[gnome-todo] task-eds: Add reversible editing

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 0bf79eb043c4dc07da73013586a2773a7c3149b6
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sun Sep 16 01:38:42 2018 -0300

    task-eds: Add reversible editing
    
    This will be useful in the future. GtdTaskEds now stores
    the original component, and redirects all editing into
    a new one.
    
    When an update is successful, this new component becomes
    the actual one, and the process repeats (another component
    is created, all editing is redirected, etc).
    
    On error, however, the original component is restored and
    we can at least show the real contents of the task, instead
    of pretending everything went fine.

 plugins/eds/gtd-provider-eds.c | 21 ++++++++--
 plugins/eds/gtd-task-eds.c     | 88 +++++++++++++++++++++++++++---------------
 plugins/eds/gtd-task-eds.h     |  4 ++
 3 files changed, 78 insertions(+), 35 deletions(-)
---
diff --git a/plugins/eds/gtd-provider-eds.c b/plugins/eds/gtd-provider-eds.c
index 2d961ae..abedede 100644
--- a/plugins/eds/gtd-provider-eds.c
+++ b/plugins/eds/gtd-provider-eds.c
@@ -281,6 +281,9 @@ on_task_created_cb (ECalClient   *client,
   if (new_uid)
     gtd_object_set_uid (GTD_OBJECT (task), new_uid);
 
+  /* Effectively apply the updated component */
+  gtd_task_eds_apply (GTD_TASK_EDS (task));
+
   GTD_EXIT;
 }
 
@@ -301,7 +304,15 @@ on_task_modified_cb (ECalClient   *client,
 
   e_cal_client_modify_object_finish (client, result, &error);
 
-  gtd_task_list_update_task (gtd_task_get_list (task), task);
+  if (!error)
+    {
+      gtd_task_eds_apply (GTD_TASK_EDS (task));
+      gtd_task_list_update_task (gtd_task_get_list (task), task);
+    }
+  else
+    {
+      gtd_task_eds_revert (GTD_TASK_EDS (task));
+    }
 
   REPORT_ERROR (_("An error occurred while modifying a task"), error);
 
@@ -458,9 +469,10 @@ gtd_provider_eds_create_task (GtdProvider *provider,
                               const gchar *title,
                               GDateTime   *due_date)
 {
+  g_autoptr (ECalComponent) component = NULL;
+  ECalComponent *updated_component;
   GtdTaskListEds *tasklist;
   GtdProviderEds *self;
-  ECalComponent *component;
   ECalClient *client;
   GtdTask *new_task;
 
@@ -481,6 +493,9 @@ gtd_provider_eds_create_task (GtdProvider *provider,
   gtd_task_set_due_date (new_task, due_date);
   gtd_task_set_list (new_task, list);
 
+  /* Use the component with the changes we've just done */
+  updated_component = gtd_task_eds_get_component (GTD_TASK_EDS (new_task));
+
   gtd_task_list_add_task (list, new_task);
 
   /* The task is not ready until we finish the operation */
@@ -488,7 +503,7 @@ gtd_provider_eds_create_task (GtdProvider *provider,
   gtd_object_push_loading (GTD_OBJECT (new_task));
 
   e_cal_client_create_object (client,
-                              e_cal_component_get_icalcomponent (component),
+                              e_cal_component_get_icalcomponent (updated_component),
                               NULL,
                               (GAsyncReadyCallback) on_task_created_cb,
                               new_task);
diff --git a/plugins/eds/gtd-task-eds.c b/plugins/eds/gtd-task-eds.c
index 3a3f7bb..7b7d800 100644
--- a/plugins/eds/gtd-task-eds.c
+++ b/plugins/eds/gtd-task-eds.c
@@ -18,6 +18,7 @@
 
 #define G_LOG_DOMAIN "GtdTaskEds"
 
+#include "gtd-eds-autoptr.h"
 #include "gtd-task-eds.h"
 
 struct _GtdTaskEds
@@ -25,6 +26,7 @@ struct _GtdTaskEds
   GtdTask             parent;
 
   ECalComponent      *component;
+  ECalComponent      *new_component;
 
   gchar              *description;
 };
@@ -79,7 +81,7 @@ set_description (GtdTaskEds  *self,
   g_clear_pointer (&self->description, g_free);
   self->description = g_strdup (description);
 
-  e_cal_component_set_description_list (self->component, &note);
+  e_cal_component_set_description_list (self->new_component, &note);
 }
 
 static void
@@ -90,7 +92,7 @@ setup_description (GtdTaskEds *self)
   GSList *l;
 
   /* concatenates the multiple descriptions a task may have */
-  e_cal_component_get_description_list (self->component, &text_list);
+  e_cal_component_get_description_list (self->new_component, &text_list);
 
   for (l = text_list; l != NULL; l = l->next)
     {
@@ -137,8 +139,8 @@ gtd_task_eds_get_uid (GtdObject *object)
 
   self = GTD_TASK_EDS (object);
 
-  if (self->component)
-    e_cal_component_get_uid (self->component, &uid);
+  if (self->new_component)
+    e_cal_component_get_uid (self->new_component, &uid);
   else
     uid = NULL;
 
@@ -156,14 +158,14 @@ gtd_task_eds_set_uid (GtdObject   *object,
 
   self = GTD_TASK_EDS (object);
 
-  if (!self->component)
+  if (!self->new_component)
     return;
 
-  e_cal_component_get_uid (self->component, &current_uid);
+  e_cal_component_get_uid (self->new_component, &current_uid);
 
   if (g_strcmp0 (current_uid, uid) != 0)
     {
-      e_cal_component_set_uid (self->component, uid);
+      e_cal_component_set_uid (self->new_component, uid);
 
       g_object_notify (G_OBJECT (object), "uid");
     }
@@ -185,7 +187,7 @@ gtd_task_eds_get_completion_date (GtdTask *task)
   idt = NULL;
   dt = NULL;
 
-  e_cal_component_get_completed (self->component, &idt);
+  e_cal_component_get_completed (self->new_component, &idt);
 
   if (idt)
     dt = convert_icaltime (idt);
@@ -220,7 +222,7 @@ gtd_task_eds_set_completion_date (GtdTask   *task,
    */
   icaltimezone_convert_time (idt, NULL, icaltimezone_get_utc_timezone ());
 
-  e_cal_component_set_completed (self->component, idt);
+  e_cal_component_set_completed (self->new_component, idt);
 
   if (idt)
     e_cal_component_free_icaltimetype (idt);
@@ -237,7 +239,7 @@ gtd_task_eds_get_complete (GtdTask *task)
 
   self = GTD_TASK_EDS (task);
 
-  e_cal_component_get_status (self->component, &status);
+  e_cal_component_get_status (self->new_component, &status);
   completed = status == ICAL_STATUS_COMPLETED;
 
   return completed;
@@ -266,8 +268,8 @@ gtd_task_eds_set_complete (GtdTask  *task,
       status = ICAL_STATUS_NEEDSACTION;
     }
 
-  e_cal_component_set_percent_as_int (self->component, percent);
-  e_cal_component_set_status (self->component, status);
+  e_cal_component_set_percent_as_int (self->new_component, percent);
+  e_cal_component_set_status (self->new_component, status);
   gtd_task_eds_set_completion_date (task, now);
 }
 
@@ -282,7 +284,7 @@ gtd_task_eds_get_creation_date (GtdTask *task)
   idt = NULL;
   dt = NULL;
 
-  e_cal_component_get_created (self->component, &idt);
+  e_cal_component_get_created (self->new_component, &idt);
 
   if (idt)
     dt = convert_icaltime (idt);
@@ -325,7 +327,7 @@ gtd_task_eds_get_due_date (GtdTask *task)
 
   self = GTD_TASK_EDS (task);
 
-  e_cal_component_get_due (self->component, &comp_dt);
+  e_cal_component_get_due (self->new_component, &comp_dt);
 
   date = convert_icaltime (comp_dt.value);
   e_cal_component_free_datetime (&comp_dt);
@@ -379,7 +381,7 @@ gtd_task_eds_set_due_date (GtdTask   *task,
 
           comp_dt.value = idt;
 
-          e_cal_component_set_due (self->component, &comp_dt);
+          e_cal_component_set_due (self->new_component, &comp_dt);
 
           e_cal_component_free_datetime (&comp_dt);
 
@@ -390,7 +392,7 @@ gtd_task_eds_set_due_date (GtdTask   *task,
           idt = NULL;
           comp_dt.tzid = NULL;
 
-          e_cal_component_set_due (self->component, NULL);
+          e_cal_component_set_due (self->new_component, NULL);
         }
     }
 
@@ -405,7 +407,7 @@ gtd_task_eds_get_position (GtdTask *task)
   GtdTaskEds *self;
 
   self = GTD_TASK_EDS (task);
-  ical_comp = e_cal_component_get_icalcomponent (self->component);
+  ical_comp = e_cal_component_get_icalcomponent (self->new_component);
 
   for (property = icalcomponent_get_first_property (ical_comp, ICAL_X_PROPERTY);
        property;
@@ -413,7 +415,7 @@ gtd_task_eds_get_position (GtdTask *task)
     {
       const gchar *name = icalproperty_get_x_name (property);
 
-      if (g_strcmp0 (name, "X-GNOME-TODO-POSITION") == 0)
+      if (g_strcmp0 (name, ICAL_X_GNOME_TODO_POSITION) == 0)
         return g_ascii_strtoll (icalproperty_get_x (property), NULL, 10);
     }
 
@@ -431,7 +433,7 @@ gtd_task_eds_set_position (GtdTask *task,
 
   self = GTD_TASK_EDS (task);
   value = g_strdup_printf ("%ld", position);
-  ical_comp = e_cal_component_get_icalcomponent (self->component);
+  ical_comp = e_cal_component_get_icalcomponent (self->new_component);
 
   for (property = icalcomponent_get_first_property (ical_comp, ICAL_X_PROPERTY);
        property;
@@ -439,14 +441,14 @@ gtd_task_eds_set_position (GtdTask *task,
     {
       const gchar *name = icalproperty_get_x_name (property);
 
-      if (g_strcmp0 (name, "X-GNOME-TODO-POSITION") == 0)
+      if (g_strcmp0 (name, ICAL_X_GNOME_TODO_POSITION) == 0)
         break;
     }
 
   if (!property)
     {
       property = icalproperty_new_x (value);
-      icalproperty_set_x_name (property, "X-GNOME-TODO-POSITION");
+      icalproperty_set_x_name (property, ICAL_X_GNOME_TODO_POSITION);
 
       icalcomponent_add_property (ical_comp, property);
     }
@@ -466,7 +468,7 @@ gtd_task_eds_get_title (GtdTask *task)
 
   self = GTD_TASK_EDS (task);
 
-  e_cal_component_get_summary (self->component, &summary);
+  e_cal_component_get_summary (self->new_component, &summary);
 
   return summary.value;
 }
@@ -486,7 +488,7 @@ gtd_task_eds_set_title (GtdTask     *task,
   new_summary.value = title;
   new_summary.altrep = NULL;
 
-  e_cal_component_set_summary (self->component, &new_summary);
+  e_cal_component_set_summary (self->new_component, &new_summary);
 }
 
 
@@ -507,8 +509,8 @@ gtd_task_eds_subtask_added (GtdTask *task,
   /* Hook with parent's :subtask_added */
   GTD_TASK_CLASS (gtd_task_eds_parent_class)->subtask_added (task, subtask);
 
-  id = e_cal_component_get_id (self->component);
-  comp = subtask_self->component;
+  id = e_cal_component_get_id (self->new_component);
+  comp = subtask_self->new_component;
   ical_comp = e_cal_component_get_icalcomponent (comp);
   property = icalcomponent_get_first_property (ical_comp, ICAL_RELATEDTO_PROPERTY);
 
@@ -534,7 +536,7 @@ gtd_task_eds_subtask_removed (GtdTask *task,
   GTD_TASK_CLASS (gtd_task_eds_parent_class)->subtask_removed (task, subtask);
 
   /* Remove the parent link from the subtask's component */
-  ical_comp = e_cal_component_get_icalcomponent (subtask_self->component);
+  ical_comp = e_cal_component_get_icalcomponent (subtask_self->new_component);
   property = icalcomponent_get_first_property (ical_comp, ICAL_RELATEDTO_PROPERTY);
 
   if (!property)
@@ -554,6 +556,7 @@ gtd_task_eds_finalize (GObject *object)
   GtdTaskEds *self = (GtdTaskEds *)object;
 
   g_clear_object (&self->component);
+  g_clear_object (&self->new_component);
 
   G_OBJECT_CLASS (gtd_task_eds_parent_class)->finalize (object);
 }
@@ -588,11 +591,7 @@ gtd_task_eds_set_property (GObject      *object,
   switch (prop_id)
     {
     case PROP_COMPONENT:
-      if (g_set_object (&self->component, g_value_get_object (value)))
-        {
-          setup_description (self);
-          g_object_notify_by_pspec (object, properties[PROP_COMPONENT]);
-        }
+      gtd_task_eds_set_component (self, g_value_get_object (value));
       break;
 
     default:
@@ -658,7 +657,7 @@ gtd_task_eds_get_component (GtdTaskEds *self)
 {
   g_return_val_if_fail (GTD_IS_TASK_EDS (self), NULL);
 
-  return self->component;
+  return self->new_component;
 }
 
 void
@@ -675,12 +674,37 @@ gtd_task_eds_set_component (GtdTaskEds    *self,
 
   object = G_OBJECT (self);
 
+  g_clear_object (&self->new_component);
+  self->new_component = e_cal_component_clone (component);
+
   setup_description (self);
 
   g_object_notify (object, "complete");
   g_object_notify (object, "creation-date");
   g_object_notify (object, "description");
   g_object_notify (object, "due-date");
+  g_object_notify (object, "position");
   g_object_notify (object, "title");
   g_object_notify_by_pspec (object, properties[PROP_COMPONENT]);
 }
+
+void
+gtd_task_eds_apply (GtdTaskEds *self)
+{
+  g_return_if_fail (GTD_IS_TASK_EDS (self));
+
+  /* Make new_component the actual component */
+  gtd_task_eds_set_component (self, self->new_component);
+}
+
+void
+gtd_task_eds_revert (GtdTaskEds *self)
+{
+  g_autoptr (ECalComponent) component = NULL;
+
+  g_return_if_fail (GTD_IS_TASK_EDS (self));
+
+  component = e_cal_component_clone (self->component);
+
+  gtd_task_eds_set_component (self, component);
+}
diff --git a/plugins/eds/gtd-task-eds.h b/plugins/eds/gtd-task-eds.h
index 11031d8..819a454 100644
--- a/plugins/eds/gtd-task-eds.h
+++ b/plugins/eds/gtd-task-eds.h
@@ -36,6 +36,10 @@ ECalComponent*       gtd_task_eds_get_component                  (GtdTaskEds
 void                 gtd_task_eds_set_component                  (GtdTaskEds         *self,
                                                                   ECalComponent      *component);
 
+void                 gtd_task_eds_apply                          (GtdTaskEds          *self);
+
+void                 gtd_task_eds_revert                         (GtdTaskEds          *self);
+
 G_END_DECLS
 
 #endif /* GTD_TASK_EDS_H */