[gnome-builder] libide/sourceview: implement matching ops using buffer signals

[Christian Hergert <chergert src gnome org>]

commit ad022f7a21372e73d85f34e12cfbede4a67442fc
Author: Christian Hergert <chergert redhat com>
Date:   Thu Oct 6 20:54:33 2022 -0700

    libide/sourceview: implement matching ops using buffer signals
    
    We don't want to be using key controllers to do this work because it can
    really get in the way of using things like Vim input methods (or any
    input methods for that matter).
    
    This requires a bit more trickery, and I'm sure we can make it better, with
    how we're detecting key presses, but it seems to be the one thing that
    works in the absence of knowing if we're in GtkTextView from a
    "commit-text" phase of a input method via a key-press.
    
    Seems to fix the issue with Vim as well.
    
    Fixes #1851

 src/libide/sourceview/ide-source-view-private.h |   2 +
 src/libide/sourceview/ide-source-view.c         | 302 +++++++++++-------------
 2 files changed, 141 insertions(+), 163 deletions(-)
---
diff --git a/src/libide/sourceview/ide-source-view-private.h b/src/libide/sourceview/ide-source-view-private.h
index 77d56a956..029104acb 100644
--- a/src/libide/sourceview/ide-source-view-private.h
+++ b/src/libide/sourceview/ide-source-view-private.h
@@ -80,6 +80,8 @@ struct _IdeSourceView
   guint highlight_current_line : 1;
   guint insert_matching_brace : 1;
   guint overwrite_braces : 1;
+  guint in_key_press : 1;
+  guint in_backspace : 1;
 };
 
 
diff --git a/src/libide/sourceview/ide-source-view.c b/src/libide/sourceview/ide-source-view.c
index 09cb0d3a9..9b5d2ff63 100644
--- a/src/libide/sourceview/ide-source-view.c
+++ b/src/libide/sourceview/ide-source-view.c
@@ -443,48 +443,6 @@ ide_source_view_click_pressed_cb (IdeSourceView   *self,
   IDE_EXIT;
 }
 
-static gboolean
-ide_source_view_maybe_delete_match (IdeSourceView *self)
-{
-  GtkTextBuffer *buffer;
-  GtkTextMark *insert;
-  GtkTextIter iter;
-  GtkTextIter prev;
-  gunichar ch;
-  gunichar match;
-
-  g_assert (IDE_IS_SOURCE_VIEW (self));
-
-  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (self));
-  insert = gtk_text_buffer_get_insert (buffer);
-  gtk_text_buffer_get_iter_at_mark (buffer, &iter, insert);
-  prev = iter;
-  if (!gtk_text_iter_backward_char (&prev))
-    return FALSE;
-
-  ch = gtk_text_iter_get_char (&prev);
-
-  switch (ch)
-    {
-    case '[':  match = ']';  break;
-    case '{':  match = '}';  break;
-    case '(':  match = ')';  break;
-    case '"':  match = '"';  break;
-    case '\'': match = '\''; break;
-    default:   match = 0;    break;
-    }
-
-  if (match && (gtk_text_iter_get_char (&iter) == match))
-    {
-      gtk_text_iter_forward_char (&iter);
-      gtk_text_buffer_delete (buffer, &prev, &iter);
-
-      return TRUE;
-    }
-
-  return FALSE;
-}
-
 static gboolean
 ide_source_view_key_pressed_cb (IdeSourceView         *self,
                                 guint                  keyval,
@@ -492,133 +450,26 @@ ide_source_view_key_pressed_cb (IdeSourceView         *self,
                                 GdkModifierType        state,
                                 GtkEventControllerKey *key)
 {
-  GtkTextBuffer *buffer;
-
   g_assert (IDE_IS_SOURCE_VIEW (self));
   g_assert (GTK_IS_EVENT_CONTROLLER_KEY (key));
 
-  buffer = GTK_TEXT_BUFFER (self->buffer);
+  self->in_backspace = keyval == GDK_KEY_BackSpace;
+  self->in_key_press = TRUE;
 
-  if (self->overwrite_braces &&
-      !gtk_text_buffer_get_has_selection (buffer))
-    {
-      GtkTextIter iter;
-      gunichar ch;
-      gboolean overwrite;
-
-      gtk_text_buffer_get_selection_bounds (buffer, &iter, NULL);
-      ch = gtk_text_iter_get_char (&iter);
-
-      switch (keyval)
-        {
-        case GDK_KEY_quotedbl:
-          overwrite = ch == '"';
-          break;
-
-        case GDK_KEY_parenright:
-          overwrite = ch == ')';
-          break;
-
-        case GDK_KEY_apostrophe:
-          overwrite = ch == '\'';
-          break;
-
-        case GDK_KEY_greater:
-          overwrite = ch == '>';
-          break;
-
-        case GDK_KEY_bracketright:
-          overwrite = ch == ']';
-          break;
-
-        case GDK_KEY_braceright:
-          overwrite = ch == '}';
-          break;
-
-        default:
-          overwrite = FALSE;
-          break;
-        }
-
-      if (overwrite)
-        {
-          GtkTextIter next = iter;
-          g_autofree char *text = NULL;
-
-          gtk_text_iter_forward_char (&next);
-          gtk_text_buffer_begin_user_action (buffer);
-          gtk_text_buffer_select_range (buffer, &iter, &next);
-          text = gtk_text_iter_get_slice (&iter, &next);
-          gtk_text_buffer_delete (buffer, &iter, &next);
-          gtk_text_buffer_insert (buffer, &iter, text, -1);
-          gtk_text_buffer_end_user_action (buffer);
-
-          return TRUE;
-        }
-    }
-
-  if (self->insert_matching_brace &&
-      !gtk_text_buffer_get_has_selection (buffer))
-    {
-      const char *insert = NULL;
-      GtkTextIter iter;
-
-      if (keyval == GDK_KEY_BackSpace)
-        {
-          if (ide_source_view_maybe_delete_match (self))
-            return TRUE;
-        }
-
-      gtk_text_buffer_get_selection_bounds (buffer, &iter, NULL);
-
-      switch (keyval)
-        {
-        case GDK_KEY_bracketleft:
-          insert = "[]";
-          break;
-
-        case GDK_KEY_braceleft:
-          insert = "{}";
-          break;
-
-        case GDK_KEY_apostrophe:
-          insert = "''";
-          break;
-
-        case GDK_KEY_parenleft:
-          insert = "()";
-          break;
-
-        case GDK_KEY_quotedbl:
-          insert = "\"\"";
-          break;
-
-#if 0
-        /* We don't do this because it makes it very annoying to do things
-         * like << in any language, without much benefit for Foo<T>.
-         *
-         * See https://gitlab.gnome.org/GNOME/gnome-builder/-/issues/1824
-         */
-        case GDK_KEY_less:
-          insert = "<>";
-          break;
-#endif
-
-        default:
-          break;
-        }
+  return FALSE;
+}
 
-      if (insert)
-        {
-          gtk_text_buffer_begin_user_action (buffer);
-          gtk_text_buffer_insert (buffer, &iter, insert, -1);
-          gtk_text_iter_backward_char (&iter);
-          gtk_text_buffer_select_range (buffer, &iter, &iter);
-          gtk_text_buffer_end_user_action (buffer);
+static gboolean
+ide_source_view_key_released_cb (IdeSourceView         *self,
+                                 guint                  keyval,
+                                 guint                  keycode,
+                                 GdkModifierType        state,
+                                 GtkEventControllerKey *key)
+{
+  g_assert (IDE_IS_SOURCE_VIEW (self));
+  g_assert (GTK_IS_EVENT_CONTROLLER_KEY (key));
 
-          return TRUE;
-        }
-    }
+  self->in_key_press = FALSE;
 
   return FALSE;
 }
@@ -659,6 +510,115 @@ ide_source_view_buffer_notify_language_cb (IdeSourceView *self,
   IDE_EXIT;
 }
 
+static void
+ide_source_view_insert_text_cb (IdeSourceView *self,
+                                GtkTextIter   *location,
+                                const char    *text,
+                                int            length,
+                                IdeBuffer     *buffer)
+{
+  const char *match = NULL;
+  GtkTextIter insert;
+  gunichar overwrite = 0;
+  gunichar ch;
+
+  g_assert (IDE_IS_MAIN_THREAD ());
+  g_assert (IDE_IS_SOURCE_VIEW (self));
+  g_assert (text != NULL);
+  g_assert (location != NULL);
+  g_assert (IDE_IS_BUFFER (buffer));
+
+  if (length != 1 || !self->in_key_press)
+    return;
+
+  ide_buffer_get_selection_bounds (buffer, &insert, NULL);
+
+  /* Do we want to allow selection overwrite to "" instead of "? */
+  if (gtk_text_buffer_get_has_selection (GTK_TEXT_BUFFER (buffer)))
+    return;
+
+  if (!gtk_text_iter_equal (&insert, location))
+    return;
+
+  ch = g_utf8_get_char (text);
+
+  switch (ch)
+    {
+    case '{': match = "}"; break;
+    case '[': match = "]"; break;
+    case '(': match = ")"; break;
+    case '"': match = "\""; overwrite = ch; break;
+    case '\'': match = "'"; overwrite = ch; break;
+    case '}': case ']': case ')': overwrite = ch; break;
+    default: break;
+    }
+
+  /* "Overwrite" the next character if necessary */
+  if (overwrite != 0 &&
+      self->overwrite_braces &&
+      gtk_text_iter_get_char (location) == overwrite)
+    {
+      gtk_text_iter_forward_char (location);
+      gtk_text_buffer_select_range (GTK_TEXT_BUFFER (buffer),
+                                    location, location);
+      g_signal_stop_emission_by_name (buffer, "insert-text");
+      return;
+    }
+
+  /* Insert a match if necessary */
+  if (match != NULL &&
+      self->insert_matching_brace &&
+      gtk_text_iter_get_char (location) != match[0])
+    {
+      guint offset = gtk_text_iter_get_offset (location);
+
+      self->in_key_press = FALSE;
+      gtk_text_buffer_insert (GTK_TEXT_BUFFER (buffer), location, match, 1);
+      gtk_text_buffer_get_iter_at_offset (GTK_TEXT_BUFFER (buffer), location, offset);
+      gtk_text_buffer_select_range (GTK_TEXT_BUFFER (buffer), location, location);
+      self->in_key_press = TRUE;
+    }
+}
+
+static void
+ide_source_view_delete_range_cb (IdeSourceView *self,
+                                 GtkTextIter   *begin,
+                                 GtkTextIter   *end,
+                                 IdeBuffer     *buffer)
+{
+  GtkTextIter prev;
+  gunichar match = 0;
+
+  g_assert (IDE_IS_MAIN_THREAD ());
+  g_assert (IDE_IS_SOURCE_VIEW (self));
+  g_assert (begin != NULL);
+  g_assert (end != NULL);
+  g_assert (IDE_IS_BUFFER (buffer));
+
+  if (!self->in_key_press ||
+      !self->in_backspace ||
+      !self->insert_matching_brace)
+    return;
+
+  gtk_text_iter_order (begin, end);
+  prev = *end;
+  gtk_text_iter_backward_char (&prev);
+
+  switch (gtk_text_iter_get_char (&prev))
+    {
+    case '{': match = '}'; break;
+    case '[': match = ']'; break;
+    case '(': match = ')'; break;
+    case '"': match = '"'; break;
+    case '\'': match = '\''; break;
+    default: break;
+    }
+
+  /* Remove matching }])"' */
+  if (match && gtk_text_iter_get_char (end) == match)
+    gtk_text_iter_forward_char (end);
+}
+
 static void
 ide_source_view_connect_buffer (IdeSourceView *self,
                                 IdeBuffer     *buffer)
@@ -697,6 +657,18 @@ ide_source_view_connect_buffer (IdeSourceView *self,
                            self,
                            G_CONNECT_SWAPPED);
 
+  /* Insert matching braces features */
+  g_signal_connect_object (buffer,
+                           "insert-text",
+                           G_CALLBACK (ide_source_view_insert_text_cb),
+                           self,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (buffer,
+                           "delete-range",
+                           G_CALLBACK (ide_source_view_delete_range_cb),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   /* Load addins immediately */
   language = gtk_source_buffer_get_language (GTK_SOURCE_BUFFER (buffer));
   _ide_source_view_addins_init (self, language);
@@ -1485,6 +1457,10 @@ ide_source_view_init (IdeSourceView *self)
                             "key-pressed",
                             G_CALLBACK (ide_source_view_key_pressed_cb),
                             self);
+  g_signal_connect_swapped (key,
+                            "key-released",
+                            G_CALLBACK (ide_source_view_key_released_cb),
+                            self);
   ide_source_view_add_controller (self, 0, key);
 
   /* Setup focus tracking */