[gnome-builder] buffers: fix tracking of failed buffer loads

[Christian Hergert <chergert src gnome org>]

commit 46cb5f91d9375c937927a27545bfb03dde15206b
Author: Christian Hergert <chergert redhat com>
Date:   Sun Jun 18 02:05:33 2017 -0700

    buffers: fix tracking of failed buffer loads
    
    If we failed loading a buffer properly, such as by encoding error, we'll
    always try to reload it at startup because it will never be removed from
    the drafts. That can cause quite a bit of pain to recover since you'd have
    to remove the drafts directory.
    
    This ensures that we track the buffer, so that we can later clean it up.
    
    It also moves some things around so that we always do the cleanup work
    from buffer-unloaded's default handler.

 libide/buffers/ide-buffer-manager.c |  109 ++++++++++++++++++++++++-----------
 1 files changed, 75 insertions(+), 34 deletions(-)
---
diff --git a/libide/buffers/ide-buffer-manager.c b/libide/buffers/ide-buffer-manager.c
index b085aab..f9e67c6 100644
--- a/libide/buffers/ide-buffer-manager.c
+++ b/libide/buffers/ide-buffer-manager.c
@@ -381,16 +381,14 @@ ide_buffer_manager_buffer_changed (IdeBufferManager *self,
 }
 
 static void
-ide_buffer_manager_add_buffer (IdeBufferManager *self,
-                               IdeBuffer        *buffer)
+ide_buffer_manager_track_buffer (IdeBufferManager *self,
+                                 IdeBuffer        *buffer)
 {
   IDE_ENTRY;
 
   g_return_if_fail (IDE_IS_BUFFER_MANAGER (self));
   g_return_if_fail (IDE_IS_BUFFER (buffer));
 
-  g_ptr_array_add (self->buffers, g_object_ref (buffer));
-
   if (self->auto_save)
     register_auto_save (self, buffer);
 
@@ -413,10 +411,6 @@ static void
 ide_buffer_manager_remove_buffer (IdeBufferManager *self,
                                   IdeBuffer        *buffer)
 {
-  IdeUnsavedFiles *unsaved_files;
-  IdeContext *context;
-  IdeFile *file;
-  GFile *gfile;
   gint position = -1;
 
   IDE_ENTRY;
@@ -426,7 +420,9 @@ ide_buffer_manager_remove_buffer (IdeBufferManager *self,
 
   for (guint i = 0; i < self->buffers->len; i++)
     {
-      if ((gpointer)buffer == g_ptr_array_index (self->buffers, i))
+      IdeBuffer *ele = g_ptr_array_index (self->buffers, i);
+
+      if (ele == buffer)
         {
           position = i;
           break;
@@ -434,17 +430,14 @@ ide_buffer_manager_remove_buffer (IdeBufferManager *self,
     }
 
   if (position == -1)
-    IDE_EXIT;
+    {
+      IDE_TRACE_MSG ("failed to locate buffer %p within buffer manager", buffer);
+      IDE_EXIT;
+    }
 
+  /* Stealing ownership from self->buffers */
   g_ptr_array_remove_index (self->buffers, position);
 
-  file = ide_buffer_get_file (buffer);
-  gfile = ide_file_get_file (file);
-
-  context = ide_object_get_context (IDE_OBJECT (self));
-  unsaved_files = ide_context_get_unsaved_files (context);
-  ide_unsaved_files_remove (unsaved_files, gfile);
-
   gtk_source_completion_words_unregister (self->word_completion, GTK_TEXT_BUFFER (buffer));
 
   unregister_auto_save (self, buffer);
@@ -469,6 +462,7 @@ ide_buffer_manager_remove_buffer (IdeBufferManager *self,
   g_signal_emit_by_name (buffer, "destroy");
   g_object_run_dispose (G_OBJECT (buffer));
 
+  /* We stole ownership from self->buffers */
   g_object_unref (buffer);
 
   DZL_COUNTER_DEC (registered);
@@ -535,10 +529,20 @@ ide_buffer_manager_load_file__load_cb (GObject      *object,
 
   context = ide_object_get_context (IDE_OBJECT (self));
 
+  /*
+   * Always track the buffer so that we can clean things up
+   * properly when teh buffer is disposed.
+   */
+  if (state->is_new)
+    g_ptr_array_add (self->buffers, g_object_ref (state->buffer));
+
   if (!gtk_source_file_loader_load_finish (loader, result, &error))
     {
       /*
        * It's okay if we fail because the file does not exist yet.
+       *
+       * TODO: Add "Failed" state to buffers so we can display something
+       *       other than the sourceview in the editor perspective.
        */
       if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
         {
@@ -562,7 +566,7 @@ ide_buffer_manager_load_file__load_cb (GObject      *object,
     }
 
   if (state->is_new)
-    ide_buffer_manager_add_buffer (self, state->buffer);
+    ide_buffer_manager_track_buffer (self, state->buffer);
 
   /*
    * If we have a navigation item for this buffer, restore the insert mark to
@@ -1230,6 +1234,38 @@ ide_buffer_manager_real_create_buffer (IdeBufferManager *self,
                        NULL);
 }
 
+static void
+ide_buffer_manager_real_buffer_unloaded (IdeBufferManager *self,
+                                         IdeBuffer        *buffer)
+{
+  IDE_ENTRY;
+
+  g_assert (IDE_IS_BUFFER_MANAGER (self));
+  g_assert (IDE_IS_BUFFER (buffer));
+
+  /*
+   * If this buffer is not modified, then we want to release any
+   * drafts associated with it as they are not necessary anymore.
+   */
+
+  if (!gtk_text_buffer_get_modified (GTK_TEXT_BUFFER (buffer)))
+    {
+      IdeUnsavedFiles *unsaved_files;
+      IdeContext *context;
+      IdeFile *file;
+      GFile *gfile;
+
+      context = ide_buffer_get_context (buffer);
+      unsaved_files = ide_context_get_unsaved_files (context);
+
+      if (NULL != (file = ide_buffer_get_file (buffer)) &&
+          NULL != (gfile = ide_file_get_file (file)))
+        ide_unsaved_files_remove (unsaved_files, gfile);
+    }
+
+  IDE_EXIT;
+}
+
 static GType
 ide_buffer_manager_get_item_type (GListModel *self)
 {
@@ -1484,14 +1520,14 @@ ide_buffer_manager_class_init (IdeBufferManagerClass *klass)
    * changes from the host file-system.
    */
   signals [LOAD_BUFFER] = g_signal_new ("load-buffer",
-                                         G_TYPE_FROM_CLASS (klass),
-                                         G_SIGNAL_RUN_LAST,
-                                         0,
-                                         NULL, NULL, NULL,
-                                         G_TYPE_NONE,
-                                         2,
-                                         IDE_TYPE_BUFFER,
-                                         G_TYPE_BOOLEAN);
+                                        G_TYPE_FROM_CLASS (klass),
+                                        G_SIGNAL_RUN_LAST,
+                                        0,
+                                        NULL, NULL, NULL,
+                                        G_TYPE_NONE,
+                                        2,
+                                        IDE_TYPE_BUFFER,
+                                        G_TYPE_BOOLEAN);
 
   /**
    * IdeBufferManager::buffer-loaded:
@@ -1551,14 +1587,16 @@ ide_buffer_manager_class_init (IdeBufferManagerClass *klass)
    * @buffer: An #IdeBuffer
    *
    * This signal is emitted when the buffer is unloaded. This allows consumers to access the
-   * buffer before the items-changed signal is emitted for which it is too late to get
-   * a pointer to the buffer.
+   * buffer before the items-changed signal is emitted; at which point it will be too late to
+   * get a pointer to the buffer.
    */
-  signals [BUFFER_UNLOADED] = g_signal_new ("buffer-unloaded",
-                                            G_TYPE_FROM_CLASS (klass),
-                                            G_SIGNAL_RUN_LAST,
-                                            0, NULL, NULL, NULL,
-                                            G_TYPE_NONE, 1, IDE_TYPE_BUFFER);
+  signals [BUFFER_UNLOADED] =
+    g_signal_new_class_handler ("buffer-unloaded",
+                                G_TYPE_FROM_CLASS (klass),
+                                G_SIGNAL_RUN_LAST,
+                                G_CALLBACK (ide_buffer_manager_real_buffer_unloaded),
+                                NULL, NULL, NULL,
+                                G_TYPE_NONE, 1, IDE_TYPE_BUFFER);
 
   g_type_ensure (GTK_SOURCE_TYPE_FILE_LOADER);
   g_type_ensure (GTK_SOURCE_TYPE_FILE_SAVER);
@@ -1800,7 +1838,10 @@ ide_buffer_manager_create_temporary_buffer (IdeBufferManager *self)
 
   g_signal_emit (self, signals [CREATE_BUFFER], 0, file, &buffer);
   g_signal_emit (self, signals [LOAD_BUFFER], 0, buffer, TRUE);
-  ide_buffer_manager_add_buffer (self, buffer);
+
+  g_ptr_array_add (self->buffers, g_object_ref (buffer));
+  ide_buffer_manager_track_buffer (self, buffer);
+
   g_signal_emit (self, signals [BUFFER_LOADED], 0, buffer);
 
   return buffer;