[gnome-builder/wip/libide] libide: add battery monitor so we can be friendly when unplugged

[Christian Hergert <chergert src gnome org>]

commit 9e8a2fc252f191ab8f6eb77fbea58eee44e4d976
Author: Christian Hergert <christian hergert me>
Date:   Tue Mar 10 16:40:04 2015 -0700

    libide: add battery monitor so we can be friendly when unplugged
    
    Various modules should consult this module before doing spurious work
    repeatedly. Such modules might include background parsing, diff generation,
    and similar tasks.

 libide/Makefile.am           |    2 +
 libide/ide-battery-monitor.c |  152 ++++++++++++++++++++++++++++++++++++++++++
 libide/ide-battery-monitor.h |   32 +++++++++
 3 files changed, 186 insertions(+), 0 deletions(-)
---
diff --git a/libide/Makefile.am b/libide/Makefile.am
index 21bbb3b..542b2e5 100644
--- a/libide/Makefile.am
+++ b/libide/Makefile.am
@@ -207,6 +207,8 @@ libide_1_0_la_SOURCES = \
        libide/git/ide-git-search-index.h \
        libide/ide-async-helper.c \
        libide/ide-async-helper.h \
+       libide/ide-battery-monitor.c \
+       libide/ide-battery-ymonitor.h \
        libide/ide-internal.h \
        libide/ide-line-change-gutter-renderer.c \
        libide/ide-line-change-gutter-renderer.h \
diff --git a/libide/ide-battery-monitor.c b/libide/ide-battery-monitor.c
new file mode 100644
index 0000000..a073ec1
--- /dev/null
+++ b/libide/ide-battery-monitor.c
@@ -0,0 +1,152 @@
+/* ide-battery-monitor.c
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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 <gio/gio.h>
+
+#include "ide-battery-monitor.h"
+
+static GDBusProxy *gUPowerProxy;
+static GDBusProxy *gUPowerDeviceProxy;
+
+G_LOCK_DEFINE_STATIC (proxy_lock);
+
+static GDBusProxy *
+ide_battery_monitor_get_proxy (void)
+{
+  GDBusProxy *proxy = NULL;
+
+  G_LOCK (proxy_lock);
+
+  if (!gUPowerProxy)
+    {
+      GDBusConnection *bus;
+
+      bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, NULL);
+
+      if (bus)
+        {
+          gUPowerProxy = g_dbus_proxy_new_sync (bus,
+                                                G_DBUS_PROXY_FLAGS_GET_INVALIDATED_PROPERTIES,
+                                                NULL,
+                                                "org.freedesktop.UPower",
+                                                "/org/freedesktop/UPower",
+                                                "org.freedesktop.UPower",
+                                                NULL,
+                                                NULL);
+          g_object_unref (bus);
+        }
+    }
+
+  proxy = gUPowerProxy ? g_object_ref (gUPowerProxy) : NULL;
+
+  G_UNLOCK (proxy_lock);
+
+  return proxy;
+}
+
+static GDBusProxy *
+ide_battery_monitor_get_device_proxy (void)
+{
+  GDBusProxy *proxy = NULL;
+
+  G_LOCK (proxy_lock);
+
+  if (!gUPowerDeviceProxy)
+    {
+      GDBusConnection *bus;
+
+      bus = g_bus_get_sync (G_BUS_TYPE_SYSTEM, NULL, NULL);
+
+      if (bus)
+        {
+          gUPowerDeviceProxy = g_dbus_proxy_new_sync (bus,
+                                                      G_DBUS_PROXY_FLAGS_GET_INVALIDATED_PROPERTIES,
+                                                      NULL,
+                                                      "org.freedesktop.UPower",
+                                                      "/org/freedesktop/UPower/devices/DisplayDevice",
+                                                      "org.freedesktop.UPower.Device",
+                                                      NULL,
+                                                      NULL);
+          g_object_unref (bus);
+        }
+    }
+
+  proxy = gUPowerDeviceProxy ? g_object_ref (gUPowerDeviceProxy) : NULL;
+
+  G_UNLOCK (proxy_lock);
+
+  return proxy;
+}
+
+gboolean
+ide_battery_monitor_get_on_battery (void)
+{
+  GDBusProxy *proxy;
+  gboolean ret = FALSE;
+
+  proxy = ide_battery_monitor_get_proxy ();
+
+  if (proxy)
+    {
+      GVariant *prop;
+
+      prop = g_dbus_proxy_get_cached_property (proxy, "OnBattery");
+      if (prop)
+        ret = g_variant_get_boolean (prop);
+      g_object_unref (proxy);
+    }
+
+  return ret;
+}
+
+gdouble
+ide_battery_monitor_get_energy (void)
+{
+  GDBusProxy *proxy;
+  gdouble ret = 0.0;
+
+  proxy = ide_battery_monitor_get_device_proxy ();
+
+  if (proxy)
+    {
+      GVariant *prop;
+
+      prop = g_dbus_proxy_get_cached_property (proxy, "Energy");
+      if (prop)
+        ret = g_variant_get_double (prop);
+      g_object_unref (proxy);
+    }
+
+  return ret;
+}
+
+gboolean
+ide_battery_monitor_get_should_conserve (void)
+{
+  gboolean should_conserve = FALSE;
+
+  if (ide_battery_monitor_get_on_battery ())
+    {
+      gdouble energy;
+
+      energy = ide_battery_monitor_get_energy ();
+      should_conserve = (energy != 0.0) && (energy < 0.50);
+    }
+
+  return should_conserve;
+}
diff --git a/libide/ide-battery-monitor.h b/libide/ide-battery-monitor.h
new file mode 100644
index 0000000..ecd4369
--- /dev/null
+++ b/libide/ide-battery-monitor.h
@@ -0,0 +1,32 @@
+/* ide-battery-monitor.h
+ *
+ * Copyright (C) 2015 Christian Hergert <christian hergert me>
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser 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_BATTERY_MONITOR_H
+#define IDE_BATTERY_MONITOR_H
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+gdouble  ide_battery_monitor_get_energy          (void);
+gboolean ide_battery_monitor_get_on_battery      (void);
+gboolean ide_battery_monitor_get_should_conserve (void);
+
+G_END_DECLS
+
+#endif /* IDE_BATTERY_MONITOR_H */