libsysprof: add scaffolding to perform category summaries

The goal here is to summarize the categories starting from a specific
frame.

src/libsysprof/sysprof-category-summary.c

@@ -0,0 +1,124 @@
+/* sysprof-category-summary.c
+ *
+ * Copyright 2023 Christian Hergert <chergert@redhat.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
+ */
+
+#include "config.h"
+
+#include "sysprof-category-summary.h"
+#include "sysprof-enums.h"
+
+struct _SysprofCategorySummary
+{
+  GObject parent_instance;
+  SysprofCallgraphCategory category;
+  guint64 count;
+  guint64 total;
+};
+
+enum {
+  PROP_0,
+  PROP_CATEGORY,
+  PROP_FRACTION,
+  N_PROPS
+};
+
+G_DEFINE_FINAL_TYPE (SysprofCategorySummary, sysprof_category_summary, G_TYPE_OBJECT)
+
+static GParamSpec *properties [N_PROPS];
+
+static void
+sysprof_category_summary_get_property (GObject    *object,
+                                       guint       prop_id,
+                                       GValue     *value,
+                                       GParamSpec *pspec)
+{
+  SysprofCategorySummary *self = SYSPROF_CATEGORY_SUMMARY (object);
+
+  switch (prop_id)
+    {
+    case PROP_CATEGORY:
+      g_value_set_enum (value, sysprof_category_summary_get_category (self));
+      break;
+
+    case PROP_FRACTION:
+      g_value_set_double (value, sysprof_category_summary_get_fraction (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+sysprof_category_summary_set_property (GObject      *object,
+                                       guint         prop_id,
+                                       const GValue *value,
+                                       GParamSpec   *pspec)
+{
+  SysprofCategorySummary *self = SYSPROF_CATEGORY_SUMMARY (object);
+
+  switch (prop_id)
+    {
+    case PROP_CATEGORY:
+      self->category = g_value_get_enum (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+sysprof_category_summary_class_init (SysprofCategorySummaryClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->get_property = sysprof_category_summary_get_property;
+  object_class->set_property = sysprof_category_summary_set_property;
+
+  properties[PROP_CATEGORY] =
+    g_param_spec_enum ("category", NULL, NULL,
+                      SYSPROF_TYPE_CALLGRAPH_CATEGORY,
+                      SYSPROF_CALLGRAPH_CATEGORY_UNCATEGORIZED,
+                      (G_PARAM_READWRITE | G_PARAM_CONSTRUCT_ONLY | G_PARAM_STATIC_STRINGS));
+
+  properties[PROP_FRACTION] =
+    g_param_spec_double ("fraction", NULL, NULL,
+                         0, 1, 0,
+                         (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+}
+
+static void
+sysprof_category_summary_init (SysprofCategorySummary *self)
+{
+}
+
+SysprofCallgraphCategory
+sysprof_category_summary_get_category (SysprofCategorySummary *self)
+{
+  return self->category;
+}
+
+double
+sysprof_category_summary_get_fraction (SysprofCategorySummary *self)
+{
+  return CLAMP (self->count / (double)self->total, .0, 1.);
+}