                       comparison = strcmp (uid, cursor->state[STATE_CURRENT].last_uid);
+       }
+
+       return comparison;
+}
diff --git a/addressbook/libedata-book/e-book-backend-sqlitedb.h 
b/addressbook/libedata-book/e-book-backend-sqlitedb.h
index d723a4e..d1a2185 100644
--- a/addressbook/libedata-book/e-book-backend-sqlitedb.h
+++ b/addressbook/libedata-book/e-book-backend-sqlitedb.h
@@ -351,6 +351,11 @@ gboolean        e_book_backend_sqlitedb_cursor_calculate
                                                 gint                 *total,
                                                 gint                 *position,
                                                 GError              **error);
+gint            e_book_backend_sqlitedb_cursor_compare
+                                                (EBookBackendSqliteDB *ebsdb,
+                                                EbSdbCursor          *cursor,
+                                                EContact             *contact,
+                                                gboolean             *matches_sexp);
 
 #ifndef EDS_DISABLE_DEPRECATED
 gboolean       e_book_backend_sqlitedb_is_summary_query