[gnome-todo] task-model: Introduce GtdTaskModel

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

commit e08149cac132ede9d7f3b7737d628e8ccc1dcebb
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Mon Sep 10 21:53:07 2018 -0300

    task-model: Introduce GtdTaskModel
    
    One more step into our model-based future. GtdTaskModel
    is internal to GtdManager - only one should be available
    at any given point in time.
    
    It is efficient and all operations are either O(1) or
    O(log n).

 src/contrib/gtd-task-model-private.h |  29 +++
 src/contrib/gtd-task-model.c         | 370 +++++++++++++++++++++++++++++++++++
 src/contrib/gtd-task-model.h         |  33 ++++
 src/meson.build                      |   1 +
 4 files changed, 433 insertions(+)
---
diff --git a/src/contrib/gtd-task-model-private.h b/src/contrib/gtd-task-model-private.h
new file mode 100644
index 0000000..7bc1c7d
--- /dev/null
+++ b/src/contrib/gtd-task-model-private.h
@@ -0,0 +1,29 @@
+/* gtd-task-model-private.h
+ *
+ * Copyright 2018 Georges Basile Stavracas Neto <georges stavracas gmail com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include "gtd-task-model.h"
+
+G_BEGIN_DECLS
+
+GtdTaskModel*        _gtd_task_model_new                         (GtdManager         *manager);
+
+G_END_DECLS
diff --git a/src/contrib/gtd-task-model.c b/src/contrib/gtd-task-model.c
new file mode 100644
index 0000000..2f7ba28
--- /dev/null
+++ b/src/contrib/gtd-task-model.c
@@ -0,0 +1,370 @@
+/* gtd-task-model.c
+ *
+ * Copyright 2018 Georges Basile Stavracas Neto <georges stavracas gmail com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#define G_LOG_DOMAIN "GtdTaskModel"
+
+#include "gtd-debug.h"
+#include "gtd-list-store.h"
+#include "gtd-manager.h"
+#include "gtd-task.h"
+#include "gtd-task-list.h"
+#include "gtd-task-model.h"
+#include "gtd-task-model-private.h"
+
+struct _GtdTaskModel
+{
+  GObject             parent;
+
+  GtdListStore       *lists;
+
+  guint               number_of_tasks;
+
+  GtdManager         *manager;
+};
+
+static void          g_list_model_iface_init                     (GListModelInterface *iface);
+
+G_DEFINE_TYPE_WITH_CODE (GtdTaskModel, gtd_task_model, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, g_list_model_iface_init))
+
+enum
+{
+  PROP_0,
+  PROP_MANAGER,
+  N_PROPS
+};
+
+static GParamSpec *properties [N_PROPS];
+
+
+/*
+ * Auxiliary methods
+ */
+
+static guint
+find_task_position_at_list_position (GtdTaskModel *self,
+                                     guint         position)
+{
+  GListModel *tasklists;
+  guint offset = 0;
+  guint i;
+
+  tasklists = gtd_manager_get_task_lists_model (self->manager);
+
+  g_assert (g_list_model_get_n_items (tasklists) > position);
+
+  for (i = 0; i < position; i++)
+    {
+      g_autoptr (GListModel) tasklist = g_list_model_get_item (tasklists, i);
+      offset += g_list_model_get_n_items (tasklist);
+    }
+
+  return offset;
+}
+
+
+/*
+ * Callbacks
+ */
+
+static void
+on_task_list_items_changed_cb (GtdTaskList  *tasklist,
+                               guint         position,
+                               guint         n_removed,
+                               guint         n_added,
+                               GtdTaskModel *self)
+{
+  guint task_position;
+  guint list_position;
+  gint diff;
+
+  list_position = gtd_list_store_get_item_position (self->lists, tasklist);
+  task_position = find_task_position_at_list_position (self, list_position) + position;
+
+  diff = (gint) n_added - (gint) n_removed;
+
+  self->number_of_tasks += diff;
+
+  g_list_model_items_changed (G_LIST_MODEL (self), task_position, n_removed, n_added);
+
+  GTD_TRACE_MSG ("Task list changed with position=%u, n_removed=%u, n_added=%u",
+                 task_position,
+                 n_removed,
+                 n_added);
+}
+
+static void
+on_manager_items_changed_cb (GListModel   *model,
+                             guint         position,
+                             guint         n_removed,
+                             guint         n_added,
+                             GtdTaskModel *self)
+{
+  guint offset;
+
+  GTD_TRACE_MSG ("Child model changed with position=%u, n_removed=%u, n_added=%u", position, n_removed, 
n_added);
+
+  offset = find_task_position_at_list_position (self, position);
+
+  if (n_removed > 0)
+    {
+      guint n_removed_tasks = 0;
+      guint i;
+
+      for (i = 0; i < n_removed; i++)
+        {
+          g_autoptr (GtdTaskList) list = NULL;
+
+          list = g_list_model_get_item (G_LIST_MODEL (self->lists), position + i);
+          g_signal_handlers_disconnect_by_func (list, on_task_list_items_changed_cb, self);
+
+          n_removed_tasks += g_list_model_get_n_items (G_LIST_MODEL (list));
+        }
+
+      self->number_of_tasks -= n_removed_tasks;
+
+      g_list_model_items_changed (G_LIST_MODEL (self),
+                                  offset,
+                                  0,
+                                  n_removed_tasks);
+
+      GTD_TRACE_MSG ("Removed %u items at %u", n_removed_tasks, offset);
+    }
+
+  if (n_added > 0)
+    {
+      GListModel *tasklists;
+      guint n_added_tasks = 0;
+      guint i;
+
+      tasklists = gtd_manager_get_task_lists_model (self->manager);
+
+      for (i = 0; i < n_added; i++)
+        {
+          g_autoptr (GtdTaskList) list = NULL;
+          guint n_tasks;
+
+          list = g_list_model_get_item (tasklists, position + i);
+          n_tasks = g_list_model_get_n_items (G_LIST_MODEL (list));
+
+          g_signal_connect_object (list,
+                                   "items-changed",
+                                   G_CALLBACK (on_task_list_items_changed_cb),
+                                   self,
+                                   0);
+
+          n_added_tasks += n_tasks;
+
+          gtd_list_store_insert (self->lists, position + i, list);
+        }
+
+      self->number_of_tasks += n_added_tasks;
+
+      g_list_model_items_changed (G_LIST_MODEL (self),
+                                  offset,
+                                  0,
+                                  n_added_tasks);
+
+      GTD_TRACE_MSG ("Added %u tasks at %u", n_added_tasks, offset);
+    }
+}
+
+
+/*
+ * GListModel iface
+ */
+
+static gpointer
+gtd_task_model_get_item (GListModel *model,
+                         guint       position)
+{
+  GtdTaskModel *self = (GtdTaskModel*) model;
+  GListModel *tasklists;
+  guint current_item = 0;
+  guint i;
+
+  tasklists = gtd_manager_get_task_lists_model (self->manager);
+
+  for (i = 0; i < g_list_model_get_n_items (tasklists); i++)
+    {
+      g_autoptr (GtdTaskList) tasklist;
+      guint n_items;
+
+      tasklist = g_list_model_get_item (tasklists, i);
+      n_items = g_list_model_get_n_items (G_LIST_MODEL (tasklist));
+
+      if (current_item + n_items > position)
+        {
+          guint list_position = position - current_item;
+
+          return g_list_model_get_item (G_LIST_MODEL (tasklist), list_position);
+        }
+
+      current_item += n_items;
+    }
+
+  return NULL;
+}
+
+static guint
+gtd_task_model_get_n_items (GListModel *model)
+{
+  GtdTaskModel *self = (GtdTaskModel*) model;
+
+  return self->number_of_tasks;
+}
+
+static GType
+gtd_task_model_get_item_type (GListModel *model)
+{
+  return GTD_TYPE_TASK;
+}
+
+static void
+g_list_model_iface_init (GListModelInterface *iface)
+{
+  iface->get_item = gtd_task_model_get_item;
+  iface->get_n_items = gtd_task_model_get_n_items;
+  iface->get_item_type = gtd_task_model_get_item_type;
+}
+
+
+/*
+ * GObject overrides
+ */
+
+static void
+gtd_task_model_finalize (GObject *object)
+{
+  GtdTaskModel *self = (GtdTaskModel *)object;
+
+  g_clear_object (&self->manager);
+  g_clear_object (&self->lists);
+
+  G_OBJECT_CLASS (gtd_task_model_parent_class)->finalize (object);
+}
+
+
+static void
+gtd_task_model_constructed (GObject *object)
+{
+  GtdTaskModel *self = (GtdTaskModel *)object;
+  GListModel *model;
+  guint i;
+
+  g_assert (self->manager != NULL);
+
+  model = gtd_manager_get_task_lists_model (self->manager);
+
+  g_signal_connect_object (model,
+                           "items-changed",
+                           G_CALLBACK (on_manager_items_changed_cb),
+                           self,
+                           0);
+
+
+  for (i = 0; i < g_list_model_get_n_items (model); i++)
+    {
+      g_autoptr (GListModel) list = g_list_model_get_item (model, i);
+
+      gtd_list_store_insert (self->lists, i, list);
+      g_signal_connect_object (list,
+                               "items-changed",
+                               G_CALLBACK (on_task_list_items_changed_cb),
+                               self,
+                               0);
+
+      self->number_of_tasks += g_list_model_get_n_items (list);
+    }
+
+  G_OBJECT_CLASS (gtd_task_model_parent_class)->constructed (object);
+}
+
+static void
+gtd_task_model_get_property (GObject    *object,
+                             guint       prop_id,
+                             GValue     *value,
+                             GParamSpec *pspec)
+{
+  GtdTaskModel *self = GTD_TASK_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_MANAGER:
+      g_value_set_object (value, self->manager);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+gtd_task_model_set_property (GObject      *object,
+                             guint         prop_id,
+                             const GValue *value,
+                             GParamSpec   *pspec)
+{
+  GtdTaskModel *self = GTD_TASK_MODEL (object);
+
+  switch (prop_id)
+    {
+    case PROP_MANAGER:
+      g_assert (self->manager == NULL);
+      self->manager = g_value_dup_object (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+gtd_task_model_class_init (GtdTaskModelClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->finalize = gtd_task_model_finalize;
+  object_class->constructed = gtd_task_model_constructed;
+  object_class->get_property = gtd_task_model_get_property;
+  object_class->set_property = gtd_task_model_set_property;
+
+  properties[PROP_MANAGER] = g_param_spec_object ("manager",
+                                                  "Manager",
+                                                  "Manager",
+                                                  GTD_TYPE_MANAGER,
+                                                  G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | 
G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+}
+
+static void
+gtd_task_model_init (GtdTaskModel *self)
+{
+  self->lists = gtd_list_store_new (GTD_TYPE_TASK_LIST);
+}
+
+GtdTaskModel*
+_gtd_task_model_new (GtdManager *manager)
+{
+  return g_object_new (GTD_TYPE_TASK_MODEL,
+                       "manager", manager,
+                       NULL);
+}
diff --git a/src/contrib/gtd-task-model.h b/src/contrib/gtd-task-model.h
new file mode 100644
index 0000000..2dc7aee
--- /dev/null
+++ b/src/contrib/gtd-task-model.h
@@ -0,0 +1,33 @@
+/* gtd-task-model.h
+ *
+ * Copyright 2018 Georges Basile Stavracas Neto <georges stavracas gmail com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <gio/gio.h>
+
+#include "gtd-types.h"
+
+G_BEGIN_DECLS
+
+#define GTD_TYPE_TASK_MODEL (gtd_task_model_get_type())
+
+G_DECLARE_FINAL_TYPE (GtdTaskModel, gtd_task_model, GTD, TASK_MODEL, GObject)
+
+G_END_DECLS
diff --git a/src/meson.build b/src/meson.build
index 1d67cc8..c610f69 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -32,6 +32,7 @@ install_headers(headers, subdir: meson.project_name())
 sources = files(
   'contrib/gtd-list-model-filter.c',
   'contrib/gtd-list-store.c',
+  'contrib/gtd-task-model.c',
   'engine/gtd-manager.c',
   'engine/gtd-plugin-manager.c',
   'interfaces/gtd-activatable.c',