[gnome-builder] settings: add IdeSettings for project vs global setings abstraction

[Garrett Regier <gregier src gnome org>]

commit 7d5438363dbf1b67d9310711f88583db4a2a4457
Author: Christian Hergert <christian hergert me>
Date:   Sun May 3 12:36:49 2015 -0700

    settings: add IdeSettings for project vs global setings abstraction
    
    We have the need to have a layered approach to settings. We need settings
    that first resolve via the project's configured settings, and then from
    the user defaults.
    
    We have a couple of ways to approach this long term, but this get's us
    started by storing project preferences in a subpath such as:
    
      /org/gnome/builder/projects/<project-name>/<relative-path>
    
    The global settings for this would be stored at:
    
      /org/gnome/builder/<relative-path>
    
    When configuring the settings via IdeSettings, we will apply the settings
    to the project directly.
    
    There is a lot still missing from here.
    
    For example, it would be nice to choose whether or not to apply the
    project settings. Otherwise, we'd need one path for GSettings and another
    path for IdeSettings.
    
    I tried writing a custom GSettingsBackend, but that become difficult in
    propagating changes from underlying backends. We might be able to get
    around this by holding on to GSettings instead of a GSettingsBackend.

 libide/Makefile.am    |    2 +
 libide/ide-context.c  |   22 +++
 libide/ide-internal.h |    4 +
 libide/ide-settings.c |  397 +++++++++++++++++++++++++++++++++++++++++++++++++
 libide/ide-settings.h |   51 +++++++
 5 files changed, 476 insertions(+), 0 deletions(-)
---
diff --git a/libide/Makefile.am b/libide/Makefile.am
index 269aed2..912c641 100644
--- a/libide/Makefile.am
+++ b/libide/Makefile.am
@@ -155,6 +155,8 @@ libide_1_0_la_public_sources = \
        ide-search-result.h \
        ide-service.c \
        ide-service.h \
+        ide-settings.c \
+        ide-settings.h \
        ide-source-location.c \
        ide-source-location.h \
        ide-source-range.c \
diff --git a/libide/ide-context.c b/libide/ide-context.c
index c81b445..29c2ee5 100644
--- a/libide/ide-context.c
+++ b/libide/ide-context.c
@@ -38,6 +38,7 @@
 #include "ide-search-engine.h"
 #include "ide-search-provider.h"
 #include "ide-service.h"
+#include "ide-settings.h"
 #include "ide-source-snippets-manager.h"
 #include "ide-unsaved-file.h"
 #include "ide-unsaved-files.h"
@@ -1740,3 +1741,24 @@ _ide_context_is_restoring (IdeContext *self)
 {
   return self->restoring;
 }
+
+/**
+ * ide_context_get_settings:
+ *
+ * Gets an #IdeSettings representing the given #GSettingsSchema.
+ *
+ * relative_path will be used to apply multiple layers of settings. Project settings will be
+ * applied to first, followed by global settings.
+ *
+ * Returns: (transfer full): An #IdeSettings.
+ */
+IdeSettings *
+ide_context_get_settings (IdeContext  *self,
+                          const gchar *schema_id,
+                          const gchar *relative_path)
+{
+  g_return_val_if_fail (IDE_IS_CONTEXT (self), NULL);
+  g_return_val_if_fail (schema_id != NULL, NULL);
+
+  return  _ide_settings_new (self, schema_id, relative_path);
+}
diff --git a/libide/ide-internal.h b/libide/ide-internal.h
index 7565061..5705284 100644
--- a/libide/ide-internal.h
+++ b/libide/ide-internal.h
@@ -27,6 +27,7 @@
 #include "ide-clang-translation-unit.h"
 #include "ide-diagnostic.h"
 #include "ide-types.h"
+#include "ide-settings.h"
 #include "ide-source-view.h"
 #include "ide-source-view-mode.h"
 #include "ide-symbol.h"
@@ -92,6 +93,9 @@ void                _ide_project_set_name              (IdeProject            *p
 void                _ide_search_context_add_provider   (IdeSearchContext      *context,
                                                         IdeSearchProvider     *provider,
                                                         gsize                  max_results);
+IdeSettings        *_ide_settings_new                  (IdeContext            *context,
+                                                        const gchar           *schema_id,
+                                                        const gchar           *relative_path);
 IdeSourceRange     *_ide_source_range_new              (IdeSourceLocation     *begin,
                                                         IdeSourceLocation     *end);
 gboolean            _ide_source_view_mode_do_event     (IdeSourceViewMode     *mode,
diff --git a/libide/ide-settings.c b/libide/ide-settings.c
new file mode 100644
index 0000000..538a6e9
--- /dev/null
+++ b/libide/ide-settings.c
@@ -0,0 +1,397 @@
+/* ide-settings.c
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * 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/>.
+ */
+
+#define G_LOG_DOMAIN "ide-settings"
+
+#include <glib/gi18n.h>
+#include <stdlib.h>
+
+#include "ide-context.h"
+#include "ide-project.h"
+#include "ide-settings.h"
+
+/**
+ * SECTION:ide-settings
+ * @title: IdeSettings
+ * @short_description: Project and Application Preferences
+ *
+ * In Builder, we need support for settings at the user level (their chosen defaults) as well
+ * as defaults for a project. #IdeSettings attempts to simplify this by providing a layered
+ * approach to settings.
+ *
+ * If a setting has been set for the current project, it will be returned. If not, the users
+ * preference will be returned. Setting a preference via #IdeSettings will always modify the
+ * projects setting, not the users default settings.
+ */
+
+struct _IdeSettings
+{
+  IdeObject  parent_instance;
+
+  gchar     *relative_path;
+  gchar     *schema_id;
+
+  GSettings *global_settings;
+  GSettings *project_settings;
+};
+
+G_DEFINE_TYPE (IdeSettings, ide_settings, IDE_TYPE_OBJECT)
+
+enum {
+  PROP_0,
+  PROP_RELATIVE_PATH,
+  PROP_SCHEMA_ID,
+  LAST_PROP
+};
+
+enum {
+  CHANGED,
+  LAST_SIGNAL
+};
+
+static GParamSpec *gParamSpecs [LAST_PROP];
+static guint       gSignals [LAST_SIGNAL];
+
+static void
+ide_settings_set_relative_path (IdeSettings *self,
+                                const gchar *relative_path)
+{
+  g_assert (IDE_IS_SETTINGS (self));
+  g_assert (relative_path != NULL);
+
+  if (relative_path != self->relative_path)
+    {
+      g_free (self->relative_path);
+      self->relative_path = g_strdup (relative_path);
+      g_object_notify_by_pspec (G_OBJECT (self), gParamSpecs [PROP_RELATIVE_PATH]);
+    }
+}
+
+static void
+ide_settings_set_schema_id (IdeSettings *self,
+                            const gchar *schema_id)
+{
+  g_assert (IDE_IS_SETTINGS (self));
+  g_assert (schema_id != NULL);
+
+  if (schema_id != self->schema_id)
+    {
+      g_free (self->schema_id);
+      self->schema_id = g_strdup (schema_id);
+      g_object_notify_by_pspec (G_OBJECT (self), gParamSpecs [PROP_SCHEMA_ID]);
+    }
+}
+
+static void
+ide_settings__global_settings_changed (IdeSettings *self,
+                                       const gchar *key,
+                                       GSettings   *global_settings)
+{
+  g_assert (IDE_IS_SETTINGS (self));
+  g_assert (key != NULL);
+  g_assert (G_IS_SETTINGS (global_settings));
+
+  g_signal_emit (self, gSignals [CHANGED], g_quark_from_string (key), key);
+}
+
+static void
+ide_settings__project_settings_changed (IdeSettings *self,
+                                        const gchar *key,
+                                        GSettings   *project_settings)
+{
+  g_assert (IDE_IS_SETTINGS (self));
+  g_assert (key != NULL);
+  g_assert (G_IS_SETTINGS (project_settings));
+
+  g_signal_emit (self, gSignals [CHANGED], g_quark_from_string (key), key);
+}
+
+static void
+ide_settings_constructed (GObject *object)
+{
+  IdeSettings *self = (IdeSettings *)object;
+  IdeContext *context;
+  IdeProject *project;
+  const gchar *project_name;
+  gchar *path;
+
+  G_OBJECT_CLASS (ide_settings_parent_class)->constructed (object);
+
+  if (self->relative_path == NULL)
+    {
+      g_autoptr(GSettingsSchema) settings_schema = NULL;
+      g_autoptr(GSettings) settings = NULL;
+      const gchar *schema_path;
+
+      settings = g_settings_new (self->schema_id);
+      g_object_get (settings, "settings-schema", &settings_schema, NULL);
+      schema_path = g_settings_schema_get_path (settings_schema);
+
+      if (!g_str_has_prefix (schema_path, "/org/gnome/builder/"))
+        {
+          g_error ("Settings schema %s is not under path /org/gnome/builder/",
+                   self->schema_id);
+          abort ();
+        }
+
+      self->relative_path = g_strdup (schema_path + strlen ("/org/gnome/builder/"));
+    }
+
+  path = g_strdup_printf ("/org/gnome/builder/%s", self->relative_path);
+  self->global_settings = g_settings_new_with_path (self->schema_id, path);
+  g_free (path);
+
+  context = ide_object_get_context (IDE_OBJECT (self));
+  project = ide_context_get_project (context);
+  project_name = ide_project_get_name (project);
+
+  path = g_strdup_printf ("/org/gnome/builder/projects/%s/%s", project_name, self->relative_path);
+  self->project_settings = g_settings_new_with_path (self->schema_id, path);
+  g_free (path);
+
+  g_signal_connect_object (self->global_settings,
+                           "changed",
+                           G_CALLBACK (ide_settings__global_settings_changed),
+                           self,
+                           G_CONNECT_SWAPPED);
+
+  g_signal_connect_object (self->project_settings,
+                           "changed",
+                           G_CALLBACK (ide_settings__project_settings_changed),
+                           self,
+                           G_CONNECT_SWAPPED);
+}
+
+static void
+ide_settings_finalize (GObject *object)
+{
+  IdeSettings *self = (IdeSettings *)object;
+
+  g_clear_pointer (&self->relative_path, g_free);
+  g_clear_pointer (&self->schema_id, g_free);
+
+  G_OBJECT_CLASS (ide_settings_parent_class)->finalize (object);
+}
+
+static void
+ide_settings_get_property (GObject    *object,
+                           guint       prop_id,
+                           GValue     *value,
+                           GParamSpec *pspec)
+{
+  IdeSettings *self = IDE_SETTINGS (object);
+
+  switch (prop_id)
+    {
+    case PROP_SCHEMA_ID:
+      g_value_set_string (value, ide_settings_get_schema_id (self));
+      break;
+
+    case PROP_RELATIVE_PATH:
+      g_value_set_string (value, ide_settings_get_relative_path (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+ide_settings_set_property (GObject      *object,
+                           guint         prop_id,
+                           const GValue *value,
+                           GParamSpec   *pspec)
+{
+  IdeSettings *self = IDE_SETTINGS (object);
+
+  switch (prop_id)
+    {
+    case PROP_SCHEMA_ID:
+      ide_settings_set_schema_id (self, g_value_get_object (value));
+      break;
+
+    case PROP_RELATIVE_PATH:
+      ide_settings_set_relative_path (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+ide_settings_class_init (IdeSettingsClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = ide_settings_constructed;
+  object_class->finalize = ide_settings_finalize;
+  object_class->get_property = ide_settings_get_property;
+  object_class->set_property = ide_settings_set_property;
+
+  gParamSpecs [PROP_RELATIVE_PATH] =
+    g_param_spec_string ("relative-path",
+                         _("Relative Path"),
+                         _("Relative Path"),
+                         NULL,
+                         (G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (object_class, PROP_RELATIVE_PATH,
+                                   gParamSpecs [PROP_RELATIVE_PATH]);
+
+  gParamSpecs [PROP_SCHEMA_ID] =
+    g_param_spec_string ("schema-id",
+                         _("Schema Id"),
+                         _("Schema Id"),
+                         NULL,
+                         (G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+  g_object_class_install_property (object_class, PROP_SCHEMA_ID, gParamSpecs [PROP_SCHEMA_ID]);
+
+  gSignals [CHANGED] =
+    g_signal_new_class_handler ("changed",
+                                G_TYPE_FROM_CLASS (klass),
+                                G_SIGNAL_RUN_LAST | G_SIGNAL_DETAILED,
+                                0,
+                                NULL, NULL,
+                                g_cclosure_marshal_VOID__STRING,
+                                G_TYPE_NONE,
+                                1,
+                                G_TYPE_STRING);
+}
+
+static void
+ide_settings_init (IdeSettings *self)
+{
+}
+
+IdeSettings *
+_ide_settings_new (IdeContext  *context,
+                   const gchar *schema_id,
+                   const gchar *relative_path)
+{
+  g_assert (IDE_IS_CONTEXT (context));
+  g_assert (schema_id != NULL);
+  g_assert (relative_path != NULL);
+
+  return g_object_new (IDE_TYPE_SETTINGS,
+                       "context", context,
+                       "schema-id", schema_id,
+                       "relative-path", relative_path,
+                       NULL);
+}
+
+const gchar *
+ide_settings_get_schema_id (IdeSettings *self)
+{
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), NULL);
+
+  return self->schema_id;
+}
+
+const gchar *
+ide_settings_get_relative_path (IdeSettings *self)
+{
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), NULL);
+
+  return self->relative_path;
+}
+
+GVariant *
+ide_settings_get_value (IdeSettings *self,
+                        const gchar *key)
+{
+  GVariant *ret;
+
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), NULL);
+  g_return_val_if_fail (key != NULL, NULL);
+
+  ret = g_settings_get_user_value (self->project_settings, key);
+  if (ret == NULL)
+    ret = g_settings_get_value (self->global_settings, key);
+
+  return ret;
+}
+
+GVariant *
+ide_settings_get_user_value (IdeSettings *self,
+                             const gchar *key)
+{
+  GVariant *ret;
+
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), NULL);
+  g_return_val_if_fail (key != NULL, NULL);
+
+  ret = g_settings_get_user_value (self->project_settings, key);
+  if (ret == NULL)
+    ret = g_settings_get_user_value (self->global_settings, key);
+
+  return ret;
+}
+
+GVariant *
+ide_settings_get_default_value (IdeSettings *self,
+                                const gchar *key)
+{
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), NULL);
+  g_return_val_if_fail (key != NULL, NULL);
+
+  return g_settings_get_default_value (self->global_settings, key);
+}
+
+#define DEFINE_GETTER(type, name, func_name, ...) \
+type \
+ide_settings_get_##name (IdeSettings *self, \
+                         const gchar *key) \
+{ \
+  GVariant *value; \
+  type ret; \
+ \
+  g_return_val_if_fail (IDE_IS_SETTINGS (self), (type)0); \
+ \
+  value = ide_settings_get_value (self, key); \
+  ret = g_variant_##func_name (value, ##__VA_ARGS__); \
+  g_variant_unref (value); \
+ \
+  return ret; \
+}
+
+DEFINE_GETTER (gboolean, boolean, get_boolean)
+DEFINE_GETTER (gint, int, get_int32)
+DEFINE_GETTER (guint, uint, get_uint32)
+DEFINE_GETTER (double, double, get_double)
+DEFINE_GETTER (gchar *, string, dup_string, NULL)
+
+#define DEFINE_SETTER(type, name, new_func, ...) \
+void \
+ide_settings_set_##name (IdeSettings *self, \
+                         const gchar *key, \
+                         type value) \
+{ \
+  GVariant *variant; \
+ \
+  g_return_if_fail (IDE_IS_SETTINGS (self)); \
+ \
+  variant = g_variant_##new_func (value, ##__VA_ARGS__); \
+  g_settings_set_value (self->project_settings, key, variant); \
+}
+
+DEFINE_SETTER (gboolean, boolean, new_boolean)
+DEFINE_SETTER (gint, int, new_int32)
+DEFINE_SETTER (guint, uint, new_uint32)
+DEFINE_SETTER (double, double, new_double)
+DEFINE_SETTER (const gchar *, string, new_string)
+
diff --git a/libide/ide-settings.h b/libide/ide-settings.h
new file mode 100644
index 0000000..6d411c1
--- /dev/null
+++ b/libide/ide-settings.h
@@ -0,0 +1,51 @@
+/* ide-settings.h
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * 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/>.
+ */
+
+#ifndef IDE_SETTINGS_H
+#define IDE_SETTINGS_H
+
+#include "ide-object.h"
+
+G_BEGIN_DECLS
+
+#define IDE_TYPE_SETTINGS (ide_settings_get_type())
+
+G_DECLARE_FINAL_TYPE (IdeSettings, ide_settings, IDE, SETTINGS, IdeObject)
+
+const gchar *ide_settings_get_relative_path (IdeSettings *self);
+const gchar *ide_settings_get_schema_id     (IdeSettings *self);
+GVariant    *ide_settings_get_value         (IdeSettings *self,
+                                             const gchar *key);
+GVariant    *ide_settings_get_default_value (IdeSettings *self,
+                                             const gchar *key);
+GVariant    *ide_settings_get_user_value    (IdeSettings *self,
+                                             const gchar *key);
+guint        ide_settings_get_uint          (IdeSettings *self,
+                                             const gchar *key);
+gint         ide_settings_get_int           (IdeSettings *self,
+                                             const gchar *key);
+gboolean     ide_settings_get_gboolean      (IdeSettings *self,
+                                             const gchar *key);
+gchar       *ide_settings_get_string        (IdeSettings *self,
+                                             const gchar *key);
+gdouble      ide_settings_get_double        (IdeSettings *self,
+                                             const gchar *key);
+
+G_END_DECLS
+
+#endif /* IDE_SETTINGS_H */