[gnome-photos/wip/rishi/tracker-sparql-templates: 2/4] Add PhotosSparqlTemplate

[Debarshi Ray <debarshir src gnome org>]

commit caed77826384b379af454877f1e121a286567515
Author: Sam Thursfield <sam afuera me uk>
Date:   Mon Feb 22 19:14:59 2021 +0100

    Add PhotosSparqlTemplate
    
    https://gitlab.gnome.org/GNOME/gnome-photos/-/merge_requests/163

 src/meson.build              |   1 +
 src/photos-sparql-template.c | 214 +++++++++++++++++++++++++++++++++++++++++++
 src/photos-sparql-template.h |  32 +++++++
 3 files changed, 247 insertions(+)
---
diff --git a/src/meson.build b/src/meson.build
index 10957ee0..d8fc4b6d 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -195,6 +195,7 @@ sources = common_sources + files(
   'photos-source.c',
   'photos-source-manager.c',
   'photos-source-notification.c',
+  'photos-sparql-template.c',
   'photos-spinner-box.c',
   'photos-thumbnail-factory.c',
   'photos-tool.c',
diff --git a/src/photos-sparql-template.c b/src/photos-sparql-template.c
new file mode 100644
index 00000000..4e38afee
--- /dev/null
+++ b/src/photos-sparql-template.c
@@ -0,0 +1,214 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 2020 Sam Thursfield <sam afuera me uk>
+ *
+ * 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/>.
+ */
+
+
+#include "config.h"
+
+#include <gio/gio.h>
+
+#include "photos-sparql-template.h"
+
+
+struct _PhotosSparqlTemplate
+{
+  GObject parent_instance;
+  gchar *template_path;
+  gchar *template_text;
+};
+
+enum
+{
+  PROP_0,
+  PROP_TEMPLATE_PATH
+};
+
+
+G_DEFINE_TYPE (PhotosSparqlTemplate, photos_sparql_template, G_TYPE_OBJECT);
+
+
+enum
+{
+  MAX_SPARQL_TEMPLATE_SIZE = 1024 * 10
+};
+
+
+static void
+photos_sparql_template_constructed (GObject *object)
+{
+  PhotosSparqlTemplate *self = PHOTOS_SPARQL_TEMPLATE (object);
+  g_autoptr (GFile) file = NULL;
+  g_autoptr (GFileInputStream) stream = NULL;
+  gchar buffer[MAX_SPARQL_TEMPLATE_SIZE + 1];
+  gsize bytes_read;
+
+  G_OBJECT_CLASS (photos_sparql_template_parent_class)->constructed (object);
+
+  file = g_file_new_for_uri (self->template_path);
+
+  {
+    g_autoptr (GError) error = NULL;
+
+    stream = g_file_read (file, NULL, &error);
+    if (error != NULL)
+      {
+        g_critical ("Unable to open template %s: %s", self->template_path, error->message);
+        g_return_if_reached ();
+      }
+  }
+
+  {
+    g_autoptr (GError) error = NULL;
+
+    if (!g_input_stream_read_all (G_INPUT_STREAM (stream), buffer, MAX_SPARQL_TEMPLATE_SIZE, &bytes_read, 
NULL, &error))
+      {
+        g_critical ("Unable to read template %s: %s", self->template_path, error->message);
+        g_return_if_reached ();
+      }
+  }
+
+  buffer[bytes_read] = '\0';
+  self->template_text = g_strdup (buffer);
+}
+
+
+static void
+photos_sparql_template_finalize (GObject *object)
+{
+  PhotosSparqlTemplate *self = PHOTOS_SPARQL_TEMPLATE (object);
+
+  g_free (self->template_path);
+  g_free (self->template_text);
+
+  G_OBJECT_CLASS (photos_sparql_template_parent_class)->finalize (object);
+}
+
+
+static void
+photos_sparql_template_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
+{
+  PhotosSparqlTemplate *self = PHOTOS_SPARQL_TEMPLATE (object);
+
+  switch (prop_id)
+    {
+    case PROP_TEMPLATE_PATH:
+      g_value_set_string (value, self->template_path);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+
+static void
+photos_sparql_template_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
+{
+  PhotosSparqlTemplate *self = PHOTOS_SPARQL_TEMPLATE (object);
+
+  switch (prop_id)
+    {
+    case PROP_TEMPLATE_PATH:
+      self->template_path = g_value_dup_string (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+
+static void
+photos_sparql_template_init (PhotosSparqlTemplate *self)
+{
+}
+
+
+static void
+photos_sparql_template_class_init (PhotosSparqlTemplateClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = photos_sparql_template_constructed;
+  object_class->finalize = photos_sparql_template_finalize;
+  object_class->get_property = photos_sparql_template_get_property;
+  object_class->set_property = photos_sparql_template_set_property;
+
+  g_object_class_install_property (object_class,
+                                   PROP_TEMPLATE_PATH,
+                                   g_param_spec_string ("template-path",
+                                                        "Template path",
+                                                        "Path to the template file.",
+                                                        NULL,
+                                                        G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
+}
+
+
+PhotosSparqlTemplate *
+photos_sparql_template_new (const gchar *template_path)
+{
+  return g_object_new (PHOTOS_TYPE_SPARQL_TEMPLATE, "template-path", template_path, NULL);
+}
+
+
+gchar *
+photos_sparql_template_get_sparql (PhotosSparqlTemplate *self, const gchar *first_binding_name, ...)
+{
+  const gchar *name;
+  const gchar *value;
+  gchar *sparql = NULL;
+  va_list ap;
+
+  sparql = g_strdup (self->template_text);
+
+  if (first_binding_name == NULL)
+    goto out;
+
+  /* FIXME: this is an inefficent way to do template substitutions
+   * because we allocate and free a copy of the string for each binding.
+   * We should check https://gitlab.gnome.org/GNOME/template-glib/
+   */
+
+  va_start (ap, first_binding_name);
+  name = first_binding_name;
+  do
+    {
+      g_autoptr (GRegex) regex = NULL;
+      g_autofree gchar *name_regex = NULL;
+      g_autofree gchar *str = NULL;
+
+      value = va_arg (ap, const gchar *);
+      if (value == NULL)
+        {
+          g_critical ("Missing value for argument \"%s\"", name);
+          break;
+        }
+
+      name_regex = g_strdup_printf ("{{\\s?%s\\s?}}", name);
+      regex = g_regex_new (name_regex, 0, 0, NULL);
+
+      str = g_steal_pointer (&sparql);
+      sparql = g_regex_replace_literal (regex, str, -1, 0, value, 0, NULL) ;
+
+      name = va_arg (ap, const gchar *);
+    } while (name != NULL);
+
+  va_end (ap);
+
+ out:
+  return sparql;
+}
diff --git a/src/photos-sparql-template.h b/src/photos-sparql-template.h
new file mode 100644
index 00000000..8ad46983
--- /dev/null
+++ b/src/photos-sparql-template.h
@@ -0,0 +1,32 @@
+/*
+ * Photos - access, organize and share your photos on GNOME
+ * Copyright © 2020 Sam Thursfield <sam afuera me uk>
+ *
+ * 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/>.
+ */
+
+#pragma once
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define PHOTOS_TYPE_SPARQL_TEMPLATE (photos_sparql_template_get_type())
+G_DECLARE_FINAL_TYPE (PhotosSparqlTemplate, photos_sparql_template, PHOTOS, SPARQL_TEMPLATE, GObject);
+
+PhotosSparqlTemplate *photos_sparql_template_new (const gchar *template_path);
+
+gchar *photos_sparql_template_get_sparql (PhotosSparqlTemplate *self, const gchar *first_binding_name, ...) 
G_GNUC_NULL_TERMINATED;
+
+G_END_DECLS