[gnome-builder] completion: add helper to remove common prefix

[Christian Hergert <chergert src gnome org>]

commit 4718ab52bbd8d609ada961779a4de8b5b6727860
Author: Christian Hergert <chergert redhat com>
Date:   Sun Mar 14 15:36:13 2021 -0700

    completion: add helper to remove common prefix
    
    Not exactly the best implementation, but seems to do the job.
    
    Related #1416

 src/libide/sourceview/ide-completion.c | 70 ++++++++++++++++++++++++++++++++++
 src/libide/sourceview/ide-completion.h | 52 +++++++++++++------------
 2 files changed, 98 insertions(+), 24 deletions(-)
---
diff --git a/src/libide/sourceview/ide-completion.c b/src/libide/sourceview/ide-completion.c
index 3ecd7da6c..e69b50a3c 100644
--- a/src/libide/sourceview/ide-completion.c
+++ b/src/libide/sourceview/ide-completion.c
@@ -1790,3 +1790,73 @@ ide_completion_fuzzy_highlight (const gchar *haystack,
 
   return g_string_free (ret, FALSE);
 }
+
+static gboolean
+find_suffix_match (const GtkTextIter *limit,
+                   const GtkTextIter *end,
+                   GtkTextIter       *found_start,
+                   GtkTextIter       *found_end,
+                   const char        *prefix,
+                   gsize              n_chars)
+{
+  g_autofree gchar *copy = g_malloc (n_chars * 4 + 1);
+  GtkTextIter mb, me;
+
+  g_utf8_strncpy (copy, prefix, n_chars);
+
+  g_print ("%s\n", prefix);
+
+  if (gtk_text_iter_backward_search (end, copy, GTK_TEXT_SEARCH_TEXT_ONLY, &mb, &me, limit))
+    {
+      if (gtk_text_iter_equal (&me, end))
+      {
+        *found_start = mb;
+        *found_end = me;
+        return TRUE;
+      }
+
+      g_print ("Blah\n");
+    }
+
+  return FALSE;
+}
+
+void
+ide_completion_remove_common_prefix (IdeCompletion *self,
+                                     GtkTextIter   *begin,
+                                     const gchar   *prefix)
+{
+  GtkTextIter rm_begin;
+  GtkTextIter rm_end;
+  GtkTextIter line_start;
+  GtkTextIter found_start, found_end;
+  gboolean found = FALSE;
+  gsize len;
+  gsize count = 1;
+
+  g_return_if_fail (IDE_IS_COMPLETION (self));
+  g_return_if_fail (self->context != NULL);
+  g_return_if_fail (begin != NULL);
+
+  if (prefix == NULL || prefix[0] == 0)
+    return;
+
+  len = g_utf8_strlen (prefix, -1);
+  line_start = *begin;
+  gtk_text_iter_set_line_offset (&line_start, 0);
+
+  while (count <= len &&
+         find_suffix_match (&line_start, begin, &found_start, &found_end, prefix, count))
+    {
+      rm_begin = found_start;
+      rm_end = found_end;
+      count++;
+      found = TRUE;
+    }
+
+  if (found)
+    {
+      gtk_text_buffer_delete (gtk_text_iter_get_buffer (begin), &rm_begin, &rm_end);
+      *begin = rm_begin;
+    }
+}
diff --git a/src/libide/sourceview/ide-completion.h b/src/libide/sourceview/ide-completion.h
index 9b31bf166..89906a534 100644
--- a/src/libide/sourceview/ide-completion.h
+++ b/src/libide/sourceview/ide-completion.h
@@ -38,44 +38,48 @@ IDE_AVAILABLE_IN_3_32
 G_DECLARE_FINAL_TYPE (IdeCompletion, ide_completion, IDE, COMPLETION, GObject)
 
 IDE_AVAILABLE_IN_3_32
-IdeCompletionDisplay *ide_completion_get_display         (IdeCompletion         *self);
+IdeCompletionDisplay *ide_completion_get_display          (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-GtkSourceView        *ide_completion_get_view            (IdeCompletion         *self);
+GtkSourceView        *ide_completion_get_view             (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-GtkTextBuffer        *ide_completion_get_buffer          (IdeCompletion         *self);
+GtkTextBuffer        *ide_completion_get_buffer           (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_block_interactive   (IdeCompletion         *self);
+void                  ide_completion_block_interactive    (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_unblock_interactive (IdeCompletion         *self);
+void                  ide_completion_unblock_interactive  (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_add_provider        (IdeCompletion         *self,
-                                                          IdeCompletionProvider *provider);
+void                  ide_completion_add_provider         (IdeCompletion         *self,
+                                                           IdeCompletionProvider *provider);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_remove_provider     (IdeCompletion         *self,
-                                                          IdeCompletionProvider *provider);
+void                  ide_completion_remove_provider      (IdeCompletion         *self,
+                                                           IdeCompletionProvider *provider);
 IDE_AVAILABLE_IN_3_32
-guint                 ide_completion_get_n_rows          (IdeCompletion         *self);
+guint                 ide_completion_get_n_rows           (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_set_n_rows          (IdeCompletion         *self,
-                                                          guint                  n_rows);
+void                  ide_completion_set_n_rows           (IdeCompletion         *self,
+                                                           guint                  n_rows);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_hide                (IdeCompletion         *self);
+void                  ide_completion_hide                 (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_show                (IdeCompletion         *self);
+void                  ide_completion_show                 (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_cancel              (IdeCompletion         *self);
+void                  ide_completion_cancel               (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-gboolean              ide_completion_is_visible          (IdeCompletion         *self);
+gboolean              ide_completion_is_visible           (IdeCompletion         *self);
 IDE_AVAILABLE_IN_3_32
-void                  ide_completion_move_cursor         (IdeCompletion         *self,
-                                                          GtkMovementStep        step,
-                                                          gint                   direction);
+void                  ide_completion_move_cursor          (IdeCompletion         *self,
+                                                           GtkMovementStep        step,
+                                                           gint                   direction);
 IDE_AVAILABLE_IN_3_32
-gboolean              ide_completion_fuzzy_match         (const gchar           *haystack,
-                                                          const gchar           *casefold_needle,
-                                                          guint                 *priority);
+gboolean              ide_completion_fuzzy_match          (const gchar           *haystack,
+                                                           const gchar           *casefold_needle,
+                                                           guint                 *priority);
 IDE_AVAILABLE_IN_3_32
-gchar                *ide_completion_fuzzy_highlight     (const gchar           *haystack,
-                                                          const gchar           *casefold_query);
+gchar                *ide_completion_fuzzy_highlight      (const gchar           *haystack,
+                                                           const gchar           *casefold_query);
+IDE_AVAILABLE_IN_3_40
+void                  ide_completion_remove_common_prefix (IdeCompletion         *self,
+                                                           GtkTextIter           *begin,
+                                                           const gchar           *prefix);
 
 G_END_DECLS