[gnome-builder/wip/chergert/layout: 72/118] buffer: add IdeBuffer::change-settled

[Christian Hergert <chergert src gnome org>]

commit 2914cd4379c786f67226974bdf1f09aa279bca2f
Author: Christian Hergert <chergert redhat com>
Date:   Sat Jul 1 19:35:06 2017 -0700

    buffer: add IdeBuffer::change-settled
    
    This signal is a convenience signal to do background work when
    the user has stopped interactively typing. We will probably
    tweak this as we go on but what is here now mimics what the
    diagnosis engine was doing.
    
    You should use this if you want to update background work based
    on changes to the editor.

 libide/buffers/ide-buffer.c |   70 +++++++++++++++++++++++++++++++++++--------
 1 files changed, 57 insertions(+), 13 deletions(-)
---
diff --git a/libide/buffers/ide-buffer.c b/libide/buffers/ide-buffer.c
index 054e514..b4ae252 100644
--- a/libide/buffers/ide-buffer.c
+++ b/libide/buffers/ide-buffer.c
@@ -52,6 +52,7 @@
 #include "vcs/ide-vcs.h"
 
 #define DEFAULT_DIAGNOSE_TIMEOUT_MSEC          333
+#define SETTLING_DELAY_MSEC                    333
 #define DEFAULT_DIAGNOSE_CONSERVE_TIMEOUT_MSEC 5000
 #define RECLAIMATION_TIMEOUT_SECS              1
 #define MODIFICATION_TIMEOUT_SECS              1
@@ -99,6 +100,8 @@ typedef struct
   gint                    hold_count;
   guint                   reclamation_handler;
 
+  guint                   settling_handler;
+
   gsize                   change_count;
 
   guint                   cancel_cursor_restore : 1;
@@ -128,6 +131,7 @@ enum {
 };
 
 enum {
+  CHANGE_SETTLED,
   CURSOR_MOVED,
   DESTROY,
   LINE_FLAGS_CHANGED,
@@ -140,6 +144,33 @@ enum {
 static GParamSpec *properties [LAST_PROP];
 static guint signals [LAST_SIGNAL];
 
+static gboolean
+ide_buffer_settled_cb (gpointer user_data)
+{
+  IdeBuffer *self = user_data;
+  IdeBufferPrivate *priv = ide_buffer_get_instance_private (self);
+
+  g_assert (IDE_IS_BUFFER (self));
+
+  priv->settling_handler = 0;
+  g_signal_emit (self, signals [CHANGE_SETTLED], 0);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+ide_buffer_delay_settling (IdeBuffer *self)
+{
+  IdeBufferPrivate *priv = ide_buffer_get_instance_private (self);
+
+  g_assert (IDE_IS_BUFFER (self));
+
+  ide_clear_source (&priv->settling_handler);
+  priv->settling_handler = gdk_threads_add_timeout (SETTLING_DELAY_MSEC,
+                                                    ide_buffer_settled_cb,
+                                                    self);
+}
+
 void
 ide_buffer_set_spell_checking (IdeBuffer *self,
                                gboolean   enable)
@@ -688,6 +719,8 @@ ide_buffer_changed (GtkTextBuffer *buffer)
   priv->change_count++;
 
   g_clear_pointer (&priv->content, g_bytes_unref);
+
+  ide_buffer_delay_settling (self);
 }
 
 static void
@@ -1288,11 +1321,9 @@ ide_buffer_dispose (GObject *object)
 
   IDE_ENTRY;
 
-  if (priv->reclamation_handler != 0)
-    {
-      g_source_remove (priv->reclamation_handler);
-      priv->reclamation_handler = 0;
-    }
+  ide_clear_source (&priv->settling_handler);
+  ide_clear_source (&priv->reclamation_handler);
+  ide_clear_source (&priv->check_modified_timeout);
 
   if (priv->context != NULL)
     {
@@ -1301,13 +1332,7 @@ ide_buffer_dispose (GObject *object)
       _ide_buffer_manager_reclaim (buffer_manager, self);
     }
 
-  if (priv->check_modified_timeout != 0)
-    {
-      g_source_remove (priv->check_modified_timeout);
-      priv->check_modified_timeout = 0;
-    }
-
-  if (priv->file_monitor)
+  if (priv->file_monitor != NULL)
     {
       g_file_monitor_cancel (priv->file_monitor);
       g_clear_object (&priv->file_monitor);
@@ -1318,7 +1343,7 @@ ide_buffer_dispose (GObject *object)
   if (priv->highlight_engine != NULL)
     g_object_run_dispose (G_OBJECT (priv->highlight_engine));
 
-  if (priv->change_monitor)
+  if (priv->change_monitor != NULL)
     {
       ide_clear_signal_handler (priv->change_monitor, &priv->change_monitor_changed_handler);
       g_clear_object (&priv->change_monitor);
@@ -1531,6 +1556,25 @@ ide_buffer_class_init (IdeBufferClass *klass)
   g_object_class_install_properties (object_class, LAST_PROP, properties);
 
   /**
+   * IdeBuffer::change-settled:
+   * @self: An #IdeBuffer
+   *
+   * This signal is emitted as short period of time after changes have
+   * occurred. It provides plugins a convenient way to wait for the editor
+   * to settle before performing expensive work.
+   *
+   * You should probably use this instead of implementing your own
+   * settling management.
+   *
+   * Since: 3.26
+   */
+  signals [CHANGE_SETTLED] =
+    g_signal_new ("change-settled",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0, NULL, NULL, NULL, G_TYPE_NONE, 0);
+
+  /**
    * IdeBuffer::cursor-moved:
    * @self: An #IdeBuffer.
    * @location: A #GtkTextIter.