entrycompletion: Export gtk_entry_completion_compute_prefix()

I want to use it in the file chooser entry autocomplete code.

1 files changed, 21 insertions, 6 deletions

diff --git a/gtk/gtkentrycompletion.c b/gtk/gtkentrycompletion.c
index 4847b9d696..b7e9b6b3e4 100644
--- a/gtk/gtkentrycompletion.c
+++ b/gtk/gtkentrycompletion.c
@@ -1693,19 +1693,32 @@ gtk_entry_completion_cursor_on_match (GtkEntryCompletion *completion,
   return TRUE;
 }
 
-static gchar *
-gtk_entry_completion_compute_prefix (GtkEntryCompletion *completion)
+/**
+ * gtk_entry_completion_compute_prefix:
+ * @completion: the entry completion
+ * @key: The text to complete for
+ *
+ * Computes the common prefix that is shared by all rows in @completion
+ * that start with @key. If no row matches @key, %NULL will be returned.
+ * Note that a text column must have been set for this function to work,
+ * see gtk_entry_completion_set_text_column() for details. 
+ *
+ * Returns: (transfer: full): The common prefix all rows starting with @key
+ *   or %NULL if no row matches @key.
+ *
+ * Since: 3.4
+ **/
+gchar *
+gtk_entry_completion_compute_prefix (GtkEntryCompletion *completion,
+                                     const char         *key)
 {
   GtkTreeIter iter;
   gchar *prefix = NULL;
   gboolean valid;
-  const gchar *key;
 
   if (completion->priv->text_column < 0)
     return NULL;
 
-  key = gtk_entry_get_text (GTK_ENTRY (completion->priv->entry));
-
   valid = gtk_tree_model_get_iter_first (GTK_TREE_MODEL (completion->priv->filter_model),
                                          &iter);
 
@@ -1874,7 +1887,9 @@ gtk_entry_completion_insert_prefix (GtkEntryCompletion *completion)
     g_signal_handler_block (completion->priv->entry,
                             completion->priv->insert_text_id);
 
-  prefix = gtk_entry_completion_compute_prefix (completion);
+  prefix = gtk_entry_completion_compute_prefix (completion,
+                                                gtk_entry_get_text (GTK_ENTRY (completion->priv->entry)));
+
   if (prefix)
     {
       g_signal_emit (completion, entry_completion_signals[INSERT_PREFIX],